Testing for Mycobacterium avium subsp. paratuberculosis infection in asymptomatic free-ranging tule elk from an infected herd.
Forty-five adult tule elk (Cervus elaphus nannodes) in good physical condition were translocated from a population located at Point Reyes National Seashore, Marin County (California, USA), to a holding pen 6 mo prior to release in an unfenced region of the park. Because infection with Mycobacterium avium subsp. paratuberculosis (Mptb) had been reported in the source population, the translocated elk underwent extensive ante-mortem testing using three Johne's disease assays: enzyme linked immunosorbent assay (ELISA); agar gel immunodiffusion assay (AGID), and fecal culture. Isolation of Mptb was made from fecal samples in six of 45 elk (13%). All AGID results were negative while ELISA results for 18 elk (40%) were considered elevated. Elevated ELISA results or Mptb isolation from fecal samples were obtained for 22 of 45 elk (49%); these elk were euthanized and necropsied. Mycobacterium avium subsp. paratuberculosis was isolated from tissue in 10 of 22 euthanized elk (45%); of these 10 cases of confirmed infection, eight had elevated ELISA results (80%) and four were fecal culture positive (40%). One of 10 cases had histopathologic lesions consistent with Mptb infection. Mycobacterium avium subsp. paratuberculosis was also isolated from tissue from one of eight fetuses sampled. The number of tule elk found to be infected was unexpected, both because of the continued overall health of the source herd and the normal clinical status of all study animals.
Manning
Elizabeth J
EJ
Johne's Testing Center, School of Veterinary Medicine, University of Wisconsin, 2015 Linden Drive, Madison, Wisconsin 53706, USA. emanning@facstaff.wisc.edu
Kucera
Thomas E
TE
Gates
Natalie B
NB
Woods
Leslie M
LM
Fallon-McKnight
Maura
M
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D002140:California / Q000453:epidemiology; D003670:Deer; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005243:Feces / Q000382:microbiology*; D005779:Immunodiffusion / Q000662:veterinary; D016927:Mycobacterium avium subsp. paratuberculosis / Q000276:immunology / Q000302:isolation & purification*; D010283:Paratuberculosis / Q000175:diagnosis* / Q000453:epidemiology
D000907:Antibodies, Bacterial