ArticleLiterature Review

Impact of climate change on vector-borne disease in the UK

Authors:
  • UK Health Security Agency
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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.

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... Ongoing climate change is anticipated to further extend the latitudinal range Ae. aegypti mosquitoes, increasing the population at risk of dengue in several African countries in Southern and Central Africa [24]. Similar increases in climatically suitable areas for the establishment of Ae. albopictus are anticipated in western, central and eastern Europe, including in southeast England, with increasing risk for dengue transmission around Mediterranean and Adriatic coasts towards the end of twenty-first century [32,33]. In China, there has been a trend of expanded geographical region for dengue infections, from South to North China in line with warming temperatures [39] and expansion of the geographic range of Ae. albopictus [36]. ...
... In China, in the absence of preventive measures, climate change is anticipated to increase the geographical range of local malaria vectors and the incidence of malaria in some regions [39]. In Europe, studies have predicted a northward spread of Anopheles mosquitoes and an extension of seasonality, enabling malaria transmission for up to 6 months per year in the years 2051-2080, particularly in Southern and South-Eastern European [15], while in the UK, southern Great Britain is predicted to be climatically suitable for Plasmodium vivax malaria transmission 2 months of the year by 2030 and for 4 months in parts of southeast England; by 2080, southern Scotland will be climatically suitable for malaria transmission for 2 months per years, with 4 months of the year conducive to malaria transmission in southern Great Britain [33]. In some areas that currently sustain year-round malaria transmission, climate change may result in a contraction of the malaria transmission season or geographic range. ...
... Bai et al. points to the additional need to focus adaptation strategies and policies on vulnerable communities while strengthening the capacity of public health system to adapt to climate change [36]. As noted by several studies, new vector control strategies, such as wetland management and integrated vector management (IVM), will be needed, despite the challenges of funding and intersectoral cooperation [17,30,33]. ...
Article
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Background Climate change is expected to alter the global footprint of many infectious diseases, particularly vector-borne diseases such as malaria and dengue. Knowledge of the range and geographical context of expected climate change impacts on disease transmission and spread, combined with knowledge of effective adaptation strategies and responses, can help to identify gaps and best practices to mitigate future health impacts. To investigate the types of evidence for impacts of climate change on two major mosquito-borne diseases of global health importance, malaria and dengue, and to identify the range of relevant policy responses and adaptation strategies that have been devised, we performed a scoping review of published review literature. Three electronic databases (PubMed, Scopus and Epistemonikos) were systematically searched for relevant published reviews. Inclusion criteria were: reviews with a systematic search, from 2007 to 2020, in English or French, that addressed climate change impacts and/or adaptation strategies related to malaria and/or dengue. Data extracted included: characteristics of the article, type of review, disease(s) of focus, geographic focus, and nature of the evidence. The evidence was summarized to identify and compare regional evidence for climate change impacts and adaptation measures. Results A total of 32 reviews met the inclusion criteria. Evidence for the impacts of climate change (including climate variability) on dengue was greatest in the Southeast Asian region, while evidence for the impacts of climate change on malaria was greatest in the African region, particularly in highland areas. Few reviews explicitly addressed the implementation of adaptation strategies to address climate change-driven disease transmission, however suggested strategies included enhanced surveillance, early warning systems, predictive models and enhanced vector control. Conclusions There is strong evidence for the impacts of climate change, including climate variability, on the transmission and future spread of malaria and dengue, two of the most globally important vector-borne diseases. Further efforts are needed to develop multi-sectoral climate change adaptation strategies to enhance the capacity and resilience of health systems and communities, especially in regions with predicted climatic suitability for future emergence and re-emergence of malaria and dengue. This scoping review may serve as a useful precursor to inform future systematic reviews of the primary literature.
... Emergence can be caused by several mechanisms, for example the evolution of an existing organism, the spreading of a new agent, the recognition of a previously present but undetected infection, the realisation that an established disease has an infectious origin or by the reemergence of a known infection after a decline in incidence (150). EIDs include vector-borne diseases where the infectious agent is transmitted by arthropod vectors such as ticks or mosquitos (101). The transmission cycles of vector-borne agents are often complex and involve one or more arthropod vector species and several wild animal hosts (101). ...
... EIDs include vector-borne diseases where the infectious agent is transmitted by arthropod vectors such as ticks or mosquitos (101). The transmission cycles of vector-borne agents are often complex and involve one or more arthropod vector species and several wild animal hosts (101). Climate change affects EIDs in many ways. ...
... Even if vector-borne disease agents can be found in blood, they are not classified among other blood-borne diseases like HIV. Transmission generally does not occur by direct blood contact, but rather through a vector, such as a tick or a mosquito (101). Consequently, the fauna of vector-borne diseases will vary geographically depending on vector species distribution and competency (15,83). ...
Thesis
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Neoehrlichia mikurensis is an emerging tick-borne human pathogen, causing neoehrlichiosis in immunosuppressed and immunocompetent individuals. It targets the vascular endothelium, leading to thromboembolic and vascular events, but can also pass without symptoms. As symptoms easily are misinterpreted, immunosuppressive treatment or chemotherapy is often incorrectly initiated. Diagnostic delay can be considerable. The overall aim of this thesis was to gain a better understanding on N. mikurensis in Sweden, focusing on human infections and public health aspects. The prevalence of N. mikurensis in different populations was examined. The symptomatology of neoehrlichiosis and the risk of transfusion-mediated transmission was studied. N. mikurensis was observed in low prevalences in ticks collected from migratory birds, in tick-bitten individuals, in patients with persistent symptoms attributed to presumed tick-bite exposure, and in blood donors. Fourteen N. mikurensis-positive individuals were identified. The majority were immunocompetent and asymptomatic. Both spontaneous clearance and persistence was observed. Two of 102 tick-bitten individuals were N. mikurensis-positive. Both presented with erythema migrans, but borreliosis was a more probable cause in both. The findings do not support a change in practice regarding first-line treatment of erythema migrans, but further studies are warranted. Persistence of N. mikurensis in blood raises questions regarding the possibility of transmission by transfusion and the risk of activating the infection if immune status is altered. N. mikurensis was identified in seven out of 1 006 blood donors. Look-back and tracing identified 12 recipients who were transfused with blood components from N. mikurensis-positive donors. Several recipients had multiple risk factors for severe neoehrlichiosis, but transfusion-transmitted neoehrlichiosis was not detected. Nevertheless, the possibility that N. mikurensis can be transmitted by transfusion cannot be excluded. Isolates from birds and blood donors were identical to previously reported Swedish human isolates. Migrating birds can act as dispersal vectors of N. mikurensis, but their role as transmission hosts is still unclear. The disease burden and public health impact of neoehrlichiosis is probably small, but information is lacking in several areas. Suspicion of neoehrlichiosis is warranted in immunocompromised and/or splenectomised patients with persistent fever, with or without thromboembolic and vascular events. Furthermore, neoehrlichiosis should be included in the differential diagnosis of anaplasmosis. Besides raised awareness, a possible mandatory notification is proposed as well as a comprehensive surveillance system for transfusiontransmitted infections. One of the priority issues is the possible need for screening of patients living in N. mikurensis-endemic areas before and during immunosuppressive treatment. http://uu.diva-portal.org/smash/record.jsf?pid=diva2%3A1678245&dswid=-4836
... A recent report by the US Centers for Disease Control and Prevention (CDC) found that tick-borne diseases in the USA had more than doubled over a period of 13 years (> 22,000 cases in 2004 to > 48,000 cases in 2016) with Lyme borreliosis accounting for 82% of all tick-borne disease reports [2]. The incidence of Lyme borreliosis and other tick-borne diseases is also increasing in Europe and Canada [3][4][5][6][7][8]. The explanation for this increased incidence of tick-borne disease is multi-factorial [9] and includes climate change [7,8], changes in human land use [10,11] and even socio-economic changes [12][13][14]. ...
... The incidence of Lyme borreliosis and other tick-borne diseases is also increasing in Europe and Canada [3][4][5][6][7][8]. The explanation for this increased incidence of tick-borne disease is multi-factorial [9] and includes climate change [7,8], changes in human land use [10,11] and even socio-economic changes [12][13][14]. ...
... The beech mast score 2 years prior had a positive and significant effect on the DIN (slope = 0.067 per class; 95%CI = 0.029 to 0.105; Figs. 8,9). Increasing the beech mast score 2 years prior from 1 (poor mast) to 5 (full mast) increased the DIN by 85.5% at each of the four elevation sites on Chaumont Mountain (Fig. 9). ...
Article
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Background The incidence of Lyme borreliosis and other tick-borne diseases is increasing in Europe and North America. There is currently much interest in identifying the ecological factors that determine the density of infected ticks as this variable determines the risk of Lyme borreliosis to vertebrate hosts, including humans. Lyme borreliosis is caused by the bacterium Borrelia burgdorferi sensu lato (s.l.) and in western Europe, the hard tick Ixodes ricinus is the most important vector. Methods Over a 15-year period (2004–2018), we monitored the monthly abundance of I. ricinus ticks (nymphs and adults) and their B. burgdorferi s.l. infection status at four different elevations on a mountain in western Switzerland. We collected climate variables in the field and from nearby weather stations. We obtained data on beech tree seed production (masting) from the literature, as the abundance of Ixodes nymphs can increase dramatically 2 years after a masting event. We used generalized linear mixed effects models and AIC-based model selection to identify the ecological factors that influence inter-annual variation in the nymphal infection prevalence (NIP) and the density of infected nymphs (DIN). Results We found that the NIP decreased by 78% over the study period. Inter-annual variation in the NIP was explained by the mean precipitation in the present year, and the duration that the DNA extraction was stored in the freezer prior to pathogen detection. The DIN decreased over the study period at all four elevation sites, and the decrease was significant at the top elevation. Inter-annual variation in the DIN was best explained by elevation site, year, beech tree masting index 2 years prior and the mean relative humidity in the present year. This is the first study in Europe to demonstrate that seed production by deciduous trees influences the density of nymphs infected with B. burgdorferi s.l. and hence the risk of Lyme borreliosis. Conclusions Public health officials in Europe should be aware that masting by deciduous trees is an important predictor of the risk of Lyme borreliosis.
