Approaches to genotyping individual miracidia of Schistosoma japonicum.

Molecular genetic tools are needed to address questions as to the source and dynamics of transmission of the human blood fluke Schistosoma japonicum in regions where human infections have reemerged, and to characterize infrapopulations in individual hosts. The life stage that interests us as a target for collecting genotypic data is the miracidium, a very small larval stage that consequently yields very little DNA for analysis. Here, we report the successful development of a multiplex format permitting genotyping of 17 microsatellite loci in four sequential multiplex reactions using a single miracidium held on a Whatman Classic FTA indicating card. This approach was successful after short storage periods, but after long storage (>4 years), considerable difficulty was encountered in multiplex genotyping, necessitating the use of whole genome amplification (WGA) methods. WGA applied to cards stored for long periods of time resulted in sufficient DNA for accurate and repeatable genotyping. Trials and tests of these methods, as well as application to some field-collected samples, are reported, along with the discussion of the potential insights to be gained from such techniques. These include recognition of sibships among miracidia from a single host, and inference of the minimum number of worm pairs that might be present in a host.

[Modeling transmission dynamics and control of schistosomiasis in the mountainous region, Sichuan].

OBJECTIVE: To use a mathematical model and computer simulation to study transmission dynamics and control of schistosomiasis in mountainous regions of Sichuan. METHODS: Based on studies of schistosomiasis japonica transmission in 20 villages in mountainous regions of Sichuan, a mathematical model was developed to characterize the impact of local environmental factors on transmission intensity. The model integrated site-specific factors and was calibrated to field epidemiological data from 3 subset villages. The dichotomic method was then used to predict different control measures. RESULTS: The study showed high variations in prevalence of infection and infection intensity across villages, ranging between 3%-73%, 0.1-100 epg (eggs per gram stool), respectively. Important factors including occupation of local residents, exposure to contaminated water, microclimatic characteristics were integrated in the model. The predictions of dichotomic models showed that continuing chemotherapy (coverage between 50%-60%) could reduce infection intensities to 30%-80%, but could not change local transmission potential; therefore, the termination of chemotherapy would be followed by bouncing back of transmission. Sustaining targeted environmental interventions through snail and parasite oval control at certain coverage (30%-50%, respectively) could reduce the transmission to relatively stable levels. The model predictions showed that an integrated control (e.g., including both chemotherapy and environmental interventions) could suppress the transmission to an undetectable level even interruption of transmission between 5-10 years. CONCLUSION: The study demonstrated the feasibility of using a dynamic model, calibrated to local data, to gain insights into complicated processes underlying the transmission and informing site-specific control strategies.

[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.

[Tribendimidine enteric coated tablet in treatment of 1,292 cases with intestinal nematode infection--a phase IV clinical trial].

OBJECTIVE: To further evaluate the efficacy and safety of tribendimidine in treatment of adult patients with intestinal nematode infections. METHODS: An open and multi-center clinical trial was conducted in the provinces of Hainan, Sichuan and Guizhou. A total of 1,292 infected cases aged 15-70 years were enrolled in the study. Modified Kato-Katz method was used to diagnose the cases with intestinal nematode infections and assess the efficacy 3-4 weeks post treatment. Patients with Ascaris lumbricoides infection were treated orally with tribendimidine enteric coated tablets at a single dose of 300 mg, while in the patients with Ancylostoma duodenale, mixed A. duodenale and A. lumbricoides, or with other helminth infections, a single dose of 400 mg was administered. RESULTS: The cure rate and effective rate of the patients with Ancylostoma infection were 88.4% (1,009/1,141) and 99.1% (1,131/1,141), respectively, while in patients with A. lumbricoides infection, they were 95.0% (419/441) and 99.8% (440/441), respectively. The cure rate of tribendimidine enteric coated tablet given to patients with Trichuris trichiura infection at a single dose of 400 mg was 76.8% (109/142). The adverse effect induced by tribendimidine was light and transient with a rate of 3.3% (42/1,292). No apparent impact was seen on blood and urine routine examinations, hepatic and renal functions as well as ECG examination. CONCLUSION: It is further confirmed that under the used dosage for expanding treatment in larger sample of patients with various ages and infected with Ancylostoma duodenale, A. lumbricoides and other helminths, tribendimidine enteric coated tablet is safe with satisfactory efficacy.

