Experimental infection of white-tailed deer (Odocoileus virginianus) with Northern European bluetongue virus serotype 8

Authors: Drolet, Barbara; Reister-Hendricks, Lindsey; RIGG, TARA - Animal And Plant Health Inspection Service (APHIS); NOL, PAULINE - Animal And Plant Health Inspection Service (APHIS); PODELL, BRENDAN - Colorado State University; MECHAM, JAMES - Retired ARS Employee; VERCAUTEREN, KURT - Animal And Plant Health Inspection Service (APHIS); VAN RIJN, PIET - Wageningen University; Wilson, William; BOWEN, RICHARD - Colorado State University

Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/2013
Publication Date: 10/25/2013
Publication URL: https://handle.nal.usda.gov/10113/62675
Citation: Drolet, B.S., Reister, L.M., Rigg, T.D., Nol, P., Podell, B.K., Mecham, J.O., Vercauteren, K.C., Van Rijn, P.A., Wilson, W.C., Bowen, R.A. 2013. Experimental infection of white-tailed deer (Odocoileus virginianus) with Northern European bluetongue virus serotype 8. Veterinary Microbiology. 13(9):619-29. DOI: 10.1089/vbz.2012.1285.

Interpretive Summary: Bluetongue is an insect-transmitted, economically important disease of sheep, cattle, deer and antelope. Of the 26 types of bluetongue virus (BTV), only five are considered endemic to the U.S., but 10 exotic types have been found in the southeast since 1999. Introductions of new types of BTV into the U.S. is a constant disease threat to livestock owners. Exotic types can become established if there are susceptible animals and insects to transmit it. One type of particular concern, BTV type 8, was recently introduced into Northern Europe causing unprecedented livestock disease and mortality. In the U.S., sheep and white-tailed deer (WTD) are the primary sentinel livestock and wildlife species, respectively, and the insects that transmit BTV feed on both. To determine if WTD could be infected by type 8, and understand the role they could play in disease spread if a similar introduction were to occur, deer were experimentally exposed to virus. All deer became infected, amplified the virus, and developed moderate to severe disease. We conclude that North American WTD are highly susceptible to BTV type 8 and may play an important role as virus sources for biting insects and disease spread.

Technical Abstract: Bluetongue (BT) is an insect-transmitted, economically important disease of domestic and wild ruminants. Although only five of the 26 reported bluetongue virus (BTV) serotypes are considered endemic to the USA, 10 exotic serotypes have been isolated primarily in the southeastern region of the country since 1999. For an exotic BTV serotype to become endemic there must be susceptible animal species and competent vectors. In the USA, sheep and white-tailed deer (WTD) are the primary sentinel livestock and wildlife species, respectively. In 2006, BTV-8 was introduced into Northern Europe and subsequently overwintered, causing unprecedented livestock disease and mortality during the 2006-2007 vector seasons. To assess the risk of the European strain of BTV-8 to North American WTD, and understand the role they could play after a similar introduction, eight seronegative WTD were inoculated with BTV-8. Body temperatures and clinical signs were recorded daily. Blood samples were analyzed for BTV RNA with quantitative real time reverse transcriptase polymerase chain reaction (qRT-PCR), serum analyzed for BTV antibodies by cELISA, and tissues taken for histopathology and qRT-PCR. All eight deer became infected and developed moderate to severe clinical disease from days 8 to 15. Peak viremia was from day 7-10 with detectable titers through the end of the study (28 days) in most deer. Serum antibody was detected by day 6, peaked by day 10 and continued through day 28. We conclude that North American WTD are highly susceptible to BTV-8 and would act as clinical disease sentinels and amplifying hosts during an outbreak.