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.

[Preparation of immunoaffinity column of zearalenone].

OBJECTIVE: To prepare immunoaffinity column of zearalenone. METHODS: The zearalenone immunoaffinity column (IAC) was prepared by coupling CNBr-activated Sepharose 4 Fast Flow (4FF) with the anti-zearalenone monoclonal antibody which was purified by caprylic acid-ammonium sulfate method. The coupling reaction was identified by UV-absorbance measurements, and the IAC prepared was evaluated by indirect-competition ELISA and HPLC. RESULTS: The column capacity was determined to be 0.40 microg when using 0.5 ml of CNBr activated Sepharose 4FF and 350 microg of purified anti-zearalenone monoclonal antibody. The mean true recoveries were in the range 76.33% - 90.10% and RSD was 6.68% - 10.93% at levels of 60 microg/kg - 300 microg/kg. 30 samples of wheat and maize were detected by the anti-ZEN IAC produced by the laboratory, 17 samples were observed to be contaminated in a comparable range from 31.33 microg/kg - 377.84 microg/kg. Detection limit based on a signal-to-noise ratio 3:1 was 10. 00 microg/kg for ZEN in wheat and maize. CONCLUSION: IAC, a simple separating method which is used in ZEN extraction from cereals, is able to purify and condense ZEN in one step. The cost of detection can be lowered down because the IAC developed is hopefully to substitute the imported IAC.