Epidemiology and risk factor analysis for canine echinococcosis in a Tibetan pastoral area of Sichuan.

OBJECTIVE: To determine the prevalence and evaluate the risk factors of canine echinococcosis based on a field survey of dog infections with Echinococcus granulosus and E. multilocularis in Chalong, Kalong, Dade and Chazha Townships in a district of Ganzi County, Sichuan Province, China. METHOD: Questionnaire associated with the acquisition of canine echinococcosis was administered to dog owners. Stray dogs were examined post-mortem and rectal faeces at necropsy were collected to validate a copro-antigen ELISA. Owned dogs were screened for Echinococcus spp. infection in faeces using the genus specific copro-ELISA and the effectiveness of dog treatment was assessed. Chi-square and one-way ANOVA were used for statistical analysis. RESULTS: The prevalence of Echinococcus spp. infection at necropsy in stray dogs was 60.9% (14/23) in 2000; E. multilocularis infection accounted for 34.8% (8/23) and E. granulosus for 26.1% (6/23). The specificity of the copro-ELISA was 80.0% and the sensitivity was 92.3%, compared with the results at necropsy. Fifty percent of owned dogs (290/580) tested was copro-antigen positive at the beginning of the project in 2000, which decreased to 17% (99/580) in the same cohort of owned dogs after praziquantel treatment (5 mg/ kg) at 6-monthly period from 2003 to 2005. Analysis for risk factors associated with copro-antigen positive dogs showed that the never tethered dogs had a higher rate (40.4%, 65/161) than dogs tethered during the day (32.3%, 109/337), or tethered at night [29.2% (21/72)], or those always tethered [20%(2/10)](P<0.01). Dogs that their owners lacked hydatid transmission knowledge [38.1% (121/318)] and did not have de-worming practice [47.7% (92/193)] had significantly higher copro-antigen positive rate than those dogs that their owners knew relevant knowledge [28.6% (75/262)] and were dewormed regularly [20.4% (79/387)](P<0.05 and P<0.01). There was no correlation between the prevalence and dog sex or age or the varieties of livestock that the owner raised. CONCLUSION: Local dogs show high prevalence with both E. granulosus and E. multilocularis. The copro-ELISA can be used to detect infection of Echinococcus in dogs. Allowing dogs to roam, lack of the basic knowledge of hydatid disease transmission and no de-worming practice for dogs are significant factors for the transmission of canine echinococcosis.

Epidemiology of schistosomiasis in the People's Republic of China, 2004.

Results from the third nationwide cluster sampling survey on the epidemiology of schistosomiasis in the People's Republic of China, conducted by the Ministry of Health in 2004, are presented. A stratified cluster random sampling technique was used, and 239 villages were selected in 7 provinces where Schistosoma japonicum remains endemic. A total of 250,987 residents 6-65 years of age were included in the survey. Estimated prevalence rates in the provinces of Hunan, Hubei, Jiangxi, Anhui, Yunnan, Sichuan, and Jiangsu were 4.2%, 3.8%, 3.1%, 2.2%, 1.7%, 0.9%, and 0.3%, respectively. The highest prevalence rates were in the lake and marshland region (3.8%) and the lowest rates were in the plain region with waterway networks (0.06%). Extrapolation to all residents in schistosome-endemic areas indicated 726,112 infections. This indicates a reduction of 16.1% compared with a nationwide survey conducted in 1995. However, human infection rates increased by 3.9% in settings where transmission is ongoing.

[Clinical observation on 899 children infected with intestinal nematodes and treated with tribendimidine enteric coated tablets].

