Rhodnius prolixus Viruses Interfere with Proliferation and Metacyclogenesis of the Chagas Disease Agent Trypanosoma cruzi

The protozoan <i>Trypanosoma cruzi</i> is the etiological agent of Chagas disease, a neglected tropical disease that mostly affects the population of Latin American countries, with an estimated 7 million infected people and more than 10,000 deaths per year worldwide. <i>T. cruzi</i> is typically transmitted by hematophagous triatomine insects, with <i>Rhodnius prolixus</i> being a major insect vector in South America. While the microbiome of triatomine insects has been investigated to a certain extent, the ternary interaction between triatomes insects, <i>T. cruzi,</i> and viruses remains virtually unexplored. In this study, we show by transmission electron microscopy and by RT-PCR that <i>Rhodnius prolixus</i> viruses (RpVs) can infect the intestine of <i>R. prolixus</i>, which places them in close contact with the gut microbiota. These observations suggest that <i>T. cruzi</i> can be infected by the insect viruses while transiting through the gut. Here, we show that the RpVs are capable of infecting the epimastigote forms of <i>T. cruzi</i> in vitro and maintain the viral load stabilized for 3 to 7 days after infection. We also show that, at least in the case of the iFlavirus RpV1, viral genomes are detectable in the <i>T. cruzi</i> cytoplasm. Interestingly, <i>R. prolixus</i> ovarian extracts enriched with RpVs decrease epimastigote proliferation and their capacity for differentiation into the ineffective metacyclic trypomastigotes in vitro. Our results start to shed light on the interaction between RpVs and <i>T. cruzi,</i> suggesting possible routes of infection and unveiling a role for viral infections in the development of this important pathogen.