Equine hepacivirus (EqHV) is a hepatotropic virus, closely related to human hepatitis C virus (HCV), that can cause acute or chronic infection in horses. As with HCV, transmission is thought to occur primarily through parenteral, particularly blood-borne, routes. Vertical transmission from mare to foal has been reported but appears to be uncommon. The high seroprevalence in horse populations and the occurrence of infection in isolated horses indicate efficient horizontal transmission routes exist. One such possibility is biological or mechanical transmission by arthropods, such as mosquitoes, stable flies, or ticks. Here, we conducted 2 complementary studies to evaluate the possible role of mosquitoes as EqHV biological vectors. In the laboratory, we orally exposed Aedes albopictus (Skuse) females to EqHV through artificial bloodfeeding with blood collected from 2 chronically infected horses. Mosquito samples (body, legs, and saliva) were collected at multiple time points post-exposure and tested for EqHV RNA by molecular assays. In the field, 2,138 mosquitoes were collected from New York and Florida, United States, and screened for EqHV RNA. No EqHV RNA was detected in any samples from the laboratory experiment or among field-collected mosquitoes. These findings indicate that the Ae. albopictus strain evaluated here is unlikely to serve as a biological vector of EqHV and corroborate previous negative findings in field-collected mosquitoes. Nevertheless, low infection rates may have gone undetected. Laboratory studies of additional horse-feeding mosquito species and expanded field collections in EqHV-endemic regions are needed to further clarify any potential role for mosquitoes in EqHV transmission.
Tick-borne diseases are a major public health threat in the United States, with Lyme disease being the most commonly reported vector-borne disease. Tick-bite prevention is predominantly focused on education and the use of repellents. Currently, the use of tick control interventions is rare, particularly on public properties, in part because deployment costs can be difficult to determine. This study focused on New Jersey, where both Ixodes scapularis Say and Amblyomma americanum (L.) (Acari: Ixodidae) are common throughout much of the state and there is a high incidence of tick-borne diseases. Ten high-use public parks in Monmouth County with high tick abundance were selected to develop tick management plans and assess their implementation cost. We calculated the cost of applying acaricides along trails and the margins of recreational fields where tick habitat is abundant, as well as the cost of deploying 4-Poster Tick Control Deer Feeders (hereafter, 4-Posters) to treat deer with acaricides. The total projected annual cost for focal acaricide treatments in all 10 parks ranged from $23,251 (low-end estimate) to $46,500 (high-end estimate). The use of 4-Posters (without other interventions), with potential for tick suppression across the landscape, was more expensive, estimated to cost $461,970 annually for a sustained program including all 10 parks. Using current tick control methods, area-wide control is considerably more expensive than more focal control efforts. This research provides local land managers with cost estimates for tick control and provides a guide for estimating the cost of deployment as new methods are developed.
Toxic sugar baits (TSBs) exploit mosquito sugar-feeding behavior to deliver orally ingested lethal toxins. Most existing TSB formulations rely on synthetic chemical insecticides, highlighting the need to evaluate alternative active ingredients compatible with TSB delivery systems. Bacillus velezensis (Bv), a bacterium with demonstrated mosquitocidal activity, represents a promising microbial active ingredient but has not previously been evaluated as the active ingredient in TSBs. We evaluated the oral toxicity effects of Bv crude toxin-containing sugar bait (BvTSB) against adult Cx. quinquefasciatus, quantifying acute mortality, longevity, and reproductive outcomes. Ingestion of BvTSB caused significant lethal mortality in both sexes compared to sugar-fed controls, with males exhibiting greater susceptibility than females. Sublethal exposure reduced adult longevity, decreased egg production, and lowered fertility. These results demonstrate that Bv adversely affects multiple life history traits relevant to mosquito population dynamics and impairs traits related to vectorial capacity. Collectively, our findings show that Bv, when used as the active ingredient in toxic sugar baits, exhibits substantial mosquitocidal activity against adult Cx. quinquefasciatus and may serve as an alternative active ingredient to conventional chemical insecticides in TSB-based vector control.
