A cross-sectional survey comparing a free treatment program for advanced schistosomiasis japonica to a general assistance program.

The prevalence and intensity of schistosomiasis has dropped dramatically in China due to an effective integrated control program. However, advanced schistosomiasis is becoming a key challenge on the road to elimination. The aims of this study were to compare the disease condition between advanced cases under the general assistance program (GAP) and free treatment program (FTP) and to determine whether the FTP should be popularized to provide an objective reference for policymakers in China's advanced schistosomiasis control program. One hundred and ninety-four patients with schistosomiasis japonica who were enrolled in the GAP or FTP participated in this study. Little significant difference was observed in the potential confounders, including general characteristics, comorbidities, and lifestyle, indicating a similar effect on the pathology of liver damage caused by schistosome infection. There was no apparent difference in the incidence of common clinical symptoms. Furthermore, no significant difference was observed in the ultrasound findings, implying that the GAP and FTP groups shared a similar degree of liver lesion. With the exception of the abnormal rates of aspartate aminotransferase (AST), alkaline phosphatase (ALP), and hyaluronic acid (HA), the other serological indicators were comparable between the groups. Overall, the FTP is not a better option for controlling advanced schistosomiasis in China. It is important to reveal the precise mechanism underlying the pathogenesis of advanced schistosomiasis so that specific approaches to treating and preventing the development of advanced schistosomiasis can be developed and schistosomiasis can be eliminated in China.

Impact and cost-effectiveness of a comprehensive Schistosomiasis japonica control program in the Poyang Lake region of China.

Schistosomiasis japonica remains a significant public-health problem in China. This study evaluated cost-effectiveness of a comprehensive schistosomiasis control program (2003-2006). The comprehensive control program was implemented in Zhangjia and Jianwu (cases); while standard interventions continued in Koutou and Xiajia (controls). Incurred costs were documented and the schistosomiasis comprehensive impact index (SCI) and cost-effectiveness ratio (Comprehensive Control Program Cost/SCI) were applied. In 2003, prevalence of Schistosoma japonicum infection was 11.3% (Zhangjia), 6.7% (Jianwu), 6.5% (Koutou), and 8.0% (Xiajia). In 2006, the comprehensive control program in Zhangjia and Jianwu reduced infection to 1.6% and 0.6%, respectively; while Koutou and Xiajia had a schistosomiasis prevalence of 3.2% and 13.0%, respectively. The year-by-year SCIs in Zhangjia were 0.28, 105.25, and 47.58, with an overall increase in cost-effectiveness ratio of 374.9%-544.8%. The SCIs in Jianwu were 16.21, 52.95, and 149.58, with increase in cost-effectiveness of 226.7%-1,149.4%. Investment in Koutou and Xiajia remained static (US$10,000 unit cost). The comprehensive control program implemented in the two case villages reduced median prevalence of schistosomiasis 8.5-fold. Further, the cost effectiveness ratio demonstrated that the comprehensive control program was 170% (Zhangjia) and 922.7% (Jianwu) more cost-effective. This work clearly shows the improvements in both cost and disease prevention effectiveness that a comprehensive control program-approach has on schistosomiasis infection prevalence.

[Current status of human Schistosoma japonicum infection and reinfection in marshland and lake regions of Xinjian County, Jiangxi Province, China].

OBJECTIVE: To understand the dynamics of human infection and reinfection of Schistosoma japonicum after chemotherapy in marshland and lake endemic regions so as to provide the evidence for developing a cost-effective control strategy. METHODS: From 2007 to 2011, the schistosome infection, intensities and reinfection of population were investigated and the results were analyzed dynamically in Caohui Village, a national schistosomiasis surveillance site in Changyi Township, Xinjian County, Jiangxi Province, China. RESULTS: The schistosome infection rate was 3.55% and the mean intensity was 1.56 in 2007, and the schistosome infection rate was 1.52% and the mean intensity was 1.60 in 2011. The reinfection rates were 2.70%, 9.09% and 2.47% in 2009, 2010, and 2011, respectively. CONCLUSION: The schistosomiasis endemic situation shows a downtrend in the village. However, the reinfection is still serious; therefore, we should strengthen the research of risk factors of reinfection and control them.

[Burden of disease in Schistosomiasis japonica. IV. Community socioeconomic determinants of chronic schistosomiasis].

