Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 8, 2009
Publication Date: January 25, 2009
Citation: Ridpath, J.F. 2009. Detection and Impact of BVDV in Wild Ruminants [abstract]. 4th U.S. BVDV Symposium. Paper No. 1-2. Technical Abstract: While BVDV is most commonly associated with cattle there is evidence, based on virus isolation and/or serology, that BVDV replicates in a wide variety of domesticated and wild ruminants including cervidae such as white tail deer, mule deer, fallow deer, elk, red deer, roe deer, and mousedeer and caprinae such big horn sheep, chamois and mountain goats. Acute BVDV infections in cattle are accompanied by immune suppression due, at least in part, to the death of immune cells within lymph nodes and gut associated lymphoid tissue and reduction in numbers of circulating white blood cells. The suppression of the immune system leaves infected cattle vulnerable to secondary infections. While limited research has been done, regarding BVDV infection, in most wildlife ruminant species is appears that acute and persistent infections occur and clinical presentation is similar to that seen in cattle. Because free ranging wild ruminant populations are frequently in contact with domestic cattle in the U.S., possible transfer of BVDV between cattle and wild ruminants has significant implications for proposed BVDV control programs. Further, reintroduction of endangered species to ecosystems that include domestic cattle may fail due to BVDV transmission from cattle to the newly introduced and BVDV naive species. The level of exposure and prevalence of persistently infected wild ruminants is largely unknown. Regional surveillance based on serology varies significantly and some studies have reported little correlation between detection of persistently infected animals in the wild and serology rates among corresponding wild populations. Recently several studies of BVDV infection in white tail deer have been reported in the literature. The clinical progression of acute disease following inoculation of fawns was similar to that seen in BVDV infections in cattle and included fever and reduction of circulating lymphocytes. Similarly the clinical presentation of BVDV associated reproductive disease in white-tailed deer and cattle is similar and includes readsorption, abortion, mummification and birth of persistently infected offspring. However, persistently infected (PI) fawns differed from PI cattle in the amount of virus associated with lymphocytes. This suggests that there may be differences in the replication and shed of the virus between cattle and cervids. Diagnostic methods developed for cattle, including virus isolation and detection of BVDV antigen or genomic material performed adequately in white tail deer. Finally, the presence of neutralizing antibody titers in pregnant white-tailed deer appears to protect against BVDV infection in fawns. Transmission between persistently infected cervids and cattle and vice versa has been confirmed under controlled experimental conditions. Recent research conducted in our laboratory indicates transmission via indirect exposure (exposure to contaminated housing and food) between acutely infected deer and naive cattle.