Clinical findings and diagnostic procedure in a milk 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 ewes behaviour changed frequently. At one time, the ewe was somno lent. 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 t he neurological symptoms and chronic weight loss, a tentative diagnosis of visna was made. Serological testing for maedi-visna was positive, and the e we was euthanised. A postmortem examination was performed, and lung and bra in samples were collected aseptically. Cell. cultures from these organs wer e positive for viral enzymatic reverse transcriptase and for maedi-visna RN A.