Sheep-associated malignant catarrhal fever ina petting zoo

In a privately owned petting zoo in Arizona, 17 deer from five different sp ecies, white-tailed deer (Odocoileus virginianus), Reeve's muntjac (Muntiac us reevesi), mule deer (Odocoileus hemionus), reindeer (Rangifer tarandus), and axis deer (Axis axis), died of suspected malignant catarrhal fever (MC F) over a period from late 1992 to early 1995. A PCR assay specific for ovi ne herpesvirus 2, the putative causative agent of sheep-associated MCF, and a competitive-inhibition enzyme-linked immunosorbent assay based on a mono clonal antibody specific to an epitope conserved among all known MCF viral isolates were used to investigate the outbreak. Ovine herpesvirus 2 DNA seq uences were detected by PCR from fresh-frozen and/or formalin-fixed, paraff in-embedded tissue samples in seven deer out of eight available animals pre viously suspected as cases by histopathology. A high seroprevalence to the virus was found among mouflon (Ovis musimon, 80%) and pygmy goats (Capra hi rcus, 61%), both of which were present on the farm during the outbreak. Six teen percent of fallow deer (Dama dama) were also seropositive to the virus . After removal of the mouflon and positive pygmy goats, no further MCF cas es occurred on the farm, confirming the importance of careful management to avoid mixing clinically susceptible species with carrier species. Until be tter control measures are available, adherence to this practice is necessar y if MCF is to be prevented in intense exposure environments such as toes a nd densely populated animal parks.