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West Nile virus (WNV) is a mosquito-borne arbovirus that remains a persistent public health challenge in the USA, with seasonal outbreaks that can lead to severe cases. In this study, we detail a real-time prediction system for WNV that incorporates an adapted compartment model to account for the transmission dynamics among birds, mosquitoes and humans, including asymptomatic cases and the influence of weather factors. Using data assimilation techniques, we generate weekly WNV case forecasts for Colorado in 2023, providing valuable insights for public health planning. Comparative analyses underscore the enhanced forecast accuracy achieved by integrating weather variables into our models., Competing Interests: We declare we have no competing interests., (© 2024 The Authors.)

Insecticide formulations with safer environmental profiles and limited off-target effects are desirable to manage medical and veterinary pests. Silver nanoparticles are insecticidal against mosquitos, nonbiting midges, and other insects. The biting midge, Culicoides sonorensis Wirth and Jones, is a vector of agriculturally important pathogens in much of the United States, and this study aimed to examine the insecticidal properties of silver nanoparticles in larvae of this species. Mortality of third-instar larvae was assessed daily for 7 days after exposure to concentrations of silver nanoparticles, sorghum polymer particles, and hybrid silver-sorghum polymer particles. Both silver nanoparticles and silver-sorghum polymer particles were insecticidal, but sorghum polymer particles alone did not significantly contribute to larval mortality. Concentrations of 100 mg/liter of silver nanoparticles achieved >50% mortality at day 7, and 200 mg/liter treatments achieved >75% larval mortality within 24 h. The antimicrobial properties of silver nanoparticles were also examined, and culturable bacteria were recovered from larval-rearing media at 200 mg/liter but not at 400 mg/liter of silver nanoparticles. These data suggest that C. sonorensis larval mortality is primarily caused by silver nanoparticle toxicity and not by the reduction of bacteria (i.e., a larval food source). This work describes the first use of silver nanoparticles in C. sonorensis and shows the potential insecticide applications of these nanoparticles against this agricultural pest. The grain-polymer particles also successfully carried insecticidal silver nanoparticles, and their utility in loading diverse compounds could be a novel toxin delivery system for biting midges and similar pests., (Published by Oxford University Press on behalf of Entomological Society of America 2024.)

Vesicular stomatitis (VS) is a viral disease that affects horses, cattle, and swine that is transmitted by direct contact and hematophagous insects. In 2023, a multi-state outbreak of vesicular stomatitis New Jersey virus (VSNJV) occurred in California, Nevada, and Texas, infecting horses, cattle, and rhinoceros. To identify possible insect vectors, we conducted insect surveillance at various locations in San Diego County, CA, including at a wildlife park. CO 2 baited traps set from mid-May to mid-August 2023 collected 2357 Culicoides biting midges and 1215 Simulium black flies, which are insect genera implicated in VSNJV transmission. Insects were pooled by species, location, and date, then tested for viral RNA. Nine RNA-positive pools of Culicoides spp. and sixteen RNA-positive pools of Simulium spp were detected. Infectious virus was detected by cytopathic effect in 96% of the RNA-positive pools. This is the first report of VSNJV in wild-caught C. bergi , C. freeborni , C. occidentalis , S. argus , S. hippovorum , and S. tescorum. The vector competency of these species for VSNJV has yet to be determined but warrants examination. Active vector surveillance and testing during disease outbreaks increases our understanding of the ecology and epidemiology of VS and informs vector control efforts.

Dengue is a vector-borne disease transmitted by Aedes mosquitoes. The worldwide spread of these mosquitoes and the increasing disease burden have emphasized the need for a spatio-temporal risk map capable of assessing dengue outbreak conditions and quantifying the outbreak risk. Given that the life cycle of Aedes mosquitoes is strongly influenced by habitat temperature, numerous studies have utilized temperature-dependent development rates of these mosquitoes to construct virus transmission and outbreak risk models. In this study, we contribute to existing research by developing a mechanistic model for the mosquito life cycle that accurately captures its non-Markovian nature. Beginning with integral equations to track the mosquito population across different life cycle stages, we demonstrate how to derive the corresponding differential equations using phase-type distributions. This approach can be further applied to similar non-Markovian processes that are currently described with less accurate Markovian models. By fitting the model to data on human dengue cases, we estimate several model parameters, allowing the development of a global spatiotemporal dengue risk map. This risk model employs temperature and precipitation data to assess the environmental suitability for dengue outbreaks in a given area., Competing Interests: Declaration of competing interest Declarations if interest none., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Japanese encephalitis is a disease caused by the Japanese encephalitis virus (JEV) and is a concern for U.S. military personnel stationed in the Republic of Korea (ROK). The recent literature reports a potential shift from GI to GV as the dominant genotype circulating in east Asia. In the ROK, GV has been reported in a few Culex spp., but not in the main JEV vector, Cx . tritaeniorhynchus . The goal of this surveillance was to shed light on the current knowledge of the epidemiology of JEV in the ROK by analyzing mosquito collection data from three consecutive years, 2021-2023, and molecularly detecting and genotyping JEV in all Culex spp. collected in several military locations across the ROK. In this study, we detected only JEV GI in Cx . tritaeniorhynchus in 2021 samples. In contrast, all 2022 and 2023 positive samples were GV and detected in Cx . bitaeniorhynchus , Cx . orientalis , and Cx . pipiens . Results support a shift in JEV genotype in the ROK and suggest that for GV, Culex spp. other than Cx . tritaeniorhynchus may be playing an important role.

Vesicular stomatitis (VS) is a vector-borne livestock disease caused by the vesicular stomatitis New Jersey virus (VSNJV). This study presents the first application of an SEIR-SEI compartmental model to analyze VSNJV transmission dynamics. Focusing on the 2014-2015 outbreak in the United States, the model integrates vertebrate hosts and insect vector demographics while accounting for heterogeneous competency within the populations and observation bias in documented disease cases. Key epidemiological parameters were estimated using Bayesian inference and Markov chain Monte Carlo (MCMC) methods, including the force of infection, effective reproduction number (Rt), and incubation periods. The model revealed significant underreporting, with only 10-24% of infections documented, 23% of which presented with clinical symptoms. These findings underscore the importance of including competence and imperfect detection in disease models to depict outbreak dynamics and inform effective control strategies accurately. As a baseline model, this SEIR-SEI implementation is intended to serve as a foundation for future refinements and expansions to improve our understanding of VS dynamics. Enhanced surveillance and targeted interventions are recommended to manage future VS outbreaks.

Japanese encephalitis virus (JEV) is associated with encephalitis in humans and reproductive and neurological illness in pigs. JEV has expanded beyond its native distribution in southeast Asia, with identifications in Europe (2010) and Africa (2016), and most recently, its spread into mainland Australia (2021-2022). The introduction of JEV into the United States (US) is a public health risk, and could also impact animal health and the food supply. To efficiently and cost-effectively manage risk, a better understanding of how and where diseases will be introduced, transmitted, and spread is required. To achieve this objective, we updated our group's previous qualitative risk assessment using an established semi-quantitative risk assessment tool (MINTRISK) to compare the overall rate of introduction and risk, including impacts, of JEV in seven US regions. The rate of introduction from the current region of distribution was considered negligible for the Northeast, Midwest, Rocky Mountain, West, Alaska, and Hawaii regions. The South region was the only region with a pathway that had a non-negligible rate of introduction; infected mosquito eggs and larvae introduced via imported used tires (very low; 95% uncertainty interval (UI) = negligible to high). The overall risk estimate for the South was very high (95% UI = very low to very high). Based on this risk assessment, the South region should be prioritized for surveillance activities to ensure the early detection of JEV. The assumptions used in this risk assessment, due to the lack of information about the global movement of mosquitoes, number of feral pigs in the US, the role of non-ardeid wild birds in transmission, and the magnitude of the basic reproduction ratio of JEV in a novel region, need to be fully considered as these impact the estimated probability of establishment., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 The Authors.)

