Dynamics of spatiotemporal distribution of schistosomiasis in Hubei Province, China.

Schistosomiasis caused by parasitic flatworms of blood flukes, remains a major public health concern in China. The significant progress in controlling schistosomiasis in China over the past decades has resulted in the remarkable reduction in the prevalence and intensity of Schistosoma japonicum infection to an extremely low level. Therefore, the elimination of schistosomiasis has been promoted by the Chinese national government. Hubei Province is the major endemic area, that is, along the middle and low reaches of the Yangtze River in the lake and marshland regions of southern China. Eliminating the transmission of schistosomiasis in Hubei Province is challenging. The current issue is to determine the distributions and clusters of schistosomiasis transmission. In this study, we assessed the spatial distribution of schistosomiasis and the risk at the county level in Hubei Province from 2011 to 2015 to provide guidance on the elimination of schistosomiasis transmission in lake and marshland regions. Spatial database of human S.japonicum infection from 2011 to 2015 at the county level in the study area was built based on the annual schistosomias is surveillance data. Moran's I, the global spatial autocorrelation statistics, was utilized to describe the spatial autocorrelation of human S. japonicum infection. In addition, purely spatial scan statistics combined with space-time scan statistics were used to determine the epidemic clusters. Infection rates of S. japonicum decreased in each endemic county in Hubei from 2011 to 2015. Human S. japonicum infection rate showed statistical significance by global autocorrelation analysis during the study period (Moran's I > 0, P < 0.01). This result suggested that there were spatial clusters present in the distribution of S. japonicum infection for the five years. Purely spatial analysis of human S. japonicum infection showed one most likely cluster and one secondary cluster from 2011 to 2015, which covered four and one counties, respectively. Spatiotemporal clustering analysis determined one most likely cluster and one secondary cluster both in 2011-2012, which appeared in 4 and 5 counties, respectively. However, the number of clustering foci decreased with time, and no cluster was detected after 2013.The clustering foci were both located at the Jianghan Plain, along the middle reaches of the Yangtze River and its connecting branch Hanbei River. Spatial distribution of human S. japonicum infections did not change temporally at the county level in Hubei Province. A declining trend in spatiotemporal clustering was observed between 2011 and 2015. However, effective control strategies and integrated prevention should be continuously performed, especially at the Jianghan Plain area along the Yangtze and Hanbei River Basin. Multivariate statistical analysis was carried out to investigate the risk of missing examinations, missing treatment, and unstandardized treatment events. The results showed that age, education level and Sanitary latrines are risk factors for missing examinations (b > 0, OR >1), and treatment times in past and feeding cattle in village group are protective factors (b < 0, OR <1). We also found that age and education level are risk factors for missing treatment (b > 0, OR >1). Study of the risk for un-standardized treatment revealed that occupation is risk factors (b > 0, OR >1), though, education level is protective factors (b < 0, OR <1). Therefore, precise prevention and control should be mainly targeted at these special populations.

A spatial analysis of human Schistosoma japonicum infections in Hubei, China, during 2009-2014.

BACKGROUND: The province of Hubei is located in the middle of China, near the middle and lower reaches of the River Yangtze, and is an area where schistosomiasis is endemic. It is challenging to control this disease in this environment, and it would be useful to identify clusters of infection and transmission, as well as their distributions during recent years. Therefore, this study aimed to analyze the spatial distribution of schistosomiasis in Hubei, in order to facilitate the effective control and elimination of this disease. METHODS: We collected schistosomiasis surveillance data from all endemic counties in Hubei during 2009-2014. A geographical information system (ArcGIS, version 10.1) was used to link the counties' geographical data with the epidemiological data, and the spatial scanning method (FleXScan v3.1.2) was used to identify spatial clusters of human infections with Schistosoma japonicum. RESULTS: In Hubei, patients who exhibited stool test results that were positive for S. japonicum accounted for > 50 % of all cases in China during 2009-2014. However, each endemic county in Hubei exhibited a declining trend in the number of human S. japonicum infections during the study period. The ArcGIS analyses revealed that the middle reaches of the River Yangtze were highly endemic for S. japonicum infections. Spatial scan analyses revealed the following infection clusters: two clusters in ten counties during 2009, two clusters in nine counties during 2010, three clusters in 12 counties during 2011, two clusters in 12 counties during both 2012 and 2013 and two clusters in ten counties during 2014. Most of the cluster regions were located in the lake and marshland regions along the basins of the River Yangtze. CONCLUSION: We successfully identified schistosomiasis clusters at the county level in Hubei during 2009-2014, and our results revealed that the clusters were typically located in lake and marshland regions. These data may be useful for controlling and eliminating schistosomiasis in other high-risk areas.

