Diversidad genética de Toxoplasma gondii en gallinas de traspatio de Tabasco (México), revela genotipos endémicos con predicción de virulencia variable en ratones.

BACKGROUND: Toxoplasmosis is a zoonosis caused by the parasite Toxoplasma gondii. The most affected population are pregnant women, newborns, and immunosuppressed patients. The State of Tabasco, Mexico, has both climatic and biotic conditions that favors the parasite's dissemination and perpetuation, which create its great genetic variability, and can also generate the appearance of more virulent variants. To date, 319 different genotypes have been described worldwide with a wide variation of its virulence levels in murine models. OBJECTIVE: To isolate and genotype Toxoplasma gondii from free-range chicken tissues and to predict the virulence of the obtained isolates by the identification of the associated genetic markers. METHODOLOGY: Heart and brain samples of 12 free-range chickens from seven municipalities of Tabasco were collected to attempt the parasite's isolation in mice. Obtained tachyzoites were propagated in NIH3T3 mice fibroblasts. Parasite DNA was extracted and used to genotype each isolate by Mn-PCR-RFLP of 15 T. gondii genetic markers. RESULTS: Twelve isolates were obtained in total. Two belonged to the genotype ToxoDB #8, tree ToxoDB #28, four ToxoDB #38 and three genotypes which has not yet been described or reported. The genotypes #8, #28 and #38 have already been described in States from the Center and Southwest regions of Mexico, whereas the three new genotypes have not been reported and were identified as the genotypes ToxoDB #344, #345 y #346. In virulence markers ROP18/ROP5, were identified combinations of alleles that can predict high and low virulence in murine models. CONCLUSIONS: Toxoplasma gondii is highly prevalent in Tabasco, Mexico since isolates were obtained in more than 50% of the sampled animals. From these isolates virulent and non-virulent variants in murine model are predicted, which could have a direct impact in public health. [ABSTRACT FROM AUTHOR]