Global population continuous growth and increasing consumers' demands for protein-rich diets have posed sustainability challenges for traditional livestock feed sources. Consequently, exploring alternative and sustainable protein sources has become imperative to address the environmental burden and resource limitations associated with conventional ingredients. With respect to food security assurance, insects have emerged as a promising solution due to their exceptional nutritional profile, rapid reproduction rates, and low environmental impact. In the present pilot study, 10% of a soybean meal-based diet was replaced by adult mosquitoes harvested from rice fields. The objective was to assess the effect of this partial substitution on meat quality aspects and consumer acceptance. A total of 40 Cobb hybrid broiler chickens were randomly placed in a control and a mosquito-fed group. The study was conducted for 42 days and carcass physicochemical, nutritional, and microbiological characteristics, as well as sensory attributes were evaluated. Overall, results regarding quality attributes were comparable between the control and the treatment group. The organoleptic evaluation showed that the thighs from the mosquito-fed group had the highest overall consumer acceptance. These outcomes indicate that mosquitoes could be successfully used as a protein source for broiler feed without compromising the quality and acceptability of the meat., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Studies have investigated the potential of using farmed insects in animal feeds; however, little research has been done using wild-caught insects for this purpose. Concerns about inadequate quantities collected, environmental impacts, and the spread of pathogens contribute to the preferred utilization of farmed insects. Nevertheless, by harvesting certain pest species from intensified agricultural operations, producers could provide their animals with affordable and sustainable protein sources while also reducing pest populations. This study explores the possibility of collecting large quantities of pest flies from livestock operations and analyzes the flies' nutritional content, potential pathogen load, and various disinfection methods. Using a newly designed mass collection-trapping device, we collected 5 kg of biomass over 13 wk, primarily house flies, from a poultry facility. While a substantial number of pests were removed from the environment, there was no reduction in the fly population. Short-read sequencing was used to compare the bacterial communities carried by flies from differing source populations, and the bacterial species present in the fly samples varied based on farm type and collection time. Drying and milling the wild-caught flies as well as applying an additional heat treatment significantly reduced the number of culturable bacteria present in or on the flies, though their pathogenicity remains unknown. Importantly, these disinfection methods did not affect the nutritional value of the processed flies. Further research is necessary to fully assess the safety and viability of integrating wild-caught insects into livestock feed; however, these data show promising results in favor of such a system., (Published by Oxford University Press on behalf of Entomological Society of America 2024.)

Animal agriculture is under pressure to increase efficiency, sustainability, and innovation to meet the demands of a rising global population while decreasing adverse environmental effects. Feed cost and availability are 2 of the biggest hurdles to sustainable production. Current diets depend on sources of grain and animal byproduct protein for essential amino acids which have limited sustainability. Insects have arisen as an attractive, sustainable alternative protein source for animal diets due to their favorable nutrient composition, low space and water requirements, and natural role in animal diets. Additionally, insects are capable of bioremediating waste streams including agricultural and food waste, manure, and plastics helping to increase their sustainability. The insect rearing industry has grown rapidly in recent years and shows great economic potential. However, state-of-the-art research is urgently needed to overcome barriers to adoption in commercial animal diets such as regulatory restrictions, production scale issues, and food safety concerns. To address this need, the USDA Agricultural Research Service "MINIstoc: Model for INsect Inclusion" project was created to bring together diverse scientists from across the world to synergistically advance insect meal production and inclusion in animal diets. Here, we provide a short review of insects as feed while describing the MINIstock project which serves as the inspiration for the Journal of Economic Entomology Special Collection "Insects as feed: sustainable solutions for food waste and animal production practices.", (Published by Oxford University Press on behalf of Entomological Society of America 2024.)

Insects are a promising source of high-quality protein, and the insect farming industry will lead to higher sustainability when it overcomes scaling up, cost effectiveness, and automation. In contrast to insect farming (raising and breeding insects as livestock), wild insect harvesting (collecting agricultural insect pests), may constitute a simple sustainable animal protein supplementation strategy. For wild harvest to be successful sufficient insect biomass needs to be collected while simultaneously avoiding the collection of nontarget insects. We assessed the performance of the USDA Biomass Harvest Trap (USDA-BHT) device to collect flying insect biomass and as a mosquito surveillance tool. The USDA-BHT device was compared to other suction traps commonly used for mosquito surveillance (Centers for Disease Control and Prevention (CDC) light traps, Encephalitis virus surveillance traps, and Biogents Sentinel traps). The insect biomass harvested in the USDA-BHT was statistically higher than the one harvested in the other traps, however the mosquito collections between traps were not statistically significantly different. The USDA-BHT collected some beneficial insects, although it was observed that their collection was minimized at night. These findings coupled with the fact that sorting time to separate the mosquitoes from the other collected insects was significantly longer for the USDA-BHT, indicate that the use of this device for insect biomass collection conflicts with its use as an efficient mosquito surveillance tool. Nevertheless, the device efficiently collected insect biomass, and thus can be used to generate an alternative protein source for animal feed., (Published by Oxford University Press on behalf of Entomological Society of America 2024.)

The use of insects as animal feed has the potential to be a green revolution for animal agriculture as insects are a rich source of high-quality protein. Insect farming must overcome challenges such as product affordability and scalability before it can be widely incorporated as animal feed. An alternative is to harvest insect pests from the environment using mass trapping devices and use them as animal feed. For example, intensive agricultural environments generate large quantities of pestiferous insects and with the right harvest technologies, these insects can be used as a protein supplement in traditional animal daily rations. Most insect trapping devices are limited by the biomass they can collect. In that context, and with the goal of using wild collected insects as animal feed, the United States Department of Agriculture-Biomass Harvest Trap (USDA-BHT) was designed and built. The USDA-BHT is a valuable mass trapping device developed to efficiently attract, harvest, and store flying insects from naturally abundant agricultural settings. The trap offers a modular design with adjustable capabilities, and it is an inexpensive device that can easily be built with commonly available parts and tools. The USDA-BHT is also user-friendly and has customizable attractants to target various pest species., (Published by Oxford University Press on behalf of Entomological Society of America 2024.)