... Environmental changes, anthropic behaviour, and animal movements in Europe over the past 20 years have led to increased threats from a range of zoonotic viral, bacterial and protozoal vector-borne diseases [1]. During the same timeframe, there has also been an emergence of conditions caused by various vector-transmitted nematodes, for which dogs and other carnivores act as reservoirs of zoonotic infection [1][2][3]. ...
... Environmental changes, anthropic behaviour, and animal movements in Europe over the past 20 years have led to increased threats from a range of zoonotic viral, bacterial and protozoal vector-borne diseases [1]. During the same timeframe, there has also been an emergence of conditions caused by various vector-transmitted nematodes, for which dogs and other carnivores act as reservoirs of zoonotic infection [1][2][3]. The movement of domestic dogs plays an important role in the epidemiology of this type of vector-borne disease, as seen, for example, with mosquito-transmitted Dirofilaria spp. ...
Article
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Background Onchocerca lupi is a filarial nematode affecting dogs, and occasionally cats and humans, in continental Europe, North Africa, the Middle East, and the USA. Adult worms are usually found in periocular nodules and enucleation is sometimes required if the infection fails to respond to other treatment options. Case presentation Here, we report the presence of O. lupi in the UK for the first time. Of two dogs re-homed from continental Europe, one developed an ocular nodule seven years after arrival from Portugal. The conjunctival perilimbal mass in its left eye was surgically removed but despite anthelminthic treatment, a further nodule developed in the same eye six months later. In the second case - a dog imported from Romania 12 months earlier - a perilimbal mass was excised from the left eye and prior anthelminthic treatment was supplemented with oral prednisolone and doxycycline. However, nodules recurred, and the left globe was subsequently enucleated. Conjunctival hyperaemia then appeared in the right eye and neither additional anthelminthic treatment nor removal of worm masses failed to prevent the further development of lesions. Excised adult worms were identified in both cases as O. lupi based on morphological characteristics, as well as PCR and sequencing of cytochrome c oxidase subunit I and 12S rRNA gene fragments. Conclusion O. lupi parasitosis can apparently remain cryptic in dogs for several years before any clinical signs manifest. Moreover, the progression of infection can be highly aggressive and recalcitrant to both surgical intervention and anthelminthic treatment. Increasingly, former stray dogs of unknown infection status are entering the UK, raising both veterinary and public health concerns.
... Two studies 52,53 also reported that contact with floodwater in conjunction with higher than normal temperatures was a risk factor for developing a water-borne disease. Alterations in temperatures can impact the ways pathogens and vectors behave in the environment, yielding implications from rising global temperatures 38,54,54 . Alterations in temperature and precipitation may also occur in conjunction with population growth and urban expansion, with east and south east Asia seeing the highest rates of urbanisation 56 . ...
... Two studies 52,53 also reported that contact with floodwater in conjunction with higher than normal temperatures was a risk factor for developing a water-borne disease. Alterations in temperatures can impact the ways pathogens and vectors behave in the environment, yielding implications from rising global temperatures 38,54,54 . Alterations in temperature and precipitation may also occur in conjunction with population growth and urban expansion, with east and south east Asia seeing the highest rates of urbanisation 56 . ...
Article
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Infectious disease outbreaks are increasingly recognised as events that exacerbate impacts or prolong recovery following disasters. Yet, our understanding of the frequency, geography, characteristics and risk factors of post-disaster disease outbreaks globally is lacking. This limits the extent to which disease outbreak risks can be prepared for, monitored and responded to following disasters. Here, we conducted a global systematic review of post-disaster outbreaks and found that outbreaks linked to conflicts and hydrological events were most frequently reported, and most often caused by bacterial and water-borne agents. Lack of adequate WASH facilities and poor housing were commonly reported risk factors. Displacement, through infrastructure damage, can lead to risk cascades for disease outbreaks; however, displacement can also be an opportunity to remove people from danger and ultimately protect health. The results shed new light on post-disaster disease outbreaks and their risks. Understanding these risk factors and cascades, could help improve future region-specific disaster risk reduction.
... A changing environment Climate change brings warmer temperatures, increasing mosquito metabolic rates and causing them to develop faster [23]. This, combined with a shorter generation internal, faster bloodmeal digestion and a longer mosquito season can lead to higher abundances [24]. Higher temperatures also lead to the establishment of new mosquito species (and consequently new viruses) not previously found in the Netherlands, as the climate becomes more favourable to them [25]. ...
... ).Replication and dissemination cycles completed ability of breeding sites[24]. Urban and natural areas are growing while rural areas are shrinking[27]. This affects all sorts of wildlife, potentially leading them to new habitats and increasing host-vector interactions. ...
Article
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Emerging pathogens pose an important threat to human and animal health. A large proportion of emerging diseases are transmitted by vectors. Recent examples such as Schmallenberg disease, tick-borne encephalitis, Usutu, and West Nile Fever have shown that Dutch livestock, wildlife, and human populations are at risk of outbreaks of emerging vector-borne diseases. Pathogen spillover to new host populations can be the starting point of emergence, but for this to occur, favourable conditions for host, vector, and virus need to align in space and time. The circumstances enabling disease emergence are constantly shifting due to global and local changes for example in human demographics, land use, international travel, and climate. Given the clear interplay between human, animal, and environmental health, it is crucial to approach the challenge of emerging vector-borne diseases with a One Health perspective. Within the One Health PACT (Predicting Arbovirus Climate Tipping points) research consortium we follow an integrated approach measuring and modelling how projected changes will impact the risk of emergence of arboviruses in the Netherlands, and translating this understanding into effective, integrated outbreak preparedness and response actions.
... In southern Africa, disease outbreaks are highly prevalent at endemic levels. The proliferation of VBDs and concerns about global climate change have given rise to questions about their potential relationship (Medlock & Leach 2015;Servadio et al. 2018;WHO 2014a). The diseases are sensitive to climatic conditions in different ways. ...
... Servadio et al. (2018) state that mosquito-borne disease outbreaks occur with the highest frequency compared to other VBDs. Common diseases transmitted by mosquitoes include Chikungunya, malaria and dengue (Medlock & Leach 2015;Parham, Waldock & Christophides 2015;WHO 2014), which are getting widespread attention from researchers and medical practitioners. One of these diseases, malaria, is of great concern as it is common in economically depressed regions and contributes significantly to the failure of these regions to meet SDGs. ...
Article
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This study used a mixed-methods research design to examine the sensitivity of vector-borne disease (VBD) patterns to the changes in rainfall and temperature trends. The research focused on malaria in Masvingo Province, Zimbabwe. The study interfaced the climate action, health and sustainable cities and communities with sustainable development goals (SDGs). Historical climate and epidemiological data were used to compute the correlations and determine the possible modifications of disease patterns. Clustered random and chain-referral sampling approaches were used to select study sites and respondents. Primary data were gathered through a questionnaire survey (n = 191), interviews and focus group discussions, with Mann–Kendal trend tests performed using XLSTAT 2020. The results show a positive correlation between malaria prevalence rates and temperature-related variables. A decline in precipitation-related variables, specifically mean monthly precipitation (MMP), was associated with an increase in malaria prevalence. These observations were confirmed by the views of the respondents, which show that climate change has a bearing on malaria spatial and temporal dynamics in Masvingo Province. The study concludes that climate change plays a contributory role in VBD dynamics, thereby impeding the attainment of the 2030 Agenda for Sustainable Development, especially SDG 3, which deals with health. The study recommends further research into appropriate adaptation mechanisms to increase the resilience of rural and urban communities against the negative transmutations associated with weather and climatic pressures.
... Urban green space including parks can provide refuge for wildlife, which in turn, can support tick populations that may present a public health risk from transmission of tickborne pathogens (Rizzoli et al. 2014;Uspensky 2014). The growing evidence of ticks infected with pathogens in urban green space (Grochowska et al. 2020) and the possibility of subsequent disease transmission needs consideration when planning the expansion or management of such spaces for climate change adaptation (Medlock and Leach 2015) and health and wellbeing strategies (Lovell et al. 2018). This is particularly important to consider in areas with high footfall and lack of knowledge of tick-borne disease risk (Bayles et al. 2013). ...
Article
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Assessing the risk of tick-borne disease in areas with high visitor numbers is important from a public health perspective. Evidence suggests that tick presence, density, infection prevalence and the density of infected ticks can vary between habitats within urban green space, suggesting that the risk of Lyme borreliosis transmission can also vary. This study assessed nymph density, Borrelia prevalence and the density of infected nymphs across a range of habitat types in nine parks in London which receive millions of visitors each year. Ixodes ricinus were found in only two of the nine locations sampled, and here they were found in all types of habitat surveyed. Established I. ricinus populations were identified in the two largest parks, both of which had resident free-roaming deer populations. Highest densities of nymphs (15.68 per 100 m2) and infected nymphs (1.22 per 100 m2) were associated with woodland and under canopy habitats in Richmond Park, but ticks infected with Borrelia were found across all habitat types surveyed. Nymphs infected with Borrelia (7.9%) were only reported from Richmond Park, where Borrelia burgdorferi sensu stricto and Borrelia afzelii were identified as the dominant genospecies. Areas with short grass appeared to be less suitable for ticks and maintaining short grass in high footfall areas could be a good strategy for reducing the risk of Lyme borreliosis transmission to humans in such settings. In areas where this would create conflict with existing practices which aim to improve and/or meet historic landscape, biodiversity and public access goals, promoting public health awareness of tick-borne disease risks could also be utilised.
... The incidence of tick-borne diseases is increasing in Europe and North America [1][2][3][4][5][6][7]. In large parts of Europe, the hard tick Ixodes ricinus is an important vector of tick-borne diseases including Lyme borreliosis and tick-borne encephalitis [8,9]. ...
