Occurrence of Coccidioides Immitis in Lesions of Slaughtered Animals.

Abstract

During the course of an epidemiological investigation of coccidioidal granuloma, examinations were made of lesions from slaughtered animals. Specimens were obtained through the cooperation of the Bakersfield Packing Company, Kern County, California. A total of 38 such specimens were examined over a period of 3 months. The following table gives the details.

Six of the positives were from cattle and one was from a sheep. The lesions seem to be localized in the upper respiratory tract and apparently no other lesions are to be found in the animals. Whether the disease would become generalized in time cannot be stated as there is no evidence available at present. A study of the histories of the infected animals reveals no common factor. The geographical distribution of these animals is as wide as that of the human cases recorded.

The method of examination was as follows: each specimen was given a serial number when brought to the laboratory. A direct smear of the pus was made using 10% KOH to demonstrate the presence of double contoured capsules. Another smear was made and stained by the acid-fast method for the presence of tubercle bacilli. This was done to eliminate tuberculosis. Some of the pus was stained with 1% hematoxylin. Cultures were made on Sabouraud's agar slants and in plain broth. These were incubated at 37.5° C. for 7 days. The average incubation for these strains was 4 days and the maximum was 6 days. The cultures were inoculated into guinea pigs as a final test in order to determine that the fungus growth was Coccidioides immitis. The autopsy specimens from these animals were examined by the same methods as above.