Background: Toxins of Bacillus thuringiensis subsp. israelensis (Bti) are safer alternatives for controlling dipteran pests such as black flies and mosquitoes. The biting midge Culicoides sonorensis (Diptera: Ceratopogonidae) is an important pest of livestock in much of the United States and larval midges utilize semi-aquatic habitats which are permissive for Bti product application. Reports suggest that Bti products are ineffective at killing biting midges despite their taxonomic relation to black flies and mosquitoes. Here, we investigate the toxicity of a Bti-based commercial insecticide and its active ingredient in larval Culicoides sonorensis. A suspected mechanism of Bti tolerance is an acidic larval gut, and we used a pH indicator dye to examine larval Culicoides sonorensis gut pH after exposure to Bti., Results: The lethal concentration to kill 90% (LC 90 ) of larvae of the commercial product (386 mg/L) was determined to be almost 10 000 times more than that of some mosquito species, and no concentration of active ingredient tested achieved 50% larval mortality. The larval gut was found to be more acidic after exposure to Bti which inhibits Bti toxin activity. By comparison, 100% mortality was achieved in larval Aedes aegypti at the product's label rate for this species and mosquito larvae had alkaline guts regardless of treatment. Altering the larval rearing water to alkaline conditions enhanced Bti efficacy when using the active ingredient., Conclusion: We conclude that Bti is not practical for larval Culicoides sonorensis control at the same rates as mosquitos but show that alterations or additives to the environment could make the products more effective. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Bluetongue virus (BTV) is a segmented, double-stranded RNA virus transmitted by Culicoides midges that infects ruminants. As global temperatures increase and geographical ranges of midges expand, there is increased potential for BTV outbreaks from incursions of novel serotypes into endemic regions. However, an understanding of the effect of temperature on reassortment is lacking. The objectives of this study were to compare how temperature affected Culicoides survival, virogenesis, and reassortment in Culicoides sonorensis coinfected with two BTV serotypes. Midges were fed blood meals containing BTV-10, BTV-17, or BTV serotype 10 and 17 and maintained at 20 °C, 25 °C, or 30 °C. Midge survival was assessed, and pools of midges were collected every other day to evaluate virogenesis of BTV via qRT-PCR. Additional pools of coinfected midges were collected for BTV plaque isolation. The genotypes of plaques were determined using next-generation sequencing. Warmer temperatures impacted traits related to vector competence in offsetting ways: BTV replicated faster in midges at warmer temperatures, but midges did not survive as long. Overall, plaques with BTV-17 genotype dominated, but BTV-10 was detected in some plaques, suggesting parental strain fitness may play a role in reassortment outcomes. Temperature adds an important dimension to host-pathogen interactions with implications for transmission and evolution.

Orbiviruses are of significant importance to the health of wildlife and domestic animals worldwide; the major orbiviruses transmitted by multiple biting midge (Culicoides) species include bluetongue virus, epizootic hemorrhagic disease virus, and African horse sickness virus. The viruses, insect vectors, and hosts are anticipated to be impacted by global climate change, altering established Orbivirus epidemiology. Changes in global climate have the potential to alter the vector competence and extrinsic incubation period of certain biting midge species, affect local and long-distance dispersal dynamics, lead to range expansion in the geographic distribution of vector species, and increase transmission period duration (earlier spring onset and later fall transmission). If transmission intensity is associated with weather anomalies such as droughts and wind speeds, there may be changes in the number of outbreaks and periods between outbreaks for some regions. Warmer temperatures and changing climates may impact the viral genome by facilitating reassortment and through the emergence of novel viral mutations. As the climate changes, Orbivirus epidemiology will be inextricably altered as has been seen with recent outbreaks of bluetongue, epizootic hemorrhagic disease, and African horse sickness outside of endemic areas, and requires interdisciplinary teams and approaches to assess and mitigate future outbreak threats., (Published by Oxford University Press on behalf of Entomological Society of America 2023.)

Rift Valley fever virus (RVFV) (Bunyavirales: Phlebovirus) is a prominent vector-borne zoonotic disease threat to global agriculture and public health. Risks of introduction into nonendemic regions are tied to changing climate regimes and other dynamic environmental factors that are becoming more prevalent, as well as virus evolutionary factors and human/animal movement. Endemic to the African continent, RVFV has caused large epizootics at the decadal scale since the early 20th century but has spread to the Arabian Peninsula and shows increasing patterns of interepizootic transmission on the annual scale. This virus can be transmitted by mosquitoes as well as through direct contact with infected tissues and can cause sporadic to widespread morbidity and mortality in domestic ungulate livestock as well as humans. High viremias in infected livestock moved for legal and illegal trade as well as in infected mosquitoes or human travelers can spread this virus worldwide. With increasing global commerce, it is likely RVFV will be introduced to new areas with suitable hosts, mosquito vector species, and environments. However, the strong mosquito component of RVFV epidemiology combined with advancements in vaccines, diagnostics, and virus evolutionary factors create opportunities for strategies to leverage models of connectivity among potential source and emerging regions to target surveillance and mitigation activities to reduce the risk of RVFV introduction, or contain the virus should it be introduced, into new regions., (Published by Oxford University Press on behalf of Entomological Society of America 2023.)

Culicoides are small biting midges with the capacity to transmit important livestock pathogens around much of the world, and their impacts on animal welfare are likely to expand. Hemorrhagic diseases resulting from Culicoides -vectored viruses, for example, can lead to millions of dollars in economic damages for producers. Chemical insecticides can reduce Culicoides abundance but may not suppress population numbers enough to prevent pathogen transmission. These insecticides can also cause negative effects on non-target organisms and ecosystems. RNA interference (RNAi) is a cellular regulatory mechanism that degrades mRNA and suppresses gene expression. Studies have examined the utility of this mechanism for insect pest control, and with it, have described the hurdles towards producing, optimizing, and applying these RNAi-based products. These methods hold promise for being highly specific and environmentally benign when compared to chemical insecticides and are more transient than engineering transgenic insects. Given the lack of available control options for Culicoides , RNAi-based products could be an option to treat large areas with minimal environmental impact. In this study, we describe the state of current Culicoides control methods, successes and hurdles towards using RNAi for pest control, and the necessary research required to bring an RNAi-based control method to fruition for Culicoides midges.

Most population genetic studies concern spatial genetic differentiation, but far fewer aim at analyzing the temporal genetic changes that occur within populations. Vector species, including mosquitoes and biting midges, are often characterized by oscillating adult population densities, which may affect their dispersal, selection, and genetic diversity over time. Here, we used a population of Culicoides sonorensis from a single site in California to investigate short-term (intra-annual) and long-term (inter-annual) temporal variation in genetic diversity over a 3 yr period. This biting midge species is the primary vector of several viruses affecting both wildlife and livestock, thus a better understanding of the population dynamics of this species can help inform epidemiological studies. We found no significant genetic differentiation between months or years, and no correlation between adult populations and the inbreeding coefficient (FIS). However, we show that repeated periods of low adult abundance during cooler winter months resulted in recurring bottleneck events. Interestingly, we also found a high number of private and rare alleles, which suggests both a large, stable population, as well as a constant influx of migrants from nearby populations. Overall, we showed that the high number of migrants maintains a high level of genetic diversity by introducing new alleles, while this increased diversity is counterbalanced by recurrent bottleneck events potentially purging unfit alleles each year. These results highlight the temporal influences on population structure and genetic diversity in C. sonorensis and provide insight into factors effecting genetic variation that may occur in other vector species with fluctuating populations., (Published by Oxford University Press on behalf of Entomological Society of America 2023.)

