Characterization of Isolates of Avian Haemophili from Brazil

Abstract

The biochemical and serological properties of 29 isolates of avian haemophili obtained from chickens in Brazil are described. Twenty-seven of the isolates had the typical biochemical properties of Haemophilus paragallinarum. The two remaining isolates had the typical properties of Pasteurella avium, formerly known as Haemophilus avium. All of the H. paragallinarum isolates were serotyped according to the Page scheme using a hemagglutination-inhibition test. Fourteen of the isolates were serovar A, one was serovar B, 11 were serovar C, and one isolate could not be serotyped. The isolates were also examined using a panel of monoclonal antibodies for Page serovars A (one monoclonal antibody available) and C (three monoclonal antibodies available). As expected, the serovar B isolate failed to react with any monoclonal antibody, whereas the 11 serovar C isolates reacted with all three serovar C monoclonal antibodies but not with the serovar A monoclonal antibody. Only eight of the 14 serovar A isolates reacted with the serovar A monoclonal antibody.