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Impact of climate change on vector-borne disease in the UK
Abstract
During the early part of the 21st century, an unprecedented change in the status of vector-borne disease in Europe has occurred. Invasive mosquitoes have become widely established across Europe, with subsequent transmission and outbreaks of dengue and chikungunya virus. Malaria has re-emerged in Greece, and West Nile virus has emerged throughout parts of eastern Europe. Tick-borne diseases, such as Lyme disease, continue to increase, or, in the case of tick-borne encephalitis and Crimean-Congo haemorrhagic fever viruses, have changed their geographical distribution. From a veterinary perspective, the emergence of Bluetongue and Schmallenberg viruses show that northern Europe is equally susceptible to transmission of vector-borne disease. These changes are in part due to increased globalisation, with intercontinental air travel and global shipping transport creating new opportunities for invasive vectors and pathogens. However, changes in vector distributions are being driven by climatic changes and changes in land use, infrastructure, and the environment. In this Review, we summarise the risks posed by vector-borne diseases in the present and the future from a UK perspective, and assess the likely effects of climate change and, where appropriate, climate-change adaptation strategies on vector-borne disease risk in the UK. Lessons from the outbreaks of West Nile virus in North America and chikungunya in the Caribbean emphasise the need to assess future vector-borne disease risks and prepare contingencies for future outbreaks. Ensuring that adaptation strategies for climate change do not inadvertently exacerbate risks should be a primary focus for decision makers.
Copyright © 2015 Elsevier Ltd. All rights reserved.
... Thus I. ricinus can act as a vector for the transmission of pathogens to humans from diverse taxa (Hillyard, 1996;Randolph, 2009b;Mannelli et al., 2012). For example, it is the UK's most common Lyme disease vector Medlock & Leach, 2015). Dobson, Taylor & Randolph (2011) found I. ricinus nymphal questing in recreational areas of Southern England peaked in most habitats in spring between April and June. ...
... The first report for I. ricinus is from 1964, 33/37 of the Park's grid squares have had at least one record (often multiple) in the last 15 years (Fig. 6A). In contrast, Ixodes hexagonus (the UK's second most common Lyme disease vector Medlock & Leach, 2015) has been recorded far less, most squares where presence has been recorded represent historic records only (Fig. 6B). The earliest H. punctata report is from 1920, but all related grid squares have had recorded presence in the last decade, mostly in its known foci in the far east of the Park (Fig. 6C). ...
Background
South Downs National Park (SDNP) is UK’s most visited National Park, and a focus of tick-borne Lyme disease. The first presumed UK autochthonous cases of tick-borne encephalitis and babesiosis were recorded in 2019–20. SDNP aims to conserve wildlife and encourage recreation, so interventions are needed that reduce hazard without negatively affecting ecosystem health. To be successful these require knowledge of site hazards.
Methods
British Deer Society members submitted ticks removed from deer. Key potential intervention sites were selected and six 50 m2 transects drag-sampled per site (mostly twice yearly for 2 years). Ticks were identified in-lab (sex, life stage, species), hazard measured as tick presence, density of ticks (all life stages, DOT), and density of nymphs (DON). Sites and habitat types were analysed for association with hazard. Distribution was mapped by combining our results with records from five other sources.
Results
A total of 87 Ixodes ricinus (all but one adults, 82% F) were removed from 14 deer (10 Dama dama; three Capreolus capreolus; one not recorded; tick burden, 1–35) at 12 locations (commonly woodland). Five key potential intervention sites were identified and drag-sampled 2015–16, collecting 623 ticks (238 on-transects): 53.8% nymphs, 42.5% larvae, 3.7% adults (13 M, 10 F). Ticks were present on-transects at all sites: I. ricinus at three (The Mens (TM); Queen Elizabeth Country Park (QECP); Cowdray Estate (CE)), Haemaphysalis punctata at two (Seven Sisters Country Park (SSCP); Ditchling Beacon Nature Reserve (DBNR)). TM had the highest DOT at 30/300 m2 (DON = 30/300 m2), followed by QECP 22/300 m2 (12/300 m2), CE 8/300 m2 (6/300 m2), and SSCP 1/300 m2 (1/300 m2). For I. ricinus, nymphs predominated in spring, larvae in the second half of summer and early autumn. The overall ranking of site hazard held for DON and DOT from both seasonal sampling periods. DBNR was sampled 2016 only (one adult H. punctata collected). Woodland had significantly greater hazard than downland, but ticks were present at all downland sites. I. ricinus has been identified in 33/37 of SDNPs 10 km2 grid squares, Ixodes hexagonus 10/37, H. punctata 7/37, Dermacentor reticulatus 1/37.
Conclusions
Mapping shows tick hazard broadly distributed across SDNP. I. ricinus was most common, but H. punctata’s seeming range expansion is concerning. Recommendations: management of small heavily visited high hazard plots (QECP); post-visit precaution signage (all sites); repellent impregnated clothing for deerstalkers; flock trials to control H. punctata (SSCP, DBNR). Further research at TM may contribute to knowledge on ecological dynamics underlying infection density and predator re-introduction/protection as public health interventions. Ecological research on H. punctata would aid control. SDNP Authority is ideally placed to link and champion policies to reduce hazard, whilst avoiding or reducing conflict between public health and ecosystem health.
... Ticks (subphylum Chelicerata, suborder Ixodida) are ectoparasites of animals and vectors of infectious agents . Lyme disease, tick-borne encephalitis, haemorrhagic fevers, tick-borne macular fever, Q-fever, babesiosis and tick paralysis are well-known tick-borne diseases, which threaten human and animal health with relevant medical costs and detrimental production losses (Medlock and Leach, 2015). The geographical distribution of ticks is expanding latitudinally and altitudinally, with mild winters, enlargements of the areas with tick host species and an increased use of recreational areas, further exacerbating the spread of vector-borne diseases (Randolph and Rogers, 2007;Medlock and Leach, 2015;Mysterud et al., 2017;Piotrowski and Rymaszewska, 2020;Van Gestel et al., 2021;Zhao et al., 2021). ...
... Lyme disease, tick-borne encephalitis, haemorrhagic fevers, tick-borne macular fever, Q-fever, babesiosis and tick paralysis are well-known tick-borne diseases, which threaten human and animal health with relevant medical costs and detrimental production losses (Medlock and Leach, 2015). The geographical distribution of ticks is expanding latitudinally and altitudinally, with mild winters, enlargements of the areas with tick host species and an increased use of recreational areas, further exacerbating the spread of vector-borne diseases (Randolph and Rogers, 2007;Medlock and Leach, 2015;Mysterud et al., 2017;Piotrowski and Rymaszewska, 2020;Van Gestel et al., 2021;Zhao et al., 2021). In this scenario, monitoring activities and educational norms to prevent tick bites (Mowbray et al., 2012;Beaujean et al., 2016) should be supported by approaches aiming to control tick diffusion and pathogen transmission (Ostfeld et al., 2006). ...
... The transmission dynamics of vector-borne diseases and the breeding process of vectors can also be influenced by longterm climate change, extreme weather events, and complex interactions among viruses, vectors, hosts, and the environment. Thus, climate change can predispose host populations to extirpation or even extinction (Jones et al., 2019;Medlock & Leach, 2015;Niedbalski & Fitzner, 2018). Extreme weather disrupts historic stable relationships between coexisting pathogenic viruses, vectors, and their hosts, which could lead to outbreaks of infectious disease in wildlife populations. ...
Pathogenic viruses are globally distributed and have caused severe diseases or death in wildlife populations, posing enormous threats to wild animals, especially threatened species. The transmission dynamics of pathogenic viral diseases are affected by complex factors and their interactions, such as climate, virus traits, host life‐history traits, and environmental conditions. The seroprevalence of viruses can reflect the historical exposure of hosts to viruses and may indicate accumulated pathogenic viral disease severity in wildlife populations. We studied viruses with demonstrated virulence that have caused diseases or death in their natural hosts among wild terrestrial mammals. We extracted data on virus traits, host species, host life‐history traits, and climate conditions from the peer‐reviewed literature to explore their effects on and interactions with virus seroprevalence in wildlife populations. Ungulates were the most studied group followed by carnivores. The seroprevalence of pathogenic viruses was positively correlated with temperature in wildlife populations. The correlation between precipitation and virus seroprevalence was complicated and depended on different interactions of variables. Gregarious animals and nonmigratory ungulates were more vulnerable to high viral seroprevalence than other species. As global temperatures increase, drought will increase, and gregarious and nonmigratory ungulates may thus experience increased spread and incidence of pathogenic viruses, especially vector‐borne viruses. Gregarious carnivores may face a high risk of outbreaks of viruses that are transmitted directly (e.g., canine distemper virus, canine parvovirus, and rabies virus). Our results can be used to inform protocols for surveillance of specific viruses and susceptible host life‐history traits to prevent epizootics in natural populations, which will be crucial for the conservation of terrestrial mammals under global climate change.
... Changing climatic conditions can cause temperature rise encouraging mosquito breeding and disease transmission by shortening the lifecycle, duration, and generation time of various vector species aiding the potential transmission of pathogens. Climate alteration can influence land use patterns further influencing habitat distribution of vector species promoting disease spread to newer areas and larger populations [4,10] adding to an increase in the incidence of similar zoonotic infections. Transforming agricultural practices can cause humans dwelling in the vicinity of vectors [2]. ...
Dirofilariasis is an uncommon zoonotic infection transmitted by mosquitoes. In humans, it generally presents as nodules in the lungs, subcutaneous tissue, peritoneal cavity, or eyes. However, the present case series is regarding adult worms of Dirofilaria repens recovered from the masseter muscle of two patients in the fourth decade of life. Diagnosis was given on the basis of worm morphology and histopathology and confirmed by polymerase chain reaction. Surgical excision of the worm was done and pharmacotherapy with diethylcarbamazine was given. This report is remarkable as these cases arrived with identical clinical presentations and resided in close proximity to each other. Such atypical infections should be borne in mind, especially in light of current climatic changes and emerging zoonotic infections.
... Moreover, rising temperatures extend the length of seasonal transmission and expand the geographical range of vectors, turning previously inhospitable regions into suitable habitats [99]. It has been observed that a 2 • C temperature rise could extend the hypothetical transmission season by up to one month and increase the geographical area of suitability by 25-30 % [100]. As temperatures continue to rise, exposure and diseases transmission increase and eventually the burden of these diseases is expected to increase. ...
This study investigates the interactions between climate change and human health with a particular focus on Qatar, using the DPSIR (Driving Forces, Pressures, States, Impacts, Responses) framework. Key drivers, including economic development and population growth, contribute to increased greenhouse gas (GHG) emissions, exerting pressure on Qatar's climate through rising temperatures and altered precipitation patterns, as modeled by the MIT Regional Climate Model (MRCM). The findings reveal critical gaps in understanding the state of climate-health interactions, including insufficient disease data, incomplete climate-health linkages, and significant research gaps. These limitations hinder targeted responses to climate-sensitive diseases, which have shown an increase over the years. The study identifies the pathways through which climatic shifts contribute to immediate health risks, such as heat-related illnesses and respiratory conditions, as well as long-term impacts, including chronic diseases and mental health challenges. Despite Qatar's efforts through national and international strategies, the DPSIR analysis highlights the urgent need for enhanced research, improved data collection, and tailored actions to address these challenges. Strengthened adaptation, resilience-building, and emission reduction strategies remain essential for safeguarding public health in the face of accelerating climate change.
... Vector-borne disease epidemiology is influenced by complex interactions between climate, wildlife, domestic animals, humans, and arthropod vectors. Over recent decades, the spread of vectors of arboviruses within Europe has been modified by factors such as climate change and land-use alterations [172,173], and the study of vector ecology has become critical for understanding VBD patterns due to the broader geographic distribution of arboviruses and more frequent outbreaks among humans and animals [174]. Additionally, the increase in global travel, including tourism travel and trade as well, has exposed Europe to a higher risk of introducing exotic arthropod vectors and local transmission of arboviruses like DENV, CHIKV, ZIKV, and CCHFV from tropical and subtropical regions [175]. ...
The rise and resurgence of vector-borne diseases (VBDs) in Europe pose an expanding public health challenge, exacerbated by climate change, globalization, and ecological disruptions. Both arthropod-borne viruses (arboviruses) transmitted by ticks such as Crimean–Congo hemorrhagic fever and arboviruses transmitted by mosquitoes like dengue, Chikungunya, Zika, and Japanese encephalitis have broadened their distribution due to rising temperatures, changes in rainfall, and increased human mobility. By emphasizing the importance of interconnected human, animal, and environmental health, integrated One Health strategies are crucial in addressing this complex issue. Europe faces increased risk due to the expanding habitats of disease-carrying organisms, the spread of new species like Aedes albopictus since 2013, and increased movement of infected individuals between countries, leading European countries to implement strategies such as enhanced surveillance systems, public awareness campaigns, and prompt outbreak response strategies. However, the lack of both targeted antiviral therapies and vaccines for many arboviruses, together with undetected or asymptomatic cases, hamper containment efforts. Therefore, it is important to have integrated strategies that combine climate modeling, disease surveillance, and public health interventions to address expected changes in disease patterns due to global changes. This review explores the spread of arboviruses in Europe, highlighting their historical context, current transmission dynamics, and their impact on public health.
... Elevated temperatures and increased CO 2 levels can weaken native species and enhance the growth of some invasive species, making them more competitive against native flora [73,74]. According to Huang et al. [75], rising mean temperatures have increased the number of invertebrate pests, while Medlock and Leach [76] observed that high temperatures have resulted in the emergence of mosquito species and related vector-borne diseases. Climate change also worsens the problem by opening new pathways for the introduction and range expansion of already-introduced species [33]. ...