Mosquitoes pose a significant risk to millions of people worldwide since they can transmit pathogens. Current methods to control mosquito populations include the use of synthetic pesticides. Nanotechnology may be a solution to develop new mosquito control. However, one barrier to expanding the impact of nanomaterials is the ability to mass-produce the particles. Here, we report a novel hybrid particle synthesis combining micro- and nanoparticles using the coprecipitation technique with the potential for mass production. These particles may have applications as a mosquito larvacide. The particles reported here were designed using a microparticle zein polymer as the core and a nanoparticle silver as the active ingredient. The hybrid NPs reported here targeted a late-stage mosquito larvae and that resulted in a high larval mortality concentration (1.0 ppm, LC 90 ) and suppression of pupal emergence at 0.1 ppm. This research demonstrates the efficacy of a plant-based core with a metal-based AI coating (AgNPs) against larval mosquitoes., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Dengue fever remains a significant public health concern in many tropical and subtropical countries, and there is still a need for a system that can effectively combine global risk assessment with timely incidence forecasting. This research describes an integrated application called PICTUREE-Aedes, which can collect and analyze dengue-related data, display simulation results, and forecast outbreak incidence. PICTUREE-Aedes automatically updates global temperature and precipitation data and contains historical records of dengue incidence (1960-2012) and Aedes mosquito occurrences (1960-2014) in its database. The application utilizes a mosquito population model to estimate mosquito abundance, dengue reproduction number, and dengue risk. To predict future dengue outbreak incidence, PICTUREE-Aedes applies various forecasting techniques, including the ensemble Kalman filter, recurrent neural network, particle filter, and super ensemble forecast, which are all based on user-entered case data. The PICTUREE-Aedes' risk estimation identifies favorable conditions for potential dengue outbreaks, and its forecasting accuracy is validated by available outbreak data from Cambodia.

The most prevalent insect sampling and surveillance problem is powering insect traps in the field. Most modern light traps use 6-V power supplies such as the Centers for Disease Control and Prevention (CDC) suction trap. Buck converter modules efficiently reduce 12-V direct current power to 6-V, which permits the use of higher voltage batteries with lower voltage traps, resulting in longer operational duration and reduced labor requirements associated with replacing and recharging batteries in the field. We evaluated several battery configurations of 6- and 12-V lead-acid batteries in various sizes (10-20 ampere-hours) and addressed, in the circuit design, common problems that occur when using the buck converter (such as crossing polarity and excessive battery depletion). The efficacy of each configuration was assessed by measuring the voltage and suction while powering a 6-V CDC light trap. The buck converter permitted the use of cheaper and more commonly available 12-V batteries to run the CDC light traps and resulted in longer effective operation time as measured by air speed., (Copyright © 2023 by The American Mosquito Control Association, Inc.)

Background: West Nile virus (WNV) is the leading cause of mosquito-borne illness in the continental USA. WNV occurrence has high spatiotemporal variation, and current approaches to targeted control of the virus are limited, making forecasting a public health priority. However, little research has been done to compare strengths and weaknesses of WNV disease forecasting approaches on the national scale. We used forecasts submitted to the 2020 WNV Forecasting Challenge, an open challenge organized by the Centers for Disease Control and Prevention, to assess the status of WNV neuroinvasive disease (WNND) prediction and identify avenues for improvement., Methods: We performed a multi-model comparative assessment of probabilistic forecasts submitted by 15 teams for annual WNND cases in US counties for 2020 and assessed forecast accuracy, calibration, and discriminatory power. In the evaluation, we included forecasts produced by comparison models of varying complexity as benchmarks of forecast performance. We also used regression analysis to identify modeling approaches and contextual factors that were associated with forecast skill., Results: Simple models based on historical WNND cases generally scored better than more complex models and combined higher discriminatory power with better calibration of uncertainty. Forecast skill improved across updated forecast submissions submitted during the 2020 season. Among models using additional data, inclusion of climate or human demographic data was associated with higher skill, while inclusion of mosquito or land use data was associated with lower skill. We also identified population size, extreme minimum winter temperature, and interannual variation in WNND cases as county-level characteristics associated with variation in forecast skill., Conclusions: Historical WNND cases were strong predictors of future cases with minimal increase in skill achieved by models that included other factors. Although opportunities might exist to specifically improve predictions for areas with large populations and low or high winter temperatures, areas with high case-count variability are intrinsically more difficult to predict. Also, the prediction of outbreaks, which are outliers relative to typical case numbers, remains difficult. Further improvements to prediction could be obtained with improved calibration of forecast uncertainty and access to real-time data streams (e.g. current weather and preliminary human cases)., (© 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Background: Proper vector surveillance relies on the ability to identify species of interest accurately and efficiently, though this can be difficult in groups containing cryptic species. Culicoides Latreille is a genus of small biting flies responsible for the transmission of numerous pathogens to a multitude of vertebrates. Regarding pathogen transmission, the C. variipennis species complex is of particular interest in North America. Of the six species within this group, only C. sonorensis Wirth & Jones is a proven vector of bluetongue virus and epizootic hemorrhagic disease virus. Unfortunately, subtle morphological differences, cryptic species, and mitonuclear discordance make species identification in the C. variipennis complex challenging. Recently, single-nucleotide polymorphism (SNP) analysis enabled discrimination between the species of this group; however, this demanding approach is not practical for vector surveillance., Methods: The aim of the current study was to develop a reliable and affordable way of distinguishing between the species within the C. variipennis complex, especially C. sonorensis. Twenty-five putative microsatellite markers were identified using the C. sonorensis genome and tested for amplification within five species of the C. variipennis complex. Machine learning was then used to determine which markers best explain the genetic differentiation between species. This led to the development of a subset of four and seven markers, which were also tested for species differentiation., Results: A total of 21 microsatellite markers were successfully amplified in the species tested. Clustering analyses of all of these markers recovered the same species-level identification as the previous SNP data. Additionally, the subset of seven markers was equally capable of accurately distinguishing between the members of the C. variipennis complex as the 21 microsatellite markers. Finally, one microsatellite marker (C508) was found to be species-specific, only amplifying in the vector species C. sonorensis among the samples tested., Conclusions: These microsatellites provide an affordable way to distinguish between the sibling species of the C. variipennis complex and could lead to a better understanding of the species dynamics within this group. Additionally, after further testing, marker C508 may allow for the identification of C. sonorensis with a single-tube assay, potentially providing a powerful new tool for vector surveillance in North America., (© 2022. The Author(s).)

The inability to distinguish between species can be a serious problem in groups responsible for pathogen transmission. Culicoides biting midges transmit many pathogenic agents infecting wildlife and livestock. In North America, the C. variipennis species complex contains three currently recognized species, only one of which is a known vector, but limited species-specific characters have hindered vector surveillance. Here, genomic data were used to investigate population structure and genetic differentiation within this species complex. Single nucleotide polymorphism data were generated for 206 individuals originating from 17 locations throughout the United States and Canada. Clustering analyses suggest the occurrence of two additional cryptic species within this complex. All five species were significantly differentiated in both sympatry and allopatry. Evidence of hybridization was detected in three different species pairings indicating incomplete reproductive isolation. Additionally, COI sequences were used to identify the hybrid parentage of these individuals, which illuminated discordance between the divergence of the mitochondrial and nuclear datasets., (© 2022. The Author(s).)

