Apparent Range Expansion of Culicoides (Hoffmania) insignis (Diptera: Ceratopogonidae) in the Southeastern United States

Haematophagous biting midges of the genus Culicoides are pests of humans, livestock, and wildlife, and some also serve as vectors of bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) worldwide. In North America, there are only two Culicoides spp. proven to transmit BTV and/or EHDV-Culicoides (Hoffmania) insignis Lutz (Diptera: Ceratopogonidae) and Culicoides (Monoculicoides) sonorensis Wirth and Jones (Diptera: Ceratopogonidae). Culicoides sonorensis is considered the primary vector due to its wide distribution across much of North America, whereas C. insignis has a neotropical distribution historically limited to peninsular Florida. However, Culicoides surveys conducted 2007 to 2015 have detected the presence of C. insignis in five southeastern states (Florida, Georgia, Alabama, Mississippi, and Louisiana), suggesting C. insignis has or is currently experiencing a northwestward range expansion in the southeastern United States. Because C. insignis has a neotropical distribution and is a known vector of BTV serotypes exotic to North America, an expanding range could pose an introduction risk of virus serotypes new to the region and/or increased transmission of circulating endemic serotypes.