La respuesta inmune de algunas especies del género Rhodnius modifica la circulación de genotipos de Trypanosoma cruzi y T. rangeli en varias regiones de América Latina

The immune response of triatomines is represented in the hemolymph, saliva, and intestine by eicosanoids, the prophenoloxidase system, antimicrobial peptides, reactive oxygen species, reactive nitrogen species, and intestinal microbiota factors. The Rhodnius genus consists of 21 species organized into three groups: pallescens, pictipes, and prolixus, acting as vectors for Trypanosoma cruzi and T. rangeli in different Latin American regions. Various studies have reported lytic activity in the hemolymph and salivary glands of Rhodnius prolixus and R. robustus from the prolixus group, targeting some T. cruzi and T. rangeli genotypes. Such lytic activity has not been observed in Triatoma and Panstrongylus species, in R. pallescens, R. colombiensis, and R. ecuadoriensis from the R. pallescens group, nor in R. pictipes from the pictipes group. Proteomic studies in R. prolixus and R. colombiensis haemolymph and salivary glands have detected differences regarding immune response proteins, strongly suggesting an association with lytic activity. Such immune response, linked to factors concerning intestinal microbiota, the vectors’ geographical distribution, and the parasite’s genotypes, has resulted in the hypothesis that the prolixus group consists of various vectors with immune factors that determine the selective transmission of some T. cruzi and T. rangeli genotypes and have modified the geographical distribution of these parasites in the American continent. The present review on the parasite-vector interaction was based on results reported between 1982 and 2023 that clearly support the proposed hypothesis.