Epizootic hemorrhagic disease (EHD) is an insect-transmitted viral disease of wild and domestic ruminants. It was first described following a 1955 epizootic in North American white-tailed deer ( Odocoileus virginianus ), a species which is highly susceptible to the causative agent of EHD, epizootic hemorrhagic disease virus (EHDV). EHDV has been detected globally across tropical and temperate regions, largely corresponding to the presence of Culicoides spp. biting midges which transmit the virus between ruminant hosts. It regularly causes high morbidity and mortality in wild and captive deer populations in endemic areas during epizootics. Although cattle historically have been less susceptible to EHDV, reports of clinical disease in cattle have increased in the past two decades. There is a pressing need to identify new methods to prevent and mitigate outbreaks and reduce the considerable impacts of EHDV on livestock and wildlife. This review discusses recent research advancements towards the control of EHDV, including the development of new investigative tools and progress in basic and applied research focused on virus detection, disease mitigation, and vector control. The potential impacts and implications of these advancements on EHD management are also discussed.

Mosquito larvae encounter diverse assemblages of bacteria (i.e., "microbiota") and fungi in the aquatic environments that they develop in. However, while a number of studies have addressed the diversity and function of microbiota in mosquito life history, relatively little is known about mosquito-fungus interactions outside several key fungal entomopathogens. In this study, we used high-throughput sequencing of internal transcribed spacer 2 (ITS2) metabarcode markers to provide the first simultaneous characterization of the fungal communities in field-collected Aedes albopictus larvae and their associated aquatic environments. Our results reveal unprecedented variation in fungal communities among adjacent but discrete larval breeding habitats. Our results also reveal a distinct fungal community assembly in the mosquito gut versus other tissues, with gut-associated fungal communities being most similar to those present in the environment where larvae feed. Altogether, our results identify the environment as the dominant factor shaping the fungal community associated with mosquito larvae, with no evidence of environmental filtering by the gut. These results also identify mosquito feeding behavior and fungal mode of nutrition as potential drivers of tissue-specific fungal community assembly after environmental acquisition. IMPORTANCE The Asian tiger mosquito, Aedes albopictus, is the dominant mosquito species in the United States and an important vector of arboviruses of major public health concern. One aspect of mosquito control to curb mosquito-borne diseases has been the use of biological control agents such as fungal entomopathogens. Recent studies also demonstrate the impact of mosquito-associated microbial communities on various mosquito traits, including vector competence. However, while much research attention has been dedicated to understanding the diversity and function of mosquito-associated bacterial communities, relatively little is known about mosquito-associated fungal communities. A better understanding of the factors that drive fungal community diversity and assembly in mosquitoes will be essential for future efforts to target mosquito-associated bacteria and fungi for mosquito and mosquito-borne disease control.

Mosquito-borne West Nile virus (WNV) is the causative agent of West Nile disease in humans, horses, and some bird species. Since the initial introduction of WNV to the United States (US), approximately 30,000 horses have been impacted by West Nile neurologic disease and hundreds of additional horses are infected each year. Research describing the drivers of West Nile disease in horses is greatly needed to better anticipate the spatial and temporal extent of disease risk, improve disease surveillance, and alleviate future economic impacts to the equine industry and private horse owners. To help meet this need, we integrated techniques from spatiotemporal epidemiology, eco-phylogenetics, and distributional ecology to assess West Nile disease risk in horses throughout the contiguous US. Our integrated approach considered horse abundance and virus exposure, vector and host distributions, and a variety of extrinsic climatic, socio-economic, and environmental risk factors. Birds are WNV reservoir hosts, and therefore we quantified avian host community dynamics across the continental US to show intra-annual variability in host phylogenetic structure and demonstrate host phylodiversity as a mechanism for virus amplification in time and virus dilution in space. We identified drought as a potential amplifier of virus transmission and demonstrated the importance of accounting for spatial non-stationarity when quantifying interaction between disease risk and meteorological influences such as temperature and precipitation. Our results delineated the timing and location of several areas at high risk of West Nile disease and can be used to prioritize vaccination programs and optimize virus surveillance and monitoring.

Vesicular stomatitis (VS) is a vector-borne livestock disease caused by vesicular stomatitis New Jersey virus (VSNJV) or vesicular stomatitis Indiana virus (VSIV). The disease circulates endemically in northern South America, Central America, and Mexico and only occasionally causes outbreaks in the United States. Over the past 20 years, VSNJV outbreaks in the southwestern and Rocky Mountain regions occurred with incursion years followed by virus overwintering and subsequent expansion outbreak years. Regulatory response by animal health officials is deployed to prevent spread from lesioned animals. The 2019 VS incursion was the largest in 40 years, lasting from June to December 2019 with 1144 VS-affected premises in 111 counties in eight states (Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas, Utah, and Wyoming) and was VSIV serotype, last isolated in 1998. A subsequent expansion occurred from April to October 2020 with 326 VS-affected premises in 70 counties in eight states (Arizona, Arkansas, Kansas, Missouri, Nebraska, New Mexico, Oklahoma, and Texas). The primary serotype in 2020 was VSIV, but a separate incursion of VSNJV occurred in south Texas. Summary characteristics of the outbreaks are presented along with VSV-vector sampling results and phylogenetic analysis of VSIV isolates providing evidence of virus overwintering.

Bluetongue virus (BTV) is a segmented RNA virus transmitted by Culicoides midges. Climatic factors, animal movement, vector species, and viral mutation and reassortment may all play a role in the occurrence of BTV outbreaks among susceptible ruminants. We used two enzootic strains of BTV (BTV-2 and BTV-10) to explore the potential for Culicoides sonorensis , a key North American vector, to be infected with these viruses, and identify the impact of temperature variations on virogenesis during infection. While BTV-10 replicated readily in C. sonorensis following an infectious blood meal, BTV-2 was less likely to result in productive infection at biologically relevant exposure levels. Moreover, when C. sonorensis were co-exposed to both viruses, we did not detect reassortment between the two viruses, despite previous in vitro findings indicating that BTV-2 and BTV-10 are able to reassort successfully. These results highlight that numerous factors, including vector species and exposure dose, may impact the in vivo replication of varying BTV strains, and underscore the complexities of BTV ecology in North America.

West Nile virus (WNV) is the most common arthropod-borne virus (arbovirus) in the United States (US) and is the leading cause of viral encephalitis in the country. The virus has affected tens of thousands of US persons total since its 1999 North America introduction, with thousands of new infections reported annually. Approximately 1% of humans infected with WNV acquire neuroinvasive West Nile Disease (WND) with severe encephalitis and risk of death. Research describing WNV ecology is needed to improve public health surveillance, monitoring, and risk assessment. We applied Bayesian joint-spatiotemporal modeling to assess the association of vector surveillance data, host species richness, and a variety of other environmental and socioeconomic disease risk factors with neuroinvasive WND throughout the conterminous US. Our research revealed that an aging human population was the strongest disease indicator, but climatic and vector-host biotic interactions were also significant in determining risk of neuroinvasive WND. Our analysis also identified a geographic region of disproportionately high neuroinvasive WND disease risk that parallels the Continental Divide, and extends southward from the US-Canada border in the states of Montana, North Dakota, and Wisconsin to the US-Mexico border in western Texas. Our results aid in unraveling complex WNV ecology and can be applied to prioritize disease surveillance locations and risk assessment.

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.

