Cost-effectiveness analysis of the integrated control strategy for schistosomiasis japonica in a lake region of China: a case study.

BACKGROUND: Schistosomiasis japonica remains an important public health concern due to its potential to cause severe outcomes and long-term sequelae. An integrated control strategy implemented in the Peoples' Republic of China has been shown to be effective to control or interrupt the transmission of schistosomiasis. The objective of this study is to estimate the disease burden of schistosomiasis and assess the cost-effectiveness of the integrated control strategy focused on different major interventions at three stages for schistosomiasis control in a lake setting, to provide reference for policy making or planning. METHODS: Annual cost data of schistosomiasis control during 2009-2019 were obtained from the control program implementers in Jiangling County, Hubei Province, China. Economic costs are provided in constant 2009 Chinese Yuan (CNY). Epidemiological data of schistosomiasis were collected from the Jiangling county station for schistosomiasis control. Disease burden of schistosomiasis was assessed by calculating years of life lost (YLLs) owing to premature death, years lived with disability (YLDs) and disability-adjusted life years (DALYs). DALYs were calculated as the sum of YLLs and YLDs. We then conducted a rudimentary cost-effectiveness analysis by determining the ratio by dividing the difference between the average cost of integrated control strategy at transmission control (2013-2016) or transmission interruption (2017-2019) and the average cost at stage of infection control (2009-2012) with the difference between the DALYs of schistosomiasis at different control stages. Descriptive statistics on the costs and DALYs were used in the analysis. RESULTS: The total economic costs for schistosomiasis control in Jiangling County from 2009 to 2019 were approximately CNY 606.88 million. The average annual economic costs for schistosomiasis prevention and control at stages of infection control (2009-2012), transmission control (2013-2016), and transmission interruption (2017-2019) were approximately CNY 41.98 million, CNY 90.19 million and CNY 26.06 million respectively. The overall disease burden caused by schistosomiasis presented a downward trend. Meanwhile, the disease burden of advanced cases showed an upward trend with the DALY increased from 943.72 to 1031.59 person-years. Most disease burden occurred in the age group over 45 years old (especially the elderly over 60 years old). Taking the infection control stage as the control, the incremental cost-effectiveness ratio of integrated control strategy was CNY 8505.5 per case averted, CNY 60 131.6 per DALY decreased at transmission control stage and CNY -2217.6 per case averted, CNY -18 116.0 per DALY decreased at transmission interruption stage. CONCLUSIONS: The disease burden of schistosomiasis decreased significantly with the implementation of the integrated prevention and control strategy. Surveillance and management on elder population should be strengthened to decrease diseases burden. There remains a need for well-conducted studies that examine the long-term cost-effectiveness of the integrated control strategy for schistosomiasis. GRAPHIC ABSTARCT.

[Assessment on the effect of joint effort for schistosomiasis control in Hubei Province].

OBJECTIVE: To analyze the progress of implementation of integrated strategy with emphasis on the control of infectious sources and effectiveness for joint-project of schistosomiasis control in Hubei province. METHODS: Data on the endemic status and implementation of each integrated intervention in 6 collaborated counties including Gongan, Hanchuan, Honghu, Jiangling, Xiantao and Yangxin during 2009-2