A Review of the Vector Status of North American Culicoides (Diptera: Ceratopogonidae) for Bluetongue Virus, Epizootic Hemorrhagic Disease Virus, and Other Arboviruses of Concern

Abstract

Purpose of Review Culicoides biting midges transmit several pathogens of veterinary importance in North America, but the vector status of many midge species is unresolved. Additionally, the available evidence of vector competence in these species is scattered and variable. The purpose of this review is to summarize current knowledge on confirmed and putative North American Culicoides arbovirus vectors. Recent Findings While the vector status of Culicoidessonorensis (EHDV, BTV, VSV) and Culicoidesinsignis (BTV) are well established, several other potential vector species have been recently identified. Frequently, these species are implicated based primarily on host-feeding, abundance, and/or detection of arboviruses from field-collected insects, and often lack laboratory infection and transmission data necessary to fully confirm their vector status. Recent genetic studies have also indicated that some wide-ranging species likely represent several cryptic species, further complicating our understanding of their vector status. Summary In most cases, laboratory evidence needed to fully understand the vector status of the putative Culicoides vectors is absent; however, it appears that several species are likely contributing to the transmission of arboviruses in North America.

Using Zoos as Sentinels for Re-Emerging Arboviruses: Vector Surveillance during an Outbreak of Epizootic Hemorrhagic Disease at the Minnesota Zoo

“…A taxonomic reassessment in 2000 raised C. sonorensis to the species level based on population sympatry and electrophoretic data [ 13 ]. For this reason, much of the available early literature on vector competence is presented using the species name C. variipennis , and the true identity of the specimens is unclear [ 26 ]. Despite this lack of clarity, it seems likely that C. variipennis retains some degree of competence for virus transmission in common with C. sonorensis , based on the present data.…”

“…The low abundance of this species collected in this study may reflect either lower abundance in the northern reaches of the species range or less availability of preferred habitats on the zoo grounds. While C. sonorensis and C. variipennis have historically been more associated with livestock and managed habitats, C. stellifer is often collected in sylvatic habitats [ 26 ]. Furthermore, it is unclear whether the midge community collected during this study is typical for this area or whether any recent changes in the midge community could have facilitated the EHD outbreak.…”

Linking vector favourable environmental conditions with serological evidence of widespread Bluetongue virus exposure in livestock in Ecuador

“…According to the WOAH, midges (genus Culicoides) are the only signi cant competent vector of BTV. They are also vectors of vesiculovirus (vesicular stomatitis) 13 , Schmallenberg virus, African horse sickness virus, Aino virus and Akabane virus 14 . As a vectorborne disease, the natural distribution and prevalence of BT are governed mainly by ecological factors modulating vector populations (e.g., rainfall, temperature, humidity, and soil characteristics).…”

Immigration and seasonal bottlenecks: High inbreeding despite high genetic diversity in an oscillating population of the biting midge,Culicoides sonorensis(Diptera: Ceratopogonidae)

“…In this study, we quantified the consequences of seasonal oscillation in adult population size on the amount and distribution of genetic diversity of the biting midge Culicoides sonorensis Wirth and Jones. This species is a confirmed vector of bluetongue virus, epizootic hemorrhagic disease virus, and vesicular stomatitis virus, and is a competent vector for a host of other pathogens (McGregor et al 2022). We used monthly demographic and genetic monitoring over a 3-year period to infer whether variation in the adult population size was associated with changes in genetic composition.…”