Biting midges of the genus Culicoides transmit disease-causing agents resulting in a significant economic impact on livestock industries in many parts of the world. Localized control efforts, such as removal of larval habitat or pesticide application, can be logistically difficult, expensive and ineffective if not instituted and maintained properly. With these limitations, a population-level approach to the management of Culicoides midges should be investigated as a means to replace or supplement existing control strategies. Next-generation control methods such as Wolbachia- and genetic-based population suppression and replacement are being investigated in several vector species. Here we assess the feasibility and applicability of these approaches for use against biting midges. We also discuss the technical and logistical hurdles needing to be addressed for each method to be successful, as well as emphasize the importance of addressing community engagement and involving stakeholders in the investigation and development of these approaches.

Vesicular stomatitis viruses (VSVs) cause a condition known as vesicular stomatitis (VS), which results in painful lesions in equines, cattle, swine, and camelids, and when transmitted to humans, can cause flu-like symptoms. When animal premises are affected by VS, they are subject to a quarantine. The equine industry more broadly may incur economic losses due to interruptions of animal trade and transportation to shows, competitions, and other events. Equine owners, barn managers, and veterinarians can take proactive measures to reduce the risk of equines contracting VS. To identify appropriate risk management strategies, it helps to understand which biting insects are capable of transmitting the virus to animals, and to identify these insect vectors' preferred habitats and behaviors. We make this area of science more accessible to equine owners, barn managers, and veterinarians, by (1) translating the most relevant scientific information about biting insect vectors of VSV and (2) identifying practical management strategies that might reduce the risk of equines contracting VSV from infectious biting insects or from other equines already infected with VSV. We address transmission risk at four different spatial scales-the animal, the barn/shelter, the barnyard/premises, and the surrounding environment/neighborhood-noting that a multiscale and spatially collaborative strategy may be needed to reduce the risk of VS., (Published by Elsevier Inc.)

Mosquito-borne viruses will continue to emerge and generate a significant public health burden around the globe. Here, we provide a longitudinal perspective on how the emergence of mosquito-borne viruses in the Americas has triggered reactionary funding by sponsored agencies, stimulating a number of publications, innovative development of traps, and augmented capacity. We discuss the return on investment (ROI) from the oscillation in federal funding that influences demand for surveillance and control traps and leads to innovation and research productivity., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

Rift Valley fever virus (RVFV) causes severe disease in domestic ungulates (cattle, goats, and sheep) and a febrile illness in humans (with ∼1% case fatality rate). This virus has been spreading geographically, and there is concern of it spreading to Europe or the Americas. Environmental temperature can significantly affect the ability of mosquitoes to transmit an arbovirus. However, these effects are not consistent among viruses or mosquito species. Therefore, we evaluated the effect of incubation temperatures ranging from 14°C to 30°C on infection and dissemination rates for Culex tarsalis and Aedes taeniorhynchus allowed to feed on hamsters infected with RVFV. Engorged mosquitoes were randomly allocated to cages and placed in incubators maintained at 14°C, 18°C, 22°C, 26°C, or 30°C. Although infection rates detected in Cx. tarsalis increased with increasing holding temperature, holding temperature had no effect on infection rates detected in Ae. taeniorhynchus . However, for both species, the percentage of mosquitoes with a disseminated infection after specific extrinsic incubation periods (4, 7, 10, 14, 17, or 21 days) increased with increasing incubation holding temperature, even after adjusting for the apparent increase in infection rate in Cx. tarsalis . The effects of environmental factors, such as ambient temperature, need to be taken into account when developing models for viral persistence and spread in nature.

Japanese encephalitis (JE) is a zoonotic, emerging disease transmitted by mosquito vectors infected with the Japanese encephalitis virus (JEV). Its potential for emergence into susceptible regions is high, including in the United States (US), and is a reason of economic concern among the agricultural community, and to public health due to high morbidity and mortality rates in humans. While exploring the complexities of interactions involved with viral transmission, we proposed a new outlook on the role of vectors, hosts and the environment under changing conditions. For instance, the role of feral pigs may have been underappreciated in our previous work, given research keeps pointing to the importance of susceptible populations of wild swine in naïve regions as key elements for the introduction of emergent vector-borne diseases. High risk of JEV introduction has been associated with the transportation of infected mosquitoes via aircraft. Nonetheless, no JEV outbreaks have been reported in the US to date and results from a qualitative risk assessment considered the risk of establishment to be negligible under the current conditions (environmental, vector, pathogen, and host). In this work, we discuss virus-vector-host interactions and ecological factors important for virus transmission and spread, review research on the risk of JEV introduction to the US considering the implications of risk dismissal as it relates to past experiences with similar arboviruses, and reflect on future directions, challenges, and implications of a JEV incursion., (Copyright © 2020 Oliveira, Cohnstaedt, Noronha, Mitzel, McVey and Cernicchiaro.)

As an emerging infectious disease, the 2019 coronavirus disease (COVID-19) has developed into a global pandemic. During the initial spreading of the virus in China, we demonstrated the ensemble Kalman filter performed well as a short-term predictor of the daily cases reported in Wuhan City. Second, we used an individual-level network-based model to reconstruct the epidemic dynamics in Hubei Province and examine the effectiveness of non-pharmaceutical interventions on the epidemic spreading with various scenarios. Our simulation results show that without continued control measures, the epidemic in Hubei Province could have become persistent. Only by continuing to decrease the infection rate through 1) protective measures and 2) social distancing can the actual epidemic trajectory that happened in Hubei Province be reconstructed in simulation. Finally, we simulate the COVID-19 transmission with non-Markovian processes and show how these models produce different epidemic trajectories, compared to those obtained with Markov processes. Since recent studies show that COVID-19 epidemiological parameters do not follow exponential distributions leading to Markov processes, future works need to focus on non-Markovian models to better capture the COVID-19 spreading trajectories. In addition, shortening the infectious period via early case identification and isolation can slow the epidemic spreading significantly., Competing Interests: None., (© 2020 The Authors.)

Background: Biting midges of the genus Culicoides vector multiple veterinary pathogens and are difficult to control. Endosymbionts particularly Wolbachia pipientis may offer an alternative to control populations of Culicoides and/or impact disease transmission in the form of population suppression or replacement strategies., Methods: Culicoides sonorensis cell lines were transfected with a Wolbachia infection using a modified shell vial technique. Infections were confirmed using PCR and cell localization using fluorescent in situ hybridization (FISH). The stability of Wolbachia infections and density was determined by qPCR. qPCR was also used to examine immune genes in the IMD, Toll and JACK/STAT pathways to determine if Wolbachia were associated with an immune response in infected cells., Results: Here we have transfected two Culicoides sonorensis cell lines (W3 and W8) with a Wolbachia infection (walbB) from donor Aedes albopictus Aa23 cells. PCR and FISH showed the presence of Wolbachia infections in both C. sonorensis cell lines. Infection densities were higher in the W8 cell lines when compared to W3. In stably infected cells, genes in the immune Toll, IMD and JAK/STAT pathways were upregulated, along with Attacin and an Attacin-like anti-microbial peptides., Conclusions: The successful introduction of Wolbachia infections in C. sonorensis cell lines and the upregulation of immune genes, suggest the utility of using Wolbachia for a population replacement and/or population suppression approach to limit the transmission of C. sonorensis vectored diseases. Results support the further investigation of Wolbachia induced pathogen inhibitory effects in Wolbachia-infected C. sonorensis cell lines and the introduction of Wolbachia into C. sonorensis adults via embryonic microinjection to examine for reproductive phenotypes and host fitness effects of a novel Wolbachia infection.

