The Discovery of New Malignant Catarrhal Fever (MCF) Viruses and Their Impact on Ruminant Disease Management and Conservation
Malignant catarrhal fever (MCF) continues to be a significant disease of captive and free-ranging wildlife throughout the world.1-3 Five rhadinovirus species have been recognized to cause clinical illness in artiodactyls and have been provisionally classified as MCF viruses.3 However, with advances in molecular technology, new rhadinoviruses are being identified and linked to classic MCF and atypical MCF-like disease with increasing frequency.4 To better understand the ecology of rhadinoviruses and their potential to cause illness, we opportunistically tested 97 species and subspecies of ruminants (over 700 different individuals) in the San Diego Zoo and Safari park collection for the presence of rhadinoviruses. DNA was extracted from blood, tissue, and swab samples and tested with a consensus-based PCR targeting the DNA polymerase gene of the family Herpesviridae followed by DNA sequencing of positive reactions. Associations with transmission were evaluated to better understand rhadinovirus epidemiology. Fifty-six species and subspecies (56/97; 58%) were infected with rhadinovirus. Forty-four different viral genotypes were identified, including 42 genetic sequences that had not been previously reported. Sixteen of the genotypes (16/44; 36%) were identified in multiple host species. Sixty-five of 134 positive animals with blood samples (49%) were viremic. Data demonstrate the diversity and prevalence of rhadinovirus infection in ruminants and propensity for interspecies transmission in captive management systems. These data will provide a valuable resource for making management recommendations to reduce spillover from reservoir hosts to susceptible hosts.
The authors would like to thank the Ellen Browning Scripps Foundation, Mrs. Shirley Sykes, and San Diego Zoo Global for funding this study. The authors also thank the many visiting students and personnel from San Diego Zoo Global that assisted in the collection and processing of data.
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