OBJECTIVE: To explore the socioeconomic determinants of chronic schistosomiasis japonica at a community (village) level. METHODS: The socioeconomic and epidemiological data (Years lived with disability, YLDs) came from the thematic research carried out in two schistosome-endemic counties, Dangtu and Hanshou, in lake areas between 2004 and 2005. A concentration index was calculated and used to assess the health inequalities between socioeconomic statuses. The community risk factors relating to chronic schistosomiasis were explored by the multiple regression model. RESULTS: The concentration index was -0.12 of Dangtu County and 0.03 of Hanshou County which indicated that there were no health inequalities due to schistosomiasis between communities with different socioeconomic statuses. There was no linear relationship between the economic levels and YLDs of chronic schistosomiasis. The results of multiple regression model showed that the distance from village to schistosome-infested water (P < 0.01) and wet land area per capita (P < 0.05) were significantly related to YLDs of chronic schistosomiasis. CONCLUSION: There is non-linear relationship between socioeconomic levels and YLDs of chronic schistosomiasis, but the distance from village to schistosome-infested water and wet land area per capita are significantly related to the latter.

[Evaluation of molluscicidal effects of contracted responsibility system in Changshan County].

OBJECTIVE: To explore a new molluscicidal pattern suitable for the complicated environments in hilly regions, so as to provide the evidence for making the strategy of Oncomelania snail control. METHODS: The contracted responsibility system for snail control was implemented by government. The quality of control work was evaluated in the same year and the recent molluscicidal effect was assessed in the next spring. RESULTS: After the intervention, the decline rate of snail areas increased from 53.4% to 100%; the compression rate of snail spots increased from 54.6% to 100%; the input of fund for snail control decreased from 2.03 Yuan/m2 to 0.69 Yuan/m2; the cost of snail control decreased from 3.73 Yuan/m2 to 0.75 Yuan/m2; the work efficiency increased from 12.0 m2/(man x day) to 36.7 m2/(man x day); the molluscicide decreased from 7.50 tons/year to 3.20 tons/year and the decline rate was 57.3%. The awareness rate and recognized rate of the contracted responsibility system for snail control were both 92.5%. CONCLUSION: The contracted responsibility system for snail control can increase financing efficiency, molluscicidal quality and work efficiency, and save molluscicide in complicated environments of hilly regions.

[Burden of disease in schistosomiasis japonica. I. Calculation and evaluation of years lived with disability of chronic schistosomiasis].

OBJECTIVE: To discuss the evaluation index of the disease burden of chronic schistosomiasis and its calculation methods. METHODS: The epidemiological data came from the thematic research carried out in two schistosome-endemic counties in lake areas between 2004 and 2005. The specific prevalence rates by age group, gender and endemic type were calculated. According to the age-specific disability weight obtained in the thematic research, the years lived with disability (YLDs) and the rates of YLD of stratified samples by age and gender, and the total YLDs of the two counties were calculated. RESULTS: The total YLDs were 1 056.26 and 3 967.43 person-years in Dangtu and Hanshou counties, respectively. The contributing rate of Grade I type village to the total YLDs of two counties was 37.95% (40.08% in Dangtu and 37.39% in Hanshou). For different stratums by age and gender, the older ones and male tended to have larger YLDs. Compared to the non-endemic areas, chronic schistosomiasis brought an average extra of 4.398 and 1.505 years per 1 000 person to population in Dangtu and Hanshou counties, respectively. CONCLUSION: The evaluation to YLDs of chronic schistosomiasis is helpful for prioritizing intervention areas and population, as well as providing a new index for the evaluation of effectiveness of control measures.

[Burden of disease in schistosomiasis japonica. II. Measurement of health inequalities due to chronic schistosomiasis].

OBJECTIVE: To measure and evaluate the health inequalities due to chronic schistosomiasis japonica. METHODS: Based on years lived with disability (YLD) caused by chronic schistosomiasis, a concentration index and Gini index, along with a concentration curve and Lorenz curve, the health inequalities between sexes, age groups or endemicities were identified and quantified. RESULTS: The age concentration index was 0.395 of females and 0.380 of males, with no significant difference between them. More than 60% of YLD was contributed by those aged > or = 45 years old who accounted for about a third of total population in both sexes. Gini index was 0.666 of Dangtu County and 0.451 of Hanshou County, and 60% of YLD was contributed by the highly endemic villages. CONCLUSIONS: The concentration index and Gini index could quantify the magnitude of health inequalities well. The priority of morbidity control should be given to those aged > or = 45 years old and living in highly endemic villages.

[Burden of disease in schistosomiasis japonica III household socioeconomic determinants of chronic schistosomiasis].

