Full Length Research Paper

Isolation of diverse bacterial species associated with maedi-visna infection of sheep in Ethiopia

Legesse Garedew¹, Gelagay Ayelet², Roman Yilma³, Aschalew Zeleke² and Esayas Gelaye²*

¹Faculty of Veterinary Medicine, Gondar University, P. O. Box 196, Gondar, Ethiopia.

²National Veterinary Institute, P. O. Box 19, Debre Zeit, Ethiopia.

³Debre Birhan Agricultural Research Center, P. O. Box: 112, Debre Birhan, Ethiopia.

*Corresponding author. E-mail: egelaye@yahoo.com.

Accepted 19 October, 2009

   Abstract

Bacterial species associated with maedi-visna (MV) infection and occurrence of respiratory disease complex (RDC) in sheep in the cool central highlands of Ethiopia was investigated. Of the 80 sheep examined, 61.25% (n= 49) were found to be MV seropositive and 38.75% (n= 31) were MV seronegative. At post-mortem examination, out of the 49 MV seropositive sheep, 75.51% (n= 37) showed pneumonic lesions in the lungs and a further 23 (74.19%) seronegative sheep were also found pneumonic. Overall, 87.5% (n= 70) of the lungs were culture positive and no bacteria were isolated from 12.5% (n= 10) of the lung samples. The majority of the bacterial species were isolated from grossly pneumonic lungs (75.71%, n= 94) and MV seropositive sheep (62.3%, n= 71). Of the total 114 bacteria isolated, 63 were gram-positive and 51 were gram-negative. Almost all gram-negative isolates (96.08%, n= 49) were recovered from pneumonic lungs. The bacterial isolates were classified into 18 genera and 23 species, some of which are known pathogens and some are opportunists. Involvement of diverse microbial groups in the development of RDC in the study area is discussed.

Key words: Diverse bacteria, Ethiopia, maedi-visna, pneumonia, sheep.