Predominance of non-archetypal Toxoplasma gondii genotypes in Brazil and Argentina: Evidence from a systematic review and meta-analysis

Abstract

Toxoplasma gondii is a zoonotic protozoan of global concern, capable of infecting all warm-blooded animals, with important implications for both public health and food safety. In South America, this parasite exhibits high genetic diversity. This study included systematically reviewed and meta-analysed genotyping data reported between 2013 and 2023, using the multiplex nested PCR-restriction fragment length polymorphisms technique. Forty-five studies were included (n_Brazil = 42; n_Argentina = 3) and hosts were categorized as birds, rodents, humans, domestic and wild animals and livestock. Among the 480 DNA samples analysed, genotypes were successfully obtained from 421, of which 22 (5.2 %) were archetypal and 399 (94.8 %) non-archetypal. Meta-analysis of proportions revealed a pooled prevalence of 0.44 (CI_95%: 0.20–0.72) for archetypal genotypes and 0.98 (CI_95%: 0.95–0.99) for non-archetypal ones. Non-archetypal genotypes predominated across all host groups. Among the most frequently reported genotypes, the following stood out: in the archetypal, Type II (#1/#3) and in the non-archetypal, #13, #108, #163 and #206. Buenos Aires (Argentina) exhibited a variety of archetypal genotypes, while Minas Gerais and Paraíba (Brazil) showed the highest diversity of non-archetypal ones. This is the first meta-analysis specifically addressing the molecular diversity of T. gondii genotypes reported in South America over the last decade. By consolidating regional evidence, it provides an updated overview of circulating genotypes and highlights critical knowledge gaps. Using pooled genotype proportions across host groups and countries, pattern synthesis and bias diagnostics (heterogeneity, subgroup analysis, funnel plots), it is demonstrated that the evidence is uneven and method-dependent, limiting inference on transmission routes; this reaffirms the need for strengthened, standardized molecular surveillance in South America.