[Competition Results of Parasitic Disease Control Techniques among Technician in Hubei Province in 2015].

Objective: Objective To understand the qualification of technicians in parasitic disease control in Hubei Province by analyzing the rusults of technique competition in 2015. Methods: Provincial competitions on basic knowledge and on skills were conducted among 68 technicians in 17 cities （prefectures） in May 2015. The results were collected and analyzed with SPSS18.0 software. Scores were descriptively analyzed, and group comparisons were made by t-test and ANOVA. Results: The average score of the 68 competitors was 77.6, with a passing rate of 76.5%. In detail, the average scores of blood slide-making, Plasmodium detection, Kato-Katz slide-making and helminth egg detection were 9.3（passing rate, 98.5%）, 14.2 （32.4%）, 8.6 （98.53%） and 22.6 （27.9%） respectively. The average scores on theoretical knowledge and blood slide-making of female competitors were （84.5±17.3） and （9.4±0.4）, respectively, significantly higher than those of the males （70.7±21.1, 9.1±0.9 respectively） （P<0.05）. The scores of Plasmodium microscopy and egg microscopy were higher in competitors from counties［（16.3±8.0）, （25.8±12.0）］ than in those from cities/prefectures ［（12.5±6.5）, （20.0±10.8）］ （P<0.05）. In addition, the average scores on theoretical knowledge and egg dection were higher in competitors from districts with schistosomiasis control task ［（84.4±18.4）, （25.4±11.0）］ than in those from areas without schistosomiasis control task［（61.1±14.7）, （16.0±10.8）］（P<0.05）. There were no statistically significant differences in scores of various items among competitors of different ages and with professional ranks (P>0.05). Conclusion: There is a good overall performance among the professionals but an imbalance in detecting capability in different areas. The microscopic examination skill also needs to be improved.

[Spatial regression analysis of relationship between schistosome infection rate of Oncomelania hupensis snails and climate factors].

OBJECTIVE: To explore the relationship between the schistosome infection rate of O. hupensis snails and the climate factors in endemic areas of schistosomiasis, so as to provide the evidence for improving the snail control. METHODS: The snail and climate data of 18 counties in Hubei Province in 2009 were collected to obtain the infection rate of O. hupensis snails and to fit the spatial regression models. RESULTS: The multiple linear regression model showed that the residuals were autocorrelated (Moran's I = 0.182 8, P < 0.01) and the spatial regression was necessary. The spatial lag model (SLM) was selected according to the results obtained by Lagrange multiplier statistics. The spatial parameter ρ of SLM was significant (p= - 0.151 5, P < 0.05) and the infection rate of O. hupensis snails was positively correlated with the annual average temperature (P < 0.05). The correlations between the infection rate of O. hupensis and the annual average relative humidity, precipitation and sunshine duration were not significant respectively (all P > 0.05). CONCLUSIONS: The spatial regression models could be well applied in the analysis of the relationship between the O. hupensis snails and climate factors. The annual average temperature is the primary climate factor influencing the infection of O. hupensis snails.

[Epidemiological analysis of malaria prevalence in Hubei Province in 2013].

