Scott A Ritchie

Scott A Ritchie
James Cook University · School of Public Health, Tropical Medicine and Rehabilitation Sciences

BSc, MSc,PhD

About

391
Publications
71,776
Reads
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16,896
Citations
Citations since 2017
109 Research Items
8863 Citations
201720182019202020212022202305001,0001,500
201720182019202020212022202305001,0001,500
201720182019202020212022202305001,0001,500
201720182019202020212022202305001,0001,500
Additional affiliations
January 2008 - present
James Cook University
Position
  • Professor
Description
  • beautiful, mate, beautiful!
October 1994 - December 2012
Queensland Government
Position
  • Director, Medical Entomology
Description
  • Managed dengue, Japanese encephalitis priograms and chaired the Aedes albopictus program.

Publications

Publications (391)
Preprint
Full-text available
Aedes aegypti is the principal mosquito vector of dengue, yellow fever, Zika and chikungunya viruses. The w Mel endosymbiotic bacteria Wolbachia pipientis has been introduced into this vector as a novel biocontrol strategy to stop transmission of these viruses. Mosquitoes with Wolbachia have been released in the field in North Queensland, Australia...
Article
Full-text available
Background Aedes albopictus is a highly invasive species and an important vector of dengue and chikungunya viruses. Indigenous to Southeast Asia, Ae. albopictus has successfully invaded every inhabited continent, except Antarctica, in the past 80 years. Vector surveillance and control at points of entry (PoE) is the most critical front line of defe...
Article
Full-text available
The Kunjin strain of West Nile virus (WNVKUN) is a mosquito-transmitted flavivirus that can infect farmed saltwater crocodiles in Australia and cause skin lesions that devalue the hides of harvested animals. We implemented a surveillance system using honey-baited nucleic acid preservation cards to monitor WNVKUN and another endemic flavivirus patho...
Article
Full-text available
In early 2022, the Japanese encephalitis virus (JEV) was identified as the cause of stillborn and mummified piglets in pig farms in southeastern Australia. Human cases and additional pig farms with infected piglets were subsequently identified across a widespread area encompassing four states. To inform surveillance and control programs, we synthes...
Article
Background: The w Mel strain of Wolbachia has been successfully introduced into Aedes aegypti mosquitoes and subsequently shown to reduce transmission of dengue and other pathogens, under both laboratory and field conditions. Here we describe the entomological outcomes of w Mel Wolbachia mosquito releases in two small communities in Nha Trang City...
Article
Full-text available
Mosquitoes carrying Wolbachia endosymbionts are being released in many countries for arbovirus control. The w Mel strain of Wolbachia blocks Aedes -borne virus transmission and can spread throughout mosquito populations by inducing cytoplasmic incompatibility. Aedes aegypti mosquitoes carrying w Mel were first released into the field in Cairns, Aus...
Preprint
Full-text available
Mosquitoes carrying Wolbachia endosymbionts are being released in many countries for arbovirus control. The w Mel strain of Wolbachia blocks Aedes -borne virus transmission and can spread throughout mosquito populations by inducing cytoplasmic incompatibility. Aedes aegypti mosquitoes carrying w Mel were first released into the field in Cairns, Aus...
Article
Full-text available
Significance With over 40% of humans at risk from mosquito-borne diseases such as dengue, yellow fever, chikungunya, and Zika, the development of environmentally friendly mosquito-control tools is critical. The release of reproductively incompatible male mosquitoes carrying a Wolbachia bacterium can drive mating events that kill the eggs. Through r...
Article
Background: The w Mel strain of Wolbachia has been successfully introduced into Aedes aegypti mosquitoes and subsequently shown to reduce transmission of dengue and other pathogens, under both laboratory and field conditions. Here we describe the entomological outcomes of w Mel Wolbachia mosquito releases in two small communities in Nha Trang City...
Article
Full-text available
With global expansion of the two main vectors of dengue, Aedes aegypti (Linnaeus, Diptera: Culicidae) and Aedes albopictus (Skuse, Diptera: Culicidae), there is a need to further develop cost-effective and user-friendly surveillance tools to monitor the population dynamics of these species. The abundance of Ae. aegypti and Ae. Albopictus, and assoc...