OBJECTIVE: To explore the socioeconomic determinants of chronic schistosomiasis japonica at household level. METHODS: The socioeconomic status of case and control families in lake and marsh schistosomiasis endemic areas were investigated by questionnaire, socioeconomic factors were analyzed by the principle components analysis, and the wealth index were calculated to evaluate the economic status at household level. Then the relation between schistosome infection and some influencing factors were analyzed by two-level Logistic regression model. RESULTS: A total of 2 716 households in 91 villages were investigated, among which 1 050 were case families and 1 666 were control families. The values of the first eigenvector of stone/brick house, house with > or = 2 floors, black/white TV, colour TV, washing machine, refrigerator, side occupation were -0.42, 0.46, -0.45, 0.46, 0.32, 0.24 and 0.16, respectively, which suggested that the first eigenvector was the comprehensive index reflecting family wealth. The results of Logistic regression model showed that there were 4 household factors significantly relating to chronic schistosomiasis, namely, the distance from residence to schistosome-infested water, source of washing water, economic status, and wet land area per capita, among which the factor that the distance from residence to schistosome - infested water < 100 m with the highest (OR = 12.590, P = 0). CONCLUSION: In the lake and marsh endemic areas, health education and other intervention to the poor family living along river or lake without safe water supply should be strengthened to control schistosomiasis.

[Risk factors of schistosomiasis transmission in marshland and lake regions in midstream of Yangtze River].

OBJECTIVE: To study the risk factors of schistosomiasis related to household economic condition and individual behavior in marshland and lake regions, so as to provide evidences for schistosomiasis control. METHODS: Six villages were sampled with the stratified cluster sampling method, 2 339 villagers from 1 247 households were surveyed by a questionnaire and meanwhile their sera were assayed for schistosomiasis by IHA. The Logistic regression was used to analyze the relationship between the results of serological examinations and risk factors. RESULTS: The Logistic regression model fitted well (R2 = 0.598 4) and it indicated that there existed a regressive relationship between the antibody positive rate and the endemic situation of village, family economic status, age, education level and infection history of schistosomiasis. CONCLUSION: Suitable measures should be made in according to the local economic situation, endemic type and population to control the transmission of schistosomiasis effectively.

[Study on family and economic burden caused by chronic Schistosomiasis japonica].

OBJECTIVE: To evaluate the family and economic burden of chronic Schistosomiasis japonica. METHODS: Relevant information on 226 chronic schistosomiasis patients from four surveillance sites in Yangxin county was collected. A questionnaire survey was conducted on 219 of them who agreed to corporate. Family burden was estimated with standard Family Burden Scale of Disease (FBS). Direct economic burden was calculated by questionnaire survey. Human capital method combined with Years Lived with Disability (YLDs) was adopted to evaluate the indirect economic burden. RESULTS: The positive rates on the dimensions of family economic burden and family entertainment were 54.8 percent and 47.0 percent respectively. The remaining dimensions were lower than 40.0 percent. Results of the questionnaire survey among 219 chronic Schistosomiasis patients showed that the total economic burden was 353,480.59 Chinese Yuan, which was 1614.07 Yuan per person. The direct and indirect economic burden were 61,679 and 291,801.59 Yuan respectively. The average direct and indirect economic burden when counted on money losses, were 281.64 and 1332.43 Yuan per person, respectively. CONCLUSION: The family burden caused by chronic Schistosomiasis japonica was serious, economically in particular. With regard to the income level of local residents, the economic burden of chronic Schistosomiasis was heavy to every household with indirect economic burden accounted for major proportion, suggesting close attention to be paid.

[Assessment of the disability weight for chronic schistosomiasis japonica in lake region].

OBJECTIVE: To estimate a suitable disability weight for chronic schistosomiasis japonica in a lake area of China. METHODS: A total of 219 chronic schistosomiasis patients from surveillance sites in Yangxin County of Hubei Province received questionnairing. The age- and sex-specific disability weights of chronic schistosomiasis were estimated based on the six classes of disability severity identified by Global Burden of Disease (GBD). All data was managed by Epidata 3.1. Statistical analysis was performed using SAS8.1. Rank sum test and Kruskal-Wallis test were used to examine the differences between disability weights. Pair-wise comparison was done by Nemenyi method. Multifactor logistic regression was used to analyze the risk factors of disability weight. RESULTS: The average disability weight was 0.122, and age-specific weight ranged from 0.020 to 0.280. The disability weight increased with age. Significant differences were found among different age groups (chi2=152.590, P<0.01). The disability weight of males (0.103) was significantly lower (Z=2.405, P<0.05) than that of females (0.147). Multi-factor logistic regression models indicated that the disability weight was significantly associated with age (OR=1.173, 95% CI: 1.130-1.217), and income level was a protective factor (OR=0.497, 95% CI: 0.319-0.775), while age was a confounding factor. CONCLUSION: An average disability weight of 0.122 for chronic schistosomiasis japonica indicates that 1/8 healthy year has lost for each survived life year of the patients, higher than the data of GBD.

