The connection between Trypanosoma cruzi transmission cycles by Triatoma brasiliensis brasiliensis: A threat to human health in an area susceptible to desertification in the Seridó, Rio Grande do Norte, Brazil.

Catarina Macedo Lopes,Letícia Paschoaletto Dias,Vanessa Lima-Neiva,Richard Reithinger,Helena Keiko Toma,Lúcia Maria Abrantes Aguiar,Jane Costa,Teresa Cristina Monte Gonçalves

doi:10.1371/journal.pntd.0009919

Catarina Macedo Lopes, Letícia Paschoaletto Dias + Show 6 more

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https://doi.org/10.1371/journal.pntd.0009919

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Abstract

An outbreak of Chagas disease, possibly involving its vector Triatoma brasiliensis brasiliensis, was identified in the state of Rio Grande do Norte (RN). Given the historical significance of this vector in public health, the study aimed to evaluate its role in the transmission dynamics of the protozoan Trypanosoma cruzi in an area undergoing desertification in the Seridó region, RN, Brazil. We captured triatomines in sylvatic and anthropic ecotopes. Natural vector infection was determined using parasitological and molecular methods and we identified discrete typing units (DTUs) of T. cruzi by analyzing the COII gene of mtDNA, 24Sα rDNA, and mini-exon gene. Their blood meals sources were identified by amplification and sequencing of the mtDNA cytochrome b gene. A total of 952 T. b. brasiliensis were captured in peridomestic (69.9%) and sylvatic ecotopes (30.4%). A wide range of natural infection rates were observed in peridomestic (36.0% - 71.1%) and sylvatic populations (28.6% - 100.0%). We observed the circulation of TcI and TcII DTUs with a predominance of Tcl in sylvatic and peridomestic environments. Kerodon rupestris, rocky cavy (13/39), Homo sapiens, human (8/39), and Bos taurus, ox (6/39) were the most frequently detected blood meals sources. Thus, Triatoma b. brasiliensis is invading and colonizing the human dwellings. Furthermore, high levels of natural infection, coupled with the detection of TcI and TcII DTUs, and also the detection of K. rupestris and H. sapiens as blood meals sources of infected T. b. brasiliensis indicate a risk of T. cruzi transmission to human populations in areas undergoing desertification.

Highlights

Chagas disease currently affects approximately 6 to 7 million people globally and presents a high morbidity and mortality rate in endemic countries [1]
Triatoma b. brasiliensis was found in all localities (Table 1), while T. petrocchiae was only collected at Inacio
Among the ecotopes searched in the peridomestic setting, intense colonization of T. b. brasiliensis was observed in cattle corral 62.4% (594/952) (Fig 2)

Summary

Introduction

Chagas disease currently affects approximately 6 to 7 million people globally and presents a high morbidity and mortality rate in endemic countries [1] This disease produces different regional epidemiological patterns and is considered a serious public health problem in Latin America [1,2], a region recognized for high diversity of triatomines (Hemiptera: Reduviidae) [3,4], insect vectors of the etiological agent Trypanosoma cruzi. In this area, vertebrate hosts of the parasite, including reservoir hosts, involved in the transmission cycles of discrete typing units (DTUs) of T. cruzi, have been found in several biomes [5,6]. Considering its anthropozoonotic character, issues related to the persistence and spread of the Chagas disease, especially in areas with low socioeconomic development, intensive environmental degradation in the context of climate change, are among the main concerns of health authorities [1,9,10]

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