[Clinical findings and diagnostic procedure in a dairy sheep with visna]

The goal of this report was to describe the clinical signs and diagnosis of Visna in a seven-year-old East Friesian milk sheep. A striking feature was that the ewe's behaviour changed frequently. At one time, the ewe was somnolent. A few minutes later, the sheep was alert and eating hay. The ewe was thin. It had a slight head tilt and a severe generalised ataxia. Based on the neurological symptoms and chronic weight loss, a tentative diagnosis of visna was made. Serological testing for maedi-visna was positive, and the ewe was euthanised. A postmortem examination was performed, and lung and brain samples were collected aseptically. Cell cultures from these organs were positive for viral enzymatic reverse transcriptase and for maedi-visna RNA.