The mosquito community of the Madrean Sky Islands of southeastern Arizona is diverse and distinct with several species that are endemic or at their northern distributional limits. We collected mosquitoes across many of southeastern Arizona's Sky Island mountain ranges. Here, we present new collection records supported by morphological and molecular evidence that indicate the presence of Aedes (Ochlerotatus) amateuri in at least two Sky Islands ranges, the Santa Rita Mountains and the Dragoon Mountains. Aedes amateuri was described in 2019, previously known only from the type locality in Nuevo Leon and Tamaulipas, Mexico. These records represent the first detection of Ae. amateuri in the USA, and the northernmost collections of this species. The results of DNA barcoding and comparison of Arizona Ae. amateuri cytochrome c oxidase subunit I sequences to those available in publicly accessible databases suggest that Ae. amateuri is present in an additional location in Mexico, south to Honduras. Detailed collection records, ecological information, and a discussion of the morphological and molecular identification of Ae. amateuri are presented.
Insecticide resistance in malaria vectors threatens control efforts. Anopheles funestus Giles s.l. increasingly contributes to malaria transmission in Côte d'Ivoire especially in central and western regions, yet resistance data remain poorly known. This study assessed the susceptibility of An. funestus s.s. from Toumbokro to major insecticides and identified underlying metabolic resistance mechanisms. Blood-fed An. funestus s.l. females were collected indoors with an electric aspirator and induced to oviposit. F1 progeny from PCR-confirmed An. funestus s.s. were exposed to permethrin (0.75%), deltamethrin (0.05%), lambda-cyhalothrin (0.05%), and DDT (4%) in WHO tube assays. Synergist assays with piperonyl butoxide (PBO) were used to evaluate enzyme-mediated resistance, and biochemical assays were used to measure activity of detoxification enzymes. Anopheles funestus s.s. showed resistance to all insecticides, with mortality rates of 78% (permethrin), 76% (deltamethrin), 44% (lambda-cyhalothrin), and 72% (DDT). Pre-exposure to PBO fully restored susceptibility to pyrethroids (100% mortality), implicating metabolic resistance, but only partially restored susceptibility to DDT (82%). Biochemical assays confirmed significantly greater cytochrome P450 monooxygenase activity in An. funestus s.s. (0.00144 nmol/mg of protein) compared with the susceptible Kisumu strain (0.00085 nmol/mg of protein). An. funestus s.s. from Toumbokro in central Côte d'Ivoire is resistant to pyrethroids and DDT, mainly via metabolic mechanisms. This resistance likely sustains its role in malaria transmission despite widespread pyrethroid-treated long-lasting insecticidal nets (LLIN) use suggesting a need for PBO-based or dual-active ingredient LLINs in vector control strategies.
Myasis caused by Cochliomyia hominivorax larvae (Coquerel, 1858), represents a significant sanitary and economic challenge under the One Health approach, affecting human health, livestock production, and biodiversity. Studies on the spatial ecology and distribution of this species in South America (SA) have been scarce. This study aimed to model real and potential suitability areas for C. hominivorax in SA, based on myiasis cases in humans and other vertebrates reported in the scientific literature. The MaxEnt model was developed using WorldClim bioclimatic variables clipped to SA, with 1,000 iterations performed to generate mean logistic distribution models. To mitigate collinearity variables with an absolute correlation coefficient of ∣r∣ < 0.7 were retained. Jackknife tests determined the relative importance of the bioclimatic variables. Brazil and Argentina contained the majority of records, followed by Colombia and Venezuela. Paraguay and French Guiana contributed fewer occurrences. The most frequently recorded hosts were cattle, cats, dogs, and pigs, with great numbers of human cases documented in Brazil and Argentina. Predictive models indicated that west-central Amazonia, eastern Paraguay, northern Argentina, northeastern Brazil, and several countries in northern SA represent moderate to high suitability for species presence (habitat suitability scores 0.80 to 1.00; AUC 0.885). The potential distribution of C. hominivorax in SA was determined by humidity and temperature gradients in tropical and subtropical environments, excluding arid or cold zones. These findings emphasize the need to strengthen epidemiological surveillance and transboundary control strategies, with special attention to domestic hosts, wildlife movement, and human cases in the Southern Hemisphere.