Article
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Background: The tick Ixodes ricinus is an important vector of tick-borne diseases including Lyme borreliosis. In continental Europe, the nymphal stage of I. ricinus often has a bimodal phenology with a large spring peak and a smaller fall peak. There is consensus about the origin of the spring nymphal peak, but there are two alternative hypotheses for the fall nymphal peak. In the direct development hypothesis, larvae quest as nymphs in the fall of the same year that they obtained their larval blood meal. In the developmental diapause hypothesis, larvae overwinter in the engorged state and quest as nymphs one year after they obtained their larval blood meal. These two hypotheses make different predictions about the time lags that separate the larval blood meal and the density of questing nymphs (DON) in the spring and fall. Methods: Inter-annual variation in seed production (masting) by deciduous trees is a time-lagged index for the density of vertebrate hosts (e.g., rodents) which provide blood meals for larval ticks. We used a long-term data set on the masting of the European beech tree and a 15-year study on the DON at 4 different elevation sites in western Switzerland to differentiate between the two alternative hypotheses for the origin of the fall nymphal peak. Results: Questing I. ricinus nymphs had a bimodal phenology at the three lower elevation sites, but a unimodal phenology at the top elevation site. At the lower elevation sites, the DON in the fall was strongly correlated with the DON in the spring of the following year. The inter-annual variation in the densities of I. ricinus nymphs in the fall and spring was best explained by a 1-year versus a 2-year time lag with the beech tree masting index. Fall nymphs had higher fat content than spring nymphs indicating that they were younger. All these observations are consistent with the direct development hypothesis for the fall peak of I. ricinus nymphs at our study site. Our study provides new insight into the complex bimodal phenology of this important disease vector. Conclusions: Public health officials in Europe should be aware that following a strong mast year, the DON will increase 1 year later in the fall and 2 years later in the spring. Studies of I. ricinus populations with a bimodal phenology should consider that the spring and fall peak in the same calendar year represent different generations of ticks.
... As highlighted by many authors, progressing climate changes are the cause of changes in the number and range of many animal species, including ticks 22,30,31 . The increase in the number of local populations of these arthropods observed in recent years in many European countries, e.g. in the Baltic states 32 , Poland [19][20][21]33 , and Germany 34,35 , or the emergence of new species of ticks in areas previously considered tick-free 36,37 contributes to an increase in the epidemic threat and the risk of transmission of new or sporadically existing tick-borne pathogens 38,39 . ...
Article
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Dermacentor reticulatus ticks are one of the most important vectors and reservoirs of tick-borne pathogens in Europe. Changes in the abundance and range of this species have been observed in the last decade and these ticks are collected in areas previously considered tick-free. This may be influenced by progressive climate change. Eastern Poland is an area where the local population of D. reticulatus is one of the most numerous among those described so far. At the same time, the region is characterized by a significant increase in the mean air temperature in recent years (by 1.81 °C in 2020) and a decrease in the average number of days with snow cover (by 64 days in 2020) and in the number of days with frost (by 20 days in 2020) on an annual basis compared to the long-term average. The aim of our research was to investigate the rhythms of seasonal activity and the population size of D. reticulatus in the era of progressive climate change. To this end, questing ticks were collected in 2017-2020. Next, the weather conditions in the years of observation were analyzed and compared with multi-year data covering 30 years preceding the study. The research results show that, in eastern Poland, there is a stable population of D. reticulatus with the peak of activity in spring or autumn (up to a maximum of 359 individuals within 30 min of collection) depending on the year of observation. Ticks of this species may also be active in winter months. The activity of D. reticulatus is influenced by a saturation deficit.
... Studies showed that though risks from vector-borne diseases are intrinsically susceptible to changes in weather and climate (18,19), the controversies around impacts of climate change on them focuses on the level to which weather and climate affect their occurrence and intensity vs. human's efforts to control pathogens and their vectors (20). On the other hand, several vector-borne diseases of public health importance are zoonotic being maintained by wildlife, and their occurrence is intrinsically less influenced by man's control efforts (21). ...
Article
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Vector-borne emerging and re-emerging diseases pose considerable public health problem worldwide. Some of these diseases are emerging and/or re-emerging at increasing rates and appeared in new regions in the past two decades. Studies emphasized that the interactions among pathogens, hosts, and the environment play a key role for the emergence or re-emergence of these diseases. Furthermore, social and demographic factors such as human population growth, urbanization, globalization, trade exchange and travel and close interactions with livestock have significantly been linked with the emergence and/or re-emergence of vector-borne diseases. Other studies emphasize the ongoing evolution of pathogens, proliferation of reservoir populations, and antimicrobial drug use to be the principal exacerbating forces for emergence and re-emergence of vector-borne infectious diseases. Still other studies equivocally claim that climate change has been associated with appearance and resurgence of vector-borne infectious diseases. Despite the fact that many important emerging and re-emerging vector-borne infectious diseases are becoming better controlled, our success in stopping the many new appearing and resurging vector-borne infectious diseases that may happen in the future seems to be uncertain. Hence, this paper reviews and synthesizes the existing literature to explore global patterns of emerging and re-emerging vector-borne infections and the challenges for their control. It also attempts to give insights to the epidemiological profile of major vector-borne diseases including Zika fever, dengue, West Nile fever, Crimean-Congo hemorrhagic fever, Chikungunya, Yellow fever, and Rift Valley fever.
... On the other hand, tick density varies from year to year, as does the proportion of ticks infected with Borrelia. Other climatic and ecological factors may also play a role and have been previously discussed in several reports and studies [31][32][33]. In our study, we additionally showed that seasonal variations in LB correlate strongly with those of TBE, the second most common tick-borne disease. ...
Article
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Lyme borreliosis (LB) is the most common tick-borne disease in Germany. Mandatory notification of acute LB manifestations (erythema migrans (EM), neuroborreliosis (NB), and Lyme arthritis (LA)) was implemented in Bavaria on 1 March 2013. We aimed to describe the epidemiological situation and to identify LB risk areas and populations. Therefore, we analyzed LB cases notified from March 2013 to December 2020 and calculated incidence (cases/100,000 inhabitants) by time, place, and person. Overall, 35,458 cases were reported during the study period (EM: 96.7%; NB: 1.7%; LA: 1.8%). The average incidence was 34.3/100,000, but annual incidence varied substantially (2015: 23.2; 2020: 47.4). Marked regional differences at the district level were observed (annual average incidence range: 4–154/100,000). The Bavarian Forest and parts of Franconia were identified as high-risk regions. Additionally, high risk for LB was found in 5–9-year-old males and in 60–69-year-old females. The first group also had the highest risk of a severe disease course. We were able to identify areas and populations in Bavaria with an increased LB risk, thereby providing a basis for targeted measures to prevent LB. Since LB vaccination is currently not available, such measures should comprise (i) avoiding tick bites, (ii) removing ticks rapidly after a bite, and (iii) treating LB early/adequately.
... Additionally, malarial parasites undergo a development phase in the mosquito. Therefore, mosquito average abundance and climate factors are important determinants of malaria transmission [8,9]. ...
Article
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Malaria is a vector-borne disease transmitted by Anopheline mosquitoes. In Korea, Plasmodium vivax malaria is an endemic disease and the main vector is Anopheles sinensis . Plasmodium vivax malaria is common in the northwestern part of South Korea, including in the city of Goyang in regions near the demilitarized zone. This study aimed to identify the best time-series model for predicting mosquito average abundance in Goyang, Korea. Mosquito data were obtained from the Mosquito Surveillance Program of the Goyang Ilsanseogu Public Health Center for the period 2008–2012. Black light traps were set up periodically in a park, a senior community center, and a village community center, public health center, drainage pumping station, cactus research center, restaurant near forest, in which many activities occur at night. In total, 9,512 female mosquitoes were collected at 12 permanent trapping sites during the mosquito season in the study period. Weekly An . sinensis average abundance was positively correlated with minimum grass temperature ( r = 0.694, p < 0.001), precipitation ( r = 0.326, p = 0.001). The results showed that seasonal autoregressive integrated moving average (SARIMA) (1,0,0)(0,0,1) 21 with minimum grass temperature variable at time lag0 weeks and the precipitation variable at time lag1 weeks provided that best model of mosquito average abundance. The multivariate model accounted for about 54.1% of the mosquito average abundance variation. Time-series analysis of mosquito average abundance and climate factors provided basic information for predicting the occurrence of malaria mosquitoes.
... For instance, Aedes vexans vexans, Ochlerotatus caspius, and Culex pipiens have a known distribution in the United Kingdom [2,23]. From a disease exposure point of view, continued vector importation events from RVF-affected countries, in combination with climatic and environmental changes, could increase the likelihood of the disease vectors being established and adapted to new environments [27]. Additionally, climatic, environmental, and genetic changes could result in changes in competence and capacity (i.e., external factors such as number and lifespan of the vector, feeding preferences of the host) of local (European) potential vectors [23], enabling them to transmit the virus once infected. ...
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Abstract: (1): Rift Valley Fever (RVF) is a zoonotic disease of significant international health concern and considered as an emerging risk to Europe, where no RVF outbreaks in humans or animals have been reported so far. (2): Using a stochastic approach, we estimated the risk of RVF virus (RVFV) introduction during the period of May to October (the period when mosquito populations, including RVFV potential vectors, are present in European countries), into previously unaffected areas (e.g., United Kingdom, UK) via virus-carrying vectors traveling in commercial aircraft from RVF-affected countries (e.g., East Africa); (3): On average N = 68 (95% CI: 0–337), RVF-virus-infected mosquitoes are estimated to be mechanically transported by planes (with N = 0 as most likely), in direct flights from RVF-affected East African countries to the UK, between May and October. This estimate is considered as low but not negligible. The model developed should be easily scaled up to other European countries by amending appropriately country-specific variables (e.g., number of flights between countries) in order to map the areas/airports of higher risk and inform risk management per country accordingly and to adopt risk-mitigation measures.
... They are vectors of many human and animal infectious pathogens, such as tick-borne encephalitis, Crimean-Congo hemorrhagic fever, Lyme disease, Q fever, babesiosis, and severe fever with thrombocytopenia syndrome [1][2][3]. Currently, tick-borne diseases have become an increasing public health threat with global climate changing, accelerated urbanization, and altered distribution of tick and their hosts [4][5][6]. ...
