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

Alessandra Guarneri,Myriam Harry,Carolina Reigada,Dayane Pires-Silva,Fernanda Von H M Fontes,Maurício Lilioso,Cleanne Limeira,Elaine Folly-Ramos,Jackeline Monsalve-Lara,Jane Costa,Carlos Eduardo Almeida

doi:10.1371/journal.pntd.0008735

Abstract

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 181 Triatoma 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 for T. 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 spixii and Kerodon rupestris) were identified as the key-host of T. brasiliensis, but also the potential Trypanosoma cruzi reservoir–able to connect the sylvatic and domestic T. cruzi cycle. Cats also deserve to be studied better, as potential T. cruzi reservoirs. By modeling the food sources + site-occupancy + T. cruzi natural infection, we identified man-made ecotopes suitable for forming dense triatomine infestations with high rates of T. cruzi natural infection, which may be taken into account for vector control measures.

Highlights

In Latina America, about eight million people are infected by Chagas disease and approximately 25 million are at risk, placing this endemic disease among the most serious parasitic illnesses in the Southern Hemisphere
ML received a scholarship in Brazil (Doctorate) of FAPESP, grant 17/21359-8; https:// bv.fapesp.br/en/bolsas/181550/integratedmolecular-approaches-to-elucidate-the-ecologicalassociations-of-triatoma-brasiliensis-f/)
We suggest that the key-host that drives these infestations are mainly Galea spixii, followed by Kerodon rupestris, which seem to be in synanthropic processes because they were found as frequent blood meals for T. brasiliensis in the sylvatic and domestic environments

Summary

Introduction

In Latina America, about eight million people are infected by Chagas disease and approximately 25 million are at risk, placing this endemic disease among the most serious parasitic illnesses in the Southern Hemisphere. Infected populations infest several municipalities from five states of that region [3,4] This species remains an operational challenge for vector control because it continually invades and colonizes human domiciles [5,6]. This triatomine was probably involved in recent Chagas disease outbreaks [7] as it was found with high densities and T. cruzi prevalence in domestic and peridomestic habitats around the outbreak area [8]. Gene flow between sylvatic and peridomestic/domestic populations, with a high prevalence of T. cruzi infection has been shown by mitochondrial gene and microsatellite variations [5] This poses a threat for vector control efforts because sylvatic populations represent perennial foci

Objectives

Methods

Results

Discussion

Conclusion