A population study of Toxoplasma gondii in the Amazon region expands current knowledge of the genetic diversity in South America

Solange M Gennari; Hilda F J Pena; Herbert S Soares; Antonio H H Minervino; Francisco F V de Assis; Bruna F Alves; Solange Oliveira; Juliana Aizawa; Ricardo A Dias; Chunlei Su

doi:10.1371/journal.pntd.0012737

A population study of Toxoplasma gondii in the Amazon region expands current knowledge of the genetic diversity in South America

PLoS Negl Trop Dis. 2024 Dec 23;18(12):e0012737. doi: 10.1371/journal.pntd.0012737. Online ahead of print.

Authors

Affiliations

¹ Department of Preventive Veterinary Medicine and Animal Health, Faculty of Veterinary Medicine and Zootechny, University of São Paulo, São Paulo, São Paulo, Brazil.
² Postgraduate Program in One Health, University of Santo Amaro, São Paulo, São Paulo, Brazil.
³ Laboratory of Animal Health, Federal University of Western Pará, Santarém, Pará, Brazil.
⁴ Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America.

PMID: 39715261
DOI: 10.1371/journal.pntd.0012737

Abstract

Previous studies have reported high diversity between and within populations of Toxoplasma gondii in South America. In the present study, isolates of T. gondii from chickens were obtained from the Amazon region. Adult free-range chickens were acquired from 29 municipalities in the Brazilian Amazon region that included Acre (n = 9 municipalities), Amapá (n = 6), Amazonas (n = 6), Pará (n = 6), and Roraima (n = 2) states and from two municipalities in Peru, three in Bolivia, one in Guyana, and one in Venezuela. Heart, brain, and blood samples were collected from 401 chickens. Anti-T. gondii serum antibodies were detected in 273 (68.1%) chickens using the Modified Agglutination Test (MAT ≥ 5), and bioassays in mice were performed using 220 birds. Isolates were obtained from 116 (52.7%) chickens with antibody titers ≥ 20. Of these isolates, 93 (84.5%) led to acute sickness in more than 50% of the infected mice within 30 days post-inoculation. The 116 isolates were genotyped using multilocus nested polymerase chain reaction-restriction fragment length polymorphism (Mn-nPCR-RFLP) with 12 markers and 15 microsatellite (MS) markers. PCR-RFLP analysis revealed 42 genotypes from the 116 isolates. Of these, 20 (46.51%) genotypes are described for the first time. The most abundant genotype was ToxoDB PCR-RFLP genotype #7 with 40 isolates. A total of 83 genotypes were observed from the 116 isolates by MS analysis. The phylogenetic network constructed of T. gondii genotypes from current and previously reported isolates, using PCR-RFLP data, revealed five groups with clear indication of geographical separation of T. gondii population in the Amazon region versus the Southeastern region of Brazil. Such spatial diversity was also observed within the Amazon region. This study expands our knowledge of T. gondii population in South America and emphasizes the importance of genetic diversity and high mouse-virulence of the parasite in the Amazon region.

Copyright: © 2024 Gennari et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.