Isolation and identification of Malaysian Pasteurella species responsible for small ruminant pneumonia for the purpose of developing an effective strain-specific vaccine

• Main Author: Mustafa, Mohamad
• Published: University of Edinburgh 1996
• Subjects: 636.089
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.659823

The aims of this study were to identify the prevalence and distribution of <I>Pasteurella haemolytica </I>serotypes causing pneumonic pasteurellosis in sheep and goats in Malaysia, assess the efficacy of a novel <I>P. haemolytica </I>vaccine in field trials and to isolate, characterise and assess the immunological significance of the polysaccharide capsule of <I>P. haemolytica </I>A2. The serotyping study indicated that there was little difference in the relative frequency of occurrence of A serotypes in the UK and in Malaysia. Serotype A2 was by far the most common and the other A serotypes did not differ significantly in order of prevalence. However, T biotypes appeared to be very rare in Malaysia compared to UK. When electrophoretic protein and lipopopolysaccharide profiles of some common strains from both countries were compared there appeared to be no significant differences among the strains. Four to five major protein bands with about twenty minor bands were shown to be present. The lipopolysaccharides profiles were of rough-type. A new <I>P. haemolytica </I>iron-regulated protein (IRP) vaccine was tested in field studies for its efficacy in preventing pasteurellosis in Malaysian sheep farms. The results showed that this vaccine generated an immune response as measured in ELISA and IHA tests. The antibody titers were significantly higher in the vaccinated sheep and there appeared to be protection against clinical pasteurellosis following vaccination. The capsular polysaccharide antigen of <I>P. haemolytica </I>A2 was identified as an important immunogen and as a candidate for a future <I>Pasteurella </I>vaccine. An outer membrane protein-polysaccharide (OMP-PS) complex was successfully prepared from an ovine isolate of <I>P. haemolytica </I>serotype A2 by precipitation from log phase culture supernatant and subsequent purification by column chromatography.