Abstract text
Trypanosoma cruzi is the etiologic agent of Chagas disease, a neglected disease endemic in Latin America. If infected people are emigrating, it is also relevant to other countries. Analyses of the interactions of T. cruzi with the triatomines and the microbiota of the latter aim to interrupt the transmission cycle.
Investigations of the initial development of different strains of T. cruzi in the stomach differ whether or not all ingested blood trypomastigotes are killed there and allowing a development only those parasites which "escaped" into the small intestine. Investigating in vitro the interactions of T. cruzi with components of the small intestine, the fragility of the parasites should be considered to avoid damages of the surface by high centrifugation forces and protein-free buffers. Focussing on the development of epimastigotes in the rectum, the compounds at the hydrophobic attachment zone of the flagellum remain to be identified. Investigations of in vitro metacyclogenesis use conditions which are not occurring in the rectum of the vector. Therefore, concentrations of oxygen, monosaccharides, free amino acids, proteins and lipids should be determined. T. cruzi induces the synthesis of intestinal antibacterial compounds, and after a knockout of these compounds more bacteria and less T. cruzi develop. However, the strong diversity of the bacteria in the gut requires very detailed analyses. Mutualistic symbionts are only known for four species triatomines. The factors enabling a strong development of mutualistic symbionts in the stomach possessing a high level of antibacterial activity and the reduction of the population of these symbionts in the small intestine possessing a low antibacterial activity are important open questions. Also the vitamin B hypothesis requires attention. So far all mutualistic symbionts are Actinomycetales, and perhaps their unique compounds, mycolic acids, are important for the triatomines. Effects of T. cruzi on triatomines seem to occur in some parasite vector systems, but in experimental infections the supply with the mutualistic symbiont should be guaranteed, and feeding triatomines on living hosts gives an impression of the relevance of observed effects in populations at the field. The proteomic map of T. cruzi, the transcriptome and genome of the triatomine Rhodnius prolixus and the genome sequence of the symbiont Rhodococcus rhodnii should be evaluated for compounds relevant for the interactions in these systems.