Article
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Dermacentor silvarum is an obligate blood sucking arthropod and transmits various pathogens to humans and domestic animals. Recently several new viruses were detected in D. silvarum as an emerging disease threat. In this study, we aimed to analyze its geographical distribution and associated pathogens. Data were collected from multiple sources, including a field survey, reference book, and literature review. We searched various electronic databases with the terms “Dermacentor silvarum” OR “D. silvarum” for studies published since 1963 and the positive rates for Dermacentor silvarum-associated pathogens were estimated by meta-analysis. D. silvarum was found only in four countries in Eurasia, ranging from 22° N to 57° N latitude. At least 20 human pathogens were associated with D. silvarum, including five species of spotted fever group rickettsiae, three species in the family of Anaplasmataceae, three genospecies in the complex Borrelia burgdorferi sensu lato, Francisella tularensis, Babesia venatorum, Coxiella buenetii, Borrelia miyamotoi, and five species of virus. Among them, Rickettsia raoultii was widely detected in D. silvarum, showing the highest pooled positive rate (25.15%; 95% CI 13.31–39.27). Our work presents the most comprehensive data and analysis (to our knowledge) for the geographical distribution of D. silvarum and associated pathogens, revealing an emerging threat to public health and stocking farming. Continued surveillance and further investigations should be enhanced.
... As the climate changes, the risk of ticks, and therefore tick-borne disease, may further increase on upland farms. Shifts in tick distribution to higher altitudes and latitudes have been predicted by other European models (Williams et al., 2015), and empirical evidence for these shifts have also been recorded in some countries (Medlock and Leach, 2015), such as Sweden (Lindgren et al., 2000) and Norway (Jore et al., 2014). These changes are likely to be driven by interactions between region and the climatic conditions which limit I. ricinus survival, with future higher temperatures at higher altitudes and latitudes, where low temperatures are currently the limiting factor in tick survival, and larger saturation deficits at lower latitudes, where low summer humidity currently limits I. ricinus survival (Jenkins et al., 2009;Pfäffle et al., 2013). ...
Article
The most abundant tick species in northern Europe, Ixodes ricinus, transmits a range of pathogens that cause disease in livestock. As I. ricinus distribution is influenced by climate, tick-borne disease risk is expected to change in the future. The aims of this work were to build a spatial model to predict current and future risk of ticks on livestock farms across Britain. Variables relating both to tick hazard and livestock exposure were included, to capture a niche which may be missed by broader scale models. A random forest machine learning model was used due to its ability to cope with correlated variables and interactions. Data on tick presence and absence on sheep and cattle farms was obtained from a retrospective questionnaire survey of 926 farmers. The ROC of the final model was 0.80. The model outputs matched observed patterns of tick distribution, with areas of highest tick risk in southwest and northwest England, Wales, and west Scotland. Overall, the probability of tick presence on livestock farms was predicted to increase by 5-7% across Britain under future climate scenarios. The predicted increase is greater at higher altitudes and latitudes, further increasing the risk of tick-borne disease on farms in these areas.
... There was no difference between male and female and no difference with adults and the other age groups. (Lawrence & Waniwa, 2020), which most likely exposed cattle to reservoir hosts, ticks and bovine theileriosis (Abdela & Bekele, 2016 the region but its proximity to the main highway and the presence of a good road network which creates new opportunities for invasive vectors (Medlock & Leach, 2015). The trade of live animals can be a significant factor in the dissemination of disease. ...
Article
Bovine theileriosis (caused by Theileria parva) is the most important tick‐borne transboundary animal disease endemic to Zimbabwe, yet, its distribution dynamics data in the country remain scant and outdated. A retrospective study was conducted to determine high‐risk areas of bovine theileriosis and associated risk factors in Zimbabwe. Records on bovine theileriosis spanning 23 years (January 1995 to December 2018) were obtained from the Epidemiological Unit of the Division of Field Veterinary Services of Zimbabwe (DVSZ). Data was analyzed using Studio R® version 11.0 for regression analysis and SatScan® version 9.4.6 for spatiotemporal clustering. Communal farmers (72 %), adult cattle (29%), the year 2018 (60%) and the hot wet season (42%) had the highest proportion (P < 0.05) of bovine theileriosis cases recorded. Seven out of the country’s ten provinces and 36 of its 59 districts were affected. Bovine theileriosis was observed to lose seasonality when cases rose exponentially in 2018. Five and four high‐risk clusters of bovine theileriosis were detected using one‐year and one‐month time aggregate respectively, all within the last seven years of the study (2011 – 2018). Two potential risk factors (province and farming system) were significantly (P < 0.05) associated with bovine theileriosis occurrence. Bovine theileriosis was found to be rampant and if left unchecked will spread and adversely affect the whole country. Improved theileriosis surveillance and control is warranted. Recommendations for control and prevention strategies revolve around better farmer awareness about the disease, correct and consistent use of acaricides, cattle movement control and disease surveillance among others.
... The effects of these changes on climate variables lead to favorable conditions for mosquito proliferation 3,4 . There has therefore been an increasing expansion of mosquito-borne diseases associated with climate change and habitat destruction 5,6 . ...
Article
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Although there are many studies on the control of mosquito vectors of the yellow fever virus (YFV) in tropical forests, there are still few ecological studies regarding abiotic factors effect on these mosquitoes. Here we characterize these effects on oviposition behavior, abundance, and diversity of mosquito vectors of YFV. The study was conducted in Córrego da Luz Municipal Park, in Casimiro de Abreu, Rio de Janeiro state, Brazil, from July 2018 to December 2019. Ovitraps were placed at ground level and 3 m high. The data were tested for normality using the Shapiro–Wilk test, followed by an independent sample analysis, the Mann–Whitney test. The Shannon Diversity Index was used to evaluate the abundance of mosquitos' eggs collected at both ground level and 3 m high. We highlight the presence of Haemagogus janthinomys and Hg. leucocelaenus, primary YFV vectors in forest areas. The abundance of Hg. leucocelaenus (63%), Hg. janthinomys (75%), and Aedes terrens (58%) was higher at the height of 3 m, while Ae. albopictus (52%) was higher at ground level. Aedes albopictus was positively correlated with temperature. Culicidae monitoring is essential for assessing the YFV transmission cycle in Atlantic forest fragments.
... In an urbanizing world with a growing human population, recreation pressure in green spaces will increase (Zipperer and Pickett, 2012) which can lead to a higher contact rate between people and wildlife, including vectors of zoonotic diseases (Medlock and Leach, 2015;Braks et al., 2016). In contrast to tropical regions, where mosquitos are the main vectors of zoonotic disease, ticks are the most common vectors in temperate zones (Mead, 2015;Stanek et al., 2012). ...
Article
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The risk of tick-borne disease in humans depends on the exposure to pathogen-infected ticks, which in turn is driven by local tick population densities, pathogen prevalence and human activity. Variation in tick densities and pathogen prevalence between green spaces differing in habitat characteristics, location and geography has been well documented. In contrast, variation within green spaces, although vital for management and prevention of disease risk, remains poorly understood. Studying this variation may lead to a better understanding of the drivers of small-scale tick distribution and reveal priority locations for tick management. We sampled ticks within green spaces at three location types representing different green space infrastructures and levels of human activity: (1) a structural element (e.g. bench); (2) the ecotone 40 meters further along the adjacent trail and; (3) the interior of the associated forest stand, 20 meters perpendicular to the trail, between (1) and (2). Drag sampling took place in 2018 and 2019 at 36 locations in 10 green spaces located in the Campine region of Flanders, Belgium. The density of questing nymphs (DON) was lowest at structural elements and slightly higher adjacent to trails. The highest tick densities were recorded in the forest interior. DON was higher in deciduous than in coniferous forests as well as in stands with a more developed shrub layer. This was true for all location types, as we observed a strong correlation of DON between location types within forest stands. This enables the prediction of DON within forest stands, thus enabling the prediction of DON near infrastructure based on the associated forest stand characteristics. Prevention and management efforts should be focused on infrastructure in or adjacent to deciduous, structure-rich forest stands, although large variation in DON at all location types indicates overall, factual risk while using green space infrastructure.
... First, numerous factors are thought to drive the abundance and diversity of ticks. These include climate, vegetation, and host-predator assemblages (Medlock and Leach, 2015;Allan et al., 2010;Hofmeester et al., 2017). Second, in poorly studied regions, it is difficult to decide which tick species are of medical importance, and which species may become medically important if environmental drivers alter their ecology. ...
Article
Ticks of small mammals pose a significant risk to public health but these hazards are poorly understood in the tropics due to the paucity of information on the disease ecology of ticks in these regions. Mapping and quantifying the diversity of small mammal/tick networks and the effects of habitat on these medically important systems is key to disease prevention. Singapore represents a microcosm of much of tropical Asia as it has a diverse, though poorly studied, community of ticks and small mammals. Singapore also has a range of terrestrial habitats exhibiting a gradient of degradation. Small mammals and their ticks were sampled across the island in four main habitat types (old secondary forest, young secondary forest, scrubland, urban) across 4.5 years. Four tick species were collected (Amblyomma helvolum, Dermacentor auratus, Haemaphysalis semermis, Ixodes granulatus) from 10 small mammal species. Habitat was found to have a significant effect on both the abundance and structure of tick communities on small mammals. Old secondary forest communities had the highest tick abundance, comparatively high connectance, niche overlap (among ticks), linkage density, and were the preferred habitat of the zoonotic tick I. granulatus. Therefore, future disease spillover is likely to emerge from tick communities in old secondary forests.
... The impact of climate change on vector survival, suitability, and pathogen transmission has been assessed for vector-borne diseases in numerous research projects. [11][12][13][14][15][16][17][18][19] Unfortunately, very limited research has included spatial and temporal heterogeneity of weather conditions, population demography, and movement information in the risk-assessment models. ...
