Genotyping of Toxoplasma gondii from pigs in Yucatan, Mexico

Cubas-Atienzar, AI; Hide, G; Jiménez-Coello, M; Ortega-Pacheco, A; Smith, JE

Abstract

Toxoplasmosis is a zoonotic disease of worldwide distribution. The parasite exhibits strong geographical patterns
of strain variation with contrasting high levels of diversity across South America and restricted variation across
North America. Little is known about the diversity of strains in the transitional area between the two continents.
Here we present data on the prevalance and diversity of Toxoplasma gondii in the Yucatan peninsula of Mexico,
through a study in commercially reared pigs. A survey of 12 farms found evidence of circulating T. gondii DNA in
125 of 632 blood samples (19.8%, CI: 16.7%–23%). In addition, 46 tongue samples were collected from culled
animals and 16 of these were positive for T. gondii DNA and 3 were positive in mouse bioassay. PCR-sequencing
was used to generate genotyping data from blood and tissue samples. Four loci (SAG1, 2, 3 and GRA6) were
reliably amplified and revealed a high diversity among Yucatan strains with evidence of recombination and
novel alleles. Sequencing data from the four loci was achieved in eight samples each of which had a different
genotype. The predominant allelic type was atypical, in relation to the dominant strain types (I, II, III), the
number of allelic variants being 27 (I, II-III, u-1-25), 20 (I, III, u1-18), 6 (I, III, u1-4) and 11 (I, II, u1-9) for the
SAG1, SAG2, SAG3 and GRA6 loci respectively. Phylogenetic analysis showed that T. gondii strains from Yucatan
shared alleles with strains originating from both North and South America. Our findings are consistent with data
from other regions of Central America and suggest the genetic population structure of the parasite, with significant
levels of allelic variation and recombination, constitutes a reservoir from which new strains may emerge.
Positive bioassay results (7.5%) indicate that consumption of undercooked pork could be a potential T. gondii
infection risk to humans.

Citation

Cubas-Atienzar, A., Hide, G., Jiménez-Coello, M., Ortega-Pacheco, A., & Smith, J. (2018). Genotyping of Toxoplasma gondii from pigs in Yucatan, Mexico. Veterinary Parasitology: Regional Studies and Reports, 14, 191-199. https://doi.org/10.1016/j.vprsr.2018.10.009

• Journal Article Type: Article
• Acceptance Date: Oct 26, 2018
• Online Publication Date: Oct 29, 2018
• Publication Date: Dec 1, 2018
• Deposit Date: Nov 27, 2018
• Publicly Available Date: Oct 29, 2019
• Journal: Veterinary Parasitology: Regional Studies and Reports
• Publisher: Elsevier
• Volume: 14
• Pages: 191-199
• DOI: https://doi.org/10.1016/j.vprsr.2018.10.009
• Publisher URL: https://doi.org/10.1016/j.vprsr.2018.10.009
• Related Public URLs: https://www.salford.ac.uk/environment-life-sciences/our-staff/els-academics/geoff-hide; https://www.journals.elsevier.com/veterinary-parasitology-regional-studies-and-reports