Genetic Diversity of Trypanosoma cruzi in Panama Inferred by Multi-locus Sequence Typing of Mitochondrial Genes.

Jose E Calzada,Barbara A Burleigh,Franklyn Samudio,Azael Saldaña,Vanessa Pineda,Corina De Juncá

doi:10.3390/microorganisms10020287

Abstract

The objective of this study was to provide information on Trypanosoma cruzi genetic diversity among isolates obtained from different biological sources circulating in endemic areas of Panama. Initial discrete typing units (DTUs) assignment was performed evaluating three single locus molecular markers (mini-exon, heat shock protein 60 and glucose-6-phosphate isomerase genes). Further diversity within TcI lineages was explored using a multi-locus sequence typing approach with six maxicircle genes. Haplotype network analysis and evolutionary divergency estimations were conducted to investigate the genetic relatedness between Panamanian TcI isolates and isolates from different endemic regions in the Americas. Our molecular approach validated that TcI is the predominant DTU circulating in Panama across different hosts and vector species, but also confirmed the presence of TcIII and TcVI circulating in the country. The phylogenetic tree topography for most Panamanian TcI isolates displayed a high level of genetic homogeneity between them. The haplotype network analysis inferred a higher genetic diversity within Panamanian TcI isolates, displaying eight different haplotypes circulating in endemic regions of the country, and revealed geographical structuring among TcI from different endemic regions in the Americas. This study adds novelty on the genetic diversity of T. cruzi circulating in Panama and complements regional phylogeographic studies regarding intra-TcI variations.

Highlights

Chagas disease, caused by Trypanosoma cruzi, is a major neglected health problem in Central America, leading to significant economic losses due to reduced productivity from early-age disability and mortality [1]
Rhodnius pallescens is the only known vector of Trypanosoma rangeli, a non-pathogenic trypanosome that is transmitted through the saliva of this triatomine [6,9,10,11,12] and which is frequently found in blood of both humans and animals in Panama
We retrospectively genotyped 32 T. cruzi Panamanian isolates: 12 from humans with different clinical profiles, four from reservoirs and 16 from vectors collected in different endemic regions of Panama between 1965 and 2016 (Figure 1 and Table 1)

Summary

Introduction

Chagas disease, caused by Trypanosoma cruzi, is a major neglected health problem in Central America, leading to significant economic losses due to reduced productivity from early-age disability and mortality [1]. In Panama, situated in the southernmost part of Central America (Figure 1), Chagas disease seems to adopt clinical and epidemiological features that may differ from the rest of the region. The main Chagas disease vector in Panama is Rhodnius pallescens;. Microorganisms 2022, 10, 287 differing from the main vector species in the rest of the Central American region. Rhodnius pallescens is the only known vector of Trypanosoma rangeli, a non-pathogenic trypanosome that is transmitted through the saliva of this triatomine [6,9,10,11,12] and which is frequently found in blood of both humans and animals in Panama. In animal organisms 2022, 10, x FOR PEER REVIEW models, it has been observed that exposure to T. rangeli may modulate immune responses that confer some degree of protection against a subsequent infection with T. cruzi [13,14,15,16]

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