Dynamics of food sources, ecotypic distribution and Trypanosoma cruzi infection in Triatoma brasiliensis from the northeast of Brazil.

Author summary Blood-sucking bugs are vectors of the parasiteTrypanosoma cruzi, which causes the Chagas disease.Triatoma brasiliensisis the main Chagas disease vector in the Caatinga eco-region of northeastern Brazil. Previous studies have already indicated that this species is associated with rodents of the Caviidae family-mainly in the sylvatic environment. In this study, we showed that these rodents are the main food sources ofT.brasiliensisalso in peridomestic environments. This association is frequently followed by numerous populations ofT.cruziinfected insects in man-made ecotopes to store materials of mineral and wood origin. We suggest that the key-host that drives these infestations are mainlyGalea spixii, followed byKerodon rupestris(both Rodentia: Caviidae), which seem to be in synanthropic processes because they were found as frequent blood meals forT.brasiliensisin the sylvatic and domestic environments. Other mammals-mainly cats-may play an important role in Chagas disease eco-epidemiology for also being an important source of food for triatomines in the sylvatic and peridomestic environments. We conclude that educational programs to avoid Chagas disease transmission should include advising local people to avoid storing wood and tiles/bricks in the peridomestic environment-shelters for key-host rodents. Besides, they must be aware that these cavies may be infected byT.cruzi; and cautions are needed if they are to be used as a source of protein by hunting. Innovative approaches used to combat Chagas disease transmission tend to combine a set of comprehensive efforts to understand the ecology of local vectors. In this work we identified molecularly the blood meal of 181Triatoma brasiliensis, distributed in 18 populations (8 sylvatic and 10 peridomestic), which were collected across a range of 240 km (East-West) and 95 km (North-South) in the semi-arid region of northeastern, Brazil. We used the vertebrate mitochondrial gene (cytochrome B) sequencing applied to DNA isolated from bug midgut to identify the insect blood meal sources via the BLAST procedure. The peridomestic populations were classified according to two main hypotheses of site-occupancy forT.brasiliensis: the first says that the infestation is mainly driven by structures that resemble its natural habitat (stony-like ecotopes) and the second assumes that it is associated with key-hosts (rodents and goats). Rodents of the Caviidae family (Galea spixiiandKerodon rupestris) were identified as the key-host ofT.brasiliensis, but also the potentialTrypanosoma cruzireservoir-able to connect the sylvatic and domesticT.cruzicycle. Cats also deserve to be studied better, as potentialT.cruzireservoirs. By modeling the food sources + site-occupancy +T.cruzinatural infection, we identified man-made ecotopes suitable for forming dense triatomine infestations with high rates ofT.cruzinatural infection, which may be taken into account for vector control measures.