EHDV-2 Infection Prevalence Varies in <i>Culicoides sonorensis</i> after Feeding on Infected White-Tailed Deer over the Course of Viremia
Sandra Y. Mendiola,
Mary K. Mills,
Elin Maki,
Barbara S. Drolet,
William C. Wilson,
Roy Berghaus,
David E. Stallknecht,
Jonathan Breitenbach,
D. Scott McVey,
Mark G. Ruder
Affiliations
Sandra Y. Mendiola
Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, 589 D.W. Brooks Drive, Athens, GA 30602, USA
Mary K. Mills
Department of Entomology, Kansas State University, 1603 Old Claflin Place, Manhattan, KS 66506, USA
Elin Maki
Arthropod-Borne Animal Diseases Research Unit, USDA, Agricultural Research Service, 1515 College Avenue, Manhattan, KS 66506, USA
Barbara S. Drolet
Arthropod-Borne Animal Diseases Research Unit, USDA, Agricultural Research Service, 1515 College Avenue, Manhattan, KS 66506, USA
William C. Wilson
Arthropod-Borne Animal Diseases Research Unit, USDA, Agricultural Research Service, 1515 College Avenue, Manhattan, KS 66506, USA
Roy Berghaus
Department of Population Health, College of Veterinary Medicine, University of Georgia, 220 College Station Road, Athens, GA 30602, USA
David E. Stallknecht
Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, 589 D.W. Brooks Drive, Athens, GA 30602, USA
Jonathan Breitenbach
Arthropod-Borne Animal Diseases Research Unit, USDA, Agricultural Research Service, 1515 College Avenue, Manhattan, KS 66506, USA
D. Scott McVey
Arthropod-Borne Animal Diseases Research Unit, USDA, Agricultural Research Service, 1515 College Avenue, Manhattan, KS 66506, USA
Mark G. Ruder
Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, 589 D.W. Brooks Drive, Athens, GA 30602, USA
Epizootic hemorrhagic disease viruses (EHDVs) are arboviral pathogens of white-tailed deer and other wild and domestic ruminants in North America. Transmitted by various species of Culicoides, EHDVs circulate wherever competent vectors and susceptible ruminant host populations co-exist. The impact of variation in the level and duration of EHDV viremia in white-tailed deer (Odocoileus virginianus) on Culicoides infection prevalence is not well characterized. Here we examined how infection prevalence in a confirmed North American vector of EHDV-2 (Culicoides sonorensis) varies in response to fluctuations in deer viremia. To accomplish this, five white-tailed deer were experimentally infected with EHDV-2 and colonized C. sonorensis were allowed to feed on deer at 3, 5, 7, 10, 12, 14, 18, and 24 days post infection (dpi). Viremia profiles in deer were determined by virus isolation and titration at the same time points. Blood-fed Culicoides were assayed for virus after a 10-day incubation (27 °C) period. We found that increases in deer EHDV blood titers significantly increased both the likelihood that midges would successfully acquire EHDV and the proportion of midges that reached the titer threshold for transmission competence. Unexpectedly, we identified four infected midge samples (three individuals and one pool) after feeding on one deer 18 and 24 dpi, when viremia was no longer detectable by virus isolation. The ability of ruminants with low-titer viremia to serve as a source of EHDV for blood-feeding Culicoides should be explored further to better understand its potential epidemiological significance.
