Location: Arthropod-borne Animal Diseases ResearchTitle: Susceptibility of white-tailed deer (Odocoileus virginianus) to experimental infection with epizootic hemorrhagic disease virus serotype 7 Author
Submitted to: Journal of Wildlife Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2011
Publication Date: 6/27/2012
Publication URL: http://www.jwildlifedis.org/content/48/3/676.full.pdf+html
Citation: Ruder, M.G., Allison, A.B., Stallknecht, D.E., Mead, D.G., Mcgraw, S.M., Carter, D.L., Kubiski, S.V., Batten, C.A., Klement, E., Howerth, E.W. 2012. Susceptibility of white-tailed deer (Odocoileus virginianus) to experimental infection with epizootic hemorrhagic disease virus serotype 7. Journal of Wildlife Diseases. 48(3):676-685. Interpretive Summary: Epizootic hemorrhagic disease viruses (EHDV) are insect-transmitted viruses of certain wild ruminants and cattle. In the US, EHDV is one of the most significant infectious diseases of white-tailed deer, whereas infection in cattle is primarily subclinical, or rarely results in mild disease. However, in 2006, EHDV-7 caused widespread disease among Israeli dairy cattle herds, resulting in significant economic loss to that industry. This virus serotype (EHDV serotype 7) is not present in the U.S. and in order to better understand the potential for this virus to impact US populations of white-tailed deer and cattle, we performed an experimental infection of white-tailed deer with EHDV-7. The results demonstrate that white-tailed deer are susceptible to infection and disease with this exotic virus. The observed disease was severe, and indistinguishable from that caused by EHDV serotypes that are already present in the U.S. Thus, we showed that white-tailed deer are a potential North American host for this exotic, cattle-virulent strain of EHDV. If our native vector of EHDV (Culicoides sonorensis) is shown to be capable of transmitting EHDV-7, then it may be possible for this virus to circulate in North America if introduced. These findings are useful to diagnosticians, veterinarians, researchers, cattle producers, wildlife professionals and others involved in livestock and wildlife health and management.
Technical Abstract: During the fall of 2006, in Israel, epizootic hemorrhagic disease virus (EHDV) serotype 7 was the cause of an intense and widespread epizootic in domestic cattle that resulted in significant economic losses for the dairy industry. The susceptibility of potential North American vector and ruminant hosts to infection with EHDV-7 is not known, which is essential when attempting to understand the potential for establishment of this exotic orbivirus in North America if it were introduced. Our primary objective was to determine if white-tailed deer (WTD; Odocoileus virginianus) are susceptible to infection with EHDV-7. Six, eight-month-old WTD were experimentally infected with EHDV-7 and all became infected and exhibited varying degrees of clinical disease. Clinical signs, clinicopathologic abnormalities, and postmortem findings were consistent with previous reports of orbiviral hemorrhagic disease (HD) in this species. Four of six animals died or were euthanized due to severity of disease, one on post-inoculation day (PID) 5 and the remaining on PID 7. All deer had detectable viremia on PID 3 that peaked on PID 5 or 6 and persisted for as long as PID 46 in one animal. Deer surviving the acute phase of disease seroconverted by PID 10. Based on the 67% mortality rate observed in this study, this strain of EHDV-7 is virulent in WTD, reaffirming their role as a sentinel species for the detection of endemic and non-endemic EHDV. Further, the observed disease was indistinguishable from previous reports of disease caused by North American EHDV and BTV serotypes, highlighting the importance of serotype-specific diagnostics during suspected HD outbreaks.