Wide distribution of Trypanosoma cruzi-infected triatomines in the State of Bahia, Brazil

Carlos G S Dos Santos,Gabriel Muricy Cunha,Roberto Fonseca Dos Santos,Gilmar Ribeiro,Rodrigo Gurgel-Gonçalves,Diego Lopes Paim Miranda,Fernanda Vaccarezza,Jamylle Reis,Fernanda Lanza,Cristiane Medeiros Moraes De Carvalho,Eduardo Oyama Lins Fonseca,Orlando Marcos Farias De Sousa,Renato Freitas De Araújo,Camila Diniz,Mitermayer G Dos Reis,Renato Barbosa Reis,Wildo Navegantes De Araújo

doi:10.1186/s13071-019-3849-1

Abstract

BackgroundThe identification of Trypanosoma cruzi and blood-meal sources in synanthropic triatomines is important to assess the potential risk of Chagas disease transmission. We identified T. cruzi infection and blood-meal sources of triatomines caught in and around houses in the state of Bahia, northeastern Brazil, and mapped the occurrence of infected triatomines that fed on humans and domestic animals.MethodsTriatominae bugs were manually captured by trained agents from the Epidemiologic Surveillance team of Bahia State Health Service between 2013 and 2014. We applied conventional PCR to detect T. cruzi and blood-meal sources (dog, cat, human and bird) in a randomized sample of triatomines. We mapped triatomine distribution and analyzed vector hotspots with kernel density spatial analysis.ResultsIn total, 5906 triatomines comprising 15 species were collected from 127 out of 417 municipalities in Bahia. The molecular analyses of 695 triatomines revealed a ~10% T. cruzi infection rate, which was highest in the T. brasiliensis species complex. Most bugs were found to have fed on birds (74.2%), and other blood-meal sources included dogs (6%), cats (0.6%) and humans (1%). Trypanosoma cruzi-infected triatomines that fed on humans were detected inside houses. Spatial analysis showed a wide distribution of T. cruzi-infected triatomines throughout Bahia; triatomines that fed on dogs, humans, and cats were observed mainly in the northeast region.ConclusionsSynanthropic triatomines have a wide distribution and maintain the potential risk of T. cruzi transmission to humans and domestic animals in Bahia. Ten species were recorded inside houses, mainly Triatoma sordida, T. pseudomaculata, and the T. brasiliensis species complex. Molecular and spatial analysis are useful to reveal T. cruzi infection and blood-meal sources in synanthropic triatomines, identifying areas with ongoing threat for parasite transmission and improving entomological surveillance strategies.

Highlights

The identification of Trypanosoma cruzi and blood-meal sources in synanthropic triatomines is impor‐ tant to assess the potential risk of Chagas disease transmission
The most salient findings about T. cruzi infection and blood-meal sources in synanthropic triatomines in Bahia were: (i) T. cruzi-infected triatomine bugs fed on human blood; (ii) T. cruzi-infected triatomines were widespread, but bugs that fed on dogs, humans, and cats were observed mainly in the northeast region; and (iii) most bugs fed on birds
Ten species were recorded inside houses in sampled municipalities, mainly Triatoma sordida, T. pseudomaculata, and the T. brasiliensis species complex

Summary

Introduction

The identification of Trypanosoma cruzi and blood-meal sources in synanthropic triatomines is impor‐ tant to assess the potential risk of Chagas disease transmission. Chagas disease is the most frequent cause of heart failure in rural populations in vector-endemic countries in Latin America [1, 2]. It is an infection caused by Trypanosoma cruzi (Chagas, 1909), a protozoan transmitted by Ribeiro Jr. et al Parasites Vectors (2019) 12:604 blood-feeding bugs [3]. The presence of ~60 species of native vectors in Brazil [9] in a wide endemic area of Chagas disease with different transmission scenarios [10] and a progressive reduction of the human and financial resources needed to sustain the continuity of the control actions, highlight the need for updated studies about surveillance of triatomines in Brazilian states

Methods

Results

Discussion

Conclusion