Article
Full-text available
Rapid advances in biological and digital support systems are revolutionizing the population control of invasive disease vectors such as Aedes aegypti . Methods such as the sterile and incompatible insect techniques (SIT/IIT) rely on modified males to seek out and successfully mate with females, and in doing so outcompete the wild male population fo...
Article
Full-text available
Effective surveillance of Aedes aegypti (Linnaeus, Diptera: Culicidae) is critical to monitoring the impact of vector control measures when mitigating disease transmission by this species. There are benefits to deploying male-specific traps, particularly when a high level of catch-specificity is desired. Here, the rationale behind the developmental...
Article
Full-text available
Aedes aegypti and Aedes albopictus vector dengue, chikungunya and Zika viruses. With both species expanding their global distributions at alarming rates, developing effective surveillance equipment is a continuing priority for public health researchers. Sound traps have been shown, in limited testing, to be highly species-specific when emitting a f...
Article
Full-text available
Background In the absence of vaccines or drugs, insecticides are the mainstay of Aedes-borne disease control. Their utility is challenged by the slow deployment of resources, poor community compliance and inadequate household coverage. Novel application methods are required.Methodology and principal findingsA 10% w/w metofluthrin "emanator" that pa...
Article
Full-text available
Population genomic approaches can characterise dispersal across a single generation through to many generations in the past, bridging the gap between individual movement and intergenerational gene flow. These approaches are particularly useful when investigating dispersal in recently altered systems, where they provide a way of inferring long‐dista...
Article
Insect-specific flaviviruses (ISFs) have been isolated from a range of mosquito species from different parts of the world. These viruses replicate efficiently in mosquitoes but do not appear to replicate in vertebrates. There is increasing evidence that ISFs persist in nature through vertical transmission, and that they interfere with the replicati...
Preprint
Full-text available
Population genomic approaches can characterise dispersal across a single generation through to many generations in the past, bridging the gap between individual movement and intergenerational gene flow. These approaches are particularly useful when investigating dispersal in recently altered systems, where they provide a way of inferring long-dista...
Article
Full-text available
The global distribution of Aedes albopictus (Skuse) is rapidly expanding which has contributed to the emergence and re-emergence of dengue and chikungunya outbreaks. Improvements in vector surveillance are necessary to facilitate optimized, evidence-based vector control operations. Current trapping technology used to target Ae. albopictus and other...
Article
Full-text available
Background: The Wolbachia incompatible insect technique (IIT) shows promise as a method for eliminating populations of invasive mosquitoes such as Aedes aegypti (Linnaeus) (Diptera: Culicidae) and reducing the incidence of vector-borne diseases such as dengue, chikungunya and Zika. Successful implementation of this biological control strategy relie...
Preprint
Full-text available
Methods such as the sterile and incompatible insect techniques (SIT/IIT) rely on modified males to seek out and successfully mate with females, and in doing so outcompete the wild male population for mates. Currently, these interventions infer the success of mating interactions between male and female insects through area-wide population surveillan...
Article
Full-text available
Simple Summary: Mosquito-borne viral diseases such as dengue, Zika and chikungunya cause a significant global health burden and are currently increasing in outbreak frequency and geographical reach. Wolbachia pipientis, an endosymbiotic bacterium, offers a solution to this. When Wolbachia is introduced into the main mosquito vector of these viruses...
Article
Full-text available
A dengue suppression strategy based on release of Aedes aegypti mosquitoes infected with the bacterium Wolbachia pipientis is being trialed in many countries. Wolbachia inhibits replication and transmission of dengue viruses. Questions remain regarding the long-term stability of virus-suppressive effects. We sequenced the Wolbachia genome and analy...
Article
Full-text available
When a mosquito feeds on a host, it ingests not only its blood meal but also an assortment of microorganisms that are present in the blood, thus acting as an environmental sampler. By using specific tests, it is possible to detect arthropod-borne viruses (arboviruses) like dengue and West Nile viruses in mosquito excreta. Here, we explored the use...
Article
Full-text available
As Aedes aegypti (Linnaeus, Diptera: Culicidae) expands its global distribution and vectors a range of debilitating arboviruses there is an increased need for enhanced mosquito surveillance. Consequently, we developed a Male Aedes Sound Trap (MAST) that requires minimal power and is highly species-specific. Two different versions of the MAST were d...
Article
Full-text available
As Aedes aegypti continues to expand its global distribution, the diseases it vectors (dengue, Zika, chikungunya and yellow fever) are of increasing concern. Modern efforts to control this species include “rear and release” strategies where lab-reared mosquitoes are distributed throughout the landscape to replace or suppress invasive populations. T...
