|Cheong, Soon Hon|
Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/13/2008
Publication Date: 3/16/2009
Publication URL: http://ddr.nal.usda.gov/dspace/bitstream/10113/30158/1/IND44193989.pdf
Citation: Alcaraz, A., Warren, A., Jackson, C., Gold, J., Mccoy, M., Cheong, S., Kimball, S., Sells, S., Taus, N.S., Divers, T., Li, H. 2009. Naturally occurring sheep-associated malignant catarrhal fever in North American pigs. Journal of Veterinary Diagnostic Investigation. 21(2):250-253. Interpretive Summary: Malignant catarrhal fever (MCF), an often fatal disease primarily of ruminants, is caused by a herpesvirus. In this report, two naturally occurring MCF cases were confirmed in pigs in New York and Kentucky, respectively. These were the first cases identified in North America, although MCF in pigs has been reported in Europe. In both cases initial diagnosis was based on histopathological changes representing typical MCF lesions in multiple tissues of the affected pigs and subsequently confirmed by molecular diagnostic assays, concluding that the sheep on the farms were the source of infection in both cases. The report emphasized that it is important to keep in mind that pigs should not be in contact with even a small number of sheep in order to minimize any unnecessary losses due to MCF, despite a low case rate of porcine MCF in North America.
Technical Abstract: Two cases of sheep-associated malignant catarrhal fever (MCF) in pigs were diagnosed on a small farm in New York State, and in Kentucky, U.S.A. In both cases initial diagnosis was based on histopathological changes representing typical lymphoproliferative vasculitis in multiple tissues of the affected pigs. The ovine herpesvirus 2 (OvHV-2) DNA was detected by PCR in the tissues of affected pigs in both cases. The amplified sequences were completely identical between the clinically affected pigs and the OvHV-2 infected sheep. Additional virological and bacteriological examination showed that the affected pigs were negative for Aujeszky’s disease, classical swine fever, porcine enterovirus or rabies. An antibody against a conserved epitope among MCF viruses was detected in a clinically affected pig and two unaffected cohort pigs, as well as in the associated sheep. This is the first report of porcine MCF in North America; the study also confirms that OvHV-2 is associated with the disease in the pigs.