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. 2023 Jun;150(7):551-578.
doi: 10.1017/S0031182023000252. Epub 2023 Mar 20.

An African perspective on the genetic diversity of Toxoplasma gondii: A systematic review

Ilze du Plooy  1 , Malitaba Mlangeni  1 , Riann Christian  1 , Ana M Tsotetsi-Khambule  1
Affiliations

An African perspective on the genetic diversity of Toxoplasma gondii: A systematic review

Ilze du Plooy et al. Parasitology. 2023 Jun.

Abstract

The study of Toxoplasma gondii genotypes is beneficial for detecting strains linked to increased disease severity and uncovering the processes involved in the transmission and distribution of this zoonotic parasite. A systematic review of literature was conducted to investigate the present status of T. gondii genetic diversity in African countries and among host species on the continent. Data from the results in the included studies were sorted, reviewed and descriptively analysed using tables, graphs and maps. Results indicate that there is a relative amount of genetic diversity with a clear difference in the population structure between geographical regions and the propensity for unique and regional genotypes to be predominant in tropical rainforest biomes, near the equator. From a clinical perspective, connections between specific T. gondii genotypes and disease manifestations were found. Theories are outlined on the dissemination of African T. gondii genotypes to other continents. The overrepresentation of samples from one geographical area and dissimilar genotyping methodologies creates challenges when concluding on the genetic diversity of T. gondii in Africa. The need for uniform genotyping methods with a continent-wide sampling of an extensive host range involving humans, domestic animals and wildlife is emphasized.

Keywords: Africa; ToxoDB; Toxoplasma gondii; genetic diversity; genotype; toxoplasmosis.

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Conflict of interest statement

None.

Figures

None
Graphical abstract
Fig. 1.
Fig. 1.
Flow diagram of the search and selection process for the publications.
Fig. 2.
Fig. 2.
Geographical distribution of T. gondii genotypes in Africa, according to clonal genotype designations. The sizes of the pie charts correlate with the total number of isolates and colours are representative of the different genotypes.
Fig. 3.
Fig. 3.
Geographical distribution of T. gondii genotypes in Africa, according to ToxoDB PCR-RFLP genotype designations. The sizes of the pie charts correlate with the total number of isolates and colours are representative of the different genotypes.
Fig. 4.
Fig. 4.
Genetic diversity of T. gondii clonal genotypes among host species displayed in percentages. Different colours are representative of each genotype.
Fig. 5.
Fig. 5.
Genetic diversity of T. gondii ToxoDB PCR-RFLP genotypes among host species displayed in percentages. Different colours are representative of each genotype.
Fig. 6.
Fig. 6.
Toxoplasma gondii clonal genotypes isolated from human samples, grouped into patient groups according to population details. Different colours are representative of the patient groups and are displayed proportionately.
Fig. 7.
Fig. 7.
Toxoplasma gondii clonal genotypes identified from all studies compared to only studies that used 5 or more molecular markers.
See this image and copyright information in PMC

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