Article
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Vector-borne disease risk assessment is crucial to optimize surveillance, preventative measures (vector control), and resource allocation (medical supplies). High arthropod abundance and host interaction strongly correlate to vector-borne pathogen transmission. Increasing host density and movement increases the possibility of local and long-distance pathogen transmission. Therefore, we developed a risk-assessment framework using climate (average temperature and rainfall) and host demographic (host density and movement) data, particularly suitable for regions with unreported or underreported incidence data. This framework consisted of a spatiotemporal network-based approach coupled with a compartmental disease model and nonhomogeneous Gillespie algorithm. The correlation of climate data with vector abundance and host-vector interactions is expressed as vectorial capacity-a parameter that governs the spreading of infection from an infected host to a susceptible one via vectors. As an example, the framework is applied for dengue in Bangladesh. Vectorial capacity is inferred for each week throughout a year using average monthly temperature and rainfall data. Long-distance pathogen transmission is expressed with human movement data in the spatiotemporal network. We have identified the spatiotemporal suitability of dengue spreading in Bangladesh as well as the significant-incidence window and peak-incidence period. Analysis of yearly dengue data variation suggests the possibility of a significant outbreak with a new serotype introduction. The outcome of the framework comprised spatiotemporal suitability maps and probabilistic risk maps for spatial infection spreading. This framework is capable of vector-borne disease risk assessment without historical incidence data and can be a useful tool for preparedness with accurate human movement data.
... It's been so long that researchers have recognized that the rise in average global temperatures is increasing the geographical existence of vector borne diseases for instance dengue fever and malaria, as the animals transmitting them are acclimatizing to more extensive regions [31]. The exact connection of respiratory illnesses such as COVID-19 or influenza with a warming planet is not much clear and needs in-depth investigations. ...
Article
Background: Coronavirus disease 2019 (COVID-19) has become a severe public health problem around the globe. Various epidemiological, statistical, and laboratory-based studies have shown that the role of temperature and other environmental factors has important influence in the transmission of coronaviruses. Scientific research is needed to answer the questions about the spread and transmission of the infection, whether people could be avoided from being infected with COVID-19 in next summer. Aim: We aim to investigate the association of daily average temperature, daily average dew point, daily average humidity, daily average wind speed, and daily average pressure with the infection caused by this novel coronavirus in Pakistan. Key findings: First, we check the correlation between environmental factors and daily infected cases of COVID-19; among them, temperature and dew point have positive linear relationship with daily infected cases of COVID-19. The thought-provoking findings of the present study suggested that higher temperature and dew point can contribute to a rise in COVID-19 disease in four provinces of Pakistan, possible to genome modifications and viral resistance to harsh environment. Moreover, it is also observed that humidity in Punjab and Sindh, and wind speed in Balochistan and Khyber Pakhtunkhwa have influenced the spreading of daily infected COVID-19 cases. Significance: Current study will serve as a guideline to develop understanding of environmental factors that influence COVID-19 spread, helping policymakers to prepare and handle a catastrophe resulting from this pandemic.
... This review also identi ed good evidence that the vector borne disease WNV is another potential health outcome that should be of immediate cause for concern for HICs during drought periods, especially as several WNV transmitting mosquitoes can now be found in many part of Europe and the USA, and several recent outbreaks have already occurred in these regions (ECDPC 2018;Medlock and Leach 2015). This is a particular concern, given some of the evidence emerging showing that drought conditions encourage the proliferation of vectors at remaining pooled bodies of water, whilst also increasing vector competence (Johnson and Sukhdeo 2013). ...
Preprint
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Introduction The health effects of drought are significant and widespread, but primarily indirect. As climate change projections indicate future increases in drought events globally, it is essential that we continue to develop the evidence base on the health consequences of drought to inform future public health policy and practice (i.e. the quantification of impacts now and in the future). Methods A systematic review was preformed using: MEDLINE, EMBASE, PsycINFO, Maternity and Infant Care, Global Health, CINAHL and Cochrane. Articles were included in the analysis if they met the following criteria: exposure was specified as drought; outcome was a defined and measured human health outcome; a distinct link had to be made between exposure and outcome; drought was defined as a shortage or deficiency that was climate related; population studied was member countries of the Organisation for Economic Co-operation and Development (OECD) to represent HICs; reported original data; published in English from May 2012 to June 2017. Results 10,383 citations were initially identified; 24 papers met the eligibility criteria. Additionally, seven papers not meeting the criteria were incorporated as supporting text. The majority of studies were from Australia and the USA. Five main categories of health effects were found: (i) water borne disease (ii) vector borne disease (iii) airborne, dust and respiratory related diseases (iv) mental health and wellbeing and (v) other health effects. Conclusion The limited evidence suggests that the mental health impacts of drought in rural and farming populations and outbreaks of West Nile Fever in places that harbour the transmitting vector represent the greatest public health concern for drought prone High-Income Countries (HICs). A range of initiatives were identified, including health services preparedness alongside targeted public health policies. Further studies are needed to address gaps in the evidence including the absence of a standardised definition and/or measure of drought exposure, and methods to measure and assess health impacts related to drought.
... Several recent publications have demonstrated how climate change can alter the distribution of vector-borne diseases transmitted by ticks, sandflies and mosquitoes. These studies investigate how changes in spatial distribution of arthropod vectors may influence future spatial distributions of vector-borne pathogens (Balasubramanian and Nikhil, 2015;Balasubramanian et al., 2019b;Balasubramanian et al., 2021;Medlock and Leach, 2015;Marques et al., 2020). Previous studies have shown that the season of the year and the field environment in which the ticks oviposit are important extrinsic factors as ticks were observed to produce a more significant number of eggs during peak and retreating of rains and when placed in the shade (Danielova et al., 2006). ...
Article
Aim: Climate and weather conditions play a crucial role in the dynamics and distribution of ticks and tick-borne diseases. In this study, we explored the influence of a heavy rainfall (flood) occurrence on the seasonal activity and density of host-seeking Haemaphysalis tick vectors in Wayanad district, Kerala, India. Methodology: Wayanad district in Kerala state was selected as the study area. Ticks were collected from December 2017 to May 2019, monthly for five consecutive days by dragging method. Tick density was analyzed with climate data obtained from the meteorological station. Results: The total number of ticks collected post-flood decreased to 59% in Kurichiyad (site 1) and 63% in Muthanga (site 2), and the seasonal nymphal peak density was shifted. A seasonal peak of tick activity was normally observed from December to February. This peak occurrence was missing after flood in the study areas created with waterlogging and vegetation overgrowth. Interpretation: The present study revealed the effect of flood events in the study sites with significant differences in the abundance of five Haemaphysalis tick species during pre and post-flood periods and forest and wildlife habitats. This difference in the changing climatic conditions and increasing annual flood seasons in the Western Ghats may shift this region's ticks questing activity and tick-borne disease ecology.
... New approaches can quantify the key features of lit environments and the generally overlooked components we mentioned above (Nilsson and Smolka, 2021). Of course, ALAN can interact with other, better known anthropogenic drivers of increased disease risk like land transformation (Meyer Steiger et al., 2016;Lee et al., 2020) and changing climatic conditions (Medlock and Leach, 2015). Teasing their individual contributions apart experimentally will advance understanding into disease risk. ...
Article
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Light is a fundamental cue regulating a host of biological responses. The artificial modification thereof demonstrably impacts a wide range of organisms. The use of artificial light is changing in type, extent and intensity. Insect vector-borne diseases remain a global scourge, but surprisingly few studies have directly investigated the interactions between artificial light and disease vectors, such as mosquitoes. Here we briefly overview the progress to date, which highlights that artificial light must be considered as a modulator of mosquito-borne disease risk. We discuss where the mechanisms may lie, and where future research could usefully be directed, particularly in advancing understanding of the biological effects of the light environment. Further understanding of how artificial light may modulate mosquito-borne disease risk may assist in employing and redesigning light regimes that do not increase, and may even mitigate, already significant disease burdens, especially in the developing world.
... For the latter, spending time in tick habitat, either in the countryside or in urban and peri-urban areas, is a major risk factor for acquiring tick bites Hansford et al., 2017), some of which can result in It seems likely that Borrelia infection within ticks, and the dominance of one genospecies over another may vary in space and time across a landscape, depending on the varying abundance of different animal hosts, and their relative roles as tick hosts and reservoirs of infection. The population densities of these mammals and birds are in turn determined by biotic and abiotic factors, such as habitat, weather and climate, and various predator/prey interactions Medlock & Leach, 2015). There are also anthropogenic factors that might influence these transmission cycles, such as land and game management . ...
Article
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The density of Borrelia burgdorferi-infected Ixodes ricinus nymphs (DIN) was investigated during 2013-2017 across a Lyme disease-endemic landscape in southern England. The density of nymphs (DON), nymph infection prevalence (NIP), and DIN varied across five different natural habitats, with the highest DIN in woodland edge and high biodiversity woodlands. DIN was significantly lower in scrub grassland compared to the woodland edge, with low DON and no evidence of infection in ticks in non-scrub grassland. Over the 5 years, DON, NIP and DIN were comparable within habitats, except in 2014, with NIP varying three-fold and DIN significantly lower compared to 2015-2017. Borrelia garinii was most common, with bird-associated Borrelia (B. garinii/valaisiana) accounting for ~70% of all typed sequences. Borrelia burgdorferi sensu stricto was more common than B. afzelii. Borrelia afzelii was more common in scrub grassland than woodland and absent in some years. The possible impact of scrub on grazed grassland, management of ecotonal woodland margins with public access, and the possible role of birds/gamebirds impacting NIP are discussed. Mean NIP was 7.6%, highlighting the potential risk posed by B. burgdorferi in this endemic area. There is a need for continued research to understand its complex ecology and identify strategies for minimizing risk to public health, through habitat/game management and public awareness.
... In recent years, the effects of meteorological factors on human health, including both communicable and noncommunicable diseases (Medlock and Leach 2015;Watts et al. 2017;Salas et al. 2019;Alahmad et al. 2020;Rocklöv and Dubrow 2020;Semenza 2020;Hiatt and Beyeler 2020), have attracted increasing attentions. Temperature, for example, is a widely accepted factor in the spread of HFMD. ...