OBJECTIVE: To evaluate the efficacy and safety of tribendimidine in treatment of children with hookworm and Ascaris lumbricoides infections. METHODS: An open and multi-center clinical trial was conducted in the provinces of Hainan, Sichuan and Guizhou. 899 children aged 4-14 years were enrolled in the study. Hookworm, A. lumbricoides or other helminth infections were diagnosed by improved Kato-Katz method. All the patients were treated orally with tribendimidine enteric coated tablet at a single dose of 200 mg. The efficacy was evaluated by stool examination 3-4 weeks post treatment. RESULTS: The cure rate and effective rate of the children with hookworm infection were 82.0% (433/528) and 99.2% (524/528), respectively, while in children with A. lumbricoides infection, they were 95.0% (576/639) and 99.8% (637/639), respectively. The efficacy of tribendimidine enteric coated tablet given to the children with Trichuris trichiura infection at a single dose of 200 mg was 36.8% (112/304). The adverse effect induced by tribendimidine, such as dizziness, nausea and vomiting, was light and transient with an adverse effect rate of 1.6% (14/899). No apparent impact was seen on the blood and urine routine examination, hepatic and renal function as well as ECG examination. Conclusion Tribendimidine given at a single dose of 200 mg exhibits lower adverse effect rate and potential efficacy in the treatment of children with hookworm and A. lumbricoides infections.

Interruption of schistosomiasis transmission in mountainous and hilly regions with an integrated strategy: a longitudinal case study in Sichuan, China.

BACKGROUND: Schistosomiasis remains a major public health concern in China. Since 2004, an integrated strategy was developed to control the transmission of Schistosoma japonicum in China. However, the long-term effectiveness of this integrated strategy for the interruption of schistosomiasis transmission remains unknown in the mountainous and hilly regions of China until now. This longitudinal study aims to evaluate the effectiveness of the integrated strategy on transmission interruption of schistosomiasis in Sichuan Province from 2005 through 2014. METHODS: The data regarding replacement of bovines with machines, improved sanitation, access to clean water, construction of public toilets and household latrines, snail control, chemotherapy, and health education were captured from the annual report of the schistosomiasis control programmes in Sichuan Province from 2005 to 2014, and S. japonicum infection in humans, bovines and snails were estimated to evaluate the effectiveness of the integrated strategy. RESULTS: During the 10-year period from 2005 through 2014, a total of 536 568 machines were used to replace bovines, and 3 284 333 household lavatories and 15 523 public latrines were built. Tap water was supplied to 19 116 344 residents living in the endemic villages. A total of 230 098 hm2 snail habitats were given molluscicide treatment, and 357 233 hm2 snail habitats received environmental improvements. There were 7 268 138 humans and 840 845 bovines given praziquantel chemotherapy. During the 10-year study period, information, education and communication (IEC) materials were provided to village officers, teachers and schoolchildren. The 10-year implementation of the integrated strategy resulted in a great reduction in S. japonicum infection in humans, bovines and snails. Since 2007, no acute infection was detected, and no schistosomiasis cases or infected bovines were identified since 2012. In addition, the snail habitats reduced by 62.39% in 2014 as compared to that in 2005, and no S. japonicum infection was identified in snails since 2007. By 2014, 88.9% of the endemic counties achieved the transmission interruption of schistosomiasis and transmission control of schistosmiasis was achieved in the whole province in 2008. CONCLUSION: The government-directed and multi-department integrated strategy is effective for interrupting the transmission of schistosomiasis in the mountainous and hilly regions of China.

[Water exposure modes and times of different populations in mountainous schistosomiasis endemic areas near Qionghai lake].

OBJECTIVE: To investigate water exposure modes and times of different populations in mountainous schistosomiasis endemic areas and to inform about the control strategies. METHODS: All 1054 residents from populations around Qionghai Lake were randomly sampled according to occupation for a retrospective questionnaire survey in November 2001. Each individual was interviewed for his/her mode, frequency, and duration of water exposure occurring between April and October 2001. RESULTS: The average exposure times and intensity were higher in farmers (median: 16 - 18 min/day and 2.41 - 2.5, respectively) who grow rice, tobacco, and vegetables than others (median: 3.74 - 7.39 min/day and 0.81 - 1.52, respectively); exposure frequency was found highest in farmers (median: 2.04 times/day) in all occupations; schoolchildren had low exposure frequency and times, but very high exposure intensity (median 2.34). Between April and June it is an agriculturally busy season, that is also a peak season of water exposure of adults. Schoolchildren's water exposure peaks on July and August, mainly due to playing water and swimming. Exposure times and intensities were higher in females than in males. CONCLUSION: Water exposure modes, times, and intensities of different populations were different in mountainous schistosomiasis endemic areas of Xichang. Between April and June should be the peak infection season of adults who are engaging in agricultural activities, while July to August should be the peak infection season for schoolchildren with non-agricultural activities.