The purpose of this risk assessment (RA) was to qualitatively estimate the risk of emergence of the Japanese encephalitis virus (JEV) in the United States (US). We followed the framework for RA of emerging vector-borne livestock diseases (de Vos et al. 2011), which consists of a structured questionnaire, whose answers to questions can be delivered in risk categories, descriptive statements, or yes or no type of answers, being supported by the literature. The most likely pathways of introduction of JEV identified were: (a) entry through infected vectors (by aircraft, cargo ships, tires, or wind); (b) import of infected viremic animals; (c) entry of viremic migratory birds; (d) import of infected biological materials; (e) import of infected animal products; (f) entry of infected humans; and (g) import/production of contaminated biological material (e.g., vaccines). From these pathways, the probability of introduction of JEV through infected adult mosquitoes via aircraft was considered very high and via ships/containers was deemed low to moderate. The probability of introduction via other pathways or modes of entry (vector eggs or larvae, hosts, and vaccines) was considered negligible. The probability of transmission of JEV was variable, ranging from low to high (in the presence of both competent vectors and hosts), depending on the area of introduction within the US. Lastly, the probability of establishment of JEV in the continental US was considered negligible. For that reason, we stopped the risk assessment at this point of the framework. This RA provides important information regarding the elements that contribute to the risk associated with the introduction of JEV in the US. This RA also indicates that infected mosquitoes transported in aircraft (and cargo ships) are the most likely pathway of JEV entry and therefore, mitigation strategies should be directed towards this pathway., (© 2019 Blackwell Verlag GmbH.)

The recent outbreaks of the insect-vectored Zika virus have demonstrated its potential to be sexually transmitted, which complicates modeling and our understanding of disease dynamics. Autochthonous outbreaks in the US mainland may be a consequence of both modes of transmission, which affect the outbreak size, duration, and virus persistence. We propose a novel individual-based interconnected network model that incorporates both insect-vectored and sexual transmission of this pathogen. This model interconnects a homogeneous mosquito vector population with a heterogeneous human host contact network. The model incorporates the seasonal variation of mosquito abundance and characterizes host dynamics based on age group and gender in order to produce realistic projections. We use a sexual contact network which is generated on the basis of real world sexual behavior data. Our findings suggest that for a high relative transmissibility of asymptomatic hosts, Zika virus shows a high probability of sustaining in the human population for up to 3 months without the presence of mosquito vectors. Zika outbreaks are strongly affected by the large proportion of asymptomatic individuals and their relative transmissibility. The outbreak size is also affected by the time of the year when the pathogen is introduced. Although sexual transmission has a relatively low contribution in determining the epidemic size, it plays a role in sustaining the epidemic and creating potential endemic scenarios.

West Nile virus (WNV)-a mosquito-borne arbovirus-entered the USA through New York City in 1999 and spread to the contiguous USA within three years while transitioning from epidemic outbreaks to endemic transmission. The virus is transmitted by vector competent mosquitoes and maintained in the avian populations. WNV spatial distribution is mainly determined by the movement of residential and migratory avian populations. We developed an individual-level heterogeneous network framework across the USA with the goal of understanding the long-range spatial distribution of WNV. To this end, we proposed three distance dispersal kernels model: 1) exponential-short-range dispersal, 2) power-law-long-range dispersal in all directions, and 3) power-law biased by flyway direction -long-range dispersal only along established migratory routes. To select the appropriate dispersal kernel we used the human case data and adopted a model selection framework based on approximate Bayesian computation with sequential Monte Carlo sampling (ABC-SMC). From estimated parameters, we find that the power-law biased by flyway direction kernel is the best kernel to fit WNV human case data, supporting the hypothesis of long-range WNV transmission is mainly along the migratory bird flyways. Through extensive simulation from 2014 to 2016, we proposed and tested hypothetical mitigation strategies and found that mosquito population reduction in the infected states and neighboring states is potentially cost-effective., Competing Interests: The authors have declared that no competing interests exist.

This work describes the use of entomological studies combined with in silico models (computer simulations derived from numerical models) to assess the efficacy of a novel device for controlled release of spatial repellents. Controlled Release Devices (CRDs) were tested with different concentrations of metofluthrin and tested against An. quadrimaculatus mosquitoes using arm-in cage, semi-field, and outdoor studies. Arm-in-cage trials showed an approximate mean values for mosquito knockdown of 40% and mosquito bite reduction of 80% for the optimal metofluthrin formulation for a 15-minute trial. Semi-field outdoor studies showed a mean mortality of a 50% for 24 hour trial and 75% for a 48 hour trial for optimal concentrations. Outdoors studies showed an approximate mean mortality rate of 50% for a 24 hour trial for optimal concentrations. Numerical simulations based on Computational Fluid Dynamics (CFD) were performed in order to obtain spatial concentration profiles for 24 hour and 48 hour periods. Experimental results were correlated with simulation results in order to obtain a functional model that linked mosquito mortality with the estimated spatial concentration for a given period of time. Such correlation provides a powerful insight in predicting the effectiveness of the CRDs as a vector-control tool. While CRDs represent an alternative to current spatial repellent delivery methods, such as coils, candles, electric repellents, and passive emanators based on impregnated strips, the presented method can be applied to any spatial vector control treatment by correlating entomological endpoints, i.e. mortality, with in-silico simulations to predict overall efficacy. The presented work therefore presents a new methodology for improving design, development and deployment of vector-control tools to reduce transmission of vector-borne diseases, including malaria and dengue., Competing Interests: NME and PG have been associated with GearJump Technologies, LLC during performance of this research work. MP and NME work for the US Army. The other authors have declared that no competing interests exist.

The diversity of nonculicid biting flies was surveyed in Sunset Zoo, Manhattan, KS, by carbon dioxide-baited traps. A total of 8,399 nonculicid biting-fly females representing 32 species and 5 families were collected. Twenty-one biting midge (Ceratopogonidae: Culicoides ) and 7 black fly (Simuliidae) species were collected, including new state records of 3 Culicoides and 1 simuliid. The species richness of Culicoides and Simuliidae within the zoo represents 72.4% and 41.2%, respectively, of the fauna known to occur in Kansas. Trap type significantly influenced ( P < 0.05) collections of the 5 species analyzed, and trapping period affected 3 species. The diversity and abundance of nonculicid biting flies in the zoo as related to animal health and wellness is discussed.