OBJECTIVE: To explore the endemic situation of malaria in Hubei Province in 2013, so as to put forward effective elimination strategies and measures. METHODS: The data of malaria cases were searched from the Disease Reporting Information System of Chinese Center for Disease Control and Prevention and analyzed with the descriptive epidemiological method for the epidemiological characteristics of malaria in Hubei Province in 2013. RESULTS: A total of 129 malaria cases were reported in Hubei Province in 2013 with the incidence of 0.02/10,000, and all of them were imported cases, in which 86 cases with Plasmodium falciparum infection, 32 cases with P. vivax infection, 7 cases with P. ovale infection and 4 cases with P. malariae infection. The distribution of malaria cases was concentrated in Wuhan City (76 cases), Yichang City (10 cases), Xiangyang City (7 cases) and Huangshi City (6 cases), accounting for 76.74% of the total cases. There was no significant seasonal variation in the reporting time of the cases. Totally 99.22% of the cases were male, the age distribution concentrated mainly on 20-49 years. The occupation distribution concentrated mainly on the worker, farmer, cadre staff and migrant worker. The main original areas of the imported cases were Africa (111 cases, 86.05%) and Asia (17 cases, 13.18%). CONCLUSIONS: There is no local malaria cases reported in Hubei Province in 2013, however, the imported malaria cases are increased. Therefore, it is necessary to further strengthen the multi-sector collaboration of vector control, while the health education should be intensified especially in the key population.

[Qualitative research on psychological experiences of advanced schistosomiasis patients].

OBJECTIVE: To understand the psychological experiences of advanced schistosomiasis patients, so as to provide the evidence for formulating a systematic and scientific nursing scheme. METHODS: Twenty advanced schistosomiasis patients were studied with the qualitative research method. RESULTS: There were 70% (14/20) patients with labor limited, 50% (10/20) with a moderate anxiety, irritability and other negative emotions, and 65% (13/20) with moderate discomfort. CONCLUSIONS: Most of advanced schistosomiasis patients have negative emotions. Therefore, the suitable psychological nursing should be given to these patients to improve their quality of life.

[Effect of standardized construction of laboratories of schistosomiasis control institutions in Hubei Province in 2013].

OBJECTIVE: To investigate the effect and current situation of the standardized construction of laboratories of schis- tosomiasis control institutions in Hubei Province, so as to provide the evidence for establishing and improving the quality control system of diagnosis of schistosomiasis after the transmission of schistosomiasis was under control. METHODS: According to the procedures of self-examination, field operation, and laboratory on-site, five laboratories were assessed, and all the results were analyzed comparatively. RESULTS: The average number of staffs were (7.00±1.58) persons, and the staffs of the laboratories of the schistosomiasis control institutions with senior professional titles in the city level were more than that in the county level (t = 5.563, P < 0.05). The average space was (3.20±1.64) rooms, and the average area was (117.00±88.29) m2. The average score of field operation was (96.40±4.49) points. The average score of laboratory on-site assessment was (106.6±6.15) points. The highest and lowest of the laboratory on-site assessment scores were environment and facilities (19.60 ± 0.55) points and management system of laboratory quality control (15.70±2.39) points (F = 2.869, P < 0.05), respectively. CONCLUSION: The cultivation of laboratory staff should be strengthened, and the diagnostic capacity should be maintained and improved. The laboratory quality control system should be paid more attention to, and the construction and management of schistosomiasis laboratories should be standardized.

Spatial analysis of Schistosomiasis in Hubei Province, China: a GIS-based analysis of Schistosomiasis from 2009 to 2013.

