Susceptibility of White-Tailed Deer (Odocoileus Virginianus) to Experimental Infection With Epizootic Hemorrhagic Disease Virus Serotype 7

Abstract

ABSTRACT:During the fall of 2006, in Israel, epizootic hemorrhagic disease virus (EHDV) serotype 7 caused 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 but is essential to understanding the potential for establishment of this exotic orbivirus in North America if it were introduced. Our primary objective was to determine whether white-tailed deer (WTD; Odocoileus virginianus) are susceptible to infection with EHDV-7. Six, 8-mo-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 because of the severity of disease, one on postinoculation day (PID) 5 and the remaining WTD on PID 7. All deer had detectable viremia on PID 3, which peaked on PID 5 or 6 and persisted for as long as PID 46 in one animal. Deer surviving the acute phase of the disease seroconverted by PID 10. Based on the 67% mortality rate we observed, this strain of EHDV-7 is virulent in WTD, reaffirming their role as a sentinel species for the detection of endemic and nonendemic EHDV. Further, the observed disease was indistinguishable from previous reports of disease caused by North American EHDV and bluetongue virus serotypes, highlighting the importance of serotypespecific diagnostics during suspected HD outbreaks.

Host and Potential Vector Susceptibility to an Emerging Orbivirus in the United States

“…29 WTD have now been experimentally infected with 4 (1, 2, 6, 7) of the 7 provisional EHDV serotypes, and clinical disease has been replicated or induced with each. 17,54,61 It is reasonable to speculate that this species is susceptible to clinical disease with all EHDV serotypes, although variation in susceptibility likely occurs among WTD subspecies. 21 Furthermore, confirmed fatal BT infections (natural or experimental) in WTD have been documented with multiple serotypes of BTV (1,3,8,10,11,12,13,17).…”

“…In a similar study, EHDV-2 was isolated from 75% (87 of 116) of midges at 4 to 14 dpf, and 36% (42 of 116) of midges had virus titers !10 2.7 TCID 50 /midge. 54 The apparently variable susceptibility of C. sonorensis to infection with different EHDV serotypes is interesting and has not been investigated. Previous studies of BTV infection in field and laboratory populations of C. sonorensis describe heterogeneity in response to oral infection among BTV serotypes, 32,33 although mechanisms of such variation remain unknown.…”

“…Maintenance media consisted of MEM with 10% fetal bovine serum and 1Â antibiotics and flasks were incubated in 5% CO 2 at 37 C. Attempts at virus isolation from tissues were performed as described. 54 Briefly, tissues were homogenized with a Tissue Tearor (Biospec Products Inc, Bartlesville, OK, US), centrifuged at 1600 Â g for 12 minutes, and the supernatant inoculated onto a CPAE monolayer. After 7 days, cells were scraped, and 100 ml of cell suspension was inoculated onto a new CPAE monolayer.…”

Genetic characterization of epizootic hemorrhagic disease virus strains isolated from cattle in Israel

“…An isolate of EHDV-7 from the 2006 outbreak in Israel was shown to be infectious but not to cause clinical disease in cattle (Eschbaumer et al, 2012). A similar study demonstrated that an EHDV-7 Israel isolate caused clinical disease in US white-tailed deer (Ruder et al, 2012a). This discrepancy is not surprising because in general white-tailed deer are more susceptible to EHDV than cattle, especially under experimental infection conditions.…”

Molecular Typing of Epizootic Hemorrhagic Disease Virus Serotypes by One-Step Multiplex RT-PCR

“…An emerging serotype in North America, EHDV-6, is detected regularly during EHD outbreaks and in surveillance samples from white-tailed deer (Wildlife Management Institute 2012). There is increased concern that the geographic distribution of EHDV-6 in North America may be changing and that there is a potential for other EHDV serotype to emerge (Ruder et al 2012). Therefore, it is critical to continue monitoring the distribution of endemic EHDV serotypes.…”