Simplified identification of somatic varieties of Pasteurella multocida causing fowl cholera.

Representative type strains as well as field strains of Pasteurella multocida from fowl cholera were examined by the indirect hemagglutination procedure and by a rapid plate agglutination test. The former method identified the specific capsular or K substance, and the latter identified the somatic antigens. Inagglutinable organisms were made agglutinable for the rapid procedure by treatment with hyaluronidase. The results confirmed the identity of representative type strains. Of the 25 field strains examined, one was identified as a type D of low pathogenicity, and the other 25 were type A: 19 serotype 8:A (Heddleston type 3), 3 serotype 5:A (Heddleston type 1), 2 Heddleston's type 4, and 1 serotype 1:A.