Widespread insecticide resistance and the potential for sublethal exposures to alter mosquito fitness have increased interest in alternative approaches such as attractive toxic sugar baits (ATSBs), yet their lethal and sublethal effects in insecticide-resistant versus susceptible populations remain poorly understood. We evaluated the lethal and sublethal effects (LC25) of a novel boric acid and dinotefuran ATSB on ingestion, mortality, blood feeding, and reproductive traits in permethrin-resistant and permethrin-susceptible Aedes aegypti. Aedes aegypti is the primary global vector of dengue, Zika, chikungunya, and yellow fever viruses, placing billions at risk and underscoring the need for sustainable vector control strategies. ATSB affected ingestion, mortality, and reproductive traits in a resistance-dependent manner. Susceptible mosquitoes exhibited reduced ATSB ingestion, whereas resistant mosquitoes showed increased ingestion, suggesting that resistance status modifies feeding responses to the bait formulation. ATSB ingestion increased acute mortality in both strains, with a stronger effect in susceptible mosquitoes, and similarly shortened survival time across strains, indicating consistent sublethal toxicity regardless of resistance status. ATSB reduced blood feeding in both strains, suggesting potential downstream effects on pathogen transmission. Fertility exhibited a significant resistance × treatment interaction, with ATSB increasing fertility in resistant mosquitoes but reducing it in the susceptible strain. These findings indicate that the effects of this ATSB on mosquito fitness and arbovirus transmission-related traits are strongly influenced by permethrin resistance, highlighting the importance of incorporating resistance status into ATSB evaluations and integrated vector control strategies.
Predator presence can influence mosquito oviposition decisions through direct and indirect cues, yet most studies have examined indirect chemical cues alone. We evaluated the relative effects of live Gambusia affinis fish (direct cue) versus fish-conditioned water (indirect cue) on oviposition by container breeding mosquitoes (mostly Aedes albopictus) in a field experiment conducted at the University of North Carolina at Greensboro. Paired oviposition cups (treatment and control) were deployed along a transect during three replicate 1-wk sessions for each treatment. Egg numbers were analyzed using paired t-tests, and oviposition responses were quantified using the Oviposition Activity Index (OAI). Live fish significantly deterred oviposition. More eggs were laid in control cups (43.2 ± 5.7) compared to cups containing fish (25.9 ± 8.2; OAI = -0.45). When analyses were restricted to cups in which fish remained present throughout the experimental period, deterrence was even stronger (OAI = -0.63). In contrast, fish-conditioned water significantly increased oviposition relative to aged-water controls (47.5 ± 9.1 vs. 30.2 ± 6.0; OAI = 0.20). These contrasting responses suggest that gravid A. albopictus females discriminate between immediate predation risk and residual environmental cues associated with prior predator presence. We hypothesize that attraction to fish-conditioned water may be mediated by microbially derived volatiles stimulated by fish excretions, whereas avoidance of live fish likely involves visual or mechanical cues. Our findings suggest that oviposition site selection reflects a trade-off between cues indicating a high-quality habitat and offspring survival risk, highlighting the multimodal nature of predator detection in container-breeding mosquitoes.
