Genotyping Of Toxoplasma Gondii Isolates From Pregnant Women In Chang Chun

Toxoplasma gondii is an obligate intracellular, apicomplexan parasite that infects all warm-blooded vertebrates, including mammals and birds. The parasite is distributed widely in the human population ,up to one-third of the human population in the world is chronically infected.Seroprevalence varies greatly among the general population and among geographical areas,depending on different environmental characteristics and alimentary habits: in Europe, seroprevalence among women of child-bearing age ranges from 10-18% in the UK, 19-29% in Spain,40% in Italy and 55% in France。T. gondii infection can be acquired by ingesting uncooked or raw infected meat (e.g. pork, lamb) or through food, water or unwashed vegetables contaminated with oocysts excreted by cats。Infection with Toxoplasma gondii is common and usually asymptomatic, but do pose threats to individuals who are immunocompromized such as cancer patients,AIDS,organ transplantation and so on。Because during pregnancy,the pathogen will be transmitted transplacentally to the fetus,both primary and re-infection during pregnancy are high risk factors especially to the foetus。Congenital toxoplasmosis leads to a wide range of clinical manifestations from mild symptoms, visual defects or development of retinochoroiditis in later life, to more severe cases of hydrocephalus, microcephaly seizures, mental retardation and even foetal death。In North America and Europe, T. gondii is highly clonal, consisting of three distinct lineages (Types I, II and III). whereas in South America, T.gondii is highly diverse with a few lineages expanded in the population,which are biologically and genetically different from those in North America and Europe,suggesting that the overall diversity of T. gondii population is high.At present, there is limited data on the diversity of T. gondii in Asia.In this study, Multilocus PCR–RFLP was performed to determine the prevalence of the different genotypes of Toxoplasma gondii (strain types I, II, and III) associated with human toxoplasmosis in china. At first,serum samples are examined for the levels of anti-T. gondii IgG by indirect ELISA。Then,DNA samples extracted from the peripheral blood of IgG positive pregnant women are used to detect 529 bp repetitive sequence of Toxoplasma gondii by PCR。Finally, Genetic characterization of T. gondii isolates was carried out by the multilocus Polymerase Chain Reaction-Restriction Frament Length Polymorphisms(PCR–RFLP) method using 12 markers, including SAG1, 5'SAG2, 3'SAG2, alt.SAG2,SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and APICO.Serum samples from 840 pregnant women in the northeast of china were examined for the levels of anti-T. gondii IgG by indirect ELISA. Anti-T. gondii IgG were detected in 80 pregant women with the seropositive rate of 9.5% . DNA samples extracted from the peripheral blood from IgG positive pregnant women were used to detect 529 bp repetitive sequence of Toxoplasma gondii by PCR. Thirty-three samples were PCR positive.The DNA were genotyped by multilocus PCR–RFLP. Eight samples were genotyped as TypeII.