Prevalence and Biotyping of Pasteurella Haemolytica Isolates from Sahel Sheep and Goats at Maiduguri, Nigeria

Abstract

P. haemolytica isolated from Sahel sheep and goat in Maiduguri was characterized phenotypically. A total of 92 P. haemolytica isolates were obtained from the nasopharyngeal swabs while a total of 15 isolates came from pneumonic lung samples. The results showed that 37(20.22%) P. haemolytica isolates were obtained from goats while 55(25.23%) came from sheep. The overall isolation rate was 22.94%. Sheep had the highest (25.23%) number of the isolates but the difference was not statistically significant (P>0.05). Prevalence rate of P. haemolytica was higher in female sheep and in sheep between 18-24 months of age but not significant statistically (P>0.05), likewise species and sex difference did not play any significant role. However, the prevalence rate was higher in diseased animals compared with the apparently normal healthy ones (P<0.05).  In all, biotype A was 60.75%, biotype T 22.43% and untypable isolates were 16.82%. Overall, biotype A occurred more significantly than biotype T (P<0.05) and appeared to be the predominant biotype in the area.  Gross pathological appearance of pneumonic lungs was characterized by pulmonary oedema, congestion and multifocal to coalescing haemorrhages with deposition of fibrin. Histopathologically, there was severe pulmonary congestion and oedema with heavy infiltration of mononuclear and leucocytic cells into the interalveolar septae with collapse of alveoli and formation of bullae. These pathological changes are similar to lesions seen in experimental pasteurellosis.