The New World screwworm, Cochliomyia hominivorax (Diptera: Calliphoridae), remains one of the most economically important livestock pests in the Americas. Although wound-associated attractants and putative contact pheromones have been identified, little is known about how mating influences cuticular chemical signals associated with reproductive communication used for Sterile Insect Technique (SIT)-based eradication programs. Here, we characterized cuticular hydrocarbon (CHC) profiles of virgin and mated male and female C. hominivorax (J-06 strain) using gas chromatography-mass spectrometry and multivariate analyses. Twenty-one major hydrocarbons, consisting primarily of n-alkanes and mono- and dimethyl-branched hydrocarbons ranging from C23 to C37 , were detected across all treatment groups. Total hydrocarbon abundance did not differ among treatments; however, CHC composition differed significantly between sexes and was strongly influenced by mating status. Virgin males and females exhibited pronounced sexual dimorphism, with males enriched in lower-molecular-weight hydrocarbons and females characterized by greater relative abundances of longer-chain compounds. Mating-induced substantial shifts in CHC composition, particularly in females. The compounds contributing most strongly to these differences were predominantly methyl- and dimethyl-branched hydrocarbons implicated in mate recognition and reproductive signaling. These findings identify mating status as a previously unrecognized determinant of CHC composition, provide the first characterization of mating-associated variation in cuticular hydrocarbons in C. hominivorax, and identify candidate chemical signatures of mating that may contribute to female monogamy and provide candidate semiochemicals for future behavioral and functional studies.
Lyme disease, caused by the bacterium Borrelia burgdorferi (Spirochaetales: Spirochaetaceae) and transmitted by the blacklegged tick, Ixodes scapularis Say (Acari: Ixodidae), in the eastern United States, is the most common vector-borne disease in North America. Human disease risk depends on interactions among ticks and sylvatic hosts, and greater host biodiversity has been hypothesized to reduce risk through the dilution effect. However, the influence of biodiversity varies with community composition, species abundance, and habitat change. We conducted a literature review to compile biological parameter estimates for 15 common host species. These parameters were used in a mathematical model incorporating tick-to-host ratio-dependent host-finding success, allowing for incomplete redistribution of ticks, to assess transmission dynamics in the northeastern United States, where human Lyme disease incidence is high. We evaluated how species richness, evenness, and habitat changes affect nymphal infection prevalence (NIP) and density of infected nymphs (DIN). Our results indicate that many small mammal species play context-dependent roles, acting as dilution hosts in communities of highly competent hosts and as amplification hosts in lower-competence communities. Varying host density revealed "tipping points," where small abundance changes led to communities producing more infected than uninfected ticks. Habitat fragmentation simulations showed that biodiversity can decrease NIP but often increases DIN. Together, these findings provide insight into B. burgdorferi transmission cycles and emphasize the need to consider NIP and DIN jointly when assessing how biodiversity alters transmission dynamics.
Mosquito host-feeding patterns strongly influence pathogen transmission potential, but landscape drivers of host use remain poorly understood for many generalist vectors. We examined whether landscape composition and spatial configuration predict blood-feeding patterns of Culex erraticus collected from natural areas across Illinois, USA. Specifically, we tested whether land-cover composition and distance from key landscape features, including forest edge, are associated with host-use shifts relevant to zoonotic pathogen transmission. Blood-fed females were identified morphologically, vertebrate hosts were determined by mitochondrial Cytochrome c Oxidase Subunit I (COI) amplicon sequencing, and landscape variables were quantified within a 1,000-m radius around each site. Among identified blood meals, Cx. erraticus fed primarily on mammals (73.1%), followed by birds (21.2%), reptiles (5.0%), and amphibians (0.7%), with white-tailed deer and humans dominating mammalian meals. The best-supported generalized linear model (GLM) for bird versus mammal feeding retained mean distance to forest edge and natural cover as predictors, although only distance to forest edge was significant, with mammal feeding declining as signed distance to forest edge became more positive, that is, farther into non-forested habitat. Among mammalian meals, the best-supported GLM for human versus non-human mammal feeding retained mean distance to forest edge as the sole predictor, with human feeding increasing at greater positive distances from forest edge. These results indicate a host shift across the forest-edge gradient and suggest that fine-scale landscape structure, particularly forest proximity, predicts host use in Cx. erraticus. This pattern may help explain spatial variation in human exposure risk to zoonotic pathogens.
