Interaction of , Triatomines and the Microbiota of the Vectors-A Review.

This review summarizes the interactions between , the etiologic agent of Chagas disease, its vectors, triatomines, and the diverse intestinal microbiota of triatomines, which includes mutualistic symbionts, and highlights open questions. strains show great biological heterogeneity in their development and their interactions. Triatomines differ from other important vectors of diseases in their ontogeny and the enzymes used to digest blood. Many different bacteria colonize the intestinal tract of triatomines, but only Actinomycetales have been identified as mutualistic symbionts. Effects of the vector on are indicated by differences in the ability of to establish in the triatomines and in colonization peculiarities, i.e., proliferation mainly in the posterior midgut and rectum and preferential transformation into infectious metacyclic trypomastigotes in the rectum. In addition, certain forms of develop after feeding and during starvation of triatomines. Negative effects of on the triatomine vectors appear to be particularly evident when the triatomines are stressed and depend on the strain. Effects on the intestinal immunity of the triatomines are induced by ingested blood-stage trypomastigotes of and affect the populations of many non-symbiotic intestinal bacteria, but not all and not the mutualistic symbionts. After the knockdown of antimicrobial peptides, the number of non-symbiotic bacteria increases and the number of decreases. Presumably, in long-term infections, intestinal immunity is suppressed, which supports the growth of specific bacteria, depending on the strain of . These interactions may provide an approach to disrupt transmission.