Experimental pasteurellosis: comparative studies on Pasteurella multocida from Asia, Africa, and North America
Heddleston, K.L.; Rhoades, K.R.; Rebers, P.A.
American Journal of Veterinary Research 28: 1003-1012
Pathogenic, immunological and serological properties and biochemical reactions of 3 strains of Past, multocida (P-1256, Asia; P-1234, Africa; and M-1404. U.S.A.) from animals with pasteurellosis were studied. Calves were infected when exposed to an aerosol, but the only calves that died were those in which septicaemia was detected. I/m exposure resulted in death in 24-48 hours. Pigs were highly susceptible to an aerosol and intranasal exposure of culture M-1404. Sheep were more refractory to culture M-1404 than were calves or pigs. Less than 10 colony-forming units of each strain were lethal for mice. Calves vaccinated with strain P-1256 were immune when exposed to cultures P-1234 or M-1404. A calf vaccinated with strain P-1234 was immune when exposed to culture M-1404. Calves that recovered after aerosol exposure were immune when re-exposed to heterologous cultures. Two strains of pasteurella isolated from birds with fowl cholera, one from a calf with shipping fever, and one from a normal calf failed to immunize calves against culture M-1404. The three strains produced agglutinins in calves that were indistinguishable by the serum plate test with each of the 3 strains as antigens. Results of passive immunity tests, in mice, with adsorbed and unadsorbed immune calf serum, indicated that strain M-1404 was antigenically identical to strain P-1256 but not to strain P-1234. Slight differences in biochemical reactions were observed among the 3 strains. A culture, P-1459, isolated in 1965 from a young bison that died from pasteurellosis in Montana, was serologically similar to the Asian strain P-1256 and to the U.S. strain M-1404 that was isolated in 1922 from a bison in Yellowstone National Park.