Provocation experiment: Pneumocystis carinii in several kinds of animals.

Provocation experiments of P. carinii in several kinds of laboratory animals were carried out in an animal house where P. carinii of rat strain had been maintained for several years. The organism propagated in cortisone treated rats, rabbits and mice without difficulty as reported by some authors in the past. The organism also propagated in the lungs of rats which had been bred with protein free diet. The present paper first indicates that guinea pig is susceptible to P. carinii. On the other hand, it becomes evident by repeated experiments, that golden hamster seems to be non-susceptible to P. carinii of rat strain even if enough dose of corticosteroid hormones is given. The presence of non-susceptible animal to a certain strain of P carinii is quite interesting from an epidemiological point of view.