PCR screening for candidate etiological agents of canine hepatitis

Problem assessed: Hepatitis, either acute or chronic, is a relatively common hepatic disease in dogs. Several forms of canine hepatitis can occur, some with a defined cause, most cases have an unknown etiology. The similarities between canine hepatitis and human viral hepatitis suggest that canine hepatitis may have a viral etiology too. Objective: To test liver tissue of dogs with hepatitis for the presence of candidate agents based on their known association with hepatitis in other mammals. Methods and approach: The following infectious agents were tested by PCR: Hepadnaviridae, Helicobacter spp., Leptospira spp., Borrelia spp., hepatitis A virus, hepatitis C virus and hepatitis E virus. Also canine adenovirus and parvovirus were included. Ninety-eight liver tissue samples of dogs with various histologically diagnoses forms of hepatitis were tested. Primers were designed on conserved regions in the genome of each of these agents, to increase the likelihood of detection by PCR. To further increase sensitivity, nested PCRs for all agents were designed. Finally, for each agent a nested short primer PCR (SPP) was performed. Results: None of these agents were detected by nested PCR and nested SPP. However, in two acute hepatitis liver samples parvovirus was detected by nested PCR, and one of these was also detected by nested SPP. Conclusions: Hepatitis in dogs is not caused by agents with high homology to known infectious agents that cause hepatitis in other species. (c) 2005 Elsevier B.V. All rights reserved.