Prosopis glandulosa (Mesquite), an invasive alien tree species, poses major threats to soil health, native vegetation, and biodiversity in South African rangelands. The negative impacts of Prosopis on socio-economic, environmental, and ecological resources outweigh the benefits. Most South African researchers are afraid that if left uncontrolled or poorly managed, it can cause severe land degradation, reduced agricultural productivity, indigenous-species shift, and ultimately the loss of biodiversity. Consequently, this will undermine key sustainable development goals related to food security and environmental conservation. In this review we conducted a systematic review, identifying 309 peer-reviewed articles from Google Scholar and Web of Science, screening and analyzing 98 of these, and ultimately reviewing 34 publications in detail. Three key research gaps were identified: (1) insufficient research focused on Prosopis invasion in South Africa; (2) limited integration and collaboration between the agricultural sector, environmental conservation sector, and governmental bodies; and (3) challenges in policy implementation within invaded areas. The study seeks to address these gaps by highlighting the impact of this alien invasive Prosopis species on land, biodiversity, and overall ecosystem stability. It also investigates policy issues surrounding invasive species and their control. Effective management of Prosopis within the country will not only control the spread but also support the broader objectives of environmental conservation, agricultural sustainability, and socio-economic development.
... The study confirmed that TBDs pose a significant threat to canine health even during colder months, which challenges the conventional understanding that tick activity decreases in autumn and winter. Recent studies have shown that climate change is contributing to the extended activity of tick populations across seasons [6,56,57]. Tick species such as I. ricinus and D. reticulatus have adapted to milder winter temperatures, allowing them to transmit pathogens during periods that are generally considered low-risk [29,43]. The extended activity of ticks during colder months, as highlighted in the present study, aligns with findings from various European regions. ...
Tick-borne diseases (TBDs) pose a growing threat to companion animals, especially dogs, due to the increasing abundance of tick populations in Europe, driven by climate change, urbanization, and the mobility of humans and animals. This study aimed to assess the prevalence of tick-borne pathogens in clinically ill dogs suspected of having developed TBDs during the autumn-winter season, as well as to detect pathogens in ticks collected during the same period in the Warmian–Masurian Voivodeship in Poland. A total of 30 dogs with clinical symptoms of babesiosis and 45 ticks from dogs were acquired for this study. Clinical symptoms in dogs included elevated body temperature > 39.0 °C (73.3%), anemia (56.7%), thrombocytopenia (80%), and dark urine (53.3%). Co-infections with Babesia spp. were identified in two combinations (Babesia spp. and Mycoplasma spp. (n = 5), Babesia spp. and Borrelia spp. (n = 2)) and one co-infection with Anaplasma spp. and Borrelia spp., highlighting the complexity of TBD diagnosis and treatment. The analyzed tick species were Ixodes ricinus (86.7%; n = 39; 18 females and 21 males) and Dermacentor reticulatus (13.3%; n = 6; 4 females and 2 males). In I. ricinus, Babesia spp. were identified in 7.7% (3/39), Mycoplasma spp. in 7.7% (3/39), Borrelia in 25.6% (10/39), and Anaplasma spp. in 10.3% (4/39). In D. reticulatus, only two pathogens—Borrelia spp. and Anaplasma spp.—were detected, both only once (16.7%; 1/6). No significant differences were observed between the prevalence of the studied pathogens and tick species, sex, or developmental stage. This study emphasizes the year-round risk of TBDs in dogs, particularly during the autumn-winter months, and underscores the need for continuous vigilance in tick prevention, broad-spectrum diagnostics, and treatment strategies.
... The ongoing expansion of I. ricinus is directly linked to climate warming (Gray et al., 2009;Medlock et al., 2013). Larval tick infestation on hosts was positively associated with T A B L E 2 Parameter estimates from the best model of number of Ixodes larvae, number of Ixodes nymphs, and infection of Borrelia burgdorferi s.l., in small mammals captured in southeast Norway (2014)(2015)(2016)(2017)(2018)(2019)(2020)(2021)(2022) cumulative heat sum, supporting previous evidence that abiotic factors are important determinants of I. ricinus abundance (Hauser et al., 2018;Medlock et al., 2013;Medlock & Leach, 2015). The life cycle of I. ricinus is typically completed within 3-6 years depending on environmental conditions related to temperature, humidity, and photoperiod that regulate activity and development (Gray, 2008;Gray et al., 2016). ...
Lyme disease is an emerging infectious disease and the most common vector‐borne zoonosis in the northern hemisphere. The pathogen that causes Lyme disease in Europe is vectored by the generalist tick Ixodes ricinus, and the emergence of Lyme disease is partly linked to how climate warming affects tick distribution and abundance. However, we lack long‐term data on tick infestations and infection prevalence in the main hosts involved in the transmission cycle. Here, we quantified the temporal trends (2014–2022) of I. ricinus infestations and the prevalence of Borrelia burgdorferi sensu lato in small mammalian hosts and linked annual variation to host abundance and climate in Norway. We found that tick infestations for both larvae (21% per year [95% CI 18–25]) and nymphs (18% [11–26]), and infection prevalence (14% [8–20]) increased over the period and were negatively associated with rodent abundance. Additionally, warmer years were associated with increased larval tick infestations on hosts. The combination of a temporal increase in both larval tick infestation and infection prevalence in hosts likely results in increased production of infected nymphs. Thus, we provide one mechanistic step toward understanding the Lyme disease emergence at northern latitudes of Europe.
... Tick-borne zoonoses (TBZs) including Lyme disease, babesiosis and tick-borne encephalitis are currently considered an emerging problem in several European countries [1][2][3][4]. Ticks are indeed expanding their altitudinal and latitudinal range, mainly due to temperature increase and loss of seasonality [5][6][7][8], being climatic and environmental factors the main drivers of tick survival and activity pattern [9,10]. ...
Tick-borne zoonoses are an emerging health issue. The expansion of ticks is mainly driven by climatic changes but also by new approaches to the management of the natural environment, increasing the abundance of vertebrate host species and thus the potential exposure to tick bites for both humans and companion animals. In this context, a holistic approach to studying ticks’ ecology is required. In the present work, we shed light on the link between environmental tick abundance (global and specific of Ixodes ricinus nymphs, as the highest zoonotic threat) and the temporal occupancy of wildlife host species retrieved from camera traps (namely, wild ruminants, mesocarnivores and wild boar). We modelled this relationship by integrating abiotic factors relevant to tick survival, such as the vegetation cover and saturation deficit, and estimated the accuracy of prediction. To collect these data, we deployed camera traps in a peri-urban Natural Park in Northwest Italy to monitor wildlife for 1 whole year while collecting ticks in front of camera traps by dragging transects every 2 weeks. Overall, wildlife temporal occupancy showed an additive impact on tick abundance for species that are preferential hosts (deer and mesocarnivores) and a detractive impact for wild boar, which also presented a lower tick burden, particularly with regard to the tick species collected in the environment (mainly I. ricinus and Haemaphysalis punctata). Accuracy of prediction was higher for I. ricinus nymphs rather than the global model. Temporal fluctuations in the tick population were also highlighted. Wildlife temporal occupancy was not constant and varied between seasons according to feeding habits. In conclusion, we highlighted the utility of camera trap data to investigate tick ecology and acarological risk. This information is crucial in informing monitoring and prevention strategies to decrease the risk of tick bites in humans and thus zoonotic risk of tick-borne diseases.
... Climate warming and land use changes support tick population expansion, and tick-borne pathogens are increasingly recognized to threaten cervid health in northern latitudes. [14][15][16] Babesia spp. are host-specific apicomplexan parasites that can cause acute hemolytic anemia in susceptible animals. ...
Outbreaks of suspected tick-borne disease (redwater fever) have been reported in captive deer of the Scottish Highlands. In this pilot study, polymerase chain reaction and amplicon sequencing were used to detect tick-borne pathogens in opportunistically collected blood and spleen samples from 63 (healthy, n = 44; diseased, n = 19) cervids, and 45 questing and feeding ticks (Ixodes ricinus) from the outbreak sites in 2021-2022. Potentially pathogenic Babesia species were detected in deer but not identified in ticks, Anaplasma phagocytophilum was detected in both deer and ticks, and Borrelia afzelii was detected in ticks but not in deer. Sequencing confirmed Babesia capreoli and Babesia cf. odocoilei parasitemia in clinically healthy red deer (Cervus elaphus), B. capreoli parasitemia in clinically healthy domestic reindeer (Rangifer tarandus tarandus), and two cases of B. cf. odocoilei-associated hemolytic anemia in white-lipped deer (Cervus albirostris), of which one was fatal despite imidocarb treatment. White-lipped deer appear to be highly susceptible to babesiosis caused by B. cf. odocoilei. This investigation highlights the importance of disease surveillance, including molecular diagnostics, for the detection of emerging tick-borne pathogens in managed populations of cervids.
... 10 Nevertheless, several outbreaks of these diseases have surged among developed countries since 2014 owing to globalization, urbanization and drastic climate changes, straining healthcare systems and claiming numerous lives. 13,14 To combat these diseases, the World Health Organization (WHO) has developed the "Global Vector Control Response (GVCR) 2017-2030," which offers guidance to nations and partners to strengthen vector control for disease prevention and outbreak response. 15 This initiative calls for program realignment, technical capacity enhancement, improved infrastructure, enhanced monitoring, and community mobilization. ...
Insect vector-borne diseases (VBDs) pose significant global health challenges, particularly in tropical and subtropical regions. The WHO has launched the “Global Vector Control Response (GVCR) 2017–2030” to address these diseases, emphasizing a comprehensive approach to vector control. This systematic review investigates the potential of malaria and dengue vaccines in controlling mosquito-borne VBDs, aiming to alleviate disease burdens and enhance public health. Following PRISMA 2020 guidelines, the review incorporated 39 new studies out of 934 identified records. It encompasses various studies assessing malaria and dengue vaccines, emphasizing the significance of vaccination as a preventive measure. The findings indicate variations in vaccine efficacy, duration of protection, and safety considerations for each disease, influencing public health strategies. The review underscores the urgent need for vaccines to combat the increasing burden of VBDs like malaria and dengue, advocating for ongoing research and investment in vaccine development.
... High temperatures can lead to heat exhaustion and heat stroke, particularly in vulnerable populations and those with chronic health conditions (Mohammad Harmay & Choi, 2023). On the other hand, the UHI effect can also create conditions that are conducive to the breeding of disease-carrying insects, which can increase the risk of vectorborne diseases such as dengue fever, chikungunya virus, and West Nile virus infections (Medlock & Leach, 2015). ...
... В последнее десятилетие на территории Европы, в том числе Республики Беларусь, и Азии отмечается устойчивая направленность к повышению уровня заболеваемости животных и людей инфекциями, передающимися клещами, расширению их нозоареалов, выявлению микст-инфекций, а также регистрации ранее неизвестных патогенов и новых нозологических форм болезней [1,2,3,4,5]. ...
Results of ixodid tick analysis for their ecological, epizootological and epidemiological significance for tick-borne pathogen spread across the Belarusian Lakeland are presented. The ticks were collected in publicly accessible areas of the Vitebsk Raion in April – November 2022: 8 routes were tracked, 18 flag-km were passed, 529 tick specimens were collected, including 350 imago ticks and 179 nymph ticks. The ixodid tick genus and species were determined using N. A. Filippova’s ixodid tick determinator. All caught ticks were tested for Borrelia spp., Anaplasma spp. ( Ehrlichia spp . ), Babesia spp. and Tick-borne encephalitis virus genetic materials with real-time polymerase chain reaction using the reagent kit for nucleic acid extraction from environmental samples in accordance with the manufacturer’s instructions. The specimens were grouped in accordance with the MG 3.1.1027-01 “Collection, recording and preparation for laboratory tests of blood-sucking arthropods being vectors of natural focal infections”; therewith, one specimen includes only one tick. Differences in the numbers of ixodid ticks and the occurrence of genetic markers of tick-borne pathogens in them were found to be associated with ecological characteristics of the examined territories. The following epidemically and epizootically significant ticks contributing to transmissible infection and invasion spread were found in the Belarusian Lakeland: ticks of Ixodes and Dermacentor genera; their frequency index was 70.1 and 29.9%, respectively. Tick-transmitted pathogen prevalence rate in the examined territories of the Vitebsk Raion was as follows: 61.7% for Borrelia spp., 25.8% for Anaplasma spp. ( Ehrlichia spp.) and 25% for Babesia spp., mixed infections were found in 10.8% of the ticks. No tick-borne encephalitis virus genetic materials were found in the specimens. Total infection rate for ixodid ticks was 22.7%.
... Therefore, it not only poses challenges for vegetable producers, but also presents serious complications for seed producers of economically important plants of the Apiaceae family [5,6]. Thanks to the global mass distribution of plant products, including seeds, the ease of pathogen spread has become a highly relevant contemporary issue [7]. ...
There exists a wide range of plant pathogens that are commonly referred to as seed-borne pathogens due to their dominant mode of spread. Treating seeds to eliminate such pathogens is therefore very important in contemporary seed production. In the present study, eight types of nanoparticles were evaluated for their effectiveness against Xanthomonas hortorum pv. carotae, a seed-borne pathogen that affects plants of the Apiaceae family. Initially, parameters considering the inhibitory and bactericidal activity of individual nanoparticles were evaluated under in vitro conditions. In this way, three nanoparticles based on copper, silver, and silver/selenium composite were identified as being the most effective. Subsequently, their ability to eliminate Xanthomonas hortorum pv. carotae from artificially infected carrot seeds was tested. This was achieved through the qPCR quantification of the pathogen in 14-day-old plantlets developed from seeds inoculated with Xhc. Based on the obtained results, copper-based nanoparticles were the most effective, resulting in an approximately 10-fold decrease in the occurrence of Xhc in plantlets compared to the untreated control. Taking into account the fact that X. hortorum pathovars also attack other important horticultural crops, the presented results may have a much wider scope than just carrot seeds.
... The expansion or contraction of VBD distribution and incidence due to climate change is difficult to predict (Lafferty 2009, Mordecai et al. 2019. Some authors predict the expansion of their distribution (González et al. 2010, Campbell et al. 2015 while others suggest a geographic shift (Medlock and Leach 2015). Hence, temperature changes could increase, decrease, or have no effect on the transmission of VBDs (Mordecai et al. 2019). ...
