Objective: To evaluate the anti-schistosomiasis effect of World Bank loan for schistosomiasis control project 1992-2001 in Jingzhou City, Hubei Province, and observe the endemic situation after two years of the end of the project.
Methods: By a retrospective longitudinal survey, information from annual reports was collected, which included disease screening, treatment and extended chemotherapy for human population and livestock, the distribution of Oncomelania hupensis and health education information from eight counties in Jinzhou prefecture from 1992 to 2003. Statistical u test was used for phased retrospective dynamic analysis.
Results: In the year 2001, schistosomiasis patients (77 009 cases) were 45.2% less than that of 1992 (140438 cases). The number of acute and advanced cases (63 and 1 032 cases, respectively) was 74.2% and 43.9% less than those of 1992 (244 and 1 841 cases, respectively). The average infection rate among residents was also reduced from 7.8% of 1992 to 4.7% (u = 28.864, P < 0.01). Number of infected cattle in 2001(3 454) was 57.0% less than that of 1992 (8 035), and the prevalence in cattle was reduced from 7.9% of 1992 to 3.7%, decreased by 53.2% (u = 9.338, P < 0.01). Snail-ridden area in 2001 was 19 368 hectares, 23.7% less than that of 1992 (25 395 ha). In 2003, two years after end of the project, number of acute schistosome infections was 100 cases, 59.0% less than that of 1992, but 58.7% more than that of 2001. The average infection rate in humans increased to 8.4% in 2003, 7.7% and 78.7% more than that of 1992 and 2001, respectively (u = 6.453, 34.804, P < 0.01). The average infection rate in cattle increased to 6.5% in 2003, 17.7% less than that of 1992, but 75.6% more than that of 2001 (u = 3.061, 5.894, P < 0.01). Snail-ridden areas also increased in 2003 with 29.3% and 69.6% more than that of 1992 and 2001, respectively.
Conclusion: Synchronous chemotherapy for residents and livestock can reduce the prevalence of schistosomiasis and control its transmission effectively in several year period, but the disease may re-emerge after chemotherapy stopped.