Genetic diversity of Toxoplasma gondii isolates from ruminants: A systematic review

Toxoplasma gondii is a protozoan capable of infecting all warm-blooded animals. This parasite has been classified into three major lineages. Our aim was to assess and compare the identified Types and genotypes in ruminants. From November 2014 to April 2015, four English language databases and four Persian databases that reported data on the T. gondii genotyping in ruminants were searched. Overall, typing results of the 250/307 T. gondii isolates in all animals showed that Type II was a predominant Type (81.4%). In addition, genotyping data from the 82/215 T. gondii isolates or strains indicated that atypical genotypes were predominant (38.13%). This systematic review has demonstrated a large degree of genetic diversity in some countries. However, in the new nomenclature of genotyping, there are atypical or exotic genotypes, such as Chinese 1, Types Br (I, II, III and IV), and Type 12. Further genotyping studies are required to corroborate the current results. •This review contains useful data about T. gondii, which is one of the neglected diseases, though very common and more damaging to public health.•We performed a review to better understand the population structure of this parasite and providing data about transmission patterns to humans.•The present study provides the available evidence of Type, genotype and genetic diversity among T. gondii isolates in ruminants.