F. Guarda

Natural occurrence of Scrapie in goats in Italy

tions had to be given at monthly intervals, before no mites were recovered. The two lighter infections, presented after this initial case, were treated with a single injection of closantel at 20 mg/kg and recovered completely within one month. At present, more than a year after completion of the treatment, none of the animals has been found to be positive for demodecosis. The range of sizes of the mites recovered suggests that bovine demodecosis may occur in Zambia as different demodicid species living under a synhospitalic phenomenon (Slingenbergh 1980) in one gland. The infection can persist for a long time if not treated, but even in a generalised infestation the animals appear to be in good physical condition. Although treatment with antiparasitic drugs has been considered by many authors to give only partial and temporary relief and many different drugs have been tested and compared, the cases presented here were successfully treated with closantel. Losson and Benakhla (1980) have reported the efficacy of closantel against D ((tis in 1980. However, they used the normal recommended dose of 5 mg/kg followed by weekly injections at 2 5 mg/kg and obtained good results only in animals with no infec-

Maedi-Visna Virus Detection in Ovine Third Eyelids

Maedi-visna is a systemic disease of sheep caused by a lentivirus, maedi-visna virus (MVV), which mainly affects the lungs and central nervous system but may also affect the mammary glands, joints and other tissues. The aim of the present study was to determine whether the third eyelid was affected in cases of systemic infection. Third eyelid and lung samples from sheep naturally infected with maedi were used. Total DNA was extracted from paraffin-wax-embedded tissues, and a nested polymerase chain reaction (PCR) was performed to amplify MVV proviral DNA. The samples were also tested by in-situ PCR and immunohistochemical methods specific for the detection of MVV proviral DNA and p25, respectively. All sheep showed moderate to severe chronic lymphoproliferative inflammation in the third eyelids. Products of the expected size were obtained by PCR from both lung and third eyelid tissue. In the nictitating membrane, MVV proviral DNA was detected in situ within macrophages, and glandular, ductal and surface epithelia. Immunohistochemistry demonstrated that the infection was productive. Taken together, these results indicate that the third eyelid may represent a target for natural MVV infection and may play a role in disease transmission.