|Mark, C - SOUTH DAKOTA STATE UNIV|
|Chase, C - SOUTH DAKOTA STATE UNIV|
Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 4, 2005
Publication Date: December 4, 2005
Citation: Mark, C.S., Ridpath, J.F., Chase, C.L. 2005. Exposure of white tailed deer to bovine diarrhea virus [abstract]. 86th Annual Meeting of the Conference of Research Workers in Animal Diseases. p. 141. Technical Abstract: The importance of white tail deer as a reservoir of bovine viral diarrhea virus (BVDV) has been a point of controversy. The objective of this project was to observe the infectivity of BVDV white tail deer isolates in white tailed deer. Eight white tailed deer fawn 2-4 weeks in age were divided into 2 groups: group 1 was inoculated with non-cytopathic (NCP) BVDV type 1b (03-24272) and group 2 was inoculated with NCP BVDV type 2a (03-20633). A control group consisted of two fawns of similar age. The two viruses were recovered in the fall of 2004 from two separate cases of unthrifty deer in southeast South Dakota. The deer were negative for chronic wasting disease but were positive for BVDV by immunohistochemistry and virus isolation. Virus was administered through oral (2.5 ml) and nasal (1 ml/nare) routes at 5.6 x 106 units/ml. Clinical observations and temperature readings were recorded daily from -3 to 13 days post-inoculation. Blood was collected on days -3, 3, 6, 9, 11, and 13 and submitted for hematology, flow cytometry, virus isolation, and serology. All fawns exposed to BVDV had an increase in basal temperature within the 13-day monitoring period. Average group temperatures were above 102.5 degrees for 6 and 7 days for group 1 (03-24272) and 2 (03-20633). Average lymphocyte count for each group was <50% of control for 1 day within each group, 43% on day 3 for group 1, and 47% on day 6 for group 2. Marked changes were observed among 3 distinct CD18+ populations. A subset in populations of CD44+, CD62-L+, and CD172a+ cells show almost complete depletion on day 3 post-inoculation followed recovery by day 9. Changes were consistent with an increase in dead or dying cells post inoculation. White tail deer are susceptible to BVDV infection from white tail deer isolates. The course of infection was similar to that seen in cattle. There was a notable decrease in circulating lymphocytes suggesting that these viruses might have an immunosuppressive effect in deer. It remains to be determined if deer can transmit the virus to cattle or if deer can become persistently infected as observed in cattle.