The transmission and incidence of vector-borne diseases rely on vector distribution and life history traits such as survival, fecundity, and feeding. Since arthropod disease vectors are ectotherms, these vital rates are strongly influenced by temperature. Chagas disease is a neglected tropical disease caused by the protozoan parasite, Trypanosoma cruzi. This parasite is transmitted when the feces of the infected triatomine enter the bloodstream of the host. One of the most important vector-species of this disease in the Southern Cone region of South America is Triatoma infestans. In this study, we evaluated the role of constant and variable environmental temperature on the feeding behavior of T. infestans. Fifth-instar nymphs were acclimatized to 4 thermal treatments comprising 2 temperatures (27 °C and 18 °C) with and without diurnal thermal variability (27 ± 5 °C and 18 ± 5 °C). Individuals were fed weekly for 7 wk to quantify their feeding. Our results showed lower feeding frequency in nymphs acclimatized to cold temperature compared to those from warmer temperature treatments. However, treatments with thermal variability presented a nonlinear effect on feeding, with an increased feeding rate in the cold, variable treatment and a decreased feeding rate in the warm, variable treatment. Individuals maintained under cold treatments, the variable temperature exhibited a higher feeding rate and the lowest amount of ingested blood among all treatments. Thus, natural diurnal temperature variation cannot be ignored if we are to make more accurate T. cruzi transmission risk predictions now and in the future.
... A large number of time series studies and cross-case studies based on ecological research design have basically elucidated the exposure-response relationship between meteorological conditions and sensitive diseases in developed countries in Europe and America (31)(32)(33). Previous epidemiological studies have found that significant changes in meteorological factors such as temperature, humidity, and precipitation can alter the exposure level of the population to certain meteorological factors, thereby increasing the risk of illness, injury, and death (12,(34)(35)(36)(37); The change in meteorological environment can create suitable conditions for the parasitism, reproduction, and transmission of mosquitoes and other vectors and parasitic pathogens, and change the density and seasonal distribution of parasites and vectors, thus affecting the epidemic process of insect vectors and parasitic infectious diseases, expanding the epidemic degree and scope, and increasing the harm to the population (9,(38)(39)(40)(41). Research in China also shows that meteorological factors can also affect the incidence rate of infectious diseases, such as bacillary dysentery (42) and hand-foot mouth (43,44). ...
Introduction
Meteorological and environmental factors can affect people’s lives and health, which is crucial among the older adults. However, it is currently unclear how they specifically affect the physical condition of older adults people.
Methods
We collected and analyzed the basic physical examination indicators of 41 older adults people for two consecutive years (2021 and 2022), and correlated them with meteorological and environmental factors. Partial correlation was also conducted to exclude unrelated factors as well.
Results
We found that among the physical examination indicators of the older adults for two consecutive years, five indicators (HB, WBC, HbAlc, CB, LDL-C) showed significant differences across the population, and they had significantly different dynamic correlation patterns with six meteorological (air pressure, temperature, humidity, precipitation, wind speed, and sunshine duration) and seven air quality factors (NO2, SO2, PM10, O3-1h, O3-8h, CO, PM2.5).
Discussion
Our study has discovered for the first time the dynamic correlation between indicators in normal basic physical examinations and meteorological factors and air quality indicators, which will provide guidance for the future development of policies that care for the healthy life of the older adults.
... Climate change can further increase the incidence rate of vector-borne diseases. Due to climate change, infectious diseases may emerge or re-emerge in different countries, like Malaria reappeared in Greece recently, and the West Nile virus struck in eastern Europe (Medlock and Leach 2015). These examples indicate that climate change expands the regions of infectious diseases (Mora et al. 2022). ...
To find a way to realize sustainable development, this paper applied a cross-sectional ARDL (CS-ARDL) method to explore the interaction between carbon emissions, economic development, and health care expenditure for OECD countries. Firstly, we conduct a cross-sectional test to check whether the data is confronted with this issue. Secondly, we conduct a panel unit root test and cointegration test to confirm whether the ARDL-based method is suitable for our data. Thirdly, we analyze the results and provide possible explanations. Lastly, we conduct a short-term causality test to detect the connection between different variables. The main conclusion of our study includes: 1) Health care is a necessity in OECD countries. 2) Environmental deterioration places a heavy burden on health care expenditure in OECD countries. 3) Health care expenditure of last year negatively affects health care expenditure. 4) There is a short-run causality relationship from CO 2 , economic development, and dependency rate of youth to health care expenditure in OECD countries. Related policy proposals are provided according to our analysis of the results.
... An extended warm season expands the geographic range of ticks and alters vector ecology. 14,15 Climate projections warn of future epidemics of vector-borne diseases such as Dengue fever, malaria, leishmaniosis, and others. 16 By 2070, the population at risk of Dengue fever and malaria might increase by up to 4.7 additional billion people relative to 1970-1999. ...
... Wymienia się również potencjalne zagrożenia związane z zielenią, takie jak wzmożona ekspozycja na zanieczyszczenia powietrza w przypadku niektórych gatunków roślin utrudniających ich rozpraszanie (Jin i in., 2014) i ekspozycja na pestycydy i herbicydy. Wskazać można także ryzyko chorób odzwierzęcych -wzrost zachorowalności na boreliozę w XXI wieku został powiązany nie tylko ze zmianami klimatycznymi i łagodniejszymi zimami, ale także z terenami zielonymi w miastach (Medlock i Leach, 2015). Niejasna jest zależność z występowaniem alergii i zachorowań na astmę -w zależności od badania, w niektórych przypadkach wykazywano spadek ryzyka tej choroby (Lovasi i in., 2008), a w innych jego wzrost (Lovasi i in., 2013). ...
... Whereas aedes albopictus is the secondary vector that is less efficient in transmitting and replicating the virus. 3 The aedes mosquito vector breeds and transmits viral infections without a specific pattern of outbreaks, especially in subtropical countries. Studies have shown that climatic variations such as temperature, humidity, and rainfall encourage the transmission of dengue fever because climate plays an important role in the mosquito population, density, and survival rate. ...
Indonesia is a country endemic to dengue fever—and Bandung is one of the cities in Indonesia that is endemic to dengue fever. There have been efforts to control mosquitoes, one of which is by eradicating their nests, but this step has not optimally reduced the incidence of cases. The increase in cases is thought to have been caused by climatic variations. This study aimed to analyze the relationship between climatic variations (temperature, humidity, and rainfall) and the incidence of dengue hemorrhagic fever (DHF). This study used a correlation design and was carried out in Bandung. This study used secondary data. The samples were taken from data on the number of DHD patients from 2016 to 2021 recorded at the Health Office of Bandung, as well as temperature, humidity, and rainfall data from the Central Bureau of Statistics of Bandung from 2016 to 2021. The correlation between variables was assessed using the person correlation test. Climatic variations that are significantly correlated with the incidence of dengue hemorrhagic fever (DHF) are minimum temperature (p=0.020, and r=-0.658), maximum temperature (p=0.006, and r=-0.739), minimum humidity (p=0.000, and r=0.825), and rainfall (p=0.037, and r=0.605). The increase in the incidence of dengue hemorrhagic fever (DHF) is caused by climatic variations (temperature, humidity, and rainfall). Therefore, it is recommended that mosquito control and DHF surveillance program should be strengthened during the season following the rainy (wet) season.
... Climate change, according to the 2014 Climate Change Report, can promote the propagation of vector-borne infections by modifying the biology of the vectors, their level of abundance and distribution over space, including their territorial expansion into new areas, and changes in the infectious agents' extrinsic incubation period. Environmental modifications aimed to offset the consequences of climate change, such as flood protection and more urban green space, might raise the risk of illnesses spread by vectors [45]. ...
Encephalitis is an inflammation of the brain, often caused by an autoimmune reaction, or in most cases because of a direct viral, bacterial, or parasitic infection. Viral encephalitides (VE) presents a significant public health concern globally, especially in West Africa. There are more than five hundred known arthropod-borne viruses (arboviruses), with over a hundred of them identified to cause encephalitic diseases in humans and animals, giving rise to a tremendous burden of the diseases and socioeconomic strains in tropical and subtropical regions worldwide. Despite their importance, few effective preventive and control measures in the form of vaccines and therapies are available, and when they are, their use is limited. These limitations are largely hinged on the paucity of information about the molecular epidemiology and transmission patterns of VE in West Africa. Here, we reviewed the transmission dynamics, molecular epidemiology, and the ecological drivers of VE in West Africa. Collectively, timely and accurate interventions are essential for encephalitic viral disease control. Moreover, the integrated health system approach, combining surveillance, vaccination, vector control, and community engagement, could be effective in preventing viral encephalitis globally.
... Similar seroprevalence estimates in the two surveys suggest no change in risk of exposure to Bb from 2003 to 2017. This is an interesting finding in light of the discussion about the potential influence of climate change on increases of tick abundance and tick-borne diseases [4,11,[22][23][24]. The interface between climatic factors, ticks, Borrelia and hosts is complex, and determinants are poorly understood. ...
Background
Lyme borreliosis (LB), caused by Borrelia burgdorferi (Bb), is the most common tick-borne infection in Germany. Antibodies against Bb are prevalent in the general population but information on temporal changes of prevalence and estimates of seroconversion (seroincidence) and seroreversion are lacking, especially for children and adolescents.AimWe aimed at assessing antibodies against Bb and factors associated with seropositivity in children and adolescents in Germany.Methods
We estimated seroprevalence via two consecutive cross-sectional surveys (2003-2006 and 2014-2017). Based on a longitudinal survey component, we estimated annual seroconversion/seroreversion rates.ResultsSeroprevalence was 4.4% (95% confidence interval (CI): 3.9-4.9%) from 2003 to 2006 and 4.1% (95% CI: 3.2-5.1%) from 2014 to 2017. Seroprevalence increased with age, was higher in male children, the south-eastern regions of Germany and among those with a high socioeconomic status. The annual seroconversion rate was 0.3% and the annual seroreversion rate 3.9%. Males were more likely to seroconvert compared with females. Low antibody levels were the main predictor of seroreversion.Conclusion
We did not detect a change in seroprevalence in children and adolescents in Germany over a period of 11 years. Potential long-term changes, for example due to climatic changes, need to be assessed in consecutive serosurveys. Seroconversion was more likely among children and adolescents than among adults, representing a target group for preventive measures. Seroreversion rates are over twice as high in children and adolescents compared with previous studies among adults. Thus, seroprevalence estimates and seroconversion rates in children are likely underestimated.
Climate change is thought to be responsible for the spread of various vector-borne diseases. The current study was conducted to evaluate the impact of different temperature and relative humidity regimes on the developmental stages of the yellow fever mosquito, Aedes aegypti (Diptera: Culicidae). The study also evaluated the impact of larval density on the survival of Ae. aegypti. In addition, the association between vector larval abundance, dengue incidence, and climatic factors were elucidated during 2016–2019 in three populated districts of Punjab, Pakistan, i.e., Lahore, Rawalpindi, and Multan. The results of the study revealed that at 10 °C and 35 °C, egg hatching and adult emergence were significantly reduced, regardless of the relative humidity. In contrast, at 20 °C and 30 °C, the rates of egg and adult survival increased with higher relative humidity. In addition, a density-dependent response was observed regarding larval survival of Ae. aegypti. Moreover, larval incidence was positively correlated with the number of dengue patients, Tmax, RH, and precipitation at Lahore (0.55, 0.23, 0.29, and 0.13), Rawalpindi (0.90, 0.30, 0.21, and 0.14), and Multan (0.05, 0.27, and 0.13) respectively, except in Multan, where a negative correlation (−0.09) with precipitation was observed. The inflow of patients had a positive correlation with the occurrence of a larval population, relative humidity, and precipitation at Lahore, Rawalpindi, and Multan districts, with the scale values of 0.55, 0.25, and 0.16; 0.90, 0.22, and 0.03; and 0.05, 0.06, and 0.03, respectively. In addition, a forecast model, ARIMA, predicted that there was a higher rate of larval occurrence in Rawalpindi, followed by Lahore. This study concluded that the role of precipitation > 200 mm prior to a 1–2-month lag, a 20–30 °C temperature range, and an RH exceeding 60% lead to the occurrence of larvae and dengue case spikes. This study will help to reinforce dengue surveillance and control strategies in Pakistan and to establish early management strategies based on changing climatic factors.
Ticks and tick-borne diseases constitute a crucial focus for the health of both humans and animals worldwide. Although numerous studies on tick-borne diseases have been conducted in China, reports on tick-borne pathogens in ticks and rodents from the China–Vietnam border are scarce. In this study, we investigated tick-borne bacterial pathogens, including Rickettsia, Anaplasmataceae, and Borrelia, in nine rodents (Rattus norvegicus) and 88 ticks collected from cattle and rodents in Jingxi, a city at the China–Vietnam border. Through molecular detection and sequence analysis, four known tick-borne pathogens were identified. Specifically, Rickettsia japonica was detected in 46.3% (37/80) of Haemaphysalis cornigera; Anaplasma phagocytophilum and Candidatus Neoehrlichia mikurensis were identified in one Ixodes granulatus and one rodent, respectively; and Borrelia valaisiana was detected in two I. granulatus. Additionally, a potentially novel species of Rickettsia, provisionally named Rickettsia sp. JX, was detected in 41.3% (33/80) of Ha. cornigera, one Rhipicephalus microplus, three I. granulatus, and nine rodents, whereas a potentially novel species of Borrelia, tentatively named Borrelia sp. JX, was detected in one I. granulatus. To the best of our knowledge, this is the first report on tick-borne bacterial pathogens in ticks and rodents from the China–Vietnam border. These results expand the knowledge of the geographical distribution and vector diversity of tick-borne bacterial pathogens in China and are conducive to the evaluation of thee potential public health risk.
