Genetic diversity of Toxoplasma gondii isolates from members of the families camelidae and equidae worldwide: a systematic review
摘要
Toxoplasma gondii is an apicomplexan parasite with a global distribution and significant public health and veterinary treatment implications. The present systematic review collates worldwide information on the genotypic diversity of T. gondii isolates infecting Camelidae (camels, alpacas, llamas, etc.) and Equidae (horses, donkeys, zebras, mules, etc.) and highlights their potential role as sentinels of environmental contamination and zoonotic spread. An exhaustive literature search of six electronic databases (PubMed, Web of Science, Scopus, ProQuest, Science Direct, and Google Scholar) from inception to 20 July 2025 identified 20 relevant studies reporting genotypic information from 103 isolates. The present analysis reveals key geographical differences: atypical genotypes predominated in the Americas (88.2%) and Africa (83.3%), reflecting high regional diversity. Asian isolates featured the greatest complexity and presented mostly mixed infections (61.1%), and the China I genotype (ToxoDB #9) emerged as the dominant individual lineage. European isolates presented a very separate profile by mainly consisting of Type III (57.1%), but atypical genotypes were also reported. These findings indicate that Camelidae and Equidae hosts carry rich and diverse populations of T. gondii that closely mirror local strains in their environment rather than classical clonal Types. The co-existence of genotypes linked with human virulence (e.g., Type I and China I) in these food animals highlights their significant risk as sources in zoonotic transmission. This review advises the adoption of high genotyping resolution and One Health approaches within subsequent surveillance exercises to effectively assess public health risk and illuminate transmission dynamics relevant to these economically and culturally significant hosts.