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.