Pathogenicity and immunity studies of Haemophilus parasuis serotypes.
After intranasal inoculation of SPF pigs with the 7 reference strains of Haemophilus parasuis only the reference strains of serotypes 1 and 5 proved to be pathogenic and were able to produce the lesions characteristic of Glässer's disease. Even though the reference strains of serotypes 2, 3, 4, 6 and 7 proved to be apathogenic, intranasal inoculation resulted in the development of circulating antibodies as demonstrated by the complement fixation test. This serological response suggests an antigenic relationship between serotypes 1 and 3 different from the relationship seen among serotypes 2, 4, 5, 6 and 7. Pigs given an aerosol with the apathogenic serotypes 2, 3, 4 and 7, respectively, resisted challenge with a virulent Danish strain of serotype 5. These results indicate that the 7 serotypes also have antigenic determinants in common and that these determinants elicit cross-protecting immunity on the respiratory mucosa.
Nielsen
R
R
National Veterinary Laboratory, Copenhagen, Denmark.
D000818:Animals; D006190:Haemophilus / Q000276:immunology / Q000472:pathogenicity*; D006192:Haemophilus Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D007109:Immunity; D010641:Phenotype; D013047:Specific Pathogen-Free Organisms; D013552:Swine; D013553:Swine Diseases / Q000276:immunology* / Q000382:microbiology