A search for field and house rodents naturally infected with kala-azar.

Abstract

The striped hamster (Cricetulus griseus) has been shown to be very susceptible to infection with kala-azar. 1

Its southern range corresponds, so far as it has been studied, with the distribution of kala-azar in China. These two facts together with other observations on the epidemiology of the disease, suggested the possibility that this hamster or some other field rodent may be a reservoir of Leishmania donovani. Assuming such a source, man might be infected in his dwelling directly from the animal or indirectly by means of some domestic rodent (rat or mouse) which had in turn become infected from an invading field rodent. In either case the probable vector or intermediate host would be some rodent ectoparasite. With this rodent-ectoparasite hypothesis in mind we have: (1) searched for hamsters and other field and house rodents naturally infected with kala-azar; (2) tested for susceptibility to infection with Leishmania donovani the common field and house rodents from an endemic area; and (3) studied the natural ectoparasites of these rodents and their capabilities as transmitters of the disease. The present paper is a brief statement of the results of the first of these investigations. The animals recorded comprise (1) those killed and examined primarily for the purpose of searching for naturally infected animals; (2) those that died in the laboratory before they had been submitted to any experimental procedure and (3) such stock rodents as were accidentally killed by liver puncture. From this study were excluded (1) all rodents that had received any injection or had been submitted to any manipulation other than liver punture; (2) all carcasses that showed decomposition of the organs; and (3) all animals regarding whose exact origin and subsequent history there was any doubt.