[The effect and influencing factors of schistosomiasis control by forbidding livestock denaturing on marshland with Oncomelania snails].

OBJECTIVE: To evaluate the effect of schistosomiasis control by forbidding livestock denaturing on marshland with Oncomelania snails and to analyse its influencing factors. METHODS: The village of Aiguo, Xinhe, Huangjia, Fanrong, Fengfu and Caomen and its respective nearby marshland, i.e., Aiguoniu, Liulingwei, Huangjianiu, Da, Goulian, and Litouzui, in Jinxian county, Jiangxi province were selected as the pilot areas for implementing the measures of forbidding livestock denaturing on the marshlands with Oncomelania snails during the period of the year 2005 to 2007. A total of 300 residents in each village were randomly chosen for stool examination with the Kato-Katz technique every year. The snail survey was carried out in spring and autumn every year on the marshlands close to the villages with systemic sampling method. The marshlands with a height 16.5 m above the sea level in Futian was selected for snail survey and planting with sesame. The residents aged 20 - 50 years old in Fengfu and Aiguo villages were studied by using questionnaire on the compliance of forbidding livestock pasturing on marshlands with Oncomelania snails. RESULTS: Before implementation of the measures, human infection rate with Schistosoma japonicum was 11.35% (90/793) in Aiguo, 4.00% (12/300) in Xinhe, 4.00% (6/150) in Huangjia, 8.00% (12/150) in Fanrong, 3.17% (4/126) in Fengfu and 6.64% (14/211) in Caomen. After implementation in 2008, human schistsome infection rate in the aforementioned 6 villages was declined to 0.18% (1/551), 0.00% (0/348), 0.00% (0/316), 2.27% (7/308), 1.17% (5/428) and 1.16% (5/430), respectively. Only in Fengfu village the decline of the human prevalence was not significant (χ(2) = 2.4, P = 0.12), while in the other 5 villages, human prevalence rate had been declined significantly (χ(2) = 126.77, P < 0.01; χ(2) = 16.31, P < 0.01; χ(2) = 18.79, P < 0.01; χ(2) = 10.39, P < 0.01; χ(2) = 14.17, P < 0.01, respectively). Infected snails were not found in 5 out of the 6 marshlands close to the villages. Three infected snails were founded in Da marshland because of poor environmental isolation. Before planting, the living snail density was 0.063/0.11 m(2) (34/540), and after planting, the living snail density was 0.0074/0.11 m(2) (4/538), a 88.25% reduction (Z = 12.47, P < 0.01) was recorded through economy crop planting at Futiandaan marshland in 2008. A total of 986 pieces of questionnaire were provided, and 968 valid ones were collected. The results of questionnaire indicate that compliance of forbidding livestock denaturing on marshland with Oncomelania snails in Aiguo and Fengfu villages was 84.38% (216/256) and 75.42% (537/712), respectively. Using logistic regression model, knowledge level on harmfulness of livestock denaturing on marshland with Oncomelania snails, willingness of culture with machine to substitute traditional cattle culture, and willingness of investment to marshland culture development are 3 varieties that affect residents' implementation of forbidding livestock denaturing on marshland with Oncomelania snails. CONCLUSION: The infected snail density and human schistosome infection rate were reduced on the marshlands of well environmental isolation after 2 - 3 years implementation of forbidding livestock denaturing on marshlands with Oncomelania snails. The key influencing factors of forbidding livestock denaturing on marshland with Oncomelania snails are knowledge level on harmfulness of livestock denaturing on the snail infested marshlands, the willingness of machine culture to substitute cattle culture, and the willingness of investment to marshland culture development.

[Observation on comprehensive control strategy for schistosomiasis with emphasis on infectious source control in Poyang Lake areas from 2009 to 2014].

OBJECTIVE: To evaluate the long-term effect of the comprehensive control strategy for schistosomiasis with emphasis on infectious source control in marshland-type endemic areas of Poyang Lake. METHODS: Three heavy endemic villages with schistosomiasis in the lake areas were selected as pilots for the comprehensive control strategy which included replacing bovine with tractors and forbidding grazing on marshlands. The data of schistosome infections of residents and Oncomelania hupensis snails were collected and analyzed statistically from 2009 to 2014. RESULTS: There were no patients with schistosomiasis through feces examinations in the 3 pilot villages. The average density of live snails in Niuzhou marshland showed a decline trend and the density was stable in Liulingwei marshland. There were no infected snails in the 2 marshlands, and no schistosome adult worms were found in the sentinel rats. CONCLUSION: The implantation of the comprehensive control strategy for schistosomiasis with emphasis on infectious source control can control the prevalence of schistosomiasis during a long period.

[Effect of health education on prevention from schistosome infection in engineering construction workers in Poyang Lake area].

OBJECTIVE: To evaluate the effect of health education on prevention from schistosome infection in engineering construction workers in Poyang Lake area. METHODS: The workers for constructing "De Chang" highway in Poyang Lake area were divided randomly into an experiment group and a control group, "health education + protective skill training" was carried out in the experiment group, whereas, no intervention was implemented in the control group. RESULTS: In the experiment group, the awareness rates of schistosomiasis control knowledge were 7.96% and 96.39% before and after the intervention, respectively; the rates of contacting infested water were 100% and 1.77% pre- and post-intervention, respectively; the work protective rates increased from zero before the intervention to 100% after the intervention; there was no person infected with schistosome after the intervention. However, in the control group, all the indexes above-mentioned had no significant changes. CONCLUSION: The intervention model "health education + protective skill training", can effectively prevent from schistosome infection in engineering construction workers in Poyang Lake area.

[Evaluation on medium-term effect of schistosomiasis comprehensive control strategy based on infectious source control in Poyang Lake area].

OBJECTIVE: To evaluate the medium-term effect and stability of the schistosomiasis comprehensive control strategy based on infectious source control after its popularization and application in marshland endemic areas. METHODS: The schistosomiasis comprehensive control strategy based on infectious source control including "replacing buffalo with machine", "marshlands isolation and grazing forbidden", etc. was implemented in all villages of Sanli Township, a heavy endemic area with schistosomiasis in Jianxian County. The infection situation of schistosomiasis in population and Oncomelania snails in 4 villages around the lake were monitored regularly for 6 consecutive years. RESULTS: The infection rate of schistosomiasis in population significantly decreased after the comprehensive control measures were carried out. Two years later, the infection rate in Huangjia Village was 0, and was sustained at zero for 5 consecutive years; the infection rate in Fengfu Village decreased by 77.24% and stabilized to zero for the next three years; the population infection rates in Fanrong Village and Caomen Village decreased by 82.33% and 82.53%, respectively, then the infection rates of the two villages kept under 1% and were 0 for 2 years and 1 year, respectively. The number of spots with infected snails in two marshlands in pilot areas decreased yearly from 10 before the intervention to 0, in which, the infection rate of snails and the number of spots with infected snails in Huangjiaoniu Marshland and Goulian Marshland decreased to zero 1 year and 3 years after the strategy was implemented, respectively, and the infected snails were not found in these marshlands in following years. CONCLUSION: Strengthening the management of buffaloes in surrounding areas and utilizing marshland resources is the main measure that can consolidate and expand the medium-term and long-term effect of the schistosomiasis 2.2 comprehensive strategy based on infectious source control.