Article
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Hand, foot, and mouth disease (HFMD) poses a great disease burden in China. However, there are few studies on the relationship between temperature variability (TV) and HFMD. Moreover, whether air pollutions have modified effects on this relationship is still unknown. Therefore, this study aims to explore the modified effects of air pollutants on TV-HFMD association in Zibo City, China. Daily data of HFMD cases, meteorological factors, and air pollutants from 2015 to 2019 were collected for Zibo City. TV was estimated by calculating standard deviation of minimum and maximum temperatures over the exposure days. We used generalized additive model to estimate the association between TV and HFMD. The modified effects of air pollutants were assessed by comparing the estimated TV-HFMD associations between different air stratums. We found that TV increased the risk of HFMD. The effect was strongest at TV03 (4 days of exposure), when the incidence of HFMD increased by 3.6% [95% CI: 1.3–5.9%] for every 1℃ increases in TV. Males, children aged 0–4 years, were more sensitive to TV. We found that sulfur dioxide (SO2) enhanced TV’s effects on all considered exposure days, while ozone (O3) reduced TV’s effects on some exposure days in whole concerned population. However, we did not detect significant effect modification by particulate matter less than 10 microns in aerodynamic diameter (PM10). These findings are of significance in developing policies and public health practices to reduce the risks of HFMD by integrating changes in temperatures and air pollutants.
... Temperature and humidity influence mosquito survival, frequency of blood feeding, and the development of parasites within mosquitos [138]. Malaria, caused by Plasmodium protozoa and transmitted by Anopheles mosquitoes [139], is endemic in sub-Saharan Africa, Asia, Oceania, South and Central America. ...
Article
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Climate change is a worsening global crisis that will continue negatively impacting population health and well-being unless adaptation and mitigation interventions are rapidly implemented. Climate change-related cardiovascular disease is mediated by air pollution, increased ambient temperatures, vector-borne disease and mental health disorders. Climate change-related cardiovascular disease can be modulated by climate change adaptation; however, this process could result in significant health inequity because persons and populations of lower socioeconomic status have fewer adaptation options. Clear scientific evidence for climate change and its impact on human health have not yet resulted in the national and international impetus and policies necessary to slow climate change. As respected members of society who regularly communicate scientific evidence to patients, clinicians are well-positioned to advocate on the importance of addressing climate change. This narrative review summarizes the links between climate change and cardiovascular health, proposes actionable items a cardiologist can execute both in their personal life and as an advocate of climate policies, and encourages communication of the health impacts of climate change when counseling patients. Our aim is to inspire the reader to invest more time in communicating the most crucial public health issue of the 21st century to their patients.
... Several rodent-borne pathogens also pose a zoonotic risk (Cleaveland et al., 2001), with the tick-borne Borrelia burgdorferi sensu lato, causative agent of Lyme disease in humans, being one of the most relevant and widespread zoonoses (Medlock and Leach, 2015). Rodent species harbour a remarkable proportion of zoonotic parasites, being one of the taxa with highest zoonotic potential (Olival et al., 2017), such that rodent-borne diseases represent a significant public health concern in many areas worldwide (Meerburg et al., 2009), including rural areas of Britain and Northern Europe. ...
Article
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Wild rodent communities represent ideal systems to study pathogens and parasites shared among sympatric species. Such studies are useful in the investigation of eco-epidemiological dynamics, improving disease management strategies and reducing zoonotic risk. The aim of this study was to investigate pathogen and parasites shared among rodent species (multi-host community) in West Wales in an area where human/wildlife disease risk was not previously assessed. West Wales is predominantly rural, with human settlements located alongside to grazing areas and semi-natural landscapes, creating a critical human-livestock-wildlife interface. Ground-dwelling wild rodent communities in Wales were live-trapped and biological samples – faeces and ectoparasites – collected and screened for a suite of pathogens and parasites that differ in types of transmission and ecology. Faecal samples were examined to detect Herpesvirus, Escherichia coli, and Mycobacterium microti. Ticks and fleas were collected, identified to species based on morphology and genetic barcodes, and then screened for Anaplasma phagocytophilum, Babesia microti, Borrelia burgdorferi sensu lato, and Bartonella sp. All the pathogens and parasites screened pose a characteristic epidemiological challenge, such as variable level of generalism, unknown zoonotic potential, and lack of data. The results showed that the bank vole Myodes glareolus had the highest prevalence of all pathogens and parasites. Higher flea species diversity was detected than in previous studies, and at least two Bartonella species were found circulating, one of which has not previously been detected in the UK. These key findings offer new insights into the distribution of selected pathogen and parasites and subsequent zoonotic risk, and provide new baselines and perspectives for further eco-epidemiological research.
... Blood-feeding is a prerequisite for oviposition of adult females, and thousands of eggs can be laid by a single female tick [1]. Bloodsucking of ticks not only harms hosts by causing tick paralysis, allergic reactions, damage to the skin, decreased productivity, and decreased immune function, but also transmits disease-causing pathogens, such as protozoa, viruses, and bacteria, from the infected hosts to other hosts in subsequent blood-feeding [2][3][4][5][6][7][8][9]. Ticks are currently considered to be second only to mosquitoes as vectors of infectious diseases to humans and animals [10]. ...
Article
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Background Ticks are important vectors and transmit diverse pathogens, including protozoa, viruses, and bacteria. Tick-borne diseases can cause damage to both human health and the livestock industries. The control and prevention of ticks and tick-borne diseases has relied heavily on acaricides. Methods In the present study, using a high-throughput RNA sequencing (RNA-Seq) technique, we performed a comprehensive time-series transcriptomic analysis throughout the embryogenesis period of Rhipicephalus turanicus . Results Altogether, 127,157 unigenes were assembled and clustered. Gene expression differences among the embryonic stages demonstrated that the most differentially expressed genes (DEGs) were observed in the comparisons of early embryonic stages (RTE5 vs. RTE10, 9726 genes), and there were far fewer DEGs in later stages (RTE25 vs. RTE30, 2751 genes). Furthermore, 16 distinct gene modules were identified according to weighted gene co-expression network analysis (WGCNA), and genes in different modules displayed stage-specific characteristics. Gene Ontology (GO) annotations and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment suggested that some genes involved in organ and tissue formation were significantly upregulated in the early embryonic developmental stages, whereas metabolism-related pathways were more enriched in the later embryonic developmental stages. Conclusions These transcriptome studies revealed gene expression profiles at different stages of embryonic development, which would be useful for interrupting the embryonic development of ticks and disrupting the transmission of tick-borne diseases. Graphical Abstract
... Although vector-borne infectious agents can be found in blood, they are generally not transmitted directly by blood contact, but by a vector, such as a tick or a mosquito [20]. As a result, vector-borne infections vary geographically depending on vector species distribution, competency, and available reservoirs [8,21]. ...
Article
Background: The tick-borne bacterium Neoehrlichia mikurensis can cause persistent asymptomatic bloodstream infections, but transfusion-mediated transmission has not been reported. This study aimed to investigate the prevalence of N. mikurensis in blood donors, and recipients of blood components from N. mikurensis-positive donors were traced. Methods: In 2019 and 2021, 1007 blood donors were recruited. Participants completed a questionnaire and additional blood samples were collected during blood donation. Detection of N. mikurensis was performed by PCR followed by sequencing. Positive donors were interviewed and retested. Look-back was performed on positive donations and on all subsequent donations. Results: N. mikurensis was detected in 7/1006 (0.7%) donors. A total of 380/1005 (38%) donors reported at least one noticed tick bite during the current season. The questionnaire could not detect any differences between negative and positive N. mikurensis-donors. Two of the positive donors were still positive on days 318 and 131 after the index donation, respectively. One donor with persistent N. mikurensis in blood experienced slight fatigue. All other had no symptoms attributable to neoehrlichiosis. Look-back included ten donations and 20 blood components. Eight components were discarded, and 12 recipients of N. mikurensis-positive donations were identified. PCR was negative in seven recipients. Five recipients had died, but their medical records gave no evidence for neoehrlichiosis. Conclusions: Although N. mikurensis was found in 0.7% of blood donors, transfusion-mediated infection was not detected, despite several recipients being at high risk for severe neoehrlichiosis. The results warrant further studies as well as raised clinical awareness.
... The emergence and spread of TBPs are increasing due to global warming and other factors, such as increased human travel, animal transport, and urban development [28]. Therefore, continuous surveillance is necessary for monitoring the emergence of human diseases caused by TBPs [29,30]. ...
Article
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Human granulocytic anaplasmosis (HGA) and human monocytic ehrlichiosis (HME) are zoonotic tick-borne diseases transmitted via tick bites. To determine the state of human Anaplasma and Ehrlichia infections caused by tick bites in the Republic of Korea (ROK), we conducted a nationwide investigation of human cases of tick bites in 2020. A total of 180 ticks were obtained, comprising Haemaphysalis longicornis (70.0%), Amblyomma testudinarium (17.8%), Ixodes nipponensis (6.1%), H. flava (4.4%), and I. persulcatus (1.7%). In three cases (1.7%; 95% CI: 0.3–4.9), A. phagocytophilum was detected in Ixodes ticks using primers for Anaplasma-specific genes (16s rRNA, ankA, and msp4). Conversely, Ehrlichia sp. was only detected in H. longicornis, in two cases (1.1%; 95% CI: 0.1–4.0). To the best of our knowledge, this is the first record of Ehrlichia sp. in ticks parasitizing humans in the ROK. As concerns remain about the possibility of HGA and HME transmission, continuous monitoring and management of the pathogens and vectors are necessary.
... With increases in urbanization, climate change, and other anthropogenic events, cases of VBDs in humans and animals will continue to rise [1,121,122]. Because animals can serve as reservoirs for zoonotic diseases that can spillover into human populations, a One Health approach involving vector and VBD surveillance in animal populations is vital for human and animal health. ...
Article
Vector-borne diseases are often zoonotic and so a One Health approach must be employed in order to investigate and control them. Therefore, surveillance of arthropod vectors and pathogens among animal populations should complement human disease surveillance. Since traditional surveillance methods to collect arthropod vectors and conduct pathogen testing from animals can be challenging, data collection can be supplemented with citizen science approaches, where the general public is actively involved in collecting animals and/or samples. In this review, we discuss considerations for researchers to create a successful vector surveillance program using citizen science approaches with different stakeholders who own, have interests in, or work with animals.
... In LD case studies, it was found that demographic profiles, such as age or gender conditions, have a positive link with LD risk (Couper et al, 2020;Schwartz et al., 2017). Age of infected people among confirmed LD cases was reported to be a bimodal distribution with peaks for children aged 5-9 years and adults aged 50-59 years old (Mead, 2015;Medlock & Leach, 2015). Moreover, males are a larger proportion of reported LD cases than females according to LD surveillance in the United States. ...