[Establishment of index system of key factors on elimination of schistosomiasis].

OBJECTIVE: To establish an index system of the key factors of elimination of schistosomiasis. METHODS: A questionnaire was designed based on the reference review, and 24 scientists working in the field of schistosomiasis control or research or management were investigated by using the Delphi method. The importance of each index reflecting the endemicity of schistosomiasis wis scored by each scientist. The assessing system for key factors of eliminating schistosomiasis was established, and the normalized weight and combined weight were calculated. RESULTS: The assessing system included three indexes in the first grade, seven indexes in the second grade and thirteen indexes in the third grade. Among the indexes in the first grade, the normalized weights of endemicity, natural environment and social environment were 0.371 1, 0.339 5, and 0.289 4, respectively. Among the indexes in the second grade, the economy showed the highest combined weight of 0.289 4 while the agriculture and sanitation both showed the lowest score of 0.112 7. Among the indexes in the third grade, the infection rate of animals showed the highest combined weight of 0.124 6 while the agriculture and plant structure both showed the lowest score of 0.053 0. CONCLUSION: The indexes of the assessing system provide the scientific evidence for surveillance work when elirnination of schistosomiasis.

[Evaluation on molluscicidal effect of chlorosalicylicamide on Oncomelania hupensis in schistosomiaisis endemic areas of eight provinces in China].

OBJECTIVE: To evaluate the effects of a novel molluscicide, the salt quinoid-2', 5-dichloro-4'-nitrosalicylanilide from niclosamide (LDS), with 10% wettable powder, in main schistosomiasis epidemic areas of China, including Hunan, Jiangxi, Hubei, Anhui, Jiangsu, Sichuan, Yunnan and Zhejiang Province. METHODS: In the immersion test, 6 effective concentrations of 10% LDS were tested respectively: 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 g/m3 in the field; at the same time, 50% wettable powder of niclosamide ethanolamine salt (WPN) with effective concentrations of 1.0 g/m was used as the molluscicide control, and the fresh water as the blank control, then the mortality rates of 0. hupensis snails were recorded at 24 h, 48 h and 72 h after the immersion. In the spraying test and powder-spraying test, 5 effective dosages of 10% LDS were tested respectively: 0.2, 0.4, 0.6, 0.8, 1.0 g/m2, while 50% WPN 1.0 g/m2 was used as the molluscicide control, and the fresh water as the blank control in the field for 1 d, 3 d and 7 d, then the mortality rates of O. hupensis snails were recorded at 1 d, 3 d and 7 d after the spraying and powder-spraying. RESULTS: The snail mortality rates of LDS using the immersion test for 72 h were more than 95% in the field of eight provinces (0.1 g/m in Sichuan, Jiangxi, Jiangsu and Zhejiang provinces, 0.2 g/m3 in Yunnan, Hunan and Hubei provinces, and 0.4 g/min Anhui Province); the snail mortality rates of LDS using the spraying test for 7 d were more than 85% (0.2 g/m2 in Hunan, Hubei, Jiangxi and Zhejiang provinces, 0.4 g/m2 in Sichuan and Anhui provinces, 0.6 g/m2 in Yunnan and Jiangsu provinces). The snail mortality rates of LDS the powder-spraying test for 7 d were more than 85% (0.6 g/m2 in Yunnan, Sichuan, Hubei, Jiangxi, Anhui, Jiangsu and Zhejiang provinces). According to the standards of "Efficacy test methods and evaluation of molluscicide for pesticide registration (NY/T 1617-2008)", LDS is a qualified molluscicide. CONCLUSIONS: LDS has good molluscicidal effects through the immersion, spraying and powder-spraying test in the fields. It is suitable for a variety of environments to control O. hupensis snails of schistosomiasis endemic areas in China. The recommended dosages of LDS are 0.1-0.2 g/m3 by the immersion method, 0.2-0.4 g/m2 by the spraying method, and 0.4-0.6 g/m2 by the powder-spraying method in the fields.

