Sero-epidemiological study on Maedi-Visna in selected areas of Ethiopia

Abstract

The study was conducted to verify the existence of Maedi-Visna virus infection (Ovine Progressive Pneumonia- OPP) in exotic sheep breed in selected areas of Ethiopia. ELISA and Hematoxylin & Eosin (HE) staining techniques were employed to examine the serum and tissue samples respectively. ELISA test of serum samples showed 88%, 19%, 10%, 6%, and 0.8% infection rate for Debre Berhan sheep breeding center, and Arsi, Bale, North Omo and Gurage zones respectively. At necropsy 11% (4/36) of the sheep examined had characteristic gross pathological lung lesions of Maedi/OPP and 33% (12/36) indicated the presence of the disease through histopathological examinations. The major histopathological findings were peribronchial and interstitial lymphocytic infiltrations and/or follicle-like aggregations, interstitial connective tissue proliferation, hyperplasia of the smooth muscles in the ducts of terminal bronchioles and alveoli. The present findings provide a clear evidence for the dissemination of Maedi-Visna virus following the distribution of exotic rams from the breeding and multiplication center. Therefore, survey in other areas is also required to have broad picture of the disease in the country which will help to design a practical control strategy of the disease at the national level.

Keywords: Ethiopia, exotic sheep breeds, maedi-visna, sero-epidemiology