Article
Full-text available
Aedes aegypti (L.) is an important vector of viruses causing dengue, Zika, chikungunya, and yellow fever and as such presents a serious threat to public health in tropical regions. Control programs involving ‘rear and release’ of modified male Ae. aegypti are underway and require effective trapping methods for surveillance of both the released inse...
Article
Full-text available
Background: The w Mel strain of Wolbachia has been successfully introduced into Aedes aegypti mosquitoes and subsequently shown in laboratory studies to reduce transmission of a range of viruses including dengue, Zika, chikungunya, yellow fever, and Mayaro viruses that cause human disease. Here we report the entomological and epidemiological outcom...
Article
Full-text available
Aedes aegypti mosquitoes infected with the wMel strain of Wolbachia are being released into natural mosquito populations in the tropics as a way of reducing dengue transmission. High temperatures adversely affect wMel, reducing Wolbachia density and cytoplasmic incompatibility in some larval habitats that experience large temperature fluctuations....
Article
Full-text available
Aedes aegypti (L.) is an important vector of viruses causing dengue, Zika, chikungunya, and yellow fever and as such is a threat to public health worldwide. Effective trapping methods are essential for surveillance of both the mosquito species and disease presence. The BG-Sentinel (BGS) is a widely used to trap Ae. aegypti but little is known of it...
Article
Aedes aegypti (Linnaeus), the primary vectors of the arboviruses dengue virus and Zika virus, continue to expand their global distributions. In efforts to better control such species, several mosquito control programs are investigating the efficacy of rearing and releasing millions of altered male Aedes throughout landscapes to reduce populations a...
Article
Full-text available
Host seeking is an essential process in mosquito reproduction. Field releases of modified mosquitoes for population replacement rely on successful host seeking by female mosquitoes, but host-seeking ability is rarely tested in a realistic context. We tested the host-seeking ability of female Aedes aegypti mosquitoes using a semi-field system. Femal...
Article
Full-text available
Background: The w Mel strain of Wolbachia has been successfully introduced into Aedes aegypti mosquitoes and subsequently shown in laboratory studies to reduce transmission of a range of viruses including dengue, Zika, chikungunya, yellow fever, and Mayaro viruses that cause human disease. Here we report the entomological and epidemiological outcom...
Article
Full-text available
Background: Sterile male rear-and-release programmes are of growing interest for controlling Aedes aegypti, including use an "incompatible insect technique" (IIT) to suppress transmission of dengue, Zika, and other viruses. Under IIT, males infected with Wolbachia are released into the suppression area to induce cytoplasmic incompatibility in unin...
Article
Full-text available
Received There is an enduring disconnect between the routine surveillance of mosquitoes that transmit dengue viruses and control activities to limit disease spread. A great variety of methods used to collect vector surveillance data exists globally, with program design typically influenced by historical, socio-cultural and cost factors. Surveillanc...
Article
Full-text available
Aedes aegypti is a vector of many significant arboviruses worldwide, including dengue, Zika, chikungunya, and yellow fever viruses. With vector control methodology pivoting toward rearing and releasing large numbers of insects for either population suppression or virus-blocking, economical remote (sentinel) surveillance methods for release tracking...
Article
Full-text available
Background : A number of new technologies are under development for the control of mosquito transmitted viruses, such as dengue, chikungunya and Zika that all require the release of modified mosquitoes into the environment. None of these technologies has been able to demonstrate evidence that they can be implemented at a scale beyond small pilots....
Article
Full-text available
Background: Malaria is the most important vector-borne disease in the world. Epidemiological and ecological studies of malaria traditionally utilize detection of Plasmodium sporozoites in whole mosquitoes or salivary glands by microscopy or serological or molecular assays. However, these methods are labor-intensive, and can over- or underestimate...
Preprint
Full-text available
Host-seeking is an essential process in mosquito reproduction. Field releases of modified mosquitoes for population transformation rely on successful host-seeking by female mosquitoes, but host-seeking ability is rarely tested in a realistic context. We tested the host-seeking ability of female Aedes aegypti mosquitoes using a semi-field system. Fe...
