Serotyping of Haemophilus paragallinarum Isolated in Malaysia

Infectious coryza (IC) is an acute respiratory disease of chickens caused by Haemophilus paragallinarum , which provokes economic loss in many parts of the world. Recently, we isolated ten H. paragallinarum from Malaysian poultry farms in Penang, Perak and Johore. Serotyping of these isolates will give information on the serotypes of H. paragallinarum that is/are present in Malaysia. This paper describes the first attempt in the serotyping of H. paragallinarum isolated in Malaysia. H. paragallinarum can be divided into at least 3 serovars; A, B and C by the agglutination test. The ability to agglutinate fresh chicken RBCs suggests that all the H. paragallinarum isolated in Malaysia are of serovar A. The HI test also supports the observation that Malaysian strains except P1-6 strain belong to serovar A.