BACKGROUND: Schistosomiasis remains a major public health problem in China. The major endemic areas are located in the lake and marshland regions of southern China, particularly in areas along the middle and low reach of the Yangtze River. Spatial analytical techniques are often used in epidemiology to identify spatial clusters in disease regions. This study assesses the spatial distribution of schistosomiasis and explores high-risk regions in Hubei Province, China to provide guidance on schistosomiasis control in marshland regions. METHODS: In this study, spatial autocorrelation methodologies, including global Moran's I and local Getis-Ord statistics, were utilized to describe and map spatial clusters and areas where human Schistosoma japonicum infection is prevalent at the county level in Hubei province. In addition, linear logistic regression model was used to determine the characteristics of spatial autocorrelation with time. RESULTS: The infection rates of S. japonicum decreased from 2009 to 2013. The global autocorrelation analysis results on the infection rate of S. japonicum for five years showed statistical significance (Moran's I > 0, P < 0.01), which suggested that spatial clusters were present in the distribution of S. japonicum infection from 2009 to 2013. Local autocorrelation analysis results showed that the number of highly aggregated areas ranged from eight to eleven within the five-year analysis period. The highly aggregated areas were mainly distributed in eight counties. CONCLUSIONS: The spatial distribution of human S. japonicum infections did not exhibit a temporal change at the county level in Hubei Province. The risk factors that influence human S. japonicum transmission may not have changed after achieving the national criterion of infection control. The findings indicated that spatial-temporal surveillance of S. japonicum transmission plays a significant role on schistosomiasis control. Timely and integrated prevention should be continued, especially in the Yangtze River Basin of Jianghan Plain area.

[Assessment of schistosomiasis endemic situation in national surveillance sites in Hubei Province from 2005 to 2010].

OBJECTIVE: To assess the schistosomiasis endemic situation in the national surveillance sites in Hubei Province, so as to provide the evidence for the prevention and control of schistosomiasis. METHODS: According to the national surveillance protocol, a longitudinal surveillance of endemic situation of schistosomiasis was carried out in 16 national surveillance sites from 2005 to 2010. RESULTS: In general, the positive rates of IHA, Kato-Katz technique and infection rates of Schistosoma japonicum decreased from 15.67%, 10.93% and 1.71% in 2005 to 10.48%, 8.54% and 0.90% in 2010, and declined by 33.12%, 22.70% and 47.95%, respectively. The infection rates of S. japonicum of the male were higher than that of the female, and the peak infection rates were in the groups aged above 30 years. The endemic situation of fishermen and farmers were relatively serious. The infection rates of S. japonicum in cattle decreased from 11.69% in 2005 to 1.41% in 2010, and declined by 88.01% (χ2 = 298.79, P < 0.001). The areas with infected Oncomelania hupensis snails, the densities of living snails, the rates of infected snails and the densities of infected snails decreased by 90.88%, 61.66%, 80.00% and 92.00%, respectively. CONCLUSION: The schistosomiasis endemic situation in the national surveillance sites in Hubei Province mitigates in 6 years, but the prevention is still a very daunting task.

[Schistosomiasis status and control strategy in Hubei Province from 2008 to 2012].

OBJECTIVE: To evaluate the effects of the schistosomiasis control mode ("Hubei mode") that includes "comprehensive measures in a whole endemic county", "co-action of Health Ministry and Province" and "replacing cattle with machine" in Hubei Province. METHODS: The data of schistosomiasis control in Hubei Province from 2008 to 2012 were collected and a database including the annual schistosome infections of human and cattle, acute schistosome infection, outbreak of schistosomiasis endemic, schistosome infected Oncomelania hupensis snails, and other prevention indicators was established and analyzed by using SPSS. RESULTS: Compared with 2008, in 2012, the infection rates declined by 64.91% and 88.63% in human and cattle respectively. The area with snails decreased from 5423.85 hm2 in 2008 to zero. There were no acute schistosomiasis patients and outbreak of schistosomiasis endemic. CONCLUSION: The schistosomiasis control mode ("Hubei mode") is effective significantly.

[Surveillance of schistosomiasis japonica in potential endemic areas in Hubei Province from 2008 to 2012].