[Study on molecular phylogeny of Schistosoma sinensium based on mitochondrial genes].

OBJECTIVE: To determine the phylogenetic position of Schistosoma sinensium in the genus Schistosoma using mitochondrial cytochrome C oxidase 1 (CO1) and NADH dehydrogenase 1(ND1) as molecular markers. METHODS: The genomic DNA of adult worms were extracted by the GNT-K method. The target regions were amplified by PCR using specific primers. The PCR products were purified before ligation into the plasmid Zero-Blunt. Recombinant plasmids were amplified in E. coli, extracted and purified using routine methods and then sequenced using M13 primers (F/R) on a Licor long-read auto-sequencer. Sequences of related schistosomes were retrieved from GenBank and aligned with our data in the sequence editor ESEE. Gene trees were constructed in PHYLIP and MEGA using both maximum parsimony and neighbor-joining methods. For parsimony analysis, all characters were treated as unordered and with equal weights. At least 3,000 cycles of bootstrapping were carried out. For analysis in MEGA, all gap columns were deleted. The third position of codon was included. RESULTS: The nucleotide and amino acid sequences of CO1 and ND1 of S. sinensium were obtained. CONCLUSION: The phylogenetic trees from these molecular data suggested that S. sinensium belongs to the Asian schistosome group, and the results coincided with the previous rDNA (ITS2 & LSU) analysis results.

[Assessment of schistosomiasis transmission interruption in Beichuan County, Sichuan Province].

OBJECTIVE: To assess whether Beichuan County reaches the national standard of schistosomiasis transmission interruption. METHODS: Three villages in Beichuan County were sampled as assessment spots, and the schistosomiasis infections of residents and domestic animals, the status of Oncomelania snails and the past records were assessed according to the Criteria for Control and Elimination of Schistosomiasis in China. RESULTS: No local schistosome infections were found in residents and cattle for successive 5 years and no snails were found for 2 successive years in the 3 villages. The files were documented completely. All the indices reached the national standard of schistosomiasis transmission being interrupted. CONCLUSION: Beichuan County has reached the national standard of schistosomiasis transmission interruption. However, the endemic surveillance of schistosomiasis still needs to continue.

[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.

[Surveillance of schistosome antibodies in population in mountainous schistosomiasis endemic regions in China].

OBJECTIVE: To understand the dynamics of schistosome antibodies in population in mountainous schistosomiasis low endemic regions, China, so as to provide the evaluation reference for immunodiagnosis. METHODS: The people who consecutively received the indirect heamagglutination assay (IHA) for schistosomiasis and Kato-Katz technique were enrolled in this study in Guixiang Village, Danling County, Sichuan Province from 2006 to 2011. The positive rates for schistosome antibodies, antibody titers and eggs per gram (EPG) were analyzed. RESULTS: A total of 353 people were investigated in this study from 2006 to 2011. The positive rates for schistosome antibodies decreased from 20.73% to 13.67%, and the geometric mean reciprocal titer (GMRT) decreased from 1.63 to 1.06. The antibodies tended to be negative in most antibody-positive people and the GMRT decreased gradually. The antibodies remained negative in most antibody-negative people. After chemotherapy in parasitology confirmed patients, the positive rate for schistosome antibodies decreased from 100% to 20%, and the GMRT decreased from 34.29 to 1.58. There was a highly positive correlation between GMRT and EPG (r = 0.94, P < 0.05). CONCLUSION: The positive rate for schistosome antibodies in population in mountainous schistosomiasis low endemic regions is relatively high (13.67%). The standardization of immunodiagnostic methods is necessary and the suitable diagnostic reagents should be developed in this region.

