Open AccessGenetic diversity of Trypanosoma cruzi parasites infecting dogs in southern Louisiana sheds light on parasite transmission cycles and serological diagnostic performance
Author(s) -
Eric Dumonteil,
Ardem Elmayan,
Alicia Majeau,
Weihong Tu,
Brandy Duhon,
Preston A. Marx,
Wendy Wolfson,
Garry Balsamo,
Claudia Herrera
Publication year - 2020
Publication title -
plos neglected tropical diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.99
H-Index - 135
eISSN - 1935-2735
pISSN - 1935-2727
DOI - 10.1371/journal.pntd.0008932
Subject(s) - trypanosoma cruzi , biology , chagas disease , parasite hosting , serology , virology , typing , genetic diversity , zoonosis , transmission (telecommunications) , genetics , population , antibody , medicine , environmental health , world wide web , computer science , electrical engineering , engineering
Background Chagas disease is a neglected zoonosis of growing concern in the southern US, caused by the parasite Trypanosoma cruzi . We genotyped parasites in a large cohort of PCR positive dogs to shed light on parasite transmission cycles and assess potential relationships between parasite diversity and serological test performance. Methodology/principal findings We used a metabarcoding approach based on deep sequencing of T . cruzi mini-exon marker to assess parasite diversity. Phylogenetic analysis of 178 sequences from 40 dogs confirmed the presence of T . cruzi discrete typing unit (DTU) TcI and TcIV, as well as TcII, TcV and TcVI for the first time in US dogs. Infections with multiple DTUs occurred in 38% of the dogs. These data indicate a greater genetic diversity of T . cruzi than previously detected in the US. Comparison of T . cruzi sequence diversity indicated that highly similar T . cruzi strains from these DTUs circulate in hosts and vectors in Louisiana, indicating that they are involved in a shared T . cruzi parasite transmission cycle. However, TcIV and TcV were sampled more frequently in vectors, while TcII and TcVI were sampled more frequently in dogs. Conclusions/significance These observations point to ecological host-fitting being a dominant mechanism involved in the diversification of T . cruzi -host associations. Dogs with negative, discordant or confirmed positive T . cruzi serology harbored TcI parasites with different mini-exon sequences, which strongly supports the hypothesis that parasite genetic diversity is a key factor affecting serological test performance. Thus, the identification of conserved parasite antigens should be a high priority for the improvement of current serological tests.