Abstract
BACKGROUND: Pneumonic pasteurellosis leads to substantial economic losses in the small ruminant Production because of high mortality and reduced productivity. A cross-sectional study was employed with the objective to isolate and identify Mannheimia haemolytica and Pasteurella multocida from outbreak cases of small ruminants in selected districts of Afar region, Ethiopia from December 2021 to June 2023. A total of 192 nasal swab samples were collected using purposive sampling technique and bacterial isolation and identification was carried out as per the standard bacteriological methods. Descriptive statistics and Pearson's chi-square (χ2) were employed to check the association between occurrence of the disease and associated risk factors and statistical significance was set at p < 0.05. RESULTS: In the current study, the overall bacterial isolation rate from clinical cases of ovine and caprine pneumonic pasteurellosis was found to be 24.48% (n = 47/192), of which M. haemolytica accounted for 17.19% (n = 33/192) of bacterial isolates, while P. multocida accounted for 7.29% (n = 14/192) from isolates recovered from nasal swabs. Moreover, the present study also indicated that goats were more affected by this disease with the bacterial occurrence rate of 32.86% (n = 23/70) as compared to sheep with 19.67% (n = 24/122) in the study districts. There was statistically significant difference across species (p = 0.041) of the study animals with occurrence of the ovine and caprine pasteurellosis in nasal swabs. The study further revealed significant variation in the incidence rates of presumptive Pasteurella isolates across the study areas with Asayita recording the highest rate at 19.70% (n = 13/66), followed by Dubti at 17.46% (n = 11/63), and Mille at 14.29% (n = 9/63) even though no statistical association was observed. CONCLUSIONS: The present study finding indicated that M. haemolytica is the predominant bacterium associated with pneumonic pasteurellosis in ovine and caprine in the study areas. This could highlights the need for developing a polyvalent vaccine incorporating M. haemolytica strains.