[Epidemic situation and prevention strategy of schistosomiasis in Ya' an City after Lushan Earthquake on April 20, 2013].

This paper analyzes the recently epidemic status of schistosomiasis, the change of natural and social factors, and field survey and evaluation data of schistosomiasis in Ya'an City after Lushan Earthquake on April 20, 2013, and proposes that it is necessary to strengthen the conventional schistosomiasis control measures, the control of exogenous infection sources, the control of Oncomelania hupensis snails and health education for ensuring no major epidemics after the disaster. This paper also recommends the direction and suggestions for future schistosomiasis control in Ya' an City.

[Risk assessment of schistosomiasis transmission in earthquake-stricken areas after the Lushan Earthquake in Sichuan Province on April 20, 2013].

OBJECTIVE: To assess the impact of the "4 x 20" Lushan Earthquake on the risk of schistosomiasis transmission in Lushan and Tianquan counties, so as to provide the evidence for formulating appropriate measures for schistosomiasis prevention and control. METHODS: Based on a comprehensive literature review, an analysis of schistosomiasis monitoring data in the earthquake affected counties, and a field investigation, a rapid assessment on the impact of the earthquake on schistosomiasis was conducted. RESULTS: Lushan and Tianquan counties were two endemic areas of schistosomiasis with high transmission level in history, especially Lushan County where Oncomelania snail distribution/density was the highest in Sichuan Province. After the earthquake, the streams and damaged ditches were blocked up, potentially leading to the spread of Oncomelania snails, and the damaged sanitary facilities may also lead to the release of excrement, contaminating the environment where snails resided. Meanwhile, the people who were relocated due to the earthquake may have higher exposures to contaminated environment. In addition, increasing population mobility (e.g. relief workers) also had the potential to bring infection sources in the earthquake affected areas. Further, animals, which may serve as reservoirs for the parasite such as homeless dogs, may also add the complexity of local schistosomiasis transmission. CONCLUSIONS: The epidemic risk of schistosomiasis in Lushan and Tianquan counties is high. To prevent the outbreak and epidemic of schistosomiasis, the victim settlements should be established appropriately and the excrement should be managed carefully. Meanwhile, the snail control should be carried out in the high-risk environments. The health education, monitoring, patient treatments and expanded chemotherapy should be carried out and strengthened.

[Mid-term evaluation on schistosomiasis control effect in Lushan earthquake-stricken areas in Sichuan Province].

OBJECTIVE: To evaluate the effect of schistosomiasis control in Lushan earthquake-stricken areas in Sichuan Province, so as to provide the evidence for formulating appropriate measures for schistosomiasis prevention and control. METHODS: According to the data of historical schistosomiasis prevalence, 5 villages were selected as research sites and field investigations were conducted. RESULTS: The average density of Oncomelania hupensis snails was 0.41 snails/0.1 m2, and there were no schistosome-infected snails. There were no acute schistosomiasis cases in these five villages. For local residents, the health education leaflets were more suitable than warning signs, and for migrant population, they were more concerned about the warning signs. CONCLUSION: After the implementation of effective prevention and control works, the epidemic risks of schistosomiasis have been controlled. However, the health education, surveillance, and prevention measures for schistosomiasis still need to be persisted in.

[Snail control by using soil pasting mixed with niclosamide].

OBJECTIVE: To evaluate the effect of snail control through soil pasting mixed with niclosamide. METHODS: Four sites were selected in different epidemic areas in Sichuan province. Soil pasting mixed with niclosamide was carried on, and the dosage was 0 g/m2, 4 g/m2, 6 g/m2, 8 g/m2 and 10 g/m2 respectively. The mortality rate of snail and the density of snail were observed after 7, 15, 30, 90 and 180 days. RESULTS: The mortality rate of snail was more than 43.3% in blank group after 30 days. The mortality rate of snail was from 75.3% to 100.0% at 4 g/m2 group after 30 days. The mortality rate of snail in 4 g/m2 group was significantly higher than that in the blank group (chi2 = 31.27, P < 0.05). There was no significant difference in the mortality rate of snail among all study groups (chi2 = 1.07, P > 0.05). The decrease rate of snail density was more than 90%. The mortality rate of snail was about 30% higher in Chantu group than Qutu group. The unit cost of Pasting-Mixing Drug with Soil was from 5 to 7 times of spray method, but the total cost was similar for the. two methods at the endpoint of the snail control. CONCLUSION: The effect of soil pasting mixed with niclosamide is good, and the dosage of 4-6 g/m2 is suggested in snail control.