The filarial nematode, Dirofilaria immitis (Leidy) (Spirurida: Onchocercidae), is an obligate mosquito-borne pathogen transmitted by at least 26 species of mosquitoes in the United States. Due to its size and migration through mosquito tissues during its first 3 larval stages (L1-L3), it can damage the mosquito to the point of death, thereby hindering transmission to its vertebrate host (eg canids and other carnivores). Mosquito species vary in competency for D. immitis, where some species facilitate the development of more viable, infectious L3 worms (host tolerance), while others produce few to no worms (host resistance). Here, we investigated how resistance and tolerance may be impacted by larval rearing conditions (ie temperature and nutrition), specifically quantifying D. immitis burden and development in 2 mosquito species (Aedes triseriatus (Say) and Aedes albopictus (Skuse)). Post-emergence, we offered either a D. immitis positive or negative blood meal to adult female mosquitoes and tracked their development for 15 days before quantifying worm burdens. For both mosquito species, growth rates increased and adult size decreased under conditions with warmer temperatures and lower nutrition. Larval conditions did not have consistent effects on the burden or development of D. immitis, but a higher proportion of Ae. triseriatus developed L3 worms than Ae. albopictus. Poor survival to the end of the incubation period and low numbers of blood-fed mosquitoes for each treatment combination may have hindered our ability to detect significant effects of larval environment on worm transmission, highlighting important considerations for future studies.
Cochliomyia hominivorax (Coquerel, 1858) is the main etiological agent of myiasis in Latin America. In vitro bioassays are essential for detecting insecticide resistance development in the laboratory. This study evaluated different in vitro bioassay methodologies targeting C. hominivorax third-instar larvae. Chlorpyrifos, fipronil, fluralaner, and doramectin, were tested using either a filter paper assay or larval immersion for three different durations. In the filter paper assays, 9 concentrations of each active ingredient were applied to filter paper discs. After drying, the discs were placed in Petri dishes and ten third-instar larvae of C. hominivorax were introduced to each disc. In the immersion assays, groups were submerged in solutions containing the same concentrations used in the filter paper tests. In both methods, each concentration was evaluated in 6 replicates at 24, 48, and 72 h after exposure for larvicidal effects and for eventual adult emergence. These were then reported as median lethal concentrations (LC50) and inhibition emergence concentrations (IE50) when possible. The 72-h exposure period was most appropriate for evaluating maximal mortality across the tested methodologies. For all active ingredients assessed, the administered doses required to induce mortality were sufficient to inhibit the emergence of the challenged individuals. The filter paper assay method demonstrated greater larvicidal efficacy for fluralaner against C. hominivorax larvae, whereas the larval immersion method exhibited higher efficacy for both fipronil and doramectin. These findings support the standardization of in vitro bioassays for preliminary screening of ectoparasiticides and for resistance monitoring in field populations.
Tunga penetrans (Linnaeus, 1758) (Siphonaptera: Tungidae) is an ectoparasitic flea whose adult females cause tungiasis by embedding into the host's skin. Environmental, social and financial challenges in tungiasis endemic areas have left this disease neglected and lacking locally available control measures. One possible approach for controlling T. penetrans targets its off-host stages; however, surveillance tools for adult fleas are still lacking. Moreover, host-seeking cues and behaviour of adult T. penetrans remain largely unknown. In this study, we show that visual cues are attractive to adult T. penetrans. Newly emerged T. penetrans responded to light stimuli across a broad spectrum, ranging from 375 nm to 690 nm. Within this range, significantly stronger attraction was observed at 430 nm over 375 nm, at 490 nm over 610 nm, and at 610 nm over 690 nm. Attraction did not differ significantly between 430 nm and 490 nm or between 535 nm and 490 nm. Overall, wavelengths between 430-535 nm induced stronger attraction in both sexes under constant electrical current conditions. In contrast, although host odor and body temperature attracted more than half of the tested adult fleas on average, the observed responses were not statistically significant. These findings suggest that visual cues in this spectral range could serve as promising attractants for capturing adult fleas. Incorporating these insights into trap strategies could support improved monitoring, surveillance, and potentially contribute to control efforts.