Background: The emergence of mosquitoes that can avoid indoor-deployed interventions, such as treated bed nets and indoor residual spraying, threatens the mainstay of malaria control in Zambia. Furthermore, the requirement for high coverage of these tools poses operational challenges. Spatial repellents are being assessed to supplement these vector control tools, but limitations exist in the residual effect of the repellent and the need for external power or heat for diffusion of the volatiles., Methods: A semi-field evaluation of a novel controlled release spatial repellent device (CRD) was conducted in Macha, Zambia. These devices emanate metofluthrin with no need for external power. Devices were deployed in huts within the semi-field system (SFS). Female Anopheles gambiae sensu stricto released within the SFS were trapped overnight by light traps and collected by aspiration the next morning inside and outside of huts to determine the extent of mosquito repellency and the impact on host-seeking and survival. Experiments studied the impact of number of devices as well as the presence of hut occupants. The study was complemented with numerical methods based on computational fluid dynamics to simulate spatial distribution of metofluthrin., Results: Presence of CRDs was associated with significant reductions in indoor counts of mosquitoes, regardless of whether huts were occupied or not. Repellency ranged from 15 to 60% compared to huts with no devices. Reducing the number of devices from 16 to 4 had little impact on repellency. When huts were occupied, indoor mosquito host-seeking was higher in the presence of CRDs, whilst survival was significantly reduced., Conclusions: This study demonstrated that deployment of as few as four CRDs within a hut was associated with reduced indoor mosquito densities. As would be expected, presence of occupants within huts, resulted in greater indoor catches (both with and without devices). The increased indoor mosquito host-seeking and mortality in huts when devices were present may be explained by the excito-repellency activity of metofluthrin. These semi-field experiments provide preliminary data on the utility of CRD spatial repellents to reduce indoor densities of An. gambiae mosquitoes. Studies will further investigate the impact of CRDs on mosquito behaviour as well as epidemiological protective efficacy.

Following a qualitative risk assessment, in which we identified and assessed all viable pathways for the introduction of the Japanese encephalitis virus (JEV) into the United States (US), we identified entry through infected vectors via aircraft and cargo ships as the most likely pathway, and thus considered it further in a quantitative risk assessment (QRA) model. The objective of this study was to evaluate the risk of introduction of JEV in the US via infected mosquitoes transported in aircraft and cargo ships arriving from Asia, using a QRA model. We created a stochastic model to quantify the probability of introduction of at least one infected mosquito in the continental US via aircraft and cargo ships, per at-risk period (March to October) or year, respectively. We modeled the following parameters: number of flights (per at-risk period, i.e., March to October) and cargo ships (per year) and per region, number of mosquitoes per flight and ship, number of mosquitoes that were not found and sensitivity of the mosquito collection method in aircraft, mosquito infection rates, and number of mosquitoes coming in aircraft per at-risk period (March to October) and cargo ships per year. Flight and cargo ship data pertained to years 2010-2016. For model building purposes, we only considered port-to-port vessels arriving from Asia to the US, we assumed that mosquitoes survive the trans-Pacific Ocean ship crossing and that the number of mosquitoes in cargo and passenger flights is similar. Our model predicted a very high risk (0.95 median probability; 95% CI = 0.80-0.99) of at least one infected mosquito being introduced in the US during the at-risk period, i.e., March to October, via aircraft transportation from JEV-affected countries in Asia. We also estimated that a median of three infected mosquitoes can enter the US during the at-risk period, i.e., March to October (95% CI = 1-7). The highest probability of introduction via aircraft was attributed to the Mediterranean California ecoregion (0.74; 95% CI = 0.50-0.90). We predicted, however, a negligible risk (0; 95% CI = 0.00-0.01) of at least one infected mosquito being introduced via cargo ships. Although the risk of introduction of JEV-infected mosquitoes by cargo ships was negligible, the risk via aircraft was estimated to be high. Our findings indicate the need to prioritize JEV prevention and control methods for aircraft-based pathways, such as aircraft disinfection. The quantitative estimates provided in this study are of interest to public health entities and other stakeholders, as they may support future interventions for preventing JEV introduction, as well as other vector-borne diseases, in the US and other countries., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Optimized visual attractants will increase insect trapping efficiency by using the target insect's innate behaviors (positive photo-taxis) as a means to lure the insect into a population control or monitoring trap. Light emitting diodes (LEDs) have created customizable lighting options with specific wavelengths (colors), intensities, and bandwidths, all of which can be customized to the target insects. Photo-attraction behavioral bioassays can use LEDs to optimize the attractive color(s) for an insect species down to specific life history stages or behaviors (mating, feeding, or seeking shelter). Researchers must then confirm the bioassay results in the field and understand the limited attractive distance of the visual attractants. The cloverleaf bioassay arena is a flexible method to assess photo attraction while also assessing a range of natural insect behaviors such as escape and feeding responses. The arena can be used for terrestrial or aerial insect experiments, as well as diurnal, and nocturnal insects. Data collection techniques with the arena are videotaping, counting contact with the lights, or physically collecting the insects as they are attracted towards the lights. The assay accounts for insects that make no-choice and the arenas can be single (noncompetitive) color or multiple (competitive) colors. The cloverleaf design causes insects with strong thigmotaxis to return to the center of the arena where they can view all the options in a competitive LED tests. The cloverleaf arena presented here has been used with mosquitoes, bed bugs, Hessian fly, house flies, biting midges, red flour beetles, and psocids. Bioassays are used to develop accurate and effective insect traps to guide the development and optimization of insect traps used to monitor pest population fluctuations for disease vector risk assessments, the introduction of invasive species, and/or be used for population suppression.

Honey bees (Apis mellifera) are effective foragers for floral and extra-floral sources of sugars and as a result may easily be exposed to toxicants in the environment, such as pesticides. Toxic sugar baits (TSB) or insecticide-laced baits are designed for insect vector management but may be a danger to foraging honey bees and their hives. During a mosquito movement study at a zoological institution, nonflowering foliage surrounding the zoo was marked with sugar solution dyed with over the counter food-coloring. Mosquitoes and other insects foraged on the marked sugar and were collected within the zoo. Additionally, four of six honey bee hives within the zoo had workers that also foraged the dyed sugar and consequently colored approximately 57 kg of honey within the hives. This observation identifies a possibility route of toxicant accumulation within the hives from TSB and possible exposure may have whole hive health implications not previously described on an individual bee level.

Japanese encephalitis virus (JEV) is a virus of the Flavivirus genus that may result in encephalitis in human hosts. This vector-borne zoonosis occurs in Eastern and Southeastern Asia and an intentional or inadvertent introduction into the United States (US) would have major public health and economic consequences. The objective of this study was to gather, appraise, and synthesize primary research literature to identify and quantify vector and host competence for JEV, using a systematic review (SR) of the literature. After defining the research question, we performed a search in selected electronic databases and journals. The title and abstract of the identified articles were screened for relevance using a set of exclusion and inclusion criteria, and relevant articles were subjected to a risk of bias assessment, followed by data extraction. Data were extracted from 171 peer-reviewed articles. Most studies were observational studies (59.1%) and reported vector competence (60.2%). The outcome measures reported pertained to transmission efficiency, host preference, and vector susceptibility to infection within vector competence; and susceptibility to infection within host competence. Regarding vector competence, the proportion of JEV infection reported across all 149 mosquito species in all observational studies ranged from 0 to 100%. In experimental studies, infection, dissemination, and transmission rates varied between 0 and 100%. Minimum infection rates (MIR) varied between 0 and 333.3 per 1000 mosquitoes. Maximum likelihood estimation (MLE) values ranged from 0 to 53.8 per 1000 mosquitoes. The host species in which mosquitoes mostly fed consisted of pigs and cattle (total of 84 blood meals taken by mosquitoes from each of these host species). As for host competence, the proportion of JEV infection varied between 0 (in rabbits, reptiles, and amphibians) and 88.9% (cattle). This SR presents comprehensive data on JEV vector and host competence, which can be used to quantify risks associated with the introduction of JEV into the US., (Copyright © 2018 Elsevier B.V. All rights reserved.)