Research And Application Of The Comprehensive Programs In Prevention And Control Of Toxoplasmosis In A Large Scale Pig Farm

Toxoplasmosis as a zoonosis is due to the Toxoplasma gondii. It is widespread all over the world and all the warm-hearted animals including human beings can be infected. During the infection, there is sub-clinical symptoms and asymptomatic in healthy man, but the embryonal dysplasia can be resulted in trimester of pregnancy. Especialiy, toxoplasmosis become a life-threaten disease in the immuno-deficiency and organ transplantation patients. The main pathways of human infection with Toxoplasma gondii is the ingestion of undercooked meat containing cysts. The majority of Chinese enjoy eating pork, the consumption of meat product is mainly pork according to the eating habits, so pigs infected with Toxoplasma gondii show serious harm on the health of citizens.The infection rate in the Chinese population was 0.09-34%, pig infection rate was 3.32%-66.39%. The infection with Toxoplasma gondii in pigs can not only cause sow abortion, stillbirth, piglets dysplasia, malformations and stunt, but also suppress immune function, leading to secondary infection of other pathogens, so toxoplasmosis has seriously affected the farming industry. At present there is no commercialized vaccine of Toxoplasma gondii, thus, the most important way to minimize the chances of infection of Toxoplasma gondii is to reduce the contaminated meat products whose source is to prevent the breeding phase from Toxoplasma infection. the purpose of present study was to investigate the prevalence of toxoplasmosis in large scale pig farms and to give an effective program in prevention and control of Toxoplasma gondii infection.AG-ELISA established in our laboratory was used in this study. Systemic serosurvey of Toxoplasma gondii in a large scale pig farm was performed for one year. The average positive rate of the four tests was 32.03%. Toxoplasma antibody positive rate of each group according to the season were:summer 31.1% (32/103), autumn 20.2%(19/94), winter 40.0%(38/95) and the spring 41.6%(32/77); Toxoplasma antibody positive rate of each group according to the agespecific were:4 weeks 23.7%(9/38),7 weeks of age 10.3% (4/39),12 weeks 22.5%(9/40),16 weeks 24.3% (9/37), replacement gilts 37.5%(12/32),1-2 parity sows 32.6%(14/43),3-4parity sows 37.8%(17/45), 5 more parity sows 44.2%(19/43) and boars 34.6% (9/26). The results shows the severity of Toxoplasma gondii infection in the winter and spring and the overall positive rate increased with age. Toxoplasma-positive rates of 7 and 16 weeks pigs were obviously increased based on epidemiological surveys. Thus, the stages of 6 and 14 weeks were chosen to drug control. During the treatment of sulfa drugs which is the targeted drugs to Toxoplasma gondii, strictly control of risk factors in the pig farm, such as the cat frequency, cleaning frequency of pigsty and breeding density were performed. Following the comprehensive program, two detections of serological positive rate showed 17.2%. The data demonstrated the effectiveness in prevention and control Toxoplasma gondii infection in large scale pig farms using the developed programs. According to the epidemic situation and the program in prevention and control of toxoplasmosis, valuable experience and basis in Toxoplasma prevention and control could be provided for other pig farms.