The New World screwworm fly, Cochliomyia hominivorax (Coquerel, 1858) (Diptera: Calliphoridae), is an obligate parasitic blowfly that causes traumatic myiasis and represents a major threat to livestock production in the Neotropics. Although eradication programs based on the Sterile Insect Technique (SIT) successfully eliminated the species from North and Central America, the risk of reinvasion remains a persistent concern. Understanding how landscape structure influences dispersal and connectivity is therefore essential for improving surveillance and control strategies. We evaluated the influence of landscape configuration on gene flow using microsatellite data from 24 populations across South America. Resistance surfaces were generated from land-use maps by assigning resistance values (0 to 100) to landscape classes, producing 10,000 alternative resistance scenarios. Resistance distances were correlated with genetic differentiation (FST), and model selection was performed using Akaike's Information Criterion (AIC). Among all scenarios, only 13 showed significant associations (r = 0.271 to 0.513). The best-supported model explained 26.3% of the variation in genetic differentiation and identified lower resistance in pasture-dominated and agricultural mosaic landscapes, whereas preserved vegetation and water bodies imposed higher resistance. Sensitivity analyses demonstrated that model performance improved with increasing sample size and stabilized at approximately 10 to 14 populations, indicating that robust inference depends on adequate sampling. These results highlight the role of landscape structure in shaping connectivity and provide a spatial framework for identifying dispersal corridors and regions vulnerable to reinvasion.
Understanding the genetic structure and diversity of Aedes aegypti (Linnaeus, 1762) populations is critical for predicting transmission dynamics and implementing effective vector control strategies. This study assessed the genetic diversity, population structure, and influence of geography and climate on Ae. aegypti populations across India. Of 308 genotyped individuals, 257 high-quality genotypes from 13 collection sites across 6 climatic regions were retained for analysis using 10 microsatellite loci. High genetic diversity was observed across all populations, consistent with substantial effective population sizes and ongoing gene flow. Moderate but biologically significant genetic differentiation was detected (global FST = 0.077), with the majority of genetic variation occurring within populations (AMOVA: 91.62%). Clustering analyses revealed weak to moderate population structuring, identifying approximately 3 genetic clusters with substantial admixture. Population assignment tests further supported extensive connectivity, with 42% of individuals assigned to nonnative populations. Bottleneck analyses found no recent demographic contractions, and all populations exhibited allele frequency distributions consistent with mutation-drift equilibrium. The Mantel test revealed no significant isolation by distance, suggesting that geographic separation alone does not drive genetic differentiation. Redundancy analysis further indicated that climatic and geographic variables did not significantly explain overall genetic variation, although partial analyses suggested a modest independent contribution of spatial structure. Overall, the genetic structure of Ae. aegypti in India may be influenced by human-mediated dispersal and local ecological processes rather than by broad geographic or climatic constraints. These findings highlight the importance of considering population connectivity in region-specific vector surveillance and control programs.
Mosquito-borne diseases are a major public health burden given the limited pharmacological options. While the adverse effects of synthetic insecticides are well documented, it is necessary to assess whether environmentally friendly interventions are effective for disease control. Although natural predators, microbial bioinsecticides and plant-based bioinsecticides have gained attention for their specificity and reduced environmental impact, no comprehensive synthesis of evidence on their effectiveness in reducing disease burden has been conducted, highlighting the need for this review. A PRISMA 2020-compliant systematic searched for literature published from 2000 to 2026 in PubMed, Cochrane, Embase, Web of Science, LILACS, and CAB Abstracts. Experimental field studies evaluating these interventions against Aedes, Anopheles, and Culex, reporting epidemiological indicators of chikungunya, dengue, Zika, lymphatic filariasis, West Nile virus, Rift Valley fever, yellow fever, malaria, or Japanese encephalitis, were eligible. Due to outcome heterogeneity, a narrative synthesis was performed instead of a meta-analysis. Eighteen studies from Asia, Africa, Central America, and South America, assessing bacterial larvicides, copepods, and larvivorous fish, were included. Only five studies performed statistical analysis to compare intervention and control groups, two of which found no significant association between the intervention and the disease outcome. The remaining sixteen reduced disease burden in intervention groups with different levels of evidence. These interventions show potential to reduce the burden of dengue, malaria, and chikungunya across diverse settings, supporting their role as promising alternative or complementary tools for disease control. Future research would benefit from more experimental designs, standardized epidemiological outcomes, and robust statistical analysis. Prospero Registration Number CRD42024628633.
Six new species of Dexosarcophaga Townsend, 1917 are described based on specimens from the Brazilian Amazon: Dexosarcophaga akamai sp. nov., Dexosarcophaga ducke sp. nov., Dexosarcophaga ribeirinha sp. nov., Dexosarcophaga harin sp. nov., Dexosarcophaga mamiraua sp. nov., and Dexosarcophaga gorayebi sp. nov. Male morphology is presented by detailed illustrations of the male terminalia and photographs. Dexosarcophaga pallida Santos, Pape, & Mello-Patiu, 2022 and Dexosarcophaga wyatti Mello-Patiu & Pape, 2000 are newly recorded from Brazil; Dexosarcophaga angrensis Lopes, 1975, Dexosarcophaga petra Santos, Pape, & Mello-Patiu, 2022, and Dexosarcophaga rudicompages (Hall, 1933) are newly recorded from the Brazilian Amazon; and Dexosarcophaga globulosa Lopes, 1946 is newly recorded from the state of Acre.
Internal controls are essential to ensure the reliability of molecular assays, confirming the integrity of nucleic acid extraction and testing process. This is particularly important in entomovirological surveillance, which relies on molecular testing of field-collected arthropod vectors. A key challenge is identifying a control target conserved among diverse vector species. We designed a novel primer-probe set for hydrolysis probe-based real-time PCR, targeting the actin-1 gene and assessed its performance across 21 mosquito and 9 sand fly species in Israel. The assay performance was compared to that of the ribosomal protein S17 (RpS17) assay, one of several endogenous controls reported in mosquito studies. The actin-1 RT-qPCR assay detected all mosquito and sand fly species tested, whereas the RpS17 assay covered only 11 mosquito and 4 sand fly species. Varying mosquito numbers per surveillance pool showed a negative correlation between pool size and actin-1 cycle threshold (Ct) values, confirming consistent detection across sample sizes. We further integrated actin-1 into 3 multiplex RT-qPCR assays: actin-1 + West Nile virus, actin-1 + Usutu virus, and actin-1 + representative phleboviruses: Toscana virus and Sandfly fever Sicilian virus. All assays reliably detected both actin-1 and their respective viral targets, with serial dilutions showing high efficiency and linearity. Differences between singleplex and multiplex testing were minimal showing no significant impact on assay sensitivity. Overall, the actin-1 RT-qPCR assay showed broad species coverage and reliable performance in multiplex RT-qPCR using field-collected specimens, supporting its use as an endogenous internal control in molecular arbovirus surveillance.
Understanding the occurrence of arthropods in the Arctic relies heavily on distributional and taxonomic evidence, yet substantial gaps and inconsistencies in available data complicate interpretation. These limitations impact our understanding of ecologically-and medically-important groups such as the mosquitoes (Diptera: Culicidae), whose Arctic diversity and biogeography remain poorly resolved. Many species were originally described from limited material, often using morphological traits that differ from those observed in more thoroughly studied southern populations. Sparse and uneven sampling across the Arctic limits our ability to accurately assess species distributions, and missing or incomplete metadata further diminishes the scientific value of existing specimens. Collectively, these issues obscure patterns of biodiversity, hinder detection of climate‑driven range shifts, and constrain efforts to evaluate the vector potential of species capable of transmitting arboviruses. As concerns grow regarding the northward expansion of mosquito‑borne pathogens, the absence of reliable baseline data poses a major challenge for assessing current and future risks to human and animal health in Arctic ecosystems. This review synthesizes historical records of Canadian Arctic mosquitoes from early natural history expeditions beginning around 1820 to the present. We evaluate the taxonomic reliability, geographic accuracy, and research relevance of these records to determine which can serve as credible baselines for contemporary biodiversity assessments. By clarifying the strengths and limitations of the historical dataset, this review aims to support improved species distribution modeling, inform future surveillance efforts, and guide research priorities in a rapidly changing Arctic.
