| Toxoplasmosis is a widespread zoonotic disease caused by Toxoplasma gondii. T. gondii infection in animals is asymptomatic. Toxoplasmosis is prevalentworldwide and about one third of the global human population has been infected with T. gondii, and approximately 7.9% of the population has been exposed to T. gondii, with an increasing incidence in recent years in the People’s Republic of China. Many kinds of livestock and poultry are infected with T. gondii, which pose a significant lose to breeding industry.Chlamydiosis is caused by an important intracellular pathogen, Chlamydia, affecting birds, a wide range of mammalian animals and humans. Chlamydia is an important zoonotic disease, which occurs in respiratory tract, intestinal tract, urinary tract, and central nervous system and leads to heavy economy losses to livestock industry.In the first part, the method of a modified agglutination test(MAT) was used to identify the prevalence of T. gondii infection in white yaks in Tianzhu county, Gansu province and in sika deer in northeast China. A total of 974 serum samples were collected from white yaks in Tianzhu county, and the positive samples were detected in 155 white yaks(15.9%). This is the first investigation of T. gondii infection in wite yaks, indicating that there is a high positive rate of T. gondii in this region. Statistically significant differences were not observed between T. gondii seroprevalence and gender, season or pregnancy in the logistic regression analysis(P > 0.05). Ages of white yaks was considered as a main risk factor associated with T. gondii infection. The results indicated that white yaks in Tianzhu are frequently exposed to T. gondii and local Tibetans are at risk of being infected with T. gondii after consumption of undercooked or raw meat from infected white yaks.A total of 847 serum samples were collected from sika deer in Harbin(208), Changchun(316), Jilin(163) and Chifeng(160). The results showed that the seroprevalence of T. gondii infection in sika deer was 13.5% and the seroprevalence in above four regions were 12.0%, 15.5%, 12.3% and 12.5%, respectively. Gender, region and season of sampling were analyzed in a multivariable logistic regression model and the season was considered as main risk factor of T. gondii infection in sika deer. The results also revealed T. gondii infection in sika deer is widespread in northeast China and necessary strategies should be taken to prevent and control of T. gondii infection in sika deer.In the second part, a serological study using indirect hemagglutination(IHA) test was performed to examine Chlamydia infection in white yaks of Tianzhu county in Gansu province and sika deer in northeast China. A total of 974 serum samples were collected from white yaks in Tianzhu county, Gansu province, and the seroprevalence of Chlamydia infection in white yaks was 16.22%. Region, gender, age and season of sampling were evaluated by a multivariate logistic regression analysis, and the results showed that season was considered as a major risk factor associated with Chlamydia infection in white yaks. The seroprevalence of Chlamydia infection in spring, summer, autumn and winter were 10.9%(24/220), 11.3%(26/231), 16.0%(40/250) and 24.9%(68/273), respectively. The result indicated that Chlamydia infection is common in white yaks in Tianzhu, which posed extensive attention.847 serum samples were collected from sika deer in northeast China and the seroprevalence of Chlamydia infection detected by IHA in sike deer was 9.45%. The prevalence of Chlamydia infection in Jilin, Chifeng, Changchun and Harbin were 6.13%, 7.50%, 7.91% and 15.87%, respectively. In the logistic regression analysis, the results showed region was considered as a major risk factor, which revealed that factor of region played an important role associated with Chlamydia infection in sika deer. Therefore, effective measures should be taken to control the spread of Chlamydia.In the third part, 414 DNA samples coming from white yaks and 450 DNA samples coming from sika deer were detected for the T. gondii infection with B1 gene by semi-nested PCR. And positive samples belonged to white yak and sika deer were charactered with 11 genetic loci using PCR-RFLP. As a result, 10 tissue pamples were positive for T. gondii infection, but only 2 samples showed complete genotyping data for all loci, identifying the geotype Toxo DB #9. Among 150 sika deer samples, 17 were positive for T. gondii B1 gene and 6 samples showed complete genotyping data, which suggested the presence of Toxo DB #9. The present study reported, for the first time, the genetic characterization of T. gondii in white yaks and sika deer in China and the results revealed that Toxo DB #9 is the major genotype in above animals.This study detected the seroprevalence of T. gondii and Chlamydia infection in white yaks from Tianzhu, northwest China, and in sika deer in northeast China by MAT and IHA, respectively. This study also genetically characterized T. gondii isolates from white yaks in Tianzhu and sika deer in Changchun using PCR-RFLP, and identified the major lineage Toxo DB #9 successfully. These results not only provided basic information for preventing and controlling T. gondii and Chlamydia infection, but also identified T. gondii Toxo DB #9 in white yaks and sika deer. |
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