OBJECTIVE: To explore the potential key risk factors of schistosomiasis transmission in potential endemic areas so as to provide the evidence for setting up the prediction and surveillance systems of schistosomiasis outbreak epidemic. METHODS: From 2008 to 2012, fixed and mobile surveillance sites in potential endemic areas of 2 counties in Hubei Province were selected. The immunological assays and stool examinations were carried out to investigate the schistosome infection situation of local people, mobile population and livestock. The distribution of Oncomelania hupensis snails was investigated in risk areas and suspicious areas, and spreading patterns of snails were observed in the rivers that directly connected with the Yangtze River. RESULTS: A total of 6 052 local people aged 6-65 years were screened by IHA immunological tests, and the positive rate of antibody was 1.19% (72/6 052). Totally 72 antibody positives were examined by Kato-Katz technique and there were no positives. A total of 5 004 mobile persons were tested by IHA immunological tests and the positive rate was 1.36% (68/5 004). Totally 68 antibody positives were examined by Kato-Katz technique and there were no positives. Totally 287.07 hm2 potential endemic areas were investigated for Oncomelania snail detection, and no snails were found. The investigation on snail spreading patterns and the surveillance on suspicious circumstances were carried out, with no snails found. CONCLUSIONS: In the schistosomiasis potential endemic areas, some positives of IHA immunological tests are found. Therefore, monitoring is still needed to be strengthened.

New integrated strategy emphasizing infection source control to curb Schistosomiasis japonica in a marshland area of Hubei Province, China: findings from an eight-year longitudinal survey.

BACKGROUND: Schistosomiasis remains a major public health problem in China. The major endemic foci are the lake and marshland regions of southern China, particularly the regions along the middle and lower reach of the Yangtze River in four provinces (Hubei, Hunan, Jiangxi, and Anhui). The purpose of our study is to assess the effect of a new integrated strategy emphasizing infection source control to curb schistosomiasis in marshland regions. METHODS: In a longitudinal study, we implemented an integrated control strategy emphasizing infection source control in 16 villages from 2005 through 2012 in marshland regions of Hubei province. The interventions included removing cattle from snail-infested grasslands, providing farmers with mechanized farm equipment, improving sanitation by supplying tap water, building lavatories and latrines, praziquantel chemotherapy, controlling snails, and environmental modification. RESULTS: Following the integrated control strategy designed to reduce the role of bovines and humans as sources of Schistosoma japonicum infection, the prevalence of human S. japonicum infection declined from 1.7% in 2005 to 0.4% in 2012 (P<0.001). Reductions were also observed in both sexes, across all age groups, and among high risk occupations. Moreover, the prevalence of bovine S. japonicum infection decreased from 11.7% in 2005 to 0.6% in 2012 (P<0.001). In addition, all the 16 villages achieved the national criteria of infection control in 2008. CONCLUSION: Our findings indicate that the integrated strategy was likely effective in controlling the transmission of S. japonicum in marshland regions in China.

[Prediction of epidemic tendency of schistosomiasis with time-series model in Hubei Province].

OBJECTIVE: To study the endemic trend of schistosomiasis japonica in Hubei Province, so as to provide the theoretical basis for surveillance and forecasting of schistosomiasis. METHODS: The time-series auto regression integrated moving average (ARIMA) model was applied to fit the infection rate of residents of Hubei Province from 1987 to 2013, and to predict the short-term trend of infection rate. RESULTS: The actual values of infection rate of residents were all in the 95% confidence internals of value predicted by the ARIMA model. The prediction showed that the infection rate of residents of Hubei Province would continue to decrease slowly. CONCLUSION: The time-series ARIMA model has good prediction accuracy, and could be used for the short-term forecasting of schistosomiasis.

[Schistosomiasis control effect of measures of replacing cattle with machine for cultivation and forbidding depasturage of livestock on marshlands in marshland and lake regions].

