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United States Department of Agriculture

Agricultural Research Service

Title: Sheep-Associated Malignant Catarrhal Fever in a Petting Zoo

Authors
item Li, Hong
item Snowder, Gary
item Crawford, T - WASHINGTON STATE UNIV.

Submitted to: Journal of Zoo and Wildlife Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 23, 1999
Publication Date: N/A

Interpretive Summary: Malignant catarrhal fever (MCF), a frequently fatal disease of cattle deer, buffalo and certain other ruminants, is caused by a herpesvirus that is carried by some species, such as sheep. Over a period from late 1992 to early 1995, seventeen deer, including white-tailed deer, muntjac deer, mule deer, reindeer and axis deer, died of suspected MCF in a privately-owned petting zoo in Arizona, USA. Recently developed two assays (PCR specific for sheep-associated MCF viral DNA and competitive inhibition ELISA specific for MCF viral antibody) were used in this retrospective study. Sheep-associated MCF viral DNA were detected by the PCR from fresh-frozen and/or formalin-fixed tissue samples in 7 deer out of 8 available cases previously suspected as MCF by histopathological lesions. A high prevalence of antibody to MCF virus was found among mouflon sheep (80%) and pygmy goats (61%), which were present on the farm during the outbreak. Sixteen percent of fallow deer were also antibody-positive to MCF virus. Following removal of the mouflon sheep and antibody-positive pygmy goats, no further MCF cases occurred on the farm, confirming the importance of careful management to avoid mixing clinically- susceptible species with carrier species. Until better control measures are available, adherence to this practice is necessary if MCF is to be prevented in intense exposure environments such as zoos and densely populated animal parks.

Technical Abstract: In a privately-owned petting zoo in Arizona, USA, seventeen deer from 5 different species, including white-tailed deer (Odocoileus virginianus), muntjac deer (Muntiacus muntjak), mule deer (Odocoileus hemionus), reindeer (Rangifer tarandus) and axis deer (Axis axis), died of suspected malignant catarrhal fever (MCF) over a period from late 1992 to early 1995. A PCR assay specific for ovine herpesvirus 2 (OHV-2), the putative causative agent of sheep-associated MCF, and a competitive-inhibition ELISA based on a monoclonal antibody specific to an epitope conserved among all known MCF viral isolates were used to investigate the outbreak. OHV-2 DNA sequences were detected by the PCR from fresh-frozen and/or formalin-fixed, paraffin-embedded tissue samples in 7 deer out of 8 available cases previously suspected as MCF by histopathology. A high seroprevalence to MCF virus was found among mouflon sheep (Ovis musimon) (80%) and pygmy goats (Capra hircus) (61%), both of which were present on the farm during the outbreak. Sixteen percent of fallow deer (Dama dama) were also seropositive to MCF virus. Following removal of the mouflon sheep and positive pygmy goats, no further MCF cases occurred on the farm, confirming the importance of careful management to avoid mixing clinically-susceptible species with carrier species. Until better control measures are available, adherence to this practice is necessary if MCF is to be prevented in intense exposure environments such as zoos and densely populated animal parks.

Last Modified: 10/22/2014
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