Analysis of sites of Toxoplasma gondii SAG2 gene in blood of HIV-positive people in Lincang City,Yunnan Province / 中国血吸虫病防治杂志

Objective To preliminarily understand the genotype characteristics of Toxoplasma gondii in blood of HIV?posi?tive persons in Lincang City,Yunnan Province. Method Two segments of SAG2 gene of T. gondii from blood samples of HIV?positive persons in Lincang City were extracted and amplified by using the nested PCR method and the genotype was identified and compared with the standard strain(Type I)of Toxoplasma gondii. Results Thirty?five SAG2 genes(241 bp)and 35 SAG2 genes(221 bp)of T. gondii were amplified from 170 blood samples of the HIV?positive people,and 4 of each case were selected and digested with enzyme,then 2 aim gene fragments of each case were chosen and compared with the standard strain (Type I)of T. gondii. The digestion of SAG2 gene(241 bp)showed the genotype of the blood samples was Type I or Type II, and the digestion of SAG2 gene(221 bp)confirmed that the genotype was Type I. Conclusion It is preliminarily confirmed that the genotype of T. gondii in blood of HIV?positive persons in Lincang City,Yunnan Province is Type I.

Genotyping of Toxoplasma gondii from Rats (Rattus rattus) in Riyadh, Saudi Arabia

Toxoplasma 3 main clonal lineages are designated as type I, II, and III; however, atypical and mixed genotypes were also reported. This study was conducted for detection of Toxoplasma gondii genotypes in rats (Rattus rattus) in Riyadh region, Saudi Arabia. PCR test on T. gondii B1 gene was conducted on ELISA IgM positive samples for confirmation of the infection. However, genetic analysis of the SAG2 locus was performed to determine T. gondii genotypes using PCR-RFLP technique. PCR test on T. gondii B1gene showed that 22 (81.5%) out of the 27 ELISA IgM positive samples have T. gondii DNA. Genotypic analysis shows that, of the total 22 PCR positive samples, only 13 (59.1%) were of type II, 7 (31.8%) were of type III, and 2 (9.1%) were of an unknown genotype. It is obvious that the prevalence of both type II and III is high in rats. No reports have been available on T. gondii genotypes among rats in Riyadh region, and only little is known about its seroprevalence in rats. Future studies on T. gondii genotypes in rats using multi-locus markers is needed in Riyadh region, Saudi Arabia for better understanding of T. gondii pathogenesis and treatment in humans and animals.

Evaluation of Recombinant SAG1, SAG2, and SAG3 Antigens for Serodiagnosis of Toxoplasmosis

Serologic tests are widely accepted for diagnosing Toxoplasma gondii but purification and standardization of antigen needs to be improved. Recently, surface tachyzoite and bradyzoite antigens have become more attractive for this purpose. In this study, diagnostic usefulness of 3 recombinant antigens (SAG1, SAG2, and SAG3) were evaluated, and their efficacy was compared with the available commercial ELISA. The recombinant plasmids were transformed to JM109 strain of Escherichia coli, and the recombinants were expressed and purified. Recombinant SAG1, SAG2, and SAG3 antigens were evaluated using different groups of sera in an ELISA system, and the results were compared to those of a commercial IgG and IgM ELISA kit. The sensitivity and specificity of recombinant surface antigens for detection of anti-Toxoplasma IgG in comparison with commercially available ELISA were as follows: SAG1 (93.6% and 92.9%), SAG2 (100.0% and 89.4%), and SAG3 (95.4% and 91.2%), respectively. A high degree of agreement (96.9%) was observed between recombinant SAG2 and commercial ELISA in terms of detecting IgG anti-Toxoplasma antibodies. P22 had the best performance in detecting anti-Toxoplasma IgM in comparison with the other 2 recombinant antigens. Recombinant SAG1, SAG2, and SAG3 could all be used for diagnosis of IgG-specific antibodies against T. gondii.

Genotype of Toxoplasma gondii from Blood of Stray Cats in Gyeonggi-do, Korea

Genotyping of Toxoplasma gondii has been performed in 23 PCR positive blood samples from stray cats in Korea. We used 2 separate PCR-restriction fragment length polymorphism (RFLP) patterns of SAG2 gene, amplifying the 5'and 3'ends of the locus. The results revealed that all samples belonged to the type I clonal lineage. Although T. gondii organisms were not isolated from the samples, the results of the present study represent that stray cats with T. gondii infection should be seriously concerned in our environment. Adequate and continuous control programs of stray cats are needed to reduce the risk of transmission of T. gondii as a zoonotic infection threatening the public health.