Oral transmission of trypanosomes of the subgenus Herpetosoma from small mammals.

The rodents Microtus agrestis, Clethrionomys glareolus, Apodemus sylvaticus and white BK rats were given either a single intraperitoneal (i.p.) injection, an intragastric (i.g.) inoculation or an oral (p.o.) inoculation of the culture forms, including metacyclic trypomastigotes, of Trypanosoma microti, T. evotomys, T. grosi and T. lewisi, respectively. Similar levels of parasitaemia were produced by each of the three routes of infection, although the prepatent period was 3-5 days shorter in the case of the i.p.-injected animals. The oral inoculation of blood from mice infected with T. musculi into uninfected mice (outbred) and from rats infected with T. lewisi into uninfected BK rats produced parasitaemia after 6-8 days. This is the first report of the oral and i.g. transmission of T. microti, T. evotomys and T. grosi into their specific homologous hosts.