Genetic Characterization of Toxoplasma gondii Isolates from Pigs in Jilin Province, Northeastern China.

Toxoplasma gondii is prevalent in humans and animals worldwide. The present study aimed to determine the genetic diversity of T. gondii isolates from pigs in Jilin province, northeastern China. A total of 100 DNA samples were extracted from the hilar lymph nodes of slaughtered pigs, and 9 (9.0%, 95% confidence interval: 3.4-14.6%) were detected positive for T. gondii B1 gene by a nested polymerase chain reaction (PCR). The positive DNA samples were typed at 11 genetic markers, including 10 nuclear loci (SAG1, 5'-SAG2, and 3'-SAG2, alternative SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, and PK1) and an apicoplast locus (Apico) using the multilocus PCR-restriction fragment length polymorphism technology. Only three isolates were completely typed at all loci, showing that they all belonged to the clonal type I. One isolate was typed at five loci, including 5' +3'-SAG2, SAG2, SAG3, GRA6, and L358, revealing the possible clonal type I. This is the first report of the genetic characterization of T. gondii isolates in pigs in Jilin province, northeastern China, which has implications for better understanding the population structure of T. gondii infection in China.

Prevalence of Toxoplasma gondii in Dogs in Zhanjiang, Southern China.

Toxoplasmosis, caused by Toxoplasma gondii, is a parasitic zoonosis with worldwide distribution. The present study investigated the prevalence of T. gondii in dogs in Zhanjiang city, southern China, using both serological and molecular detection. A total of 364 serum samples and 432 liver tissue samples were collected from the slaughter house between December 2012 and January 2013 and were examined for T. gondii IgG antibody by ELISA and T. gondii DNA by semi-nested PCR based on B1 gene, respectively. The overall seroprevalence of T. gondii IgG antibody was 51.9%, and T. gondii DNA was detected in 37 of 432 (8.6%) liver tissue samples. These positive DNA samples were analyzed by PCR-RFLP at 3'- and 5'-SAG2. Only 8 samples gave the PCR-RFLP data, and they were all classified as type I, which may suggest that the T. gondii isolates from dogs in Zhanjiang city may represent type I or type I variant. This study revealed the high prevalence of T. gondii infection in dogs in Zhanjiang city, southern China. Integrated measures should be taken to prevent and control toxoplasmosis in dogs in this area for public health concern.

Genetic characterization of Toxoplasma gondii from cats in Yunnan Province, Southwestern China.

BACKGROUND: Cats are the definitive hosts of Toxoplasma gondii. The distribution of genetic diversity of T. gondii in cats is of importance to understand the transmission of this parasite. The objective of this study was to genetically characterize T. gondii isolates from cats in Yunnan province, southwestern China. METHODS: Genomic DNA was extracted from 5-10 g cat tissue samples (brain, tongue, heart, and liver). Using multilocous polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology, we determined genetic diversity of T. gondii isolates from cats in Yunnan province. RESULT: In total, 175 stray cats were tested for T. gondii DNA, respectively, 44 (25.14%) of which were found to be positive for the T. gondii B1 gene by PCR amplification. The positive DNA samples were typed at 11 genetic markers, including 10 nuclear markers, namely, SAG1, 5'-3'SAG2, alternative SAG2, SAG3, GRA6, L358, PK1, BTUB, c22-8, c29-2 and an apicoplast locus Apico. Of these, 16 isolates from cats were genotyped with data for more than 9 loci, revealed 5 genotypes in total, of which 11 of 16 samples were identified as ToxoDB#9, two samples may belong to genotye #225, one was Type II, one was ToxoDB#3, and one was ToxoDB#20 (http://toxodb.org/toxo/). CONCLUSIONS: The results of the present study indicated a wide distribution of T. gondii infection in cats in Yunnan province, which may pose significant public health concerns. To our knowledge, the present study is the first report of T. gondii prevalence and genotypes in cats in southwestern China, and the first report of Type II T. gondii from cats in China.

Seroprevalence of Toxoplasma gondii infection in pigs in Jiangxi Province, Southeastern China.

Toxoplasma gondii is the causative agent of toxoplasmosis in humans and a wide range of animal species. In the current study, a serological investigation using an indirect hemagglutination (IHA) test was carried out to determine the seroprevalence of T. gondii infection in pigs in Jiangxi Province, southeastern China. A total of 1232 serum samples were collected from pigs in 10 administrative districts in Jiangxi, and specific antibodies were detected in 282 pigs (22.9%) with the titers ≥1:64. Positive pigs were found in each administrative district, with prevalence ranging from 5.0% to 46.2%. Age and season were found to be associated with T. gondii infection. Lactating sows (odds ratio [OR]=15.4, 95% confidence interval [CI]=6.8-35.2, p<0.01), pregnant sows (OR=11.5, 95% CI=5.3-24.8, p<0.01), nonpregnant sows (OR=13.7, 95% CI=6.4-29.3, p<0.01), breeding boars (OR=9, 95% CI=3.8-21.4, p<0.01), and fattening pigs (OR=4.9, 95% CI=2.1-11.7, p<0.01) all had a greater risk of acquiring infection compared to the weanling pigs. There is a higher risk of infection in the spring (OR=1.7, 95% CI=1.1-2.6, p=0.01) and the summer (OR=2.1, 95% CI=1.3-3.2, p<0.01) than in the winter. This is the first documentation of T. gondii seroprevalence in pigs in Jiangxi Province, which enriches the epidemiological data of T. gondii infection in pigs in China. The results of this study indicate that pigs in Jiangxi Province are frequently exposed to T. gondii, posing a direct threat to the pig industry as well as to public health. Integrated strategies are needed to strengthen future prevention and control of T. gondii infection in pigs in this region.

Genetic characterization of Toxoplasma gondii from pigs from different localities in China by PCR-RFLP.

BACKGROUND: Toxoplasma gondii is a widely prevalent protozoan parasite that causes serious toxoplasmosis in humans and animals. The present study aimed to determine the genetic diversity of T. gondii isolates from pigs in Jiangxi, Sichuan, Guangdong Provinces and Chongqing Municipality in China using multilocous polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology. METHODS: A total of 38 DNA samples were extracted from hilar lymph nodes of pigs with suspected toxoplasmosis, and were detected for the presence of T. gondii by semi-nested PCR of B1 gene. The positive DNA samples were typed at 11 genetic markers, including 10 nuclear loci, namely, SAG1, 5'-SAG2 and 3'-SAG2, alternative SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and an apicoplast locus Apico. RESULTS: Twenty-five of the 38 DNA samples were T. gondii B1 gene positive. Complete genotyping data for all loci could be obtained for 17 of the 25 samples. Two genotypes were revealed (ToxoDB PCR-RFLP genotypes #9 and #3). Sixteen samples belong to genotype #9 which is the major lineage in mainland China and one sample belongs to genotype #3 which is Type II variant. CONCLUSIONS: To our knowledge, this is the first report of genetic typing of T. gondii isolates from pigs in Jiangxi, Sichuan Province and Chongqing Municipality, and the first report of ToxoDB #3 T. gondii from pigs in China. These results have implications for the prevention and control of foodborne toxoplasmosis in humans.