Maedi-Visna virus infection in a Merino lamb with nervous signs.

A Maedi-Visna virus (MVV) infection was diagnosed in a 10-month-old lamb from a Turkish flock. The animal suddenly showed nervous signs and died within 2 days. At necropsy, different pulmonary and nervous lesions were observed. A Coenurus cerebraliscyst was also present in the right-brain hemisphere. Severe nonpurulent meningoencephalitis and lymphoproliferative pneumonia were detected by histopathology. MVV proviral DNA was demonstrated by polymerase chain reaction (PCR) in formalin-fixed and paraffin-embedded samples collected from the brain and the lungs. This unusual report in a young animal confirms that not only adult sheep but also lambs can develop MVV disease. Th e hypothesis that concurrent nervous and pulmonary diseases increase the severity of the lesions due to MVV and reduce the incubation time should be better evaluated. [ABSTRACT FROM AUTHOR]