Infection Experiments in Monkeys with Human,Macaque and Ateles Strains of Strongyloides.

Abstract

Species of Strongyloides occur naturally in several primates. Those which have come under the observation of the writer have been in man, Simia troglodytes, Pithecus rhesus, Ateles geoffroyi, Cebus capuchinus imitator, and Saimiri örstedi örstedi. In man the infection occurs in 6.3% of the hospital and free-clinic patients in New Orleans and in 20% of the hospital and village population of Panama. Over a period of 2 years a colony of 12 rhesus monkeys in New Orleans has had an infection of 87.5%. Of 6 red spider monkeys from Panama 4 (66.6%) were positive, and of 3 capuchin monkeys and 15 marmosets one each was infected with Strongyloides. In man cultural studies made on material from cases observed by the writer showed both direct and indirect types with a preponderance of the direct type. All of the other strains studied have been consistently indirect in their mode of development.

Morphologically it is difficult to differentiate these primate strains, although they can be readily distinguished from the Strongyloides of the dog, the rat and the sheep. It has seemed desirable, therefore, to test certain of these strains by cross-infection experiments. For this purpose human, macaque and red spider strains, which had been studied over a period of several weeks, were selected. Six monkeys were inoculated by applying the inoculum to the abdominal skin for 30 minutes. Red spider monkeys (one each) were inoculated with about 10,000 f₂ larvae (1) of an autochthonous strain, (2) of a human direct strain and (3) of a rhesus strain. Rhesus monkeys (one each) were inoculated with about 10,000 f₂ larvae (1) of an autochthonous strain, (2) of a direct human strain and (3) of a red spider strain.