Article
In this perspective, I discuss the great eras of vector control, centring on Aedes aegypti, the primary vector of dengue, Zika and several other viruses. Since the discovery and acceptance of the role of mosquitoes as vectors of disease agents, several significant strategies have been developed and deployed to control them and the diseases they tra...
Article
Full-text available
Background: Malaria transmission varies in intensity amongst Solomon Island villages where Anopheles farauti is the only vector. This variation in transmission intensity might be explained by density-dependent processes during An. farauti larval development, as density dependence can impact adult size with associated fitness costs and daily surviv...
Article
A promising strategy for reducing the transmission of dengue and other arboviral human diseases by Aedes aegypti mosquito vector populations involves field introductions of the endosymbiotic bacteria Wolbachia. Wolbachia infections inhibit viral transmission by the mosquito, and can spread between mosquito hosts to reach high frequencies in the vec...
Article
Full-text available
Wolbachia bacteria are now being introduced into Aedes aegypti mosquito populations for dengue control. When Wolbachia infections are at a high frequency, they influence the local transmission of dengue by direct virus blocking as well as deleterious effects on vector mosquito populations. However, the effectiveness of this strategy could be influe...
Data
Temperatures in sentinel containers placed within the wMel release zone in suburban Cairns. (A) Temperatures recorded by data loggers placed in sentinel buckets (solid lines) and small containers (dashed lines). Containers were either left in the open (red lines), placed in a garden bed (blue lines) or placed under cover (black lines). All containe...
Data
Temperature cycles of thermocyclers in the first (A) and second (B) egg thermal tolerance experiment. (EPS)
Data
All temperature, hatch proportion and Wolbachia density data for experiments. (XLSX)
Data
Temperature cycles experienced in buckets (solid lines), plant pots (dashed lines) and cups (dotted lines) in 99% shade (black lines) and 50% shade (red lines) during the first field experiment from the 10th to the 17th of January 2018. (EPS)
Article
Full-text available
Mosquito-borne diseases are a major public health concern globally and early detection of pathogens is critical to implement vector management and control strategies. Existing methods for pathogen detection include screening sentinel animals for antibodies and analyzing mosquitoes for pathogen presence. While these methods are effective, they are a...
Article
Arbovirus surveillance is crucial for the implementation of vector-borne disease control measures. Recently, it has been demonstrated that mosquitoes with a disseminated arbovirus infection excrete viral RNA, which can be detected by molecular methods. Thereby, mosquito excreta has been proposed as a sample type that could be utilized for arbovirus...
Article
Full-text available
As the incidence of arboviral diseases such as dengue, Zika, chikungunya, and yellow fever increases globally, controlling their primary vector, Aedes aegypti (L.) (Diptera: Culicidae), is of greater importance than ever before. Mosquito control programs rely heavily on effective adult surveillance to ensure methodological efficacy. The Biogents Se...
Article
Full-text available
Challenges in maintaining high effectiveness of classic vector control in urban areas has renewed the interest in indoor residual spraying (IRS) as a promising approach for Aedes-borne disease prevention. While IRS has many benefits, application time and intrusive indoor applications make its scalability in urban areas difficult. Modifying IRS to a...
Article
Full-text available
Japanese encephalitis virus (JEV) is a major cause of neurological disease in Asia. It is a zoonotic flavivirus transmitted between water birds and/or pigs by Culex mosquitoes; humans are dead-end hosts. In 1995, JEV emerged for the first time in northern Australia causing an unprecedented outbreak in the Torres Strait. In this article, we revisit...
Article
Full-text available
Background Species in the Anopheles farauti complex are major malaria vectors in the Asia Pacific region. Anopheline mosquitoes exhibit circadian and diel rhythms in sugar- and blood-feeding (biting), flight activity, oviposition, and in some species, a short-lived dusk/early night associated swarming behaviour during which mating occurs. A behavio...
Preprint
Full-text available
A promising strategy for reducing the transmission of dengue and other arboviral human diseases by Aedes aegypti mosquito vector populations involves field introductions of the endosymbiotic bacteria Wolbachia . Wolbachia infections inhibit viral transmission by the mosquito, and can spread between mosquito hosts to reach high frequencies in the ve...
Article
Full-text available
Background : A number of new technologies are under development for the control of mosquito transmitted viruses, such as dengue, chikungunya and Zika that all require the release of modified mosquitoes into the environment. None of these technologies has been able to demonstrate evidence that they can be implemented at a scale beyond small pilots....