[Influencing factors of changes of Oncomelania snail densities in Poyang Lake region, Nanchang City, 2011].

OBJECTIVE: To explore the influencing factors of the significant decrease of snail densities in Poyang Lake region, Nanchang City, 2011. METHODS: According to the elevation of the environment, 5 grasslands where there were high snail densities and their elevations were from 14 to 17 m were selected as study areas. The data of snails in the past three years and the hydrological information in the past five years were collected and analyzed. The current snail status was surveyed and the fishermen were interviewed. RESULTS: The snail density of Poyang Lake region in Jinxian County decreased by 91.2% in 2011 compared with that in 2009 (P < 0.01). In 2010, the water levels were 13.90 m in April and 16.07 m in May respectively in Xingzi Station, and the rainfalls were 312 mm in April and 356 mm in May in Poyang Lake region; in 2011, the water levels were 8.73 m in April and 10.31 m in May respectively in Xingzi Station, and the rainfalls were 90 mm in April and 145 mm in May respectively in Poyang Lake region, which were lower than those during the past five years. There was no any other apparently unusual phenomenon. CONCLUSION: The significant decrease of snail densities in Poyang Lake region in 2011 may be related to the long soaking time of marshland in 2010 and low rainfall in the first half of 2011.

[Current status of schistosomiasis control knowledge and effect of interventions among primary school pupils in Anyi County].

OBJECTIVE: To understand the status of schistosomiasis control knowledge and the effect of interventions among primary school pupils in the areas of schistosomiasis transmission interrupted. METHODS: Six kinds of information materials about schistosomiasis control, including the schistosomiasis health education teaching material, schistosomiasis health education box, schistosomiasis health education stationary kits, schistosomiasis health education ball-point pen, collections of wall charts about schistosomiasis control and schistosomiasis health education curriculum schedule, were used to spread the schistosomiasis control information in the experimental group, and then, the effect was evaluated. RESULTS: The awareness rates, correct rates of attitude, and persuasion rates of schistosomiasis control had no significant difference between the experimental group and control group before the intervention (P > 0.05). The awareness rate, correct rate of attitude, and persuasion rate of schistosomiasis control increased from 12.88%, 6.82% and 3.79% before the intervention to 97.64%, 62.20%, 71.65% after the intervention, respectively, in the experiment group (P < 0.01), but in the control group, there was no significant difference between the pre- and post-intervention (P > 0.05). The collections of wall charts about schistosomiasis control and schistosomiasis health education box were more favorable. CONCLUSION: The effect of schistosomiasis health education is very well in the areas of schistosomiasis transmission interrupted

[Study on an intervention model of "schools without infected students with schistosoma japonica" in heavy endemic areas].

OBJECTIVE: To study an intervention model of "schools without infected students with schistosoma japonica", to control and prevent students from schistosoma infection. METHODS: Twelve primary schools of four heavy endemic counties (districts) with schistosomiasis in the Poyang Lake areas were selected as the study fields, of which, ten schools were the experimental groups, and the other two schools were the control groups by cluster random sampling. All enrolment students were the target population. The baseline survey was carried out in 2005, and an intervention model, "information dissemination + behavior participation + behavior encouragement", was applied in the experiment groups in 2006 - 2008, then the effect of intervention was assessed. RESULTS: Before intervention (2005), the anti-schistosomiasis knowledge awareness rate of experimental and control groups were 14.75% (324/2196) and 16.58% (91/549), and the different was not significant (χ(2) = 1.14, P > 0.05); the rate of accurate attitude of anti-schistosomiasis were 14.71% (323/2196) and 11.84% (65/549) in experimental and control groups, and the difference was not significant (χ(2) = 2.98, P > 0.05); the rate of contacting infected water were 15.44% (18 988/122 976) and 15.03% (4622/30 744) in experimental and control group and the difference was not significant (χ(2) = 3.13, P > 0.05); and the infection rate of schistosomiasis of experiment control groups were 9.65% (212/2196) and 10.56% (58/549), the difference was not significant (χ(2) = 0.41, P > 0.05). After one year intervention (2006), the anti-schistosomiasis knowledge awareness rate of experimental and control groups were 97.79% (2032/2078) and 18.11% (98/541), and the different was significant (χ(2) = 1794.31, P < 0.01); the rate of accurate attitude of anti-schistosomiasis were 99.09% (2059/2078) and 13.49% (73/541) in experimental and control group, and the difference was significant (χ(2) = 2077.45, P < 0.01). After 1 - 3 years intervention (2006 - 2008), there were no any contactors with infected water and infectors with schistosome in students of the experiment group in successive 3 years. While in the control group of the same period, the rate contacting infected water were 16.12% (4884/30 296), 11.11% (3079/27 720) and 12.25% (3451/28 168); the infection rate of schistosomiasis were 8.87% (48/541), 7.47% (37/495) and 7.95% (40/503), respectively. CONCLUSION: The intervention model of health promotion, "information dissemination + behavior participation + behavior encouragement", can effectively control and prevent students from infecting schistosoma japonica in heavy endemic areas with schistosomiasis.

