Prevalence of Mannheimia haemolytica in Syrian Awassi sheep

Abstract

The aim of the present study was to evaluate the prevalence of Mannheimia haemolytica in Syrian Awassi sheep. Between 2008 and 2012, 1520 nasal swabs from pneumonic and apparently healthy sheep, and 110 pneumonic lungs samples were collected and subjected to bacteriological, biochemical and PCR assays. A total of 191 isolates (11.7%) were identified as M. haemolytica, 44 (2.7%) were M. ruminalis and 18 (1.1%) were M. glucosida. All 191 isolates of M. haemolytica gave an amplified product of 1146 bp size by PCR when lktaA primer was applied. The highest rate of M. haemolytica isolation was from pneumonic lungs tissue (21.8%) and pneumonic sheep (14.1%), and the lowest was from apparently healthy sheep (8.5%). Geographical and seasonal distribution of M. haemolytica showed that the majority of the isolates originated from sheep reared in the Syrian Desert (30%) and Euphrates basin (26.7%), and a significant increase (P≤0.05) in the rate of positive isolates in summer and winter as compared to spring. These findings indicate that M. haemolytica may play an important role in development of pneumonia in Syrian Awassi sheep, especially in eastern parts of Syria, where drought and shortage of rain hit these zones periodically.