Surveillance for chronic wasting disease and other infectious agents in mule deer (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus) in southern Saskatchewan
Chronic wasting disease (CWD) was detected in Saskatchewan wild deer populations in 2000 which prompted disease management actions consisting of population reduction. Little is known about population structure, health status, interactions or movement patterns of deer in Saskatchewan and these factors are important in designing a management program for CWD. As part of an ongoing study on deer movement patterns of wild deer in southern Saskatchewan, a survey was conducted to: 1) determine prevalence of CWD and selected infectious agents in mule deer (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus), and 2) identify infectious agents which could be used as a surrogate measure of the effectiveness of the adopted CWD management strategies. Tonsil biopsies, feces and blood were collected from 254 mule deer and 43 white-tailed deer during winters of 2006, 2007 and 2008. Immunohistochemical staining of tonsil biopsies for CWD revealed a prevalence of 2.4% (6/249) in mule deer and 0% (0/43) in white-tailed deer. Parasitological investigation of 253 fecal samples from mule deer identified eggs of nematodes in the superfamily Trichostrongyloidea (29.2%); and parasitic stages of the following genera: Nematodirus (7.1%), Skrjabinema (14.3%), Trichuris (0.8%), Moniezia (16.2%), Thysanosoma (12.2%), Orthostrongylus (35.2%), Eimeria (13.4%) and Giardia (0%, 0/137). A similar investigation of 42 white-tailed deer fecal samples identified parasitic stages of nematodes in the super family Trichostrongyloidea (4.8%) and in genera of Orthostrongylus (2.4%), Moniezia (2.4%) and Eimeria (2.4%). Dorsal-spined larvae were detected in 2.4% of the white-tailed deer fecal samples. In serum samples from 253 mule deer, antibodies (Ab) were detected against bovine herpesvirus1 (BoHV-1) (34.8%), parainfluenza-3 (PI-3) (56.5%), bovine virus diarrhoea virus (BVDV-1) (30.8%) and Neospora caninum (15.4%, 36/245). In serum samples from 40 white-tailed deer, Ab to BoHV-1(32.5%), PI-3 (35%), BVD-1 (12.5%) and Neospora caninum (20.5%, 8/39) was detected. Based on relative host specificity, moderate prevalence and horizontal routes of transmission, herpesvirus, parainfluenza 3, Eimeria and Skrjabinema were identified as infectious agents which could potentially be used to evaluate the effectiveness of disease management strategies, which may in turn predict the response of CWD to these same strategies. Using polymerase chain reaction (PCR) a herpesvirus was detected, in 42.1% (40/95) of retropharyngeal lymph nodes from hunter-submitted mule deer and white-tailed deer heads from Saskatchewan in 2007. DNA sequences of the partial DNA polymerase gene from this virus were 98 - 100% identical to mule deer lymphotropic herpesvirus (mule deer-LHV). A 3.6 kb contiguous sequence of mule deer-LHV genome was generated by genome walking (GenBank Accession number: HM014314). Use of a mule deer-LHV-specific PCR on buffy coat samples collected during winters of 2007 and 2008, detected mule deer-LHV in 42.1% (67/158) of mule deer and 33.3% (8/24) of white-tailed deer. Very little DNA sequence diversity in the partial sequences of glycoprotein B (gB) gene and the intergenic spacer regions between DPOL and gB gene of mule deer-LHV was observed among deer from different wildlife management zones. Mule deer-LHV is also a potential marker for evaluating the effectiveness of disease management activities because of its moderate prevalence, host specificity, ease of sample collection and the availability of a rapid and low-cost method for its detection. A variable region of the mule deer-LHV genome needs to be identified if this virus to be used as an inferential tool for studying host population structure.
DegreeMaster of Science (M.Sc.)
SupervisorBollinger, Trent K.
CommitteeWobeser, Garry; Waldner, Cheryl; Hill, Janet E.; Jenkins, Emily; Kidney, Beverly; Chilton, Neil
Copyright DateJanuary 2011
chronic wasting disease