[Establishment and application of school-based health promotion and intervention model of schistosomiasis in lake-type endemic area].

OBJECTIVE: To establish an intervention model of school health promotion, and apply it in developing "schistosomiasis-free schools". METHODS: At the pilot stage, all students of Henghu primary school and Banshan primary school in Xinjian County of Jiangxi Province were selected as experiment group and control group, respectively. A baseline survey covered knowledge and attitude on schistosomiasis control, water contact behaviors and Schistosoma japonicum infection rate. Two health promotion intervention models, i.e. "information communication + training of protection skill + reward & punishment" (model A, 1993-1999) and "information communication + behavior participation + encouragement" (model B, 2000-2007), were implemented in Henghu school. The effect of two models was compared by infection rate. At the application stage, all students of 8 schools in Xinjian County, Nanchang County, and Jinxian County were chosen for evaluation of the effectiveness of Model B with same methods and index. RESULTS: Before intervention there was no significant statistical difference on the passed rate of anti-schistosomiasis knowledge, correct rate of anti-schistosomiasis attitude, frequency of infested water exposure and the infection rate between Henghu and Banshan schools (P > 0.05). In Henghu school, the intervention showed significant effect on the scores of knowledge and attitude after one year (P < 0.01), raised from 9.0% and 55.1% before intervention to 94.4% and 98.9% after intervention, respectively. The frequency of infested water exposure and the infection rate significantly decreased from 14.6% and 13.5% before intervention to 1.9% and 2.3%, respectively (P < 0.01). In 2-7 years after intervention, there were only one or two schistosomiasis cases each year. At the application stage, no schistosomiasis cases were found among Model B target population in two successive years after intervention. CONCLUSION: The practice of Model B can be extended to other schools in endemic area to develop "schistosomiasis-free schools".

A drug-based intervention study on the importance of buffaloes for human Schistosoma japonicum infection around Poyang Lake, People's Republic of China.

Schistosomiasis japonica is a zoonosis of major public health importance in southern China. We undertook a drug intervention to test the hypothesis that buffalo are major reservoirs for human infection in the marshlands/lake areas, where one million people are infected. We compared human and buffalo infection rates and intensity in an intervention village (Jishan), where humans and buffalo were treated with praziquantel, and a control village (Hexi), where only humans were treated, in the Poyang Lake region. Over the four-year study, human incidence in Jishan decreased but increased in Hexi. Adjustment of incidence by age, sex, water exposure, year, and village further confirmed the decreased human infection in Jishan. Chemotherapy for buffaloes resulted in a decrease in buffalo infection rates in Jishan, which coincided with the reduction in human infection rates there in the last two years of the study. Mathematical modeling predicted that buffalo are responsible for 75% of human transmission in Jishan.

The role of health education and health promotion in the control of schistosomiasis: experiences from a 12-year intervention study in the Poyang Lake area.

