Location, location, location: Optimizing surveillance efforts for Culicoides sonorensis and bluetongue virus through trap placement and attractant choices
We conducted a 6 week trapping study on 3 dairies in southern California. CDC suction traps baited with CO2, UV, or CO2+UV were positioned near either larval development sites, near animals, or in open fields adjacent to the dairy, away from all known attractants. Culicoides were sorted by sex and parity to look for differences between trap and site. Pars were tested for BTV using qRT-PCR. On average, CO2+UV traps collected more pars than the other traps, though not always significantly. Traps placed in field sites, away from the most intuitive locations for collecting Culicoides, collected the highest numbers of pars. The proportion of parity was affected not only by location of the traps, but also by the bait used. Our findings have implications for estimation of BTV prevalence in midges, especially when pools are not sorted by parity status.