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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.

Two hundred sixty Haemophilus spp isolates that had been obtained from the respiratory tract and other sites of swine were acquired from diagnostic laboratories, primarily in the United States and Canada. The majority of isolates (243/260) were biochemically characterized as H parasuis; however, a few isolates of taxa distinct from H parasuis (taxa "minor group," D, E, and F) were identified. Fourteen H parasuis serovars were identified, and of those previously described, the most prevalent were 5 (24.3% of isolates), 4 (16.1%), 2 (8.2%), and 7 (3.7%). Three new serovars that were also prevalent included ND4 (11.1%), ND3 (8.6%), and ND5 (6.6%). Serovars 1, 3, 6, C, D, and new serovars ND1 and ND2 were infrequently identified, and 15.2% of isolates were nontypeable. It was not uncommon to isolate multiple serovars from swine of the same herd or related herds. Distribution of serovars among isolates from the United States and Canada was generally similar; however, a higher prevalence of serovar 5 and a lower prevalence of serovars 2, ND3, and ND5 were evident in isolates from Canada. Comparison of isolates obtained from the respiratory tract of swine without polyserositis with those obtained from swine with polyserositis revealed an increased frequency of serovars 4 and 5, and a decreased frequency of serovar 2, among isolates from swine with polyserositis. However, all prevalent serovars were isolated from swine with polyserositis, and data were not indicative of an association between serovar, site of isolation, or pathogenic potential.