Toxoplasma gondiifrom Gabonese forest, Central Africa: first report of an African wild population

Abstract

AbstractThe protozoanToxoplasma gondiiis a ubiquitous and highly prevalent parasite that can theoretically infect all warm-blooded vertebrates. In humans, toxoplasmosis causes infections in both immunodeficient and immunocompetent patients, congenital toxoplasmosis, and ocular lesions. These manifestations have different degrees of severity. Clinical severity is determined by multiple factors, including the genotype of theT. gondiistrain involved in the infection.T. gondiiexhibits remarkable genetic diversity, which varies according to geography and ecotype (domestic or wild). Previous studies have demonstrated that wild strains ofT. gondiiare of particular epidemiological interest, as they have been associated with more severe forms of toxoplasmosis in different regions of the world. However, no data on wild strains ofT. gondiiare available from Africa. In this study, we describe for the first time a wildT. gondiipopulation from Africa. Wild animals from the forest environment of Gabon, Central Africa, were screened for chronic infection withT. gondiiusing quantitative PCR. The infectingT. gondiistrains were genotyped whenever possible by the analysis of 15 microsatellite markers and by whole-genome sequencing. A new genotype was identified and was found to be highly divergent from previously describedT. gondiipopulations worldwide, including those from the domestic environment in Gabon. Whole genome-based analyses indicated that this strain was genetically closer to a wild Pan-American population than to domestic African populations. This discovery marks the first description of a wildT. gondiipopulation in Africa. The role of wildT. gondiistrains in the incidence of severe toxoplasmosis in Africa remains unclear and requires further investigation.Author SummaryThe emergence of new pathogens from wildlife is today a well-recognized health threat. Studying these infectious agents has proven to be challenging due to the difficulty in accessing to samples from wild animals. In the present study, we took advantage of a recent survey on the viral carriage of wild animals from Gabon, Central Africa, to screen animal samples for the presence of the zoonotic protozoanToxoplasma gondii, a ubiquitous and highly prevalent parasite that can theoretically infect all warm-blooded vertebrates, including humans. This parasite is the etiological agent of toxoplasmosis, a disease causing a substantial public health burden worldwide through different clinical manifestations and varying degrees of severity. A novel genotype was identified and found to be highly divergent from previously describedT. gondiipopulations worldwide, including those from the domestic environment in Gabon. This discovery marks the first description of a wildT. gondiipopulation in Africa. It has been shown that wild strains ofT. gondiiare of significant epidemiological relevance, as they have been associated with more severe forms of toxoplasmosis in different regions of the world. The implications of wildT. gondiistrains in the incidence of severe toxoplasmosis in Africa remain unclear and merit further investigation.