The objectives of this study were to examine the short-term effects of health education and health promotion in the control of schistosomiasis, and to monitor the long-term impact on re-infection patterns. The study was carried out in six Schistosoma japonicum-endemic villages located in the Poyang Lake area. Three different interventions were implemented, namely (i) health education by means of video tapes, training in prevention of infection, and a 'rewards/punishment' programme for schoolchildren, (ii) promotion of an understanding of schistosomiasis and its control plus training in prevention of infection for women, and (iii) encouragement of compliance with regard to chemotherapy plus training in prevention of infection for men. The 1-year post-intervention follow-up showed that both awareness and appropriate behaviour were strengthened in all three study groups along with a significant increase in the level of knowledge on how to avoid schistosomiasis. For example, the majority of women had abandoned the practice of washing clothes in schistosome-infested water and re-infection rates were sharply reduced as a consequence. In addition, the frequency of water contact among schoolchildren decreased and remained so for the long term. Overall, the approach emphasising health education and health promotion in combination with chemotherapy was highly successful in reducing re-infection rates among inhabitants of S. japonicum-endemic villages and people's compliance with regard to chemotherapy increased significantly over the course of the study.

Optimal combined approaches of field intervention for schistosomiasis control in China.

Before the mid 1980s, the emphasis in schistosomiasis control in China was on transmission control. Thus, the aim was to eliminate the intermediate host snail by environmental management, combined with chemotherapy, water supply and sanitation, and hygiene improvement. During the last 20 years, however, control approaches mainly consisting of large-scale praziquantel-based chemotherapy and health education started to be advocated and also increasingly applied. Here, we review the literature with an emphasis on combined approaches of field interventions that have been implemented for schistosomiasis control in China over the past 50 years. The interventions consist of both pilot studies and large-scale implementation during different historical periods. The feasibility and effectiveness of the various combined approaches are examined and analysed in relation to local economic conditions and the prevailing scientific and technical expertise. Finally, a set of recommendations is put forward for contemporary schistosomiasis control readily adapted to different eco-epidemiological settings in China.

The role of 'passive chemotherapy' plus health education for schistosomiasis control in China during maintenance and consolidation phase.

In order to explore the possibility of further optimising schistosomiasis control during the maintenance and consolidation phase in China, two highly endemic villages were selected to compare the strategy of 'passive chemotherapy' plus health education to that of mass chemotherapy singly. Emphasis was placed on treatment coverage with praziquantel among individuals infected with Schistosoma japonicum and costs incurred for treating an infected person. The results show that the former strategy was almost as good as the latter producing treatment coverage rates among egg-positives of 96.2-97.1% during 2 years, while corresponding rates of 100% were achieved in the village where mass chemotherapy was employed. Importantly, the cost of the former strategy was only about half that of mass chemotherapy, i.e. 49.0% in the first year and 54.6% in the following. Moreover, 'passive chemotherapy' together with health education can conveniently be integrated into the primary health care system making it an attractive strategy for schistosomiasis control during the maintenance and consolidation phase.

[Rapid identification of Oncomelania hupensis snail habitat in the Poyang Lake region by Geographic Information System (GIS) and Remote Sensing (RS)].

OBJECTIVE: To identify Oncomelania hupensis snail habitats and areas with high transmission potential by GIS/RS. METHODS: Marshland areas near high endemic villages of schistosomiasis in the Poyang Lake region were selected. Corresponding map was digitized and (Landsat 5 TM) image was corrected according to the digital map. The image in dry seasons was calculated by both normalized difference vegetation index (NDVI) and tasseled cap model. RESULTS: Result showed that snails spots were distributed in class 6, 7 and 8. Farther analysis of both NDVI and tasseled cap model showed that the snail habitats were mainly distributed in the areas where NDVI value was more than 110, and in tasseled cap wetness value between -10 to 3 with correction rate 94.93%. CONCLUSION: First step was to use unsupervised classification to define the class 6, 7 and 8 snail habitat environment. Second step was to extract the value by NDVI model, and to define a healthy vegetation as snail suspicious habitat when NDVI value was more than 110. Then the third step was to use tasseled cap wetness model to define the areas as snail habitats which value was between -10 to 3.