In Japan, while there has not yet been a confirmed increase in dengue fever incidence, the vector mosquito, Aedes albopictus, is widely distributed, indicating the potential for more frequent outbreaks in the future. In this study, we develop a mathematical model by constructing the reproduction number from a bottom-up approach, allowing us to evaluate the long-term risk of dengue. Although the model is relatively simple, relying on temperature as the predictive variable, it has proven effective in estimating the likelihood of transmission and epidemics. Even in relatively optimistic scenarios, the inter-epidemic period—during which there is no risk of dengue fever outbreaks—was reduced by approximately 20 days in Tokyo. Geographically, the regions at risk for dengue are expected to shift northward, and in more pessimistic scenarios, the risk could extend as far as Hokkaido. The mosquito biting rate was found to influence the reproduction number in a quadratic manner, mathematically reinforcing the importance of focusing efforts on mosquito bite prevention. Considering future regional adaptation strategies is essential.
The interplay between pesticide use and climate change presents significant challenges to community health, particularly among vulnerable populations. Climate change alters environmental conditions, influencing the behavior, distribution, and degradation of pesticides, resulting in varied exposure patterns and health risks. This chapter examines the impacts of extreme weather events, rising temperatures, and shifting precipitation patterns on pesticide persistence and movement, heightening both direct and indirect health risks. It highlights the different vulnerabilities of rural and urban communities, emphasizing how demographic and socioeconomic factors—such as age, income level, and preexisting health conditions—increase susceptibility to these threats. Moreso, this chapter explores implications for vector-borne diseases, where climate-induced changes in disease vectors necessitate increased pesticide use, compounding health risks. An assessment of current regulatory and policy frameworks reveals critical gaps in addressing the simultaneous threats of pesticide exposure and climate change, underscoring the need for integrated strategies that prioritize community health and environmental sustainability. This chapter concludes with proposed mitigation and adaptation strategies, including community-based interventions, climate-smart agricultural practices, and enhanced health surveillance systems, aimed at protecting vulnerable populations and improving public health outcomes.
One of the most important canine vector-borne diseases in the Mediterranean region is canine leishmaniosis and there are frequent reports that it is spreading to the North and East of Europe. Romania is one of the countries traditionally considered non-endemic. However, L. infantum infections in dogs, humans and one jackal, as well as vector-competent sandflies have been recently reported in the country. To determine the seroprevalence of this infection we collected sera from 110 stray dogs, from two counties (Galați and Călărași), from the south-east of Romania and investigated for the presence of IgG antibodies against Leishmania by an in-house ELISA. Anti-Leishmania antibodies were detected in 5 stray dogs from the county of Galați. The prevalence in the county of Galați was 8.33% and the overall prevalence was 4.54%. These results are comparable to what was reported before in the southern county of Vâlcea and suggest that stray dogs from the south of Romania are exposed to L. infantum. There is a need for more studies in order to understand the situation of L. infantum infections in Romania.
Climate warming is expected to substantially impact the global landscape of mosquito‐borne disease, but these impacts will vary across disease systems and regions. Understanding which diseases, and where within their distributions, these impacts are most likely to occur is critical for preparing public health interventions. While research has centered on potential warming‐driven expansions in vector transmission, less is known about the potential for vectors to experience warming‐driven stress or even local extirpations. In conservation biology, species risk from climate warming is often quantified through vulnerability indices such as thermal safety margins—the difference between an organism's upper thermal limit and its habitat temperature. Here, we estimated thermal safety margins for 8 mosquito species that are the vectors of malaria, dengue, chikungunya, Zika, West Nile and other major arboviruses, across their known ranges to investigate which mosquitoes and regions are most and least vulnerable to climate warming. We find that several of the most medically important mosquito vector species, including Ae. aegypti and An. gambiae , have positive thermal safety margins across the majority of their ranges when realistic assumptions of mosquito behavioral thermoregulation are incorporated. On average, the lowest climate vulnerability, in terms of both the magnitude and duration of thermal safety, was just south of the equator and at northern temperate range edges, and the highest climate vulnerability was in the subtropics. Mosquitoes living in regions including the Middle East, the western Sahara, and southeastern Australia, which are largely comprised of desert and xeric shrubland biomes, have the highest climate vulnerability across vector species.
Environmental factors significantly influence the spread of various infectious diseases, particularly those carried by vectors, such as malaria and dengue. There is substantial evidence highlighting the impact of environmental variables on the transmission and proliferation of malaria and dengue worldwide. Against this backdrop, the current study aims to assess the effects of atmospheric carbon dioxide, air temperature, relative humidity, and precipitation on two prevalent vector-borne diseases, namely malaria and dengue, utilizing a data bank spanning over two decades (2001-2022). The research was conducted in two major districts in the state of West Bengal (India), namely, Jalpaiguri and Diamond Harbour, situated in the northernmost and southernmost parts of the state respectively. Correlation analysis on the data sets revealed significant positive impacts of environmental variables on the incidence of both malaria and dengue at both the locations.
Environmental factors significantly influence the spread of various infectious diseases, particularly those carried by vectors, such as malaria and dengue. There is substantial evidence highlighting the impact of environmental variables on the transmission and proliferation of malaria and dengue worldwide. Against this backdrop, the current study aims to assess the effects of atmospheric carbon dioxide, air temperature, relative humidity, and precipitation on two prevalent vector-borne diseases, namely malaria and dengue, utilizing a data bank spanning over two decades (2001-2022). The research was conducted in two major districts in the state of West Bengal (India), namely, Jalpaiguri and Diamond Harbour, situated in the northernmost and southernmost parts of the state respectively. Correlation analysis on the data sets revealed significant positive impacts of environmental variables on the incidence of both malaria and dengue at both the locations.
The changing nature of disasters through the increased frequency and intensity of natural hazards underscores the need for an all-hazards approach to disaster risk management. This paper proposes for planetary health considerations to be embedded within the all-hazards approach, recognising the inextricable link between human well-being and the health of the planet and its ability to sustain human survival for the years to come. A planetary health approach emphasises the importance of recognising and addressing anthropogenic drivers of environmental destruction that triggers an increase in disaster risks and vulnerabilities. This is uncovered in the paper through presenting and discussing two mutually connected feedback loops between governance of the planet’s finite resources and governance of socioeconomic systems at country and global institutional levels. In essence, the paper proposes for planetary health considerations in disaster risk management to both inform and be rooted in shifts in how governance works by generating greater and more focused political will for both mitigation and adaptation measures which must include investing in nature-based solutions, emphasising communications designed for community action, and transforming education systems to contribute towards building community resilience against rising disaster risks.
Environmental factors significantly influence the spread of various infectious diseases, particularly those carried by vectors, such as malaria and dengue. There is substantial evidence highlighting the impact of environmental variables on the transmission and proliferation of malaria and dengue worldwide. Against this backdrop, the current study aims to assess the effects of atmospheric carbon dioxide, air temperature, relative humidity, and precipitation on two prevalent vector-borne diseases, namely malaria and dengue, utilizing a data bank spanning over two decades (2001-2022). The research was conducted in two major districts in the state of West Bengal (India), namely, Jalpaiguri and Diamond Harbour, situated in the northernmost and southernmost parts of the state respectively. Correlation analysis on the data sets revealed significant positive impacts of environmental variables on the incidence of both malaria and dengue at both the locations.
Environmental factors significantly influence the spread of various infectious diseases, particularly those carried by vectors, such as malaria and dengue. There is substantial evidence highlighting the impact of environmental variables on the transmission and proliferation of malaria and dengue worldwide. Against this backdrop, the current study aims to assess the effects of atmospheric carbon dioxide, air temperature, relative humidity, and precipitation on two prevalent vector-borne diseases, namely malaria and dengue, utilizing a data bank spanning over two decades (2001-2022). The research was conducted in two major districts in the state of West Bengal (India), namely, Jalpaiguri and Diamond Harbour, situated in the northernmost and southernmost parts of the state respectively. Correlation analysis on the data sets revealed significant positive impacts of environmental variables on the incidence of both malaria and dengue at both the locations.
Environmental factors significantly influence the spread of various infectious diseases, particularly those carried by vectors, such as malaria and dengue. There is substantial evidence highlighting the impact of environmental variables on the transmission and proliferation of malaria and dengue worldwide. Against this backdrop, the current study aims to assess the effects of atmospheric carbon dioxide, air temperature, relative humidity, and precipitation on two prevalent vector-borne diseases, namely malaria and dengue, utilizing a data bank spanning over two decades (2001-2022). The research was conducted in two major districts in the state of West Bengal (India), namely, Jalpaiguri and Diamond Harbour, situated in the northernmost and southernmost parts of the state respectively. Correlation analysis on the data sets revealed significant positive impacts of environmental variables on the incidence of both malaria and dengue at both the locations.
Environmental factors significantly influence the spread of various infectious diseases, particularly those carried by vectors, such as malaria and dengue. There is substantial evidence highlighting the impact of environmental variables on the transmission and proliferation of malaria and dengue worldwide. Against this backdrop, the current study aims to assess the effects of atmospheric carbon dioxide, air temperature, relative humidity, and precipitation on two prevalent vector-borne diseases, namely malaria and dengue, utilizing a data bank spanning over two decades (2001-2022). The research was conducted in two major districts in the state of West Bengal (India), namely, Jalpaiguri and Diamond Harbour, situated in the northernmost and southernmost parts of the state respectively. Correlation analysis on the data sets revealed significant positive impacts of environmental variables on the incidence of both malaria and dengue at both the locations.
The chikungunya virus (CHIKV) is an alphavirus transmitted to humans mainly through the bite of infected Aedes aegypti and Aedes albopictus mosquitoes. It has recently resurfaced in various parts of the world, triggering widespread outbreaks. CHIKV infection results in chikungunya fever (CHIKF), a temporary febrile illness typically enduring for 7-10 days. Symptoms include rash, fatigue, severe poly-arthralgia affecting the hands and feet, and myalgia. Chronic CHIKF, lasting more than 3 months, affects over 40% of those infected, leading to arthritic changes such as bone erosion, enthesopathies, periostitis, and persistent joint pain. We conducted a narrative review to discuss the musculoskeletal manifestations of CHIKV infection as well as its effects on bone health and to explore current data linking CHIKV infection with os-teoporosis. We performed a comprehensive literature search including peer-reviewed publications. Patients with chronic infection develop an incapacitating arthritis that may persist for months to years and thereby impose a burden on the population in terms of disability-adjusted life years (DALY). A recent increase in outbreaks may be related to virus evolution, globalization/international travel, and climate change, thus potentially turning CHIKV into a major global health threat. Several studies have elucidated the impact of CHIKV infection on bone health and its correlation with arthritic changes. Various cellular and molecular factors contribute to bone erosion during chikungunya virus infection. In CHIKV infection and other arthritogenic alphavirus infections, inflammatory processes marked by the production of interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and interleukin-1 (IL-1), along with an elevated receptor activator of NF-kB ligand/osteoprotegerin (RANKL/OPG) ratio, promote the formation of osteoclasts from monocytic precursors. Consequently, this leads to increased bone resorption and bone pathologies. The literature on osteoporosis and Chikungunya fever is a promising area of research with implications for clinical practice and scientific understanding. Further research in this field has the potential to improve outcomes for individuals affected by these conditions and expand our knowledge of the relationship between viral infections and bone health.
This project compared iNaturalist mosquito observations in the UK and Ireland with existing long-term mosquito UK datasets to assess representativeness of seasonal and distribution trends in citizen scientist-recorded observations. Our analyses indicate that iNaturalist provides species composition, seasonal occurrence, and distribution figures consistent with existing datasets and is therefore a useful surveillance tool for recording information on human interactions with mosquitoes and monitoring species of concern. Analysis of images uploaded to the iNaturalist project also provided insights into human-biting behavior.
Usutu virus (USUV) is an emerging flavivirus that can infect birds and mammals. In humans, in severe cases, it may cause neuroinvasive disease. The innate immune system, and in particular the interferon response, functions as the important first line of defense against invading pathogens such as USUV. Many, if not all, viruses have developed mechanisms to suppress and/or evade the interferon response in order to facilitate their replication. The ability of USUV to antagonize the interferon response has so far remained largely unexplored. Using dual-luciferase reporter assays we observed that multiple of the USUV nonstructural (NS) proteins were involved in suppressing IFN-β production and signaling. In particular NS4A was very effective at suppressing IFN-β production. We found that NS4A interacted with the mitochondrial antiviral signaling protein (MAVS) and thereby blocked its interaction with melanoma differentiation-associated protein 5 (MDA5), resulting in reduced IFN-β production. The TM1 domain of NS4A was found to be essential for binding to MAVS. By screening a panel of flavivirus NS4A proteins we found that the interaction of NS4A with MAVS is conserved among flaviviruses. The increased understanding of the role of NS4A in flavivirus immune evasion could aid the development of vaccines and therapeutic strategies.
Environmental factors significantly influence the spread of various infectious diseases, particularly those carried by vectors, such as malaria and dengue. There is substantial evidence highlighting the impact of environmental variables on the transmission and proliferation of malaria and dengue worldwide. Against this backdrop, the current study aims to assess the effects of atmospheric carbon dioxide, air temperature, relative humidity, and precipitation on two prevalent vector-borne diseases, namely malaria and dengue, utilizing a data bank spanning over two decades (2001-2022). The research was conducted in two major districts in the state of West Bengal (India), namely, Jalpaiguri and Diamond Harbour, situated in the northernmost and southernmost parts of the state respectively. Correlation analysis on the data sets revealed significant positive impacts of environmental variables on the incidence of both malaria and dengue at both the locations.