An attempt to study the economic loss arising from Schistosoma japonicum infection and the benefits derived from treatment.

From the northern and southern portions of Leyte Province, which are endemic for schistosomiasis, a total of 801 infected individuals were interviewed, examined, and classified into mild, moderate, severe and very severe forms of disease with an assumed loss of working capacity for each category. The frequency rate or number of spells of illness for the past year under observation were correlated with the degree of incapacity to get the total days lost per person per year. Following a series of computations, of which the disability rate was considered as the most important, a total of 45.4 days lost per infected person per year was arrived at. Treatment of the disease with praziquantel was carried out and the patients were followed up one year after treatment, at which time the same methodology was applied. The results show that the 45.4 days lost prior to treatment went down to 4 days lost. There was an economic gain of 41.4 days as a result of treatment. This can be expressed in terms of financial value if we consider half of the infected cases as breadwinners receiving a minimum wage. It should be noted that a number of assumptions in this study were made. It is, however, hoped that this work will serve as a guide and a starting point for others to carry out related studies on economic loss and subsequent economic benefits to justify budgetary requests/allocations for the implementation of various preventive and control measures.

The social and economic context and determinants of schistosomiasis japonica.

A variety of biological and social factors govern schistosomiasis japonica in China. Social factors include those at a national and regional level, such as policies and patterns of development, which impact on local economic activities, and affect community, household and personal risk factors of infection. Drawing on research conducted in China, we illustrate how social structural and related factors influence individual risk and prevalence of infection. At a macro-level, political changes have occurred resulting in the shift from collective to family-based production, leading to clustering of infection in families. Industrialization and urbanization, and associated increased population mobility, have also influenced patterns of transmission and infection. Types of activities and local production patterns determine the exposure of individuals to schistosome-infested water sources. Fishermen have the most frequent water contact, aquatic workers the second and farmers the third; the relative risk of Schistosoma japonicum infection follows the same order. Among farmers, human infection is significantly related to agricultural production in rice fields infested with the intermediate host snail, and to rates of the infection in livestock. Risk of S. japonicum infection is also influenced by the domestic environment, including both the location of the house in relation to snail-colonized water sources, access to safe water, and improved sanitation. Household wealth and income determine family ability to provide and maintain safe water and sanitation, while determining or interacting with other variables. At an individual level, sex, age, educational level and ethnicity are all associated with different patterns of water use and water contact behaviour thereby affecting infection rates. Schistosomiasis impairs the growth and nutrition of children and the physical work capacity of adults, and so affects economic development. Given this, we note the importance of further research and social and contextual aspects of schistosomiasis infection in order to develop and sustain sound control strategies.

Applications and outcomes of periodic epidemiological surveys for schistosomiasis and related economic evaluation in the People's Republic of China.

The great success in schistosomiasis control in China is attributable to a range of factors. Periodic epidemiological surveys (PES) used for monitoring and adapting control interventions over time are an integral feature of the national schistosomiasis control programme. PES have enabled the dynamic trends of schistosomiasis epidemics to be closely pursued and have assisted in analysing subtle changes in endemicity. The results can be summarised mathematically allowing the variation in efficacy of control measures to be readily determined and enabling control strategies to be adjusted and updated. PES have been used in both cross-sectional and longitudinal pilot studies selected by appropriate sampling methods. In the early 1990s, when the World Bank Loan Project for schistosomiasis control commenced, economic evaluations were initiated in parallel. Cost-effectiveness analysis became a necessary tool to identify the most financially feasible yet effective options among a range of alternative control strategies. There was, however, a lack of standardised approaches rendering study comparisons across sites difficult. The global burden of disease study established the disability adjusted life year (DALY) as a measure of population health, combining in a single indicator years lost from premature death and years of life lived with disability. However, a recent meta-analysis reveals that the burden of schistosomiasis is underestimated, and hence, needs to be revised. It is envisaged that after the revision of DALYs lost due to schistosomiasis japonica, they will become an essential measure in future schistosomiasis control assessments in China and in other schistosome-endemic areas of the world.

An economic evaluation of the national schistosomiasis control programme in China from 1992 to 2000.