OBJECTIVE: To evaluate the schistosomiasis control effect of the measures of replacing cattle with machine for cultivation and forbidding depasturage of livestock on marshlands in marshland and lake regions. METHODS: The retrospective review and field survey were implemented in the Jiangling and Gongan counties of Hubei Province where were implemented with the measure of replacing cattle with machine for cultivation, and Yuanjiang and Huarong counties of Hunan Province where were implemented with the measure of forbidding the depasturage of livestock on marshlands. The schistosome infection status of human, cattle, and Oncomelania hupensis snails, and schistosome-infested field excreta were surveyed from 2007 to 2013. The effects of the interventions were compared before and after their implementations. RESULTS: The 6 villages of Hubei Province were implemented with the measure of replacing cattle with machine for cultivation, and 7 villages of Hunan Province were implemented with the measure of forbidding the depasturage of livestock on marshlands. From 2007 to 2013, the schistosome infection rates of residents declined from 3.95% to 0.70% (χ2 = 128.376, P < 0.05), with the descend range of 82.53%. The descend ranges of the measures of replacing cattle with machine for cultivation and forbidding the depasturage of livestock on marshlands were 83.081% and 81.62% respectively, and there was no significant difference between the two measures (χ2 = 0.132, P > 0.05). The infection rate of cattle decreased from 3.66% in 2007 to 0.65% in 2013, and the descend range was 82.24% (χ2 = 13.692, P < 0.05). The field excreta was surveyed in the snail breeding place in 2013. The investigated area was 157.435 hm2, and 625 samples of field feces of cattle were collected with the density of field excreta of 3.97/hm2, and the positive rate was 1.12% (7/625). The schistosome infection rate of snails and the density of infected snails decreased successively from 2007, and no infected snails were detected from 2011 to 2013. CONCLUSIONS: The schistosomiasis endemic situation are decreased significantly after the interventions of replacing cattle with machine for cultivation and forbidding the depasturage of livestock on marshlands. Therefore, schistosomiasis control effect of these measures is notable in the marshland and lake regions.

[Retrospective investigation on endemic situation of schistosomiasis in Hubei Province].

OBJECTIVE: To explore the changing rules of schistosomiasis infection and Oncomelania hupensis snail situation in areas where schistosomiasis transmission was controlled or interrupted or transmission rebounded after the interruption. METHODS: Daye City, Wuxue City and Jingshan County were selected and investigated retrospectively to collect the schistosomiasis epidemiological information 10 years before they reached the criteria of transmission controlled and the subsequent years until 2008. The database of retrospective investigation was established for analyzing the trends and rules of the changes of snail status and human infection status. RESULTS: In Daye City, there was no snail areas and schistosomiasis patients and cattle after reaching the criteria of transmission interrupted in 1987. The infection rate of residents were positively correlative with the infection rate of cattle and snail areas (r = 0.865, 0.843, P < 0.01). In Wuxue City, the proportion of snail areas occupying the historic snail areas kept a steady from the transmission controlled to transmission interrupted, but it began to rebound to the highest level in the history (8.93%) after the transmission interrupted for 3 years. In Jingshan County, the infection rates of residents and cattle were all stable from 1% to 2% after the transmission controlled. The proportion of snail areas occupying the historic snail areas was rebounded from 1.63% in 1985 to 21.50% in 2008, and the densities of living snails rebounded from 2005. CONCLUSIONS: The infected snails could be the sensitive indicator of the rebound of snail situation and human infection. The elimination of schistosomiasis still depends on the control of snail areas, including strengthening the infected snail control.

[Impact of implementation of Three Gorges Project on schistosomiasis endemic situation in Hubei Province].

OBJECTIVE: To understand the change of hydrological regime in the Yangtze River and schistosomiasis endemic situation after the implementation of Three Gorges Project in Hubei Province. METHODS: The data of hydrological regime of the Yangtze River, schistosomiasis epidemic situation, and Oncomelania hupensis snail status were collected and analyzed in Hubei Province from 2002 to 2012. RESULTS: After the implementation of the Three Gorges Project in 2003, the water level of the Yangtze River slightly rose from January to March, the average water level in May and August both reduced compared with that in 2002, and the time of water withdrawal was moved up. The endemic situation of schistosomiasis showed a decline tendency in areas along the Yangtze River in Hubei Province. The positive rate of serological tests in the residents and the Schistosoma ja- ponicum infection rate in bovine decreased by 2.97% and 92.64% respectively. The numbers of human and bovine infected with S. japonicum decreased by 48.35% and 94.48%, respectively. CONCLUSION: After the implementation of the Three Gorges Project, the schistosomiasis endemic situation shows a decline tendency in the areas along the Yangtze River in Hubei Province, but the long-term monitoring still need to be carried out.

