Relaciones huésped-parásito en Tripanosomiasis Rangeli I. Infección intestinal y hemolinfática comparativa de Rhodnius prolixus y Triatoma infestans

In this initial contribution on host-parasite relationships in Rangeli Trypanosomiasis, the results on the infection of 837 nymphs of Rhodnius prolixus and 827 of Triatoma infestans , by artificial xenodiagnosis, with two different strains of T. rangeli , are discussed. The insects were divided in groups in different experiments and in sorne cases the feces were examined and in others only the hemolymph. R. prolixus gave higher rates of infection, by feces exam· ination, than T. infestans at 15 and 30 days. The Venezuelan strain produced higher rates than the Costa Rican strain in both species. The rates in the two species were even higher when the insects were examined by dissecting the intostine, due to the lack of colonization of the flagellates in the rectum: With the Venezuelan strain T. infestans tended to lose the infection, and the same was true for both species with the Costa Rican strain. In the groups where hemolymph was examined for up to two months, it was shown that the haemocoele is more commonly invaded in Rhodnius, and at a higher rate with Venezuelan strain. With this strain a few T. infestans gave light infections with only a few flagellates present, and the Costa Rican strain gave not a single infection in this species. There was no correlation between the feces and hemolymph since it was possible to find insects positive in the latter and negative in the former or viceversa. The implications of the results as far as the experimental conditions used, the life cycle in the invertebrate, and the influence of the insect and different strains of the flagellate are discussed.