Introdução: Os flebotomíneos constituem um grupo muito diversificado de dípteros nos trópicos americanos, tendo a reputação de ocorrer durante todo o ano, no entanto, não se conhece muito bem se sofrem flutuações sazonais no número de espécies e na abundância das suas populações. Objetivo: verificar se a riqueza e abundância das espécies de flebotomíneos variam sazonalmente, de acordo com a variação da temperatura e da precipitação pluviométrica em municípios da Amazônia maranhense. Métodos: O estudo foi realizado durante dois anos (maio/2012 e abril/2014) em fragmentos florestais e nos ambientes intradomiciliares e peridomiciliares rurais dos municípios de Senador La Rocque (SLR), Santa Luzia (STL) e Governador Nunes Freire (GNF), Estado do Maranhão. Resultados: Os flebotomíneos ocorreram o ano todo, com picos de abundância na estação chuvosa e na transição com a estação seca, mas em meses diferentes, de acordo com as áreas. Houve inversão de dominância das espécies entre as estações; e correlação positiva com a precipitação pluviométrica em GNF (rs = 0.8252; p = 0.0009) e SLR (rs = 0,4308; p = 0,1620); e correlação negativa com a temperatura em STL (rs = -0,7122; p = 0.0093). Os vetores Bichromomyia flaviscutellata, Nyssomyia whitmani, Migonemyia migonei e Lutzomyia longipalpis comportaram-se como espécies constantes, justificando sua relevância na epidemiologia das leishmanioses. Conclusão: Os flebotomíneos sofrem variações mensais e sazonais, sendo a riqueza e abundância favorecidas durante a estação chuvosa, período mais sugestivo para a implementação de estratégias de controle vetorial das leishmanioses, por representar maior risco para transmissão de casos dessas enfermidades.
The absence of habitat-based guidance for wetland managers on the British mosquito assemblages has in recent years prevented development of the ecological aspect of medical entomology in the UK. This has been particularly relevant in the context of emerging mosquito-borne disease and the creation of wetlands for biodiversity and flood-alleviation goals. This study aimed to provide empirically derived habitat-based predictions in order to assess the suitability of English wetland habitats for mosquitoes. Entomological field data on mosquito density and diversity were collected at 12 English wetlands in 2017 and 2018 using immature and adult mosquito surveys. Wetlands were chosen representing a number of wetland categories that included coastal, urban, wet woodland and established freshwater wetlands to identify key species and functional groups to inform predictions of mosquitoes by aquatic habitat type. Nineteen species were recorded from eight functional groups, totalling 38,577 adult female (19 mosquito species groups) and ~2,000 immature mosquitoes in 13 aquatic habitat types. Approximately 90% of all trapped mosquitoes were attributed to one of five species groups. The most common species were: Aedes (Och.) caspius (Pallas, 1771) (~35% of all mosquitoes), associated with coastal estuarine and flooded grassland sites, Ae. cantans/annulipes (19.7%) in wet woodland field sites, Anopheles claviger (16.2%) and Coquillettidia richiardii (12.6%) with the widest occurrence, found in nearly all field sites, and Ae. detritus (6.9%) in brackish field sites. Across the study, adult mosquito activity increased from week 21 with wet woodland Aedes mosquitoes, until week 40 with open-flood water species, with greatest diversity of species during weeks 23–30. The resulting data inform efforts towards developing predictive tools for non-entomologists to accurately predict the presence and abundance of British mosquitoes in a given habitat, using local knowledge of seasonal aquatic habitats.
Sustainable and effective means to control flying insect vectors are critically needed, especially with widespread insecticide resistance and global climate change. Understanding and controlling vectors requires accurate information about their movement and activity, which is often lacking. The Photonic Fence (PF) is an optical system that uses machine vision, infrared light, and lasers to identify, track, and interdict vectors in flight. The PF examines an insect’s outline, flight speed, and other flight parameters and if these match those of a targeted vector species, then a low-power, retina-safe laser kills it. We report on proof-of-concept tests of a large, field-sized PF (30 mL × 3 mH) conducted with Aedes aegypti, a mosquito that transmits dangerous arboviruses, and Diaphorina citri, a psyllid which transmits the fatal huanglongbing disease of citrus. In tests with the laser engaged, < 1% and 3% of A. aegypti and D. citri, respectfully, were recovered versus a 38% and 19% recovery when the lacer was silenced. The PF tracked, but did not intercept the orchid bee, Euglossa dilemma. The system effectively intercepted flying vectors, but not bees, at a distance of 30 m, heralding the use of photonic energy, rather than chemicals, to control flying vectors.
Unique among medical texts, the Oxford Handbook of Clinical Medicine is a complete and concise guide to the core areas of medicine that also encourages thinking about the world from the patient's perspective, offering a holistic, patient-centred approach. Loved and trusted by millions for over three decades, the Oxford Handbook of Clinical Medicine continues to be a truly indispensable companion for the practice of modern medicine. Now in its eleventh edition, the Oxford Handbook of Clinical Medicine includes three new authors on the writing team, bringing a fresh perspective to the content. Each page has been updated to reflect the latest changes in practice and best management, and the chapters on haematology, oncology, surgery, and radiology have been extensively reworked. Figures and illustrations have been carefully revised and updated in response to reader feedback, key references have been honed to the most up-to-date and relevant, and the text has undergone a thorough review process to ensure the level and coverage are pitched correctly.
The Oxford Handbook of Clinical Medicine provides a unique resource for medical students and junior doctors as a definitive guide to medicine. It is divided into 19 chapters, each covering a core area, including chest medicine, endocrinology, gastroenterology, renal medicine, haematology, infectious diseases, neurology, oncology and palliative care, rheumatology, surgery, clinical chemistry, radiology, practical procedures, and emergency medicine. It presents clinical information in a clear way that makes it easy to revise, remember, and implement on the ward. It gives reliable advice on what to do, and when and how to do it, with clinical photographs and diagrams that bring theory to life. It weaves history, literature, art, and philosophy into its survey of medicine, casting new light on the specialties and encouraging the reader to see beyond the practical aspects of medicine and adopt a patient-centred approach to care.
The introduction and rapid dispersal of the African flavivirus West Nile virus (WNV) throughout North America, and the high fatality rate due to encephalitis in birds, horses, other wildlife species and humans, has attracted major attention worldwide. Usutu virus, another flavivirus, came to prominence in 2001, when it was identified as the agent responsible for a drop in the bird population in Austria; previously this encephalitic virus was found only in birds and mosquitoes in Africa. Sindbis virus, a pathogenic alphavirus that causes arthritis, is widespread throughout Africa, Europe, Asia and Australia, infecting a range of arthropods and vertebrates and is genetically related to encephalitic viruses in North America. Currently there is no evidence that any of these viruses cause disease in the UK. Here the presence of virus-specific neutralizing antibodies is reported in the sera of resident and migrant birds in the UK, implying that each of these viruses is being introduced to UK birds, possibly by mosquitoes. This is supported by nucleotide sequencing that identified three slightly different sequences of WNV RNA in tissues of magpies and a blackbird. The detection of specific neutralizing antibodies to WNV in birds provides a plausible explanation for the lack of evidence of a decrease in the bird population in the UK compared with North America. The potential health risk posed to humans and animals by these viruses circulating in the UK is discussed.
The incidence of mosquito-borne diseases is increasing in Europe, partly due to the incursion of a number of invasive species known to be vectors of dengue and chikungunya viruses, but also due to the involvement of native species in the transmission of West Nile virus and malaria. For some of these pathogens, there is a risk of the re-emergence of vector-borne diseases that were once widespread in Europe, but declined partly due to large-scale land-drainage projects. Some mosquito species exploit container habitats as breeding sites in urban areas; an adaptation to human-made micro-habitats resulting from increased urbanisation. However, many species thrive in natural wetland ecosystems. Owing to the impacts of climate change there is an urgent need for environmental adaptation, such as the creation of new wetlands to mitigate coastal and inland flooding. In some cases, these initiatives can be coupled with environmental change strategies to protect a range of endangered flora and fauna species by enhancing and extending wetland landscapes, which may by driven by European legislation, particularly in urban areas. This paper reviews field studies conducted in England to assess the impact of newly created wetlands on mosquito colonisation in a) coastal, b) urban and c) arable reversion habitats. It also considers the impact of wetland management on mosquito populations and explores the implications of various water and vegetation management options on the range of British mosquito species. Understanding the impact of wetland creation and management strategies on mosquito prevalence and the potential risk of increasing the levels of nuisance or disease vector species will be crucial in informing health and well-being risk assessments, guiding targeted control, and anticipating
the social effects of extreme weather and climate change. Although new wetlands will certainly extend aquatic habitats for mosquitoes, not all species will become a major nuisance or a vector concern as a result. Understanding how the design and management of wetlands might exacerbate mosquito densities is crucial if we are to manage nuisance mosquitoes and control vector species in the event of a disease outbreak. This entomological evidence-base will ensure that control strategies achieve optimal efficacy at minimal cost.
As part of efforts to more fully understand the potential risks posed by West Nile virus (WNV) and Usutu virus (USUV) in the UK, and following on from previous reports of a potential bridge vector Culex modestus for these viruses, at wetland sites in North Kent, mosquito surveillance was undertaken more widely across the Isle of Sheppey, the Hoo Peninsula and the Kent mainland.
Larval surveys were conducted and Mosquito Magnet® adult traps were used to collect adult mosquitoes. Pools of female mosquitoes were tested for the presence of WNV using real-time reverse transcriptase polymerase chain reaction. A subset of samples was tested for USUV.
Culex modestus was found in both the pre-imaginal and imago stage at all five locations surveyed, accounting for 90% of adult mosquitoes collected. WNV or USUV were not detected in any sample.
Although no mosquitoes have been shown to be virus positive, the field survey data from this study demonstrated the dominance of an important bridge vector species for WNV in this region. Its wide geographical distribution highlights the need to update risk assessments on WNV introduction, and to maintain vigilance for WNV in the South East of England.
PUBLIC Health England (PHE) recently investigated a tick infestation in a family home in Essex (East of England) during September 2014. Specimens removed from two pet dogs and within the property were submitted to the PHE Tick Recording Scheme and identified as the brown dog tick, Rhipicephalus sanguineus (15 males, 14 females and one nymph), a non-native species. House infestations are rarely documented in the UK (Best and others 1969, Fox and Sykes 1985) but may become more common with the increased importation of R …
THE mosquito Culex modestus is considered the main bridge vector of West Nile virus in continental Europe, responsible for transmitting the virus from birds to humans (Balenghien and others 2008). Cx modestus was reported in three nature reserves in north Kent in 2010 (Golding and others 2012) – 60 years after the previous UK report. Isolated specimens were then reported from Dorset and Cambridgeshire (Medlock and Vaux 2012).
Lyme borreliosis is an emerging infectious human disease caused by the Borrelia burgdorferi sensu lato complex of bacteria with reported cases increasing in many areas of Europe and North America. To understand the drivers of disease risk and the distribution of symptoms, which may improve mitigation and diagnostics, here we characterize the genetics, distribution, and environmental associations of B. burgdorferi s.l. genospecies across Scotland. In Scotland, reported Lyme borreliosis cases have increased almost 10-fold since 2000 but the distribution of B. burgdorferi s.l. is so far unstudied. Using a large survey of over 2200 Ixodes ricinus tick samples collected from birds, mammals, and vegetation across 25 sites we identified four genospecies: Borrelia afzelii (48%), Borrelia garinii (36%), Borrelia valaisiana (8%), and B. burgdorferi sensu stricto (7%), and one mixed genospecies infection. Surprisingly, 90% of the sequence types were novel and, importantly, up to 14% of samples were mixed intra-genospecies co-infections, suggesting tick co-feeding, feeding on multiple hosts, or multiple infections in hosts. B. garinii (hosted by birds) was considerably more genetically diverse than B. afzelii (hosted by small mammals), as predicted since there are more species of birds than small mammals and birds can import strains from mainland Europe. Higher proportions of samples contained B. garinii and B. valaisiana in the west, while B. afzelii and B. garinii were significantly more associated with mixed/deciduous than with coniferous woodlands. This may relate to the abundance of transmission hosts in different regions and habitats. These data on the genetic heterogeneity within and between Borrelia genospecies are a first step to understand pathogen spread and could help explain the distribution of patient symptoms, which may aid local diagnosis. Understanding the environmental associations of the pathogens is critical for rational policy making for disease risk mitigation and land management.
As our Review 1 on dengue in the WHO European region went to press in The Lancet Infectious Diseases, a new autochthonous dengue case was reported in southern France on Aug 20. 2 The patient lives in the city of Toulon, in a region where the invasive mosquito species Aedes albopictus (an efficient vector of dengue virus) has been established since 2007 and is now abundant. Because a prevention plan for dengue and chikungunya is active in France, control measures were immediately applied in the patient's neighbourhood, including suppression of mosquito larval development sites, spraying of insecticides against adult mosquitoes, and strengthening of disease and entomological surveillance. In 2014, Japan and the USA have been facing the same concern regarding re-emergence of autochthonous dengue, probably transmitted by A albopictus. This event emphasises the present risk of dengue transmission in Europe in areas where competent mosquito vectors are established. As we reminded readers, 1 dengue used to be a severe threat in southern Europe in areas where Aedes aegypti was established before its disappearance in the 1950s. The recent invasion of A albopictus in large parts of southern Europe and the resurgence of A aegypti in some areas make the return of dengue possible and generate a substantial risk for other mosquito-borne diseases (eg, chikungunya, zika infections). In Europe, both A aegypti and A albopictus will definitely spread further, as suggested by statistical and biological models. 1 Thus, this case again stresses the need for action in areas at risk, such as to implement surveillance of mosquito vector, for example by use of guidelines developed by the European Centre for Disease Prevention and Control (ECDC), 3 and to develop prevention plans like in France. 4 Preparedness is essential for planning adequate and efficient measures in both pre-emptive scheme and outbreak response (panel).
During the summer of 2014, all the pre-requisites for autochthonous transmission of chikungunya virus are present in southern France: a competent vector, Aedes albopictus, and a large number of travellers returning from the French Caribbean islands where an outbreak is occurring. We describe the system implemented for the surveillance of chikungunya and dengue in mainland France. From 2 May to 4 July 2014, there were 126 laboratory-confirmed imported chikungunya cases in mainland France. © 2014, European Centre for Disease Prevention and Control (ECDC). All rights reserved.
