EXPERIMENTAL EPIDEMIOLOGY OF COCCIDIOIDOMYCOSIS. I. EPIZOOTIOLOGY OF NATURALLY EXPOSED MONKEYS AND DOGS
ARMY BIOLOGICAL LABS FREDERICK MD
Pagination or Media Count:
Animals from constant populations of monkeys and dogs 24 of each divided among 3 exposure sites housed for 1 year in the open in a known endemic area for coccidioidomycosis Tucson, Arizona were removed, upon contracting infection with Coccidioides immitis, to air-conditioned quarters for further observation and were immediately replaced at the exposure sites with other susceptible animals. Periodic soil and air samples were obtained, and appropriate climatic data were recorded throughout the 1-year period. Clinical and laboratory observations were continuously recorded for all animals, and complete necropsies were performed at the termination of the experiment. Approximately 15 of the monkeys and 58 of the dogs became infected, the majority during the cooler months. Comparison of the pathogenesis of the disease in the naturally infected monkeys with that in experimentally infected monkeys indicated a natural airborne infectious dose of probably less than 10 arthrospores. The infection rate, as well as the extent of disease, in the naturally infected dogs was greater than in either the naturally infected monkeys or the experimentally infected dogs, and was attributed to their contact with the ground. The lack of mortality in the naturally infected animals of either species indicated very low natural infectious doses of Coccidioides immitis. The ecological and climatic parameters of this study were similar to those of other studies in the same general area.