Spatio-temporal characterization of Trypanosoma cruzi infection and discrete typing units infecting hosts and vectors from non-domestic foci of Chile.

Camila Ihle-Soto,Pedro E Cattan,Carezza Botto-Mahan,David E Gorla,Sylvia Ortiz,Viviana Estadella,Berenice Cornejo-Villar,Eduardo Costoya,Héctor J Hernández,Antonella Bacigalupo,Juana P Correa,Aldo Solari,Ricardo E Gürtler

doi:10.1371/journal.pntd.0007170

Abstract

BackgroundTrypanosoma cruzi is a protozoan parasite that is transmitted by triatomine vectors to mammals. It is classified in six discrete typing units (DTUs). In Chile, domestic vectorial transmission has been interrupted; however, the parasite is maintained in non-domestic foci. The aim of this study was to describe T. cruzi infection and DTU composition in mammals and triatomines from several non-domestic populations of North-Central Chile and to evaluate their spatio-temporal variations.Methodology/Principal findingsA total of 710 small mammals and 1140 triatomines captured in six localities during two study periods (summer/winter) of the same year were analyzed by conventional PCR to detect kDNA of T. cruzi. Positive samples were DNA blotted and hybridized with specific probes for detection of DTUs TcI, TcII, TcV, and TcVI. Infection status was modeled, and cluster analysis was performed in each locality. We detected 30.1% of overall infection in small mammals and 34.1% in triatomines, with higher rates in synanthropic mammals and in M. spinolai. We identified infecting DTUs in 45 mammals and 110 triatomines, present more commonly as single infections; the most frequent DTU detected was TcI. Differences in infection rates among species, localities and study periods were detected in small mammals, and between triatomine species; temporally, infection presented opposite patterns between mammals and triatomines. Infection clustering was frequent in vectors, and one locality exhibited half of the 21 clusters found.Conclusions/SignificanceWe determined T. cruzi infection in natural host and vector populations simultaneously in a spatially widespread manner during two study periods. All captured species presented T. cruzi infection, showing spatial and temporal variations. Trypanosoma cruzi distribution can be clustered in space and time. These clusters may represent different spatial and temporal risks of transmission.

Highlights

Chagas disease is a zoonotic parasitic disease, endemic in 22 countries of America, caused by the flagellated protozoa Trypanosoma cruzi
Due to the high number of minicircle copies and conserved sequences, they are used in the diagnosis of infection through polymerase chain reaction (PCR), using primers that bind to the CSB [8]
Detailed number of small mammals and triatomines captured by locality and study period is available in S2 Table

Summary

Introduction

Chagas disease is a zoonotic parasitic disease, endemic in 22 countries of America, caused by the flagellated protozoa Trypanosoma cruzi. This disease affects approximately 7 million people in the world and represents the third parasitic disease of major world impact [1]. Trypanosoma cruzi is a protozoan parasite that is transmitted by triatomine vectors to mammals. It is classified in six discrete typing units (DTUs). The aim of this study was to describe T. cruzi infection and DTU composition in mammals and triatomines from several non-domestic populations of North-Central Chile and to evaluate their spatio-temporal variations

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