This paper reports the first detection of Borrelia miyamotoi in UK Ixodes ricinus ticks. It also
reports on the presence and infection rates of I. ricinus for a number of other tick-borne
pathogens of public health importance. Ticks from seven regions in southern England were
screened for B. miyamotoi, Borrelia burgdorferi sensu lato (s.l.), Anaplasma phagocytophilum and
Neoehrlichia mikurensis using qPCR. A total of 954 I. ricinus ticks were tested, 40 were positive
for B. burgdorferi s.l., 22 positive for A. phagocytophilum and three positive for B. miyamotoi,
with no N. mikurensis detected. The three positive B. miyamotoi ticks came from three
geographically distinct areas, suggesting a widespread distribution, and from two separate years,
suggesting some degree of endemicity. Understanding the prevalence of Borrelia and other
tick-borne pathogens in ticks is crucial for locating high-risk areas of disease transmission.
Climate warming is changing distributions and phenologies of many organisms and may also impact on vectors of disease-causing pathogens. In Europe, the tick Ixodes ricinus is the primary vector of medically important pathogens (e.g., Borrelia burgdorferi sensu lato, the causative agent of Lyme borreliosis). How might climate change affect I. ricinus host-seeking behavior (questing)? We hypothesize that, in order to maximize survival, I. ricinus have adapted their questing in response to temperature in accordance with local climates. We predicted that ticks from cooler climates quest at cooler temperatures than those from warmer climates. This would suggest that I. ricinus can adapt and therefore have the potential to be resilient to climate change. I. ricinus were collected from a cline of climates using a latitudinal gradient (northeast Scotland, North Wales, South England, and central France). Under laboratory conditions, ticks were subjected to temperature increases of 1°C per day, from 6 to 15°C. The proportion of ticks questing was recorded five times per temperature (i.e., per day). The theoretical potential to quest was then estimated for each population over the year for future climate change projections. As predicted, more ticks from cooler climates quested at lower temperatures than did ticks from warmer climates. The proportion of ticks questing was strongly associated with key climate parameters from each location. Our projections, based on temperature alone, suggested that populations could advance their activity season by a month under climate change, which has implications for exposure periods of hosts to tick-borne pathogens. Our findings suggest that I. ricinus have adapted their behavior in response to climate, implying some potential to adapt to climate change. Predictive models of I. ricinus dynamics and disease risk over continental scales would benefit from knowledge of these differences between populations.
On 6 December 2013, two laboratory-confirmed cases of chikungunya without a travel history were reported on
the French part of the Caribbean island of Saint Martin, indicating the start of the first documented outbreak of
chikungunya in the Americas. Since this report, the virus spread to several Caribbean islands and French
Guiana, and between 6 December 2013 and 27 March 2014 more than 17,000 suspected and confirmed cases
have been reported. Further spread and establishment of the disease in the Americas is likely, given the high
number of people travelling between the affected and non-affected areas and the widespread occurrence of
efficient vectors. Also, the likelihood of the introduction of the virus into Europe from the Americas and
subsequent transmission should be considered especially in the context of the next mosquito season in Europe.
Clinicians should be aware that, besides dengue, chikungunya should be carefully considered among travellers
currently returning from the Caribbean region.
Significance
This study is the first multimalaria model intercomparison exercise. This is carried out to estimate the impact of future climate change and population scenarios on malaria transmission at global scale and to provide recommendations for the future. Our results indicate that future climate might become more suitable for malaria transmission in the tropical highland regions. However, other important socioeconomic factors such as land use change, population growth and urbanization, migration changes, and economic development will have to be accounted for in further details for future risk assessments.
The Asian bush or rock pool mosquito Aedes japonicus japonicus is one of the most expansive culicid species of the world. Being native to East Asia, this species was detected out of its original distribution range for the first time in the early 1990s in New Zealand where it could not establish, though. In 1998, established populations were reported from the eastern US, most likely as a result of introductions several years earlier. After a massive spread the mosquito is now widely distributed in eastern North America including Canada and two US states on the western coast. In the year 2000, it was demonstrated for the first time in Europe, continental France, but could be eliminated. A population that had appeared in Belgium in 2002 was not controlled until 2012 as it did not propagate. In 2008, immature developmental stages were discovered in a large area in northern Switzerland and bordering parts of Germany. Subsequent studies in Germany showed a wide distribution and several populations of the mosquito in various federal states. Also in 2011, the species was found in southeastern Austria (Styria) and neighbouring Slovenia. In 2013, a population was detected in the Central Netherlands, specimens were collected in southern Alsace, France, and the complete northeastern part of Slovenia was found colonized, with specimens also present across borders in adjacent Croatia. Apparently, at the end of 2013 a total of six populations occurred in Europe although it is not clear whether all of them are completely isolated. Similarly, it is not known whether these populations go back to the same number of introductions. While entry ports and long-distance continental migration routes are also obscure, it is likely that the international used tyre trade is the most important mode of intercontinental transportation of the mosquito. Aedes j. japonicus does not only display an aggressive biting behaviour but is suspected to be a vector of various disease agents and to displace indigenous culicid species. Therefore, Aedes j. japonicus might both cause public health problems in the future and have a significant impact on the biodiversity of the invaded territories.
Global environmental change is causing spatial and temporal shifts in the distribution of species and the associated diseases of humans, domesticated animals and wildlife. In the on-going debate on the influence of climate change on vectors and vector-borne diseases, there is a lack of a comprehensive interdisciplinary multi-factorial approach utilizing high quality spatial and temporal data.
We explored biotic and abiotic factors associated with the latitudinal and altitudinal shifts in the distribution of Ixodes ricinus observed during the last three decades in Norway using antibodies against Anaplasma phagocytophilum in sheep as indicators for tick presence. Samples obtained from 2963 sheep from 90 farms in 3 ecologically different districts during 1978 - 2008 were analysed. We modelled the presence of antibodies against A. phagocytophilum to climatic-, environmental and demographic variables, and abundance of wild cervids and domestic animals, using mixed effect logistic regressions.
Significant predictors were large diurnal fluctuations in ground surface temperature, spring precipitation, duration of snow cover, abundance of red deer and farm animals and bush encroachment/ecotones. The length of the growth season, mean temperature and the abundance of roe deer were not significant in the model.
Our results highlight the need to consider climatic variables year-round to disentangle important seasonal variation, climatic threshold changes, climate variability and to consider the broader environmental change, including abiotic and biotic factors. The results offer novel insight in how tick and tick-borne disease distribution might be modified by future climate and environmental change.
Global climate change can seriously impact on the epidemiological dynamics of vector-borne diseases. In this study we investigated how future climatic changes could affect the climatic niche of Ixodes ricinus (Acari, Ixodida), among the most important vectors of pathogens of medical and veterinary concern in Europe.
Species Distribution Modelling (SDM) was used to reconstruct the climatic niche of I. ricinus, and to project it into the future conditions for 2050 and 2080, under two scenarios: a continuous human demographic growth and a severe increase of gas emissions (scenario A2), and a scenario that proposes lower human demographic growth than A2, and a more sustainable gas emissions (scenario B2). Models were reconstructed using the algorithm of "maximum entropy", as implemented in the software Maxent 3.3.3e; 4,544 occurrence points and 15 bioclimatic variables were used.
In both scenarios an increase of climatic niche of about two times greater than the current area was predicted as well as a higher climatic suitability under the scenario B2 than A2. Such an increase occurred both in a latitudinal and longitudinal way, including northern Eurasian regions (e.g. Sweden and Russia), that were previously unsuitable for the species.
Our models are congruent with the predictions of range expansion already observed in I. ricinus at a regional scale and provide a qualitative and quantitative assessment of the future climatically suitable areas for I. ricinus at a continental scale. Although the use of SDM at a higher resolution should be integrated by a more refined analysis of further abiotic and biotic data, the results presented here suggest that under future climatic scenarios most of the current distribution area of I. ricinus could remain suitable and significantly increase at a continental geographic scale. Therefore disease outbreaks of pathogens transmitted by this tick species could emerge in previous non-endemic geographic areas. Further studies will implement and refine present data toward a better understanding of the risk represented by I. ricinus to human health.
Chikungunya was, from the European perspective, considered to be a travel-related tropical mosquito-borne disease prior to the first European outbreak in Northern Italy in 2007. This was followed by cases of autochthonous transmission reported in South-eastern France in 2010. Both events occurred after the introduction, establishment and expansion of the Chikungunya-competent and highly invasive disease vector Aedes albopictus (Asian tiger mosquito) in Europe. In order to assess whether these outbreaks are indicative of the beginning of a trend or one-off events, there is a need to further examine the factors driving the potential transmission of Chikungunya in Europe. The climatic suitability, both now and in the future, is an essential starting point for such an analysis.
The climatic suitability for Chikungunya outbreaks was determined by using bioclimatic factors that influence both vector and pathogen. Climatic suitability for the European distribution of the vector Aedes albopictus was based upon previous correlative environmental niche models. Climatic risk classes were derived by combining climatic suitability for the vector with known temperature requirements for pathogen transmission, obtained from outbreak regions. In addition, the longest potential intra-annual season for Chikungunya transmission was estimated for regions with expected vector occurrences.In order to analyse spatio-temporal trends for risk exposure and season of transmission in Europe, climate change impacts are projected for three time-frames (2011--2040, 2041--2070 and 2071--2100) and two climate scenarios (A1B and B1) from the Intergovernmental Panel on Climate Change (IPCC). These climatic projections are based on regional climate model COSMO-CLM which builds on the global model ECHAM5.
European areas with current and future climatic suitability of Chikungunya transmission are identified. An increase in risk is projected for Western Europe (e.g. France and Benelux-States) in the first half of the 21st century and from mid-century onwards for central parts of Europe (e.g. Germany). Interestingly, the southernmost parts of Europe do not generally provide suitable conditions in these projections. Nevertheless, many Mediterranean regions will persist to be climatically suitable for transmission. Overall, the highest risk of transmission by the end of the 21st century was projected for France, Northern Italy and the Pannonian Basin (East-Central Europe). This general tendency is depicted in both the A1B and B1 climate change scenarios.
In order to guide preparedness for further outbreaks, it is crucial to anticipate risk as to identify areas where specific public health measures, such as surveillance and vector control, can be implemented. However, public health practitioners need to be aware that climate is only one factor driving the transmission of vector-borne disease.
Significance
The potential impacts of climate change on human health are possibly large and not yet well understood, especially for vector-borne diseases. This study provides projections of how climate change may affect the population of a West Nile virus mosquito vector across the southern United States. Using a climate-driven mosquito population model, we simulate vector abundance under base and future climate. Under future climate, many locations exhibit a lengthening of the mosquito season with a decrease in summer populations. These impacts are not uniform geographically and vary with local temperature and precipitation conditions. The results imply that disease-transmission studies and vector-control programs must be targeted locally to maximize their effectiveness.
Background
The recent notifications of autochthonous cases of dengue and chikungunya in Europe prove that the region is vulnerable to these diseases in areas where known mosquito vectors (Aedes albopictus and Aedes aegypti) are present. Strengthening surveillance of these species as well as other invasive container-breeding aedine mosquito species such as Aedes atropalpus, Aedes japonicus, Aedes koreicus and Aedes triseriatus is therefore required. In order to support and harmonize surveillance activities in Europe, the European Centre for Disease Prevention and Control (ECDC) launched the production of ‘Guidelines for the surveillance of invasive mosquitoes in Europe’. This article describes these guidelines in the context of the key issues surrounding invasive mosquitoes surveillance in Europe.
Methods
Based on an open call for tender, ECDC granted a pan-European expert team to write the guidelines draft. It content is founded on published and grey literature, contractor’s expert knowledge, as well as appropriate field missions. Entomologists, public health experts and end users from 17 EU/EEA and neighbouring countries contributed to a reviewing and validation process. The final version of the guidelines was edited by ECDC (Additional file 1).
Results
The guidelines describe all procedures to be applied for the surveillance of invasive mosquito species. The first part addresses strategic issues and options to be taken by the stakeholders for the decision-making process, according to the aim and scope of surveillance, its organisation and management. As the strategy to be developed needs to be adapted to the local situation, three likely scenarios are proposed. The second part addresses all operational issues and suggests options for the activities to be implemented, i.e. key procedures for field surveillance of invasive mosquito species, methods of identification of these mosquitoes, key and optional procedures for field collection of population parameters, pathogen screening, and environmental parameters. In addition, methods for data management and analysis are recommended, as well as strategies for data dissemination and mapping. Finally, the third part provides information and support for cost estimates of the planned programmes and for the evaluation of the applied surveillance process.
Conclusion
The ‘Guidelines for the surveillance of invasive mosquitoes in Europe’ aim at supporting the implementation of tailored surveillance of invasive mosquito species of public health importance. They are intended to provide support to professionals involved in mosquito surveillance or control, decision/policy makers, stakeholders in public health and non-experts in mosquito surveillance. Surveillance also aims to support control of mosquito-borne diseases, including integrated vector control, and the guidelines are therefore part of a tool set for managing mosquito-borne disease risk in Europe.
Vector-borne diseases are medically important in humans and animals but were long considered tropical and known to first affect production animals. This is no longer true and we can see today that they are common in domestic animals and that they are also present in temperate countries, especially in Europe. In recent years, an increase in the diagnosis of vector borne diseases among humans and animals has been observed, which may partly due to the development of diagnostic tools. Their study requires exchanges and collaborations between the many actors involved, especially since the epidemiology seems to be constantly evolving. The veterinary practitioner is the first one to notice the emergence of cases and to implement prevention measures. He also acts as a sentinel to alert epidemiologists. Many factors can explain the epidemiological changes, i.e. all human factors, such as the increase in commercial transportation, but also owners traveling with their pet during the holidays, the development of "outdoor" activities, the increase of individual housings with gardens; to these human factors must be added the ignorance of the risks, linked to animals in general and to wildlife in particular; then the environmental changes: forest fragmentation, establishment of parks; the increase of wild mammal populations (deer, carnivores, rodents, etc.); finally, climate changes. Climate change is a reality which may explain the increase of density of arthropod vectors, but also of their hosts, changes in periods of activity and variations in geographical distribution. The authors show the proof of the climate modifications and then explain how it has an impact in Europe on ticks, mosquitoes, sandflies and even fleas. They conclude on the practical consequences for veterinary practitioners, especially with the diagnosis of parasitic diseases or diseases in areas where they usually do not occur. However, not any epidemiological modification should be linked to climate change, since many other factors are involved and often even overriding.
