Ovine herpesvirus type 2-induced malignant catarrhal fever in a heifer

The clinical, pathological, and molecular findings due to malignant catarrhal fever lesions induced by ovine herpesvirus type 2 (OvHV-2) are described in a 12-month-old, mixed-breed, heifer from northern Paraná, Brazil. The animal demonstrated clinical signs including manifestations of aggressive behavior, nystagmus, incoordination, decumbency, paddling movements, and death within 48 hours, after which was submitted for routine necropsy. Brain fragments were used in PCR assays for identification of infectious agents (OvHV-2; bovine herpesvirus-1 and -5; and Histophilus somni). Rabies was discarded in test done at official state diagnostic laboratory. Significant pathological alterations include disseminated vasculitis with lymphoplasmacytic inflammatory infiltrate within the brain, kidneys, liver, and myocardium. PCR assay amplified the specific422base pair fragment of the OvHV-2 tegument protein gene from the brain; all other evaluations were negative. These findings confirm the participation of OvHV-2 in the etiopathogenesis of the disease observed in this mixed-breed heifer.