[Surveillance of schistosomiasis in Hubei Province in 2013].

OBJECTIVE: To understand the dynamic schistosomiasis situation in Hubei Province so as to provide the evidence for formulating the effective control strategy. METHODS: According to the Scheme of Schistosomiasis Surveillance in Hubei Province (the 2009 edition) , 207 endemic villages were selected and investigated for the schistosome infections of residents and livestock, and the distribution of Oncomelania hupensis snails. RESULTS: The average infection rates of residents and cattle were 0.35% and 0.15% respectively, and the endemic situation of fishermen and farmers were relatively serious (0.44% and 0.42%, respectively). The density of living snails was 0.30 snail/0.1m2, but no infected snails were found. CONCLUSION: The endemic situation of schistosomiasis in Hubei Province was stable in 2013, but the efforts for the infectious source control still should be strengthened.

[Molluscicidal effect of plastic film mulch covering method].

OBJECTIVE: To evaluate the molluscicidal effect of the plastic film mulch covering method. METHODS: In the barren land with a lot of Oncomelania hupensis snails, 3 experimental groups were set up, in which respectively using 3 different methods: a simple plastic film mulch covering method, film assisted with ammonium bicarbonate, and film assisted with amine molluscicide. In the canals, two experimental groups were set up, in which respectively using 2 different methods: simple plastic film mulch covering method and film assisted with ammonium bicarbonate. In above-mentioned areas, obstacles were cleared artificially. In each experiment group, 4 observation spots were set up, and 100 living snails were pot in each spot, and then, the plastic film mulch was evenly covered. The status of the snails was observed 3, 7, 15 and 30 days after the intervention. RESULTS: In the barren land, the snail death rates of the simple plastic film group were 20.77% and 96.92% 15 days and 30 days after the intervention, respectively. The snail death rate of the film assisted with amine molluscicide group was 80.46% 3 days after the intervention. In all the experiment groups, the snail death rates were from 96.92 to 100% 30 days after the intervention. CONCLUSION: The plastic film mulch covering method has a great molluscicide effect in the hill subtype and water network type of schistosomiasis epidemic areas.

[Surveillance and forecast for schistosome infectivity of Yangtze River and Hanbeihe River during flooding in Hubei Province].

OBJECTIVE: To investigate the schistosome infectivity of the water body of the Yangtze River and Hanbeihe River during flooding in Hubei Province. METHODS: The Oncomelania snail status was investigated in 17 sites of the Yangtze River and Hanbei River, and the infectivity of schistosome in sentinel mice was also determined. RESULTS: In the Yangtze River and Hanbei River, the average densities of living snails were 0.35 snails/0.1 m2 and 0.67 snails/0.1 m2 respectively, and the average infection rates of snails were 0.33% and 0.05%, respectively. The sentinel mouse surveillances were carried out twice in 10 sites of the Yangtze River. During the first surveillance the infection rate was 5.5% with 4 positive environment sites, and that was 5.5% with 7 positive environment sites in the second surveillance. The sentinel mouse surveillance was carried out once in 7 sites of the Hanbeihe River, and the infection rate was 11.9% with 4 positive environment sites. CONCLUSIONS: By monitoring schistosome infection of the water body, we can understand the threat of environment and provide warning information to prevent from the outbreak and spread of acute schistosomiasis. We can also indirectly get many messages about the quality of snail investigation and the effect of mollusciciding.

[Evaluation for schistosomiasis transmission control in Hongshan District of Wuhan City].

The status of schistosomiasis transmission control in Hongshan District of Wuhan City was evaluated. The schistosome infection rates of human and cattle were both below 1%, no local acute schistosomiasis patient occurred, and infected snails were not found during the period of 2008 to 2010. The files and data were well-documented. Therefore, Hongshan District reached the national criteria for schistosomiasis transmission control.