Spotted fever group (SFG) rickettsiae have recently been identified for the first time in UK ticks. This included the findings of Rickettsia helvetica in Ixodes ricinus and Rickettsia raoultii in Dermacentor reticulatus. This paper further investigates the occurrence of SFG rickettsiae in additional geographically distinct populations of D. reticulatus, and for the first time, investigates the occurrence of SFG rickettsiae in UK populations of Haemaphysalis punctata ticks.
Questing D. reticulatus and H. punctata were collected at a number of sites in England and Wales. DNA from questing ticks was extracted by alkaline lysis and detection of rickettsiae DNA was performed, in addition to detection of A. phagocytophilum, N. mikurensis, C. burnetii and B. burgdorferi sensu lato.
This paper builds on previous findings to include the detection of spotted fever Rickettsia which showed the highest homology to Rickettsia massiliae in Haemaphysalis punctata, as well as R. helvetica in D. reticulatus. The occurrence of SFG rickettsiae in D. reticulatus in the UK appears to be confined only to Welsh and Essex populations, with no evidence so far from Devon. Similarly, the occurrence of SFG rickettsiae in H. punctata appears confined to one of two farms known to be infested with this tick in North Kent, with no evidence so far from the Sussex populations. Anaplasma phagocytophilum, Neoehrlichia mikurensis, Coxiella burnetii and Borrelia burgdorferi sensu lato DNA was not detected in any of the ticks.
These two tick species are highly restricted in their distribution in England and Wales, but where they do occur they can be abundant. Following detection of these SFG rickettsiae in additional UK tick species, as well as I. ricinus, research should now be directed towards clarifying firstly the geographic distribution of SFG rickettsiae in UK ticks, and secondly to assess the prevalence rates in ticks, wild and domesticated animals and humans to identify the drivers for disease transmission and their public health significance.
Introduction.
Climate change projections indicate that droughts will become more intense in the 21 century in some areas of the world. The El Niño Southern Oscillation is associated with drought in some countries, and forecasts can provide advance warning of the increased risk of adverse climate conditions. The most recent available data from EMDAT estimates that over 50 million people globally were affected by drought in 2011. Documentation of the health effects of drought is difficult, given the complexity in assigning a beginning/end and because effects tend to accumulate over time. Most health impacts are indirect because of its link to other mediating circumstances like loss of livelihoods.
Methods.
The following databases were searched: MEDLINE; CINAHL; Embase; PsychINFO, Cochrane Collection. Key references from extracted papers were hand-searched, and advice from experts was sought for further sources of literature. Inclusion criteria for papers summarised in tables include: explicit link made between drought as exposure and human health outcomes; all study designs/methods; all countries/contexts; any year of publication. Exclusion criteria include: drought meaning shortage unrelated to climate; papers not published in English; studies on dry/arid climates unless drought was noted as an abnormal climatological event. No formal quality evaluation was used on papers meeting inclusion criteria.
Results.
87 papers meeting the inclusion criteria are summarised in tables. Additionally, 59 papers not strictly meeting the inclusion criteria are used as supporting text in relevant parts of the results section. Main categories of findings include: nutrition-related effects (including general malnutrition and mortality, micronutrient malnutrition, and anti-nutrient consumption); water-related disease (including E coli, cholera and algal bloom); airborne and dust-related disease (including silo gas exposure and coccidioidomycosis); vector borne disease (including malaria, dengue and West Nile Virus); mental health effects (including distress and other emotional consequences); and other health effects (including wildfire, effects of migration, and damage to infrastructure).
Conclusions.
The probability of drought-related health impacts varies widely and largely depends upon drought severity, baseline population vulnerability, existing health and sanitation infrastructure, and available resources with which to mitigate impacts as they occur. The socio-economic environment in which drought occurs influences the resilience of the affected population. Forecasting can be used to provide advance warning of the increased risk of adverse climate conditions and can support the disaster risk reduction process. Despite the complexities involved in documentation, research should continue and results should be shared widely in an effort to strengthen drought preparedness and response activities.
West Nile virus (WNV) has historically been considered among the least virulent members of the Japanese serogroup complex (family Flaviviridae, genus Flavivirus). The WNV natural cycle involves birds as the main amplifying hosts and several species of mosquito as vectors. Many outbreaks occurred during the past decade, causing severe human encephalitis in the Old World, and the virus has become established in many European countries. Emergence of WNV is difficult to predict and even more difficult to prevent. In this review, the latest information on the epidemiology, transmission dynamics and clinical aspects of WNV is presented, with particular focus on specific factors likely to trigger changes in the distribution of the disease in Europe, such as climate changes and their consequences on the potential vectors of WNV or bird migration routes. The control of some anthropogenic and environmental factors could help prevent extension and re-emergence of WNV epidemics.
An outbreak of dengue fever in Madeira island was reported in 2012. Clinical and laboratory findings of the first two laboratory-confirmed autochthonous cases are reported. Both cases had fever (≥38 °C) and petechial rash. Symptoms also included myalgia, asthenia, nausea, vomiting, anorexia, diffuse abdominal pain, and diarrhoea. The two cases were confirmed by serology and one tested positive for a dengue viral sequence. Dengue virus serotype DEN-1 was identified with probable Central or South American origin.
Many factors are involved in determining the latitudinal and altitudinal spread of the important tick vector Ixodes ricinus (Acari: Ixodidae) in Europe, as well as in changes in the distribution within its prior endemic zones. This paper builds on published literature and unpublished expert opinion from the VBORNET network with the aim of reviewing the evidence for these changes in Europe and discusses the many climatic, ecological, landscape and anthropogenic drivers. These can be divided into those directly related to climatic change, contributing to an expansion in the tick's geographic range at extremes of altitude in central Europe, and at extremes of latitude in Scandinavia; those related to changes in the distribution of tick hosts, particularly roe deer and other cervids; other ecological changes such as habitat connectivity and changes in land management; and finally, anthropogenically induced changes. These factors are strongly interlinked and often not well quantified. Although a change in climate plays an important role in certain geographic regions, for much of Europe it is non-climatic factors that are becoming increasingly important. How we manage habitats on a landscape scale, and the changes in the distribution and abundance of tick hosts are important considerations during our assessment and management of the public health risks associated with ticks and tick-borne disease issues in 21st century Europe. Better understanding and mapping of the spread of I. ricinus (and changes in its abundance) is, however, essential to assess the risk of the spread of infections transmitted by this vector species. Enhanced tick surveillance with harmonized approaches for comparison of data enabling the follow-up of trends at EU level will improve the messages on risk related to tick-borne diseases to policy makers, other stake holders and to the general public.
SUMMARY Lyme borreliosis (LB) is the most common arthropod-borne disease of humans in the Northern hemisphere. In Europe, the causative agent, Borrelia burgdorferi sensu lato complex, is principally vectored by Ixodes ricinus ticks. The aim of this study was to identify environmental factors influencing questing I. ricinus nymph abundance and B. burgdorferi s.l. infection in questing nymphs using a large-scale survey across Scotland. Ticks, host dung and vegetation were surveyed at 25 woodland sites, and climatic variables from a Geographical Information System (GIS) were extracted for each site. A total of 2397 10 m2 transect surveys were conducted and 13 250 I. ricinus nymphs counted. Questing nymphs were assayed for B. burgdorferi s.l. and the average infection prevalence was 5·6% (range 0·8-13·9%). More questing nymphs and higher incidence of B. burgdorferi s.l. infection were found in areas with higher deer abundance and in mixed/deciduous compared to coniferous forests, as well as weaker correlations with season, altitude, rainfall and ground vegetation. No correlation was found between nymph abundance and infection prevalence within the ranges encountered. An understanding of the environmental conditions associated with tick abundance and pathogen prevalence may be used to reduce risk of exposure and to predict future pathogen prevalence and distributions under environmental changes.
Abstract:
Summary: During the last decades dengue incidences are emerging significantly around the globe. Currently, about one fifth of the human population lives in dengue risk zones, which are mainly located in (sub-) tropical regions of Southeast Asia and the Western Pacific. Dengue infections in European population mainly referred to returning travellers from tropical endemic regions. Nevertheless, vector establishment in Europe already took place and therefore the risk increases. Currently, autochthonous cases of dengue fever have been reported in Europe. Studies estimating the risk of dengue epidemics regarding changing climatic conditions in Europe are missing. Therefore, we close this gap by using the temperature constraints for virus amplification within the vector Aedes aegypti from two laboratory experiments. We transfer these findings to the changing European climate based on data provided from a regional climate model (COSMO-CLM; A1B and B1 scenario). Daily mean temperature were averaged for the time-steps 2011–2040, 2041–2070 and 2071–2100 in order to reduce natural variability but rather point out climatic trends for risk assessments. For both scenarios the strongest increase of temperature is projected after mid-century. Results indicate a growing threat of virus amplification in Europe especially towards the end of this century. Larger parts of the Mediterranean will be at risk. The southwest of the Iberian Peninsular appears to be especially threatened. Even in some parts of Central Europe, such as Southwest Germany, dengue virus amplification can no longer be excluded at the end of the century. However, it is unlikely that Aedes aegypti will serve as an efficient vector in Europe. In fact, it is Aedes albopictus that is an invasive species in Europe and potential differences in extrinsic incubation period between Ae. aegypti and Ae. albopictus have to be identified. Policy and public health authorities have to consider these emerging biorisks in order to establish surveillance systems and develop counteraction strategies. Hence, we strongly emphasize the need for a growing European awareness in the face of biological hazards that are responding to climatic changes.
Malaria (ague) was once common in many parts of Great Britain (GB). Here we identify areas currently at risk from vivax malaria
and examine how this pattern may change as a consequence of global warming during this century. We used a mathematical model
to describe how temperature affects the risk of vivax malaria, transmitted by a common British mosquito, Anopheles atroparvus. This model was linked with present-day temperature surfaces and future temperature change scenarios for GB, and used to map
areas suitable for malaria transmission. We found an excellent agreement between the present-day risk map for malaria and
historical records of ague distribution. This study demonstrates that many parts of GB are warm enough for malaria transmission
and the extent of these areas are likely to increase in the future. Health services need to remain aware of the possibility
of locally-transmitted malaria, particularly in marshland areas in southern England.
The Asian tiger mosquito (Aedes albopictus) is an invasive species that has the potential to transmit infectious diseases such as dengue and chikungunya fever. Using high-resolution observations and regional climate model scenarios for the future, we investigated the suitability of Europe for A. albopictus using both recent climate and future climate conditions. The results show that southern France, northern Italy, the northern coast of Spain, the eastern coast of the Adriatic Sea and western Turkey were climatically suitable areas for the establishment of the mosquito during the 1960-1980s. Over the last two decades, climate conditions have become more suitable for the mosquito over central northwestern Europe (Benelux, western Germany) and the Balkans, while they have become less suitable over southern Spain. Similar trends are likely in the future, with an increased risk simulated over northern Europe and slightly decreased risk over southern Europe. These distribution shifts are related to wetter and warmer conditions favouring the overwintering of A. albopictus in the north, and drier and warmer summers that might limit its southward expansion.
Background
The world is facing an increased threat from new and emerging diseases, and there is concern that climate change will expand areas suitable for transmission of vector borne diseases. The likelihood of vivax malaria returning to the UK was explored using two markedly different modelling approaches. First, a simple temperature-dependent, process-based model of malaria growth transmitted by Anopheles atroparvus, the historical vector of malaria in the UK. Second, a statistical model using logistic-regression was used to predict historical malaria incidence between 1917 and 1918 in the UK, based on environmental and demographic data. Using findings from these models and saltmarsh distributions, future risk maps for malaria in the UK were produced based on UKCIP02 climate change scenarios.
Results
The process-based model of climate suitability showed good correspondence with historical records of malaria cases. An analysis of the statistical models showed that mean temperature of the warmest month of the year was the major factor explaining the distribution of malaria, further supporting the use of the temperature-driven processed-based model. The risk maps indicate that large areas of central and southern England could support malaria transmission today and could increase in extent in the future. Confidence in these predictions is increased by the concordance between the processed-based and statistical models.
Conclusion
Although the future climate in the UK is favourable for the transmission of vivax malaria, the future risk of locally transmitted malaria is considered low because of low vector biting rates and the low probability of vectors feeding on a malaria-infected person.
There has been growing interest in Europe in recent years in the establishment and spread of invasive mosquitoes, notably the incursion of Aedes albopictus through the international trade in used tires and lucky bamboo, with onward spread within Europe through ground transport. More recently, five other non-European aedine mosquito species have been found in Europe, and in some cases populations have established locally and are spreading. Concerns have been raised about the involvement of these mosquito species in transmission cycles of pathogens of public health importance, and these concerns were borne out following the outbreak of chikungunya fever in Italy in 2007, and subsequent autochthonous cases of dengue fever in France and Croatia in 2010. This article reviews current understanding of all exotic (five introduced invasive and one intercepted) aedine species in Europe, highlighting the known import pathways, biotic and abiotic constraints for establishment, control strategies, and public health significance, and encourages Europe-wide surveillance for invasive mosquitoes.
The risk posed to the United Kingdom by West Nile virus (WNV) has previously been considered low, due to the absence or scarcity of the main Culex sp. bridge vectors. The mosquito Culex modestus is widespread in southern Europe, where it acts as the principle bridge vector of WNV. This species was not previously thought to be present in the United Kingdom.
