First isolation and genotyping of Toxoplasma gondii strains from domestic animals in Tunisia

Arwa Lachkhem,Homayoun Riahi,Marie-Laure Dardé,Nicolas Plault,Aurélien Mercier,Karine Passebosc,Lokman Galal,Hamouda Babba,Ibtissem Lahmar

doi:10.1038/s41598-021-88751-1

Abstract

The isolation and molecular typing of Toxoplasma gondii strains provide an essential basis for a better understanding of the parasite’s genetic diversity, determinants of its geographical distribution and associated risks to human health. In this study, we isolated and genetically characterized T. gondii strains from domestic animals in Southern and coastal area of Tunisia. Blood, hearts and/or brains were collected from 766 domestic animals (630 sheep and 136 free-range chickens). Strain isolation from these samples was performed using mouse bioassay and genotyping was carried out with a multiplex PCR technique using 15 microsatellite markers. Thirty viable strains of T. gondii were successfully isolated from tissues of sheep (19/142) and chickens (11/33). In addition, 3 strains could be successfully genotyped from animal tissues for which mouse bioassay was unsuccessful. A large predominance of type II strains (n = 29) was found in the sampled regions, followed by type III (n = 3) and, for the first time in Tunisia, a single isolate of Africa 4 lineage from a sheep. Analyses of population genetics showed the presence of a divergent population of type II lineage in Tunisia, supporting limited recent migrations of strains between Tunisia and other countries of the world.

Highlights

The isolation and molecular typing of Toxoplasma gondii strains provide an essential basis for a better understanding of the parasite’s genetic diversity, determinants of its geographical distribution and associated risks to human health
In Tunisia, previous studies mention a high prevalence of T. gondii in humans and domestic animals, but the genetic diversity of strains circulating in the country is still poorly known
The objective of this study was to describe the diversity of T. gondii strains circulating in Tunisia among domestic animals intended for human consumption

Summary

Introduction

The isolation and molecular typing of Toxoplasma gondii strains provide an essential basis for a better understanding of the parasite’s genetic diversity, determinants of its geographical distribution and associated risks to human health. We isolated and genetically characterized T. gondii strains from domestic animals in Southern and coastal area of Tunisia. Hearts and/or brains were collected from 766 domestic animals (630 sheep and 136 free-range chickens) Strain isolation from these samples was performed using mouse bioassay and genotyping was carried out with a multiplex PCR technique using 15 microsatellite markers. Toxoplasma gondii is a zoonotic apicomplexan parasite infecting humans and other warm-blooded animals including livestock[1,2] and poultry[3,4]. In Tunisia, previous studies mention a high prevalence of T. gondii in humans and domestic animals, but the genetic diversity of strains circulating in the country is still poorly known. The genotypic analysis of the isolates from 14 cases of congenital toxoplasmosis by multilocus RFLP revealed the presence of different

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Conclusion