Bacterins and Drugs for the Control of Experimental Fowl Cholera

FOWL cholera, caused by the bacteria Pasteurella multoctda, is one of the oldest poultry diseases studied. In fact, in 1880 Pasteur grew this organism in pure culture and used it in some of his fundamental experiments in the attenuation of bacteria. Much research has been done on controlling this disease by immunization, but no real progress was shown until 1958.6 Certainly the major problem with this disease in flocks has been its chronic nature. Recent11 work in Russia showed that the organism is difficult to kill under natural environmental conditions. The organism survived 2-4 months in fowl carcasses left out-of-doors in the winter at -25?C to 2?C temperatures. In buried carcasses it survived for 5 months. In spring at temperatures of -13.5 to +22?C, it survived 3-4 months in the heart, liver, and spleen, and 2-21/2 months in the intestines. In summer, at 8-29?C, it survived for 25 days in exposed carcasses and for 3 months in buried carcasses. Research in South Dakota4 has indicated that most outbreaks were acute. Epizootiological studies suggested older birds as the carriers and most probable source of infection in young birds. The researchers were unable to immunize birds with a chick embryo vaccine inactivated with formalin. They found that oxytetracycline (Terramycin; Pfizer) was the most effective of the antibiotics they tested against experimental fowl cholera infections.