The World Bank Loan Project, by far the largest effort in China for schistosomiasis control since control activities were initiated in the mid 1950s, was carried out for a 9-year period commencing in 1992 in the 8 provinces where Schistosoma japonicum remained endemic when the project started. To evaluate its impact, a retrospective economic evaluation was done in 2001. Six representative counties, i.e. Huarong in Hunan province, Qianjiang in Hubei province, Yugan in Jiangxi province, Tongling in Anhui province, Xichang in Sichuan province and Dali in Yunnan province, were selected for the study. The total financial input in these counties from 1992 to 2000 was RMB Yuan 90.334 million with the World Bank loan accounting for 40.9%. Control efforts resulted in reduction of human prevalence rates in the six counties from 0.7-9.0% in 1992 to 0.1-2.7% in 2000. With regard to S. japonicum infection in bovines, a high reduction was observed in Qianjiang, and smaller decreases were noted in four counties, while there was an increase in Dali. In general, the areas infested by the intermediate host snail fluctuated around the initial level. The net benefit-cost ratio was 6.20, which means that this project gained US$ 6.20 for every dollar spent. The correlation coefficients of the net benefit-cost ratio to the human and bovine infection rates at the beginning of the project were 0.55 and 0.66, respectively. It is conceivable that further progress in schistosomiasis control is an important feature for sustained growth of the local economy, particularly in areas where control of the disease has been most challenging.

Cost-effectiveness analysis of the impacts on infection and morbidity attributable to three chemotherapy schemes against Schistosoma japonicum in hyperendemic areas of the Dongting Lake region, China.

A study was carried out in 8 villages endemic with S. japonicum in Hunan Province, China from 1998 to 2000 to evaluate the cost-effectiveness in preventing schistosome infection and related morbidity under three chemotherapy schemes: (1) 'clue' chemotherapy, consisting of treatment to those with contact with infected water and/or symptoms of infection; (2) 'mass' chemotherapy-treatment to all the villagers except those not able to take praziquantel; and (3) 'screen' chemotherapy-treatment prescribed to the stool egg positive cases after Kato-Katz examination. An itemized cost menu was used to estimate the cost incurred to each scheme, from the perspective of the health care provider. The numbers of cases prevented by chemotherapy schemes were estimated through standardized attributable fractions of the outcomes to absence of chemotherapy before intervention. The cost-effectiveness ratios were calculated using weighted ranks of unit costs of the four outcome measurements: the costs per case with infection, liver and spleen abnormality (as determined by ultrasonography) prevented and 1% reduction in intensity of infection (as estimated by egg per gram feces, EPG) after the two years of intervention. Sensitivity of total cost to changes in the costs of personnel, praziquantel and other key factors were analyzed. It is demonstrated that all the three schemes had a significant impacts on the prevalence and intensity of infection, but the overall effects on liver and spleen morbidity of the residents varied between schemes. Mass chemotherapy achieved the best cost-effectiveness ratio, with unit costs of preventing cases of infection, liver and spleen abnormality and 1% reduction of EPG being RMB yuan 161.2, 99.8, 219.3 and 176.3, respectively. However, clue and screen chemotherapy schemes did not show significant prevention of liver damages in the villagers. The unit costs per case prevented for the outcomes were RMB yuan 140.2, 602.7 and 169.3, respectively for clue chemotherapy, while RMB yuan 190.0, 448.4 and 145.0 respectively for screen chemotherapy. The study concluded that mass chemotherapy should still be the choice of preference in areas where prevalence of infection and frequencies of contact with infested water by residents are high, particularly if the drug cost could be further reduced. Clue chemotherapy could be an alternative to mass chemotherapy, especially when the frequency of water contact is not as high as 80% recorded in our study. Screen chemotherapy is the least favored option in the hyperendemic area of Hunan Province.

Analysis of social factors and human behavior attributed to family distribution of schistosomiasis japonica cases.

An investigation of family distribution patterns of schistosomiasis japonica was carried out in four pilot villages in Yunnan Province. Family clustering of the disease was present in Bihuayuan Village before and after economic reform (site A); however, such clustering did not occur in Tuanshan and Liantie Villages (sites B and C) in the same periods. Being contrary to the stage prior to economic reform family clustering existed in Zhonghe Village (site D) after the reform. The results obtained from single- and multifactor analysis showed that the main human behavior related to family distribution of schistosomiasis in mountainous regions of Yunnan Province included the frequency of laborer migration, contact with cercariae-infested water in public places or family microenvironments with a high transmission potential, promiscuous defecation and status of cattle grazing. The frequency of laborer migration and human contact with cercariae-infested water in public places in sites B and C without family clustering was higher than that in sites A and D with family clustering. Place for promiscuous defecation and cattle grazing in site A converged compared with that in sites B and C.