[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.

[Investigation on current status of advanced schistosomiasis in Sichuan Province, 2010].

OBJECTIVE: To understand the current distribution and characteristics of patients with advanced schistosomiasis in Sichuan Province, so as to provide the scientific evidence for improving the management and treatment of advanced schistosomiasis. METHODS: The patients who had been diagnosed as advanced schistosomiasis or were supposed with advanced schistosomiasis were the objects of the investigation. The epidemiological survey and medical examination were used to investigate these persons one by one according to the national standard. RESULTS: There were 1 684 patients with confirmed diagnosis in 7 cities of Sichuan Province. There were 1 066 cases of splenomegaly including post-surgery (63.30%), 545 cases of ascites (32.36%), 44 cases of multiple granulomas in the colon (2.61%), and 29 cases of dwarf (1.72%). Most of the patients were old and 51.72% of them were more than 60 years old. A total of 1 331 patients (79.04%) needed treatment and assistance at present, and 36.44% of them who had ascites needed internal medicine treatment. CONCLUSION: There are also many patients with advanced schistosomiasis in Sichuan Province, and ascites and splenomegaly (post-surgery) were the main types. The patients with ascites should be the important objects of the treatment and assistance in the future.

[Effect of ecological civilized homestead construction on schistosomiasis control].

OBJECTIVE: To evaluate the effect of Ecological Civilized Homestead Construction on schistosomiasis control. METHODS: The data of ecological civilized homestead construction and schistosomiasis control were collected and analyzed in Meiwan Village, Shuangqiao Town, Danling County, Sichuan Province from 2004 to 2010. RESULTS: Ecological Civilized Homestead Construction was carried out from 2004 to 2010. Totally 454 bio-gas pools were built. All the farmers used well water. The popularized rates of the household bio-gas pool, sanitary toilet, sewage treatment pool reached 100%. The number of cattle was 4, which decreased by 91.30% compared with that in 2004, and all the cattle were fed in captivity. The schistosome infection rates of populations were 0.26% and 0.30% in 2005 and 2008, respectively, and nobody was infected in other years. The infection rate of cattle was 0 from 2004 to 2010. The awareness rate of knowledge about schistosomiasis control achieved 100% in the population over 6 years old. Most of the farmers could use certain protective measures while they were farming. CONCLUSION: The effect of ecological civilized homestead construction on schistosomiasis control is remarkable.

[Effect of comprehensive control pattern on soil-transmitted nematodiasis in Danling County].

The comprehensive control pattern centering on health education, deworming and improving drinking water and lavatories was adopted to control soil-transmitted nematodiasis in Danling County, Sichuan Province from 2007-2009. In 2009, the infection rate of soil-transmitted nematodes decreased from 57.12% of the baseline survey in 2006 to 10.06%.

[Surveillance of schistosomiasis in Sichuan Province, 2005-2010].

OBJECTIVE: To understand the epidemic trend of schistosomiasis in Sichuan Province so as to provide the evidence for formulating schistosomiasis control strategy. METHODS: According to the National Schistosomiasis Surveillance Protocol, the national surveillance sites in Sichuan Province were selected. The schistosomiasis surveillance was carried out continuously from 2005 to 2010. RESULTS: Nine national schistosomiasis surveillance sites were established in Pujiang, Guanghan, Zhongjiang, Fucheng, Dongpo, Danling, Renshou, Xichang and Dechang counties. The Oncomelania hupensis snail area decreased from 351 853 m2 in 2005 to 128 285 m2 in 2010, the snail density from 0.70 to 0.21 per 0.1 m2, the snail infection rate from 0.06% to 0, the positive rate of human serum schistosome antibody from 19.41% to 7.62%, the schistosome infection rate of human population from 1.93% to 0.10%, and the infection rate of livestock from 4.50% to 1.02%. The snails were found mainly in ditch, rice field and other moist field. CONCLUSIONS: Though the endemic of schistosomiasis has reached a low level in Sichuan Province, the endemic situation fluctuates at a narrow range in some surveillance sites. Therefore, the surveillance work should be carried out continuously.