Mosquito larval surveys carried out in 2010 identified substantial populations of Cx. modestus at two sites in marshland in southeast England. Host-seeking-adult traps placed at a third site indicate that the relative seasonal abundance of Cx. modestus peaks in early August. DNA barcoding of these specimens from the United Kingdom and material from southern France confirmed the morphological identification.
Cx. modestus appears to be established in the North Kent Marshes, possibly as the result of a recent introduction. The addition of this species to the United Kingdom's mosquito fauna may increase the risk posed to the United Kingdom by WNV.
Among the invasive mosquitoes registered all over the world, Aedes species are particularly frequent and important. As several of them are potential vectors of disease, they present significant health concerns for 21st century Europe. Five species have established in mainland Europe, with two (Aedes albopictus and Aedes japonicus) becoming widespread and two (Ae. albopictus and Aedes aegypti) implicated in disease transmission to humans in Europe. The routes of importation and spread are often enigmatic, the ability to adapt to local environments and climates are rapid, and the biting nuisance and vector potential are both an ecomonic and public health concern. Europeans are used to cases of dengue and chikungunya in travellers returning from the tropics, but the threat to health and tourism in mainland Europe is substantive. Coupled to that are the emerging issues in the European overseas territorities and this paper is the first to consider the impacts in the remoter outposts of Europe. If entomologists and public health authorities are to address the spread of these mosquitoes and mitigate their health risks they must first be prepared to share information to better understand their biology and ecology, and share data on their distribution and control successes. This paper focusses in greater detail on the entomological and ecological aspects of these mosquitoes to assist with the risk assessment process, bringing together a large amount of information gathered through the ECDC VBORNET project.
(1) Laboratory and ecological work extending over six years provided an insight into the ecology of Aedes cantans in southern England. This mosquito oviposits among leaf litter of shaded, temporary woodland pools during June-September. In September adults die off and the population exists only as eggs which are in a state of obligatory diapause until about the beginning of January. Diapause is probably initiated by a reduction in temperature and/or day length, the factors terminating diapause were not determined. Larvae appear in natural habitats in January and pupae are formed in late April or early May. (2) Collections of leaf litter samples from a ditch each December enabled the total numbers of viable eggs of A. cantans to be estimated, and by using emergence traps in April and May the absolute size of the emerging adult populations were estimated. Comparison of the two population estimates showed there was about 95% mortality of the overwintering immature stages. Regular sampling of the immature stage showed the decreasing proportion in each successive instar. From this, survivorship curves and life-tables were constructed and these showed that mortality was greatest in the younger instars. (3) Coelomomyces fungi, an indescent virus, mermithid nematodes and other infections caused some larval deaths. Precipitin tests identified the most important predators of pre-adults as larval Dytiscidae (Coleoptera), and adult predacious flies were common predators of emerging adults. None of these factors, however, accounted for much of the observed mortality, the principal causes of which remain undiscovered. (4) Adult populations were sampled by sweep-netting vegetation, by suction traps and by human bait catches. By studying the age structure, seasonal abundance, incidence of sugar and blood feeding of females it was found that nulliparous adults fed initially on sugar secretions and did not commence blood feeding until about three weeks after emergence. Unfed nullipars had the ovaries in stage I of development. Some eight-week-old females were still nullipars. In unfed parous females the ovaries were in stage II. A proportion of nulliparous females required two blood-meals for complete ovarian development. Maximum biting was just after sunset, and the biting season extended from about June-September, having a peak in July. (5) A. cantans females were fed in the laboratory on rabbits. The times required for blood digestion at different temperatures were determinated. There was a decrease in fecundity associated with a decrease in adult size, and also a reduction in numbers of eggs in successive ovipositions. Blood was usually digested after eight or nine days, after which about thirty-two eggs were laid. Some fifteen days were required for embryonic development, after which eggs remained viable for many months, even years, if relative humidities were about 85% or higher. The effect of both continual soaking and repeated soaking on the egg hatching pattern was investigated, as also the relationship between temperature and instar durations.
We engaged in field studies of native mosquitoes in a Cambridgeshire Fen, investigating a) the habitat specificity and seasonal dynamics of our native fauna in an intensively managed wetland, b) the impact of water-level and ditch management, and c) their colonization of an arable reversion to flooded grassland wetland expansion project. Studies from April to October, 2010 collected 14,000 adult mosquitoes (15 species) over 292 trap-nights and ∼4,000 pre-imaginal mosquitoes (11 species). Open floodwater species (Aedes caspius and Aedes cinereus, 43.3%) and wet woodland species (Aedes cantans/annulipes and Aedes rusticus, 32.4%) dominated, highlighting the major impact of seasonal water-level management on mosquito populations in an intensively managed wetland. In permanent habitats, managing marginal ditch vegetation and ditch drying significantly affect densities of pre-imaginal anophelines and culicines, respectively. This study presents the first UK field evidence of the implications of wetland expansion through arable reversion on mosquito colonization. Understanding the heterogeneity of mosquito diversity, phenology, and abundance in intensively managed UK wetlands will be crucial to mitigating nuisance and vector species through habitat management and biocidal control.
© 2015 The Society for Vector Ecology.
Urban wetlands are being created in the UK as part of sustainable urban drainage strategies, to create wetland habitats lost during development, to provide a habitat for protected species, and to increase the public's access to ‘blue-space’ for the improvement of health and well-being. Sewage treatment reedbeds are also being incorporated into newly constructed wetlands to offer an alternative approach to dealing with sewage. This field study aims to provide the first UK evidence of how such newly constructed aquatic habitats are colonized by mosquitoes. A number of new aquatic habitats were surveyed for immature mosquitoes every fortnight over the first two years following wetland construction. The majority of mosquitoes collected were Culex sp. and were significantly associated with the sewage treatment reedbed system, particularly following storm events and sewage inflow. Other more natural aquatic habitats that were subject to cycles of drying and re-wetting contributed the majority of the remaining mosquitoes colonizing. Colonization of permanent habitats was slow, particularly where fluctuations in water levels inhibited emergent vegetation growth. It is recommended that during the planning process for newly constructed wetlands consideration is given on a case-by-case basis to the impact of mosquitoes, either as a cause of nuisance or as potential vectors. Although ornithophagic Culex dominated in this wetland, their potential role as enzootic West Nile virus vectors should not be overlooked.
The phlebotomine sand flies (Diptera: Psychodidae, Phlebotominae) are vectors of several infectious pathogens. The presence of a sand fly vector is considered to be a risk factor for the emergence of leishmaniasis in temperate Europe. Hence, the occurrence of phlebotomine sand flies and any changes in their distribution is important in determining the potential change in distribution of leishmaniasis in Europe. Therefore, published evidence for a changing distribution of the important phlebotomine sand fly vectors of leishmaniasis and phlebovirus infection in Europe is reviewed. This paper presents evidence of an increasing risk of establishment by sand fly species, especially for the Atlantic Coast and inland parts of Germany, Switzerland, and Austria. In addition to detection in potentially appropriate areas, the findings show areas of potential future establishment of the species. The most important and urgent necessity within the community of entomologists working on phlebotomines is the need to record the extremes of distribution of each species and obtain data on their regional presence/absence along with increased sharing of the data throughout European projects.
An understanding of how climate variables drive seasonal dynamics of mosquito populations is critical to mitigating negative impacts of potential outbreaks, including both nuisance effects and risk of mosquito-borne infectious disease. Here, we identify climate variables most affecting seasonal dynamics of two major floodwater mosquitoes, Aedes vexans (Meigen, 1830) and Aedes sticticus (Meigen, 1838) (Diptera: Culicidae), along the lower courses of the Dyje River, at the border between the Czech Republic and Austria. Monthly trap counts of both floodwater mosquitoes varied both across sites and years. Despite this variability, both models used to fit the observed data at all sites (and especially that for Ae. sticticus) and site-specific models fitted the observed data quite well. The most important climate variables we identified-temperature and especially flooding-were driving seasonal dynamics of both Aedes species. We suggest that flooding determines seasonal peaks in the monthly mosquito trap counts while temperature modulates seasonality in these counts. Hence, floodwater mosquitoes indeed appear worthy of their name. Moreover, the climate variables we considered for modeling were able reasonably to predict mosquito trap counts in the month ahead. Our study can help in planning flood management; timely notification of people, given that these mosquitoes are a real nuisance in this region; public health policy management to mitigate risk from such mosquito-borne diseases as that caused in humans by the Tahyna virus; and anticipating negative consequences of climate change, which are expected only to worsen unless floods, or the mosquitoes themselves, are satisfactorily managed.
This article aimed to review all literature on drought and vector-borne disease to enable an assessment of the possible impact of drought on the changing risk of vector-borne diseases in the UK.
A systematic literature review was performed.
Using a search strategy developed from a combination of terms for drought and selected outcomes, the authors systematically reviewed all available literature from 1990 to 2012 on the impact of drought on vector-borne diseases. The following databases were searched: PubMed, Web of Science, and EMBASE. After reviewing the abstracts, 38 articles were found to fit the inclusion and exclusion criteria.
Evidence found drought followed by re-wetting can have a substantial effect on water table levels, vegetation, and aquatic predators; all factors which influence mosquito populations. Several studies found an association between a drought during the previous year and West Nile virus incidence. Urban mosquito vectors of dengue virus and chikungunya virus are adaptable by nature and are able to exploit a multitude of additional aquatic habitats created as a response to drought (i.e. water storage containers). Tick populations are likely to be negatively affected by drought as they are dependent upon high levels of humidity and soil moisture.
Further research is needed to identify public health interventions and environmental control measures for an invasive mosquito problem or arthropod-borne disease outbreak in the UK.
Coastal realignment is now widely instituted in the UK as part of local flood risk management plans to compensate for the loss of European protected habitat and to mitigate the effects of sea-level rise and coastal squeeze. Coastal aquatic habitats have long been known to provide suitable habitats for brackish-water mosquitoes and historically, coastal marshes were considered to support anopheline mosquito populations that were responsible for local malaria transmission. This study surveyed the eight largest managed realignment (MRA) sites in England (Essex and the Humber) for mosquito habitats. The apparent absence of anopheline mosquitoes exploiting aquatic habitats at all of these sites suggests that the risk of malaria associated with MRA sites is currently negligible. However, three of the eight sites supported populations of two nuisance and potential arboviral vector species, Aedes detritus and Aedes caspius. The aquatic habitats that supported mosquitoes resulted from a) specific design aspects of the new sea wall (ballast to mitigate wave action and constructed saline borrow ditches) that could be designed out or managed or b) isolated pools created through silt accretion or expansion of flooded zones to neighbouring pasture. The public health risks and recommendations for management are discussed in this report. This report highlights the need for pro-active public health impact assessments prior to MRA development in consultation with the Health Protection Agency, as well as the need for a case-by-case approach to design and management to mitigate mosquito or mosquito-borne disease issues now and in the future.
There are currently five invasive Aedes mosquito species known to be established in Europe, namely Aedes albopictus, Aedes aegypti, Aedes japonicus, Aedes atropalpus and Aedes koreicus. Aedes albopictus and Aedes aegypti are the incriminated vectors in the recent outbreaks of chikungunya and dengue fever in Europe. However, both laboratory experiments and field observations indicate that these invasive mosquitoes have a potential to also transmit other pathogens of public health importance. Increasing travel and pathogen introduction, expansion of vector distribution, and both environmental and climatic changes are likely to raise the risk of pathogen transmission by these invasive Aedes mosquitoes. Their vector status and their involvement in pathogen transmission are dynamic processes that shape the future of mosquito-borne disease epidemiology in Europe. Beside vector surveillance, enhanced disease surveillance will enable the early detection of cases and the prompt implementation of control measures.
This paper presents preliminary findings towards developing a UK-specific approach to reducing public exposure to woodland questing Ixodes ricinus tick populations by harnessing existing biodiversity-enhancing woodland ride (i.e., linear non-wooded herbaceous habitat either side of track within woodland) management strategies. This preliminary study in an English woodland firstly assesses whether ecological and environmental factors determine presence and density of questing Ixodes ricinus along woodland rides. Secondly, it sets these findings in the context of woodland ride management guidelines in England in order to understand what impact ride management strategies might have on numbers of questing ticks and tick survival. Nymph and adult I. ricinus presence and abundance were modelled in relation to relevant microclimate and ecological parameter variables. Predictor variables for increased questing nymph abundance included ride orientation, mat depth, occurrence of bracken/bramble and animal tracks, ride/path width, and sward height. Ticks thrive in the ecotonal habitat of a woodland ride, therefore we urge woodland managers to consider the impact of their ride management on ticks and human exposure to ticks. Possible recommendations for mitigating questing I. ricinus in line with biodiversity management guidelines rides are discussed in this paper and include seasonal mowing regimes, management of mulch/mat, and bracken/bramble management through use of scalloped ride edges.
Port health authorities have played an important role in the control of infectious diseases worldwide. The International Health Regulations (2005) further clarifies this role and provides a legal statutory instrument that aims to assist the international community to prevent and respond to global public health risks. Eleven UK sea and airports participated in a pilot, investigating the challenges ports could face in attempting to monitor for mosquitoes. The study also examined the types of habitat that could support mosquitoes. There is a concern that exotic vector species, such as Aedes albopictus, could invade and become established in the UK. Environments in and around the ports differed, and this was reflected in the species of mosquitoes caught. Ports used different methods to collect mosquitoes and developed a range of techniques for surveying, which suited the conditions at their port. This paper discusses the implications of invasive mosquito surveillance to UK port health authorities.
During the last decades the disease vector Aedes albopictus (Ae. albopictus) has rapidly spread around the globe. The spread of this species raises serious public health concerns. Here, we model the present distribution and the future climatic suitability of Europe for this vector in the face of climate change. In order to achieve the most realistic current prediction and future projection, we compare the performance of four different modelling approaches, differentiated by the selection of climate variables (based on expert knowledge vs. statistical criteria) and by the geographical range of presence records (native range vs. global range).