High Parasitic Loads Quantified in Sylvatic Triatoma melanica , a Chagas Disease Vector.

is a sylvatic vector species in Brazil. In We aimed to characterize the discrete typing units (DTUs), the parasitic loads, and the blood meal sources of insects collected in rocky outcrops in rural areas in the state of Minas Gerais. An optical microscope (OM) and kDNA-PCR were used to examine natural infection by , and positive samples were genotyped by conventional multilocus PCR. Quantification of the load was performed using qPCR, and the blood meal sources were identified by Sanger sequencing the 12S rRNA gene. A total of 141 were captured. Of these, ~55% (61/111) and ~91% (63/69) were positive by OM and KDNA-PCR, respectively. We genotyped ~89% (56/63) of the -positive triatomines, with TcI (~55%, 31/56) being the most prevalent DTU, followed by TcIII (~20%, 11/56) and TcII (~7%, 4/56). Only TcI+TcIII mixed infections were detected in 10 (~18%) specimens. A wide range of variation in the parasitic loads of was observed, with an overall median value of 10 parasites/intestine, with females having higher loads than N2, N4, and N5. TcII showed lower parasitic loads compared to TcI and TcIII. The OM positive diagnosis odds ratio between infection when the parasite load is 10 compared to 10 was approximately 29.1. The most frequent blood meal source was (~58%), followed by (~18%), (~8%), (~8%) and (~8%). Our findings characterize biological and epidemiological aspects of the sylvatic population of in the study area, highlighting the need to extend surveillance and control to this vector.