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Currently Lyme disease (LD) is the most common vector-borne disease in the United States. Understanding the potential effects of urban expansion on LD risk is an emerging global health concern. The U.S. Northeastern corridor has experienced a spatio-temporal increase in Lyme disease (LD) and rapid urban expansion over the past decades. The effects of LULCC factors on LD incidence thus were investigated based on county unit through a geographical detector and statistical methods along the Northeastern I-95 corridor during the year of 2008–2018. Analyses indicated that the Northeastern I-95 corridor was characterized by both higher urbanization and increasing LD cases. About 28% of the study area is covered by urban land, which is more than nine times that of the U.S. average. And LD incidence in the study area was calculated up to 39.1 cases per 100,000 population, nearly five times higher than that of the entire United States (8.3 cases according to CDC). In addition, the similar spatial distribution and spatial pattern between LD cases increase and urban expansion were confirmed. The statistical results showed that their similarity in spatial trend was up to 84.9%. Meanwhile, the correlation coefficients also verified that urban expansion has a significant positive correlation with LD incidence (r = 0.511) at the 99% confidential level. Geographical detector analysis further proved that urban expansion is the dominant factor for LD cases increase (P = 0.21). Moreover, the geographic location where the county is located is also a crucial factor for LD cases' impact (P = 0.15). Regional analysis revealed that LD risk appeared in urbanizing areas rather than urbanized and rural areas. These results suggested that rapidly urbanizing areas may become LD hotspots. Our studies improve understanding of LD occurrence in the context of urbanization and provide a more precise public health message to mitigate the tick-borne disease.
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The acquisition of new hosts is a fundamental mechanism by which parasitic organisms expand their host range and perpetuate themselves on an evolutionary scale. Among pathogens, viruses, due to their speed of evolution, are particularly efficient in producing new emergence events. However, even though these phenomena are particularly important to the human species and therefore specifically studied, the processes of virus emergence in a new host species are very complex and difficult to comprehend in their entirety. In order to provide a structured framework for understanding emergence in a species (including humans) a comprehensive qualitative model is anindispensable cornerstone. This model explicitly describes all the stages necessary for a virus circulating in the wild to come to the crossing of the epidemic threshold. We have therefore developed a complete descriptive model explaining all the steps necessary for a virus circulating in host populations to emerge in a new species. This description of the parameters presiding over the emergence of a new virus allows us to understand their nature and importance in the emergence process.
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Ticks transmit a wide range of pathogens. The spread of tick-borne infections is an emerging, yet often overlooked, threat in the context of climate change. The infections have rapidly increased over the past few years in South Korea despite no significant changes in socio-economic circumstances. We investigated the impact of climate change on the surge of tick-borne infections and identified potential disease hotspots at 5 km by 5 km resolution. A composite index was constructed based on multiple climate and environmental indicators, and compared with the observed tick-borne infections. The surge of tick-borne episodes corresponded to the rising trend of the index over time. High-risk areas identified by the index can be used to prioritize locations for disease prevention activities. Monitoring climate risk factors may provide an opportunity to predict the spread of the infections in advance.
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Over 1 million dogs are imported into the United States and roughly 340,000 dogs into the United Kingdom yearly. Although the official number of dogs arriving to Canada is currently unknown, local animal professionals estimate that thousands of dogs are imported into Canada each year. Dog importation may be increasing globally while regulation and surveillance are still limited, resulting in concerns for the health and welfare of imported dogs. To date, few studies have investigated how the source location of dogs influences the owner-dog relationship. The current report presents two independent studies that were conducted to assess whether owners of imported dogs reported a poorer owner-dog relationships compared to owners of Canadian-born dogs. In both studies, an online survey was distributed to dog owners (Study 1: n = 803; Study 2: n = 878) in British Columbia, Canada, containing questions on various aspects of the owner-dog relationship. The first study included questions from the Lexington Attachment to Pets Scale, Canine Behavioral Assessment and Research Questionnaire, Human-Animal Bond questionnaire, Monash Dog Owner Relationship Scale, and constructed questions about training methods, expectations, and health. The second study was comprised of original questions assessing difficult behaviour, training practices, health, attachment, and perceived level of burden of owning a dog. Both studies found no evidence of a poorer owner-dog relationship in non-Canadian-sourced dogs. In fact, owners of Canadian-sourced dogs used harsh training methods more frequently and had higher expectations for their dog. While no signs of poorer owner-dog relationship in non-Canadian-sourced dogs were found, future research should continue the investigation of age, health, and backgrounds of incoming dogs.
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A tick infestation is one of the most common arthropod‐related skin diseases in Hokkaido, the northernmost island of Japan. Ticks also act as an infectious disease vector for humans. Tick‐borne encephalitis (TBE), a highly mortal central nervous system infection caused by TBE virus (TBEV), has sporadically occurred there recently. However, there have been no epidemiological data on the current surveillance of human tick bites and the prevalence of TBEV in human‐feeding ticks. This study was performed to clarify those indeterminate issues. One hundred and fifty‐three ixodid ticks feeding on humans were collected from 150 outpatients in Hokkaido during the season of April to August 2018. None of the cases showed any infectious symptoms. These ticks were morphologically identified to species, and a cytopathic assay on baby hamster kidney cells was carried out to detect TBEV from each tick. The tick collection consisted of 108 Ixodes persulcatus (one nymph and 107 adult females), 44 female Ixodes ovatus, and one female Haemaphysalis japonica. No tick extracts showed positive results of the cytopathic assay, suggesting the non‐existence of TBEV in the present specimens. However, the survey to detect TBEV from human‐feeding ticks is still important to monitor the occurrence of TBE, because human tick bites by I. ovatus, a possible vector of TBEV, are increasing even in the northern and eastern areas of Hokkaido.
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Background The tick Ixodes ricinus is an important vector of tick-borne diseases including Lyme borreliosis. In continental Europe, the nymphal stage of I. ricinus often has a bimodal phenology with a large spring/early summer peak and a smaller fall peak. While there is consensus about the origin of the spring nymphal peak, there are two alternative hypotheses for the fall nymphal peak, direct development versus delayed diapause. These two hypotheses make different predictions about the time lags of the correlations between the spring peak, the fall peak, and seed production (masting) by deciduous trees. Methods To determine which hypothesis is most important for explaining the fall peak, we used data from a long-term surveillance study (15 years) on the density of I. ricinus nymphal ticks at 4 different elevation sites in an area of Switzerland that is endemic for Lyme borreliosis, and long-term data on the mast of the European beech tree from the literature. Results I. ricinus nymphs had a bimodal phenology at the three lower elevation sites, but a unimodal phenology at the top elevation site. At the lower elevation sites, the density of nymphs (DON) in the fall was strongly correlated with the DON in the spring of the following year. The inter-annual variation in the densities of I. ricinus nymphs in the fall and spring were best explained by a 1-year versus a 2-year time lag with the beech tree masting index. Fall nymphs had higher fat content and are younger than spring nymphs. All of these observations are consistent with the direct development hypothesis for the fall peak of I. ricinus nymphs at our study site. Our study provides new insight into the complex bimodal phenology of this important disease vector. Conclusions Public health officials in Europe should be aware that following a strong mast year, the DON will increase 1 year later in the fall and 2 years later in the spring and summer. Population ecology studies of I. ricinus should consider that the spring and fall peak in the same calendar year represent different generations of ticks.
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Climate change is likely to increase the risk of drought which impacts on health are not quite known well due to its creeping nature. This study maps the publications on the consequences of drought on human health, directly or indirectly, from January 2008 to December 2018. We searched Scopus, Web of Science, PsycINFO, google scholar and Pubmed. 378 articles were included. Poisson regression analysis was performed to evaluate the relationship between the number of articles and some variables such as the continent of the study, article type, subject, and climate event type (climate change or just drought). Data were analyzed using Microsoft Excel 2019 and SPSS version 26. Based on the results, Asia had the highest number of publications (91) compared to North America (82), while the number of articles from South America (16) was lower significantly. The majority of articles had used quantitative analysis (175), and review articles were the second most frequent (104). Most of the articles had focused on the social impacts of drought. The number of articles has increased over the years and most of them were not in the health area primarily. Also, a noticeable amount of the knowledge comes from analysis of previously collected data and review articles. To mitigate and reduce the impacts of drought on the different dimensions of health, we need to understand them through more investigations with precise data and methods, especially in less developed countries with a more vulnerable population, and mental health consequences of drought that have been less considered.
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The 3-5year epidemic cycle of dengue fever in Thailand makes it a major re-emerging public health problem resulting in being a burden in endemic areas. Although the Thai Ministry of Public Health adopted the WHO dengue control strategy, all dengue virus serotypes continue to circulate. Health officers and village health volunteers implement some intervention options but there is a need to ascertain most appropriate (or a combination of) interventions regarding the environment and contextual factors that may undermine the effectiveness of such interventions. This study aims to understand the dengue-climate relationship patterns at the district level in the southern region of Thailand from 2002 to 2018 by examining the statistical association between dengue incidence rate and eight environmental patterns, testing the hypothesis of equal incidence of these. Data on environmental variables and dengue reported cases in Nakhon Si Thammarat province situated in the south of Thailand from 2002 to 2018 were analysed to (1) detect the environmental factors that affect the risk of dengue infectious disease; to (2) determine if disease risk is increasing or decreasing over time; and to (3) identify the high-risk district areas for dengue cases that need to be targeted for interventions. To identify the predictors that have a high and significant impact on reported dengue infection, three steps of analysis were used. First, we used Partial Least Squares (PLS) Regression and Poisson Regression, a variant of the Generalized Linear Model (GLM). Negative coefficient in correspondence with the PLS components suggests that sea-level pressure, wind speed, and pan evaporation are associated with dengue occurrence rate, while other variables were positively associated. Using the Akaike information criterion in the stepwise GLM, the filtered predictors were temperature, precipitation, cloudiness, and sea level pressure with the standardized coefficients showing that the most influential variable is cloud cover (three times more than temperature and precipitation). Also, dengue occurrence showed a constant negative response to the average increase in sea-level pressure values. In southern Thailand, the predictors that have been locally determined to drive dengue occurrence are temperature, rainfall, cloud cover, and sea-level pressure. These explanatory variables should have important future implications for epidemiological studies of mosquito-borne diseases, particularly at the district level.
