Triatomine vectors transmit Trypanosoma cruzi , the etiological agent of Chagas disease in humans. Transmission to humans typically occurs when contaminated triatomine feces come in contact with the bite site or mucosal membranes. In the Southern Cone of South America, where the highest burden of disease exists, Triatoma infestans is the principal vector for T . cruzi . Recent studies of other vector-borne illnesses have shown that arthropod microbiota influences the ability of infectious agents to colonize the insect vector and transmit to the human host. This has garnered attention as a potential control strategy against T . cruzi , as vector control is the main tool of Chagas disease prevention. Here we characterized the microbiota in T . infestans feces of both wild-caught and laboratory-reared insects and examined the relationship between microbial composition and T . cruzi infection using highly sensitive high-throughput sequencing technology to sequence the V3-V4 region of the 16S ribosomal RNA gene on the MiSeq Illumina platform. We collected 59 wild (9 with T . cruzi infection) and 10 lab-reared T . infestans (4 with T . cruzi infection) from the endemic area of Arequipa, Perú. Wild T . infestans had greater hindgut bacterial diversity than laboratory-reared bugs. Microbiota of lab insects comprised a subset of those identified in their wild counterparts, with 96 of the total 124 genera also observed in laboratory-reared insects. Among wild insects, variation in bacterial composition was observed, but time and location of collection and development stage did not explain this variation. T . cruzi infection in lab insects did not affect α- or β-diversity; however, we did find that the β-diversity of wild insects differed if they were infected with T . cruzi and identified 10 specific taxa that had significantly different relative abundances in infected vs . uninfected wild T . infestans ( Bosea , Mesorhizobium , Dietzia , and Cupriavidus were underrepresented in infected bugs; Sporosarcina , an unclassified genus of Porphyromonadaceae , Nestenrenkonia , Alkalibacterium , Peptoniphilus , Marinilactibacillus were overrepresented in infected bugs). Our findings suggest that T . c...

Guinea pigs are important reservoirs of Trypanosoma cruzi, the causative parasite of Chagas disease. Interestingly, captured colonies of T. infestans, the main vector of T. cruzi in the Southern Cone of South America, sporadically present with infection prevalence rates above 80%. Such high values are not consistent with the relatively short 7–8 week parasitemic period that has been reported in the literature. We experimentally measured the infectious periods of a group of T. cruzi-infected guinea pigs with two methods: xenodiagnosis and direct microscopy, each performed weekly for a year. Another group of infected guinea pigs received only direct microscopy weekly, to control for the effect that inoculation by triatomine saliva may have on parasitemia in the host. We observed infectious periods longer than those previously reported in a number of guinea pigs from both the xenodiagnosis and control groups. While some guinea pigs were infectious for a short time, other “super-shedders” were parasitemic up to 22 weeks after infection, and/or positive by xenodiagnosis for a year after infection. This heterogeneity in infectiousness has strong implications for T. cruzi transmission dynamics and control, as super-shedder guinea pigs may play a disproportionate role in pathogen spread.