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Invasion biology examines species originated elsewhere and moved with the help of humans, and those species’ impacts on biodiversity, ecosystem services, and human well-being. In a globalized world, the emergence and spread of many human infectious pathogens are quintessential biological invasion events. Some macroscopic invasive species themselves contribute to the emergence and transmission of human infectious agents. We review conceptual parallels and differences between human epidemics and biological invasions by animals and plants. Fundamental concepts in invasion biology regarding the interplay of propagule pressure, species traits, biotic interactions, eco-evolutionary experience, and ecosystem disturbances can help to explain transitions between stages of epidemic spread. As a result, many forecasting and management tools used to address epidemics could be applied to biological invasions and vice versa. Therefore, we advocate for increasing cross-fertilization between the two disciplines to improve prediction, prevention, treatment, and mitigation of invasive species and infectious disease outbreaks, including pandemics.
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Abstract: Climate change causes global effects on multiple levels. The anthropogenic input of greenhouse gases increases the atmospheric mean temperature. It furthermore leads to a higher probability of extreme weather events (e.g., heat waves, floods) and thus strongly impacts the habitats of humans, animals, and plants. Against this background, research and innovation activities are increasingly focusing on potential health-related aspects and feasible adaptation and mitigation strategies. Progressing urbanization and demographic change paired with the climate change- induced heat island effect exposes humans living in urban habitats to increasing health risks. By employing scientometric methods, this scoping study provides a systematic bird’s eye view on the epistemic landscapes of climate change, its health-related effects, and possible technological and nature-based interventions and strategies in order to make urban areas climate proof. Based on a literature corpus consisting of 2614 research articles collected in SCOPUS, we applied network-based analysis and visualization techniques to map the different scientific communities, discourses and their interrelations. From a public health perspective, the results demonstrate the range of either direct or indirect health effects of climate change. Furthermore, the results indicate that a public health-related scientific discourse is converging with an urban planning and building science driven discourse oriented towards urban blue and green infrastructure. We conclude that this development might mirror the socio-political demand to tackle emerging climate change-induced challenges by transgressing disciplinary boundaries.
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Canine babesiosis is a serious disease among tick-borne haemoprotozoan diseases that threaten dog health. To find out the prevalence of canine babesiosis and its main pathogenic species in Shaanxi Province, the study was centered on the infection of babesiosis in dogs in different regions of the Province. First, a total of 367 blood samples were collected in Shaanxi Province, and 53 Babesia nucleic-acid-positive samples were found by polymerase chain reaction (PCR) identification, with a positive rate of 14.44%, and Babesia gibsoni was found by sequencing analysis. Further analysis showed that the prevalence of canine babesiosis was significantly different in 5 regions. There was no significant difference in infection rates between age groups, with the lowest prevalence in young dogs (10.81%) and the highest in adult dogs (17.29%). The infection rate in male dogs was higher than in female dogs. The morbidity of canine Babesia spp. was significantly different between different seasons, with the highest infection rate in autumn (27.78%) and the lowest in winter (6.10%). In conclusion, the epidemicity of canine Babesia spp. in dogs was mainly affected by region and season, and B. gibsoni was the most common canine Babesia spp. within Shaanxi Province in our study. These results provide basic data for the prevention and control of canine babesiosis in this region.
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Background The range of the ornate dog tick Dermacentor reticulatus is rapidly expanding in Europe. This tick species is the vector of canine babesiosis, caused by Babesia canis , and also plays a role in the transmission of Theileria equi and Babesia caballi in equids. Methods The geographic range of D. reticulatus in the Czech Republic was re-assessed, and an up-to-date distribution map is presented based on material and data obtained during a nationwide citizen science campaign. Received and flagged individuals of D. reticulatus were also analysed for the presence of B. canis DNA. Results In striking contrast to historical records, D. reticulatus was found in all regions of the Czech Republic, with most reports coming from the southeast and northwest of the country. Between February 2018 and June 2021, the project team received 558 photo reports of ticks and 250 packages containing ticks. Of the former, 71.1% were identified as Dermacentor sp. with the remainder identified as Ixodes sp., Haemaphysalis sp., Argas sp. or Hyalomma sp. The majority of specimens in the subset of ticks that were received ( N = 610) were D. reticulatus ( N = 568, 93.7%), followed by Ixodes ricinus and Hyalomma spp. A total of 783 adult D. reticulatus , either received (568) or collected by flagging (215), were tested for the presence of B. canis DNA using species-specific nested PCR targeting part of the 18S rRNA gene; B. canis DNA was demonstrated in 22 samples (2.81%). Conclusions The continuous spread of D. reticulatus in the Czech Republic was documented in this study. In addition, DNA of B. canis was also detected in a number of ticks, suggesting the establishment of B. canis in the Czech Republic. These results suggest that veterinarians need to consider the possibility of canine babesiosis even in dogs without a history of travel. Graphical Abstract
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Increases in temperature and extreme weather events due to global warming can create an environment that is beneficial to mosquito populations, changing and possibly increasing the suitable geographical range for many vector‐borne diseases. West Nile Virus (WNV) is a flavivirus, maintained in a mosquito‐avian host cycle that is usually asymptomatic but can cause primarily flu‐like symptoms in human and equid accidental hosts. In rare circumstances, serious disease and death are possible outcomes for both humans and horses. The main European vector of WNV is the Culex pipiens mosquito. This study examines the effect of environmental temperature on WNV establishment in Europe via Culex pipiens populations through use of a basic reproduction number (R0) model. A metric of thermal suitability derived from R0 was developed by collating thermal responses of different Culex pipiens traits and combining them through use of a next generation matrix. WNV establishment was determined to be possible between 14°C and 34.3°C, with the optimal temperature at 23.7°C. The suitability measure was plotted against monthly average temperatures in 2020 and the number of months with high suitability mapped across Europe. The average number of suitable months for each year from 2013 to 2019 was also calculated and validated with reported equine West Nile fever cases from 2013 to 2019. The widespread thermal suitability for WNV establishment highlights the importance of European surveillance for this disease and the need for increased research into mosquito and bird distribution. This article is protected by copyright. All rights reserved
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A significant fraction of Brazil's population has been exposed to drought in recent years, a situation that is expected to worsen in frequency and intensity due to climate change. This constitutes a current key environmental health concern, especially in densely urban areas such as several big cities and suburbs. For the first time, a comprehensive assessment of the short‐term drought effects on weekly non‐external, circulatory, and respiratory mortality was conducted in 13 major Brazilian macro‐urban areas across 2000–2019. We applied quasi‐Poisson regression models adjusted by temperature to explore the association between drought (defined by the Standardized Precipitation‐Evapotranspiration Index) and the different mortality causes by location, sex, and age groups. We next conducted multivariate meta‐analytical models separated by cause and population groups to pool individual estimates. Impact measures were expressed as the attributable fractions among the exposed population, from the relative risks (RRs). Overall, a positive association between drought exposure and mortality was evidenced in the total population, with RRs varying from 1.003 [95% CI: 0.999–1.007] to 1.010 [0.996–1.025] for non‐external mortality related to moderate and extreme drought conditions, from 1.002 [0.997–1.007] to 1.008 [0.991–1.026] for circulatory mortality, and from 1.004 [0.995–1.013] to 1.013 [0.983–1.044] for respiratory mortality. Females, children, and the elderly population were the most affected groups, for whom a robust positive association was found. The study also revealed high heterogeneity between locations. We suggest that policies and action plans should pay special attention to vulnerable populations to promote efficient measures to reduce vulnerability and risks associated with droughts.
Chapter
Seabirds are one of the most threatened bird groups on the planet, with approximately 30% at risk of extinction. The primary cause of population decline and extinction are non-native species introduced to islands, such as mammals, and which subsequently prey on seabirds or damage habitats. These “invasive species” are impacting 46% of seabird species and over 170 million individual seabirds globally. Of seabirds impacted, 66% are currently listed as globally threatened on the International Union for the Conservation of Nature (IUCN) Red List, highlighting the urgent need to remove the threat of invasive species to prevent seabird extinctions. In this chapter we discuss these impacts in detail, including a brief history of invasion processes that have led to this global problem. We also describe emerging invasive species threats and investigate how climate change will further exacerbate the impacts of invasive species on seabirds. We conclude this chapter with a discussion on the successful management and reduction of invasive species, which have resulted in substantial conservation gains for seabirds and whole island ecosystems worldwide.
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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.
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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.
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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 …
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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).
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Lyme borreliosis is an emerging infectious humandisease 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 characterise 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: B. afzelii (48%), B. garinii (36%) B. 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 understanding 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
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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).
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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.
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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.
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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.
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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.
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Malaria is an important disease that has a global distribution and significant health burden. The spatial limits of its distribution and seasonal activity are sensitive to climate factors, as well as the local capacity to control the disease. Malaria is also one of the few health outcomes that has been modeled by more than one research group and can therefore facilitate the first model intercomparison for health impacts under a future with climate change. We used bias-corrected temperature and rainfall simulations from the Coupled Model Intercomparison Project Phase 5 climate models to compare the metrics of five statistical and dynamical malaria impact models for three future time periods (2030s, 2050s, and 2080s). We evaluated three malaria outcome metrics at global and regional levels: climate suitability, additional population at risk and additional person-months at risk across the model outputs. The malaria projections were based on five different global climate models, each run under four emission scenarios (Representative Concentration Pathways, RCPs) and a single population projection. We also investigated the modeling uncertainty associated with future projections of populations at risk for malaria owing to climate change. Our findings show an overall global net increase in climate suitability and a net increase in the population at risk, but with large uncertainties. The model outputs indicate a net increase in the annual person-months at risk when comparing from RCP2.6 to RCP8.5 from the 2050s to the 2080s. The malaria outcome metrics were highly sensitive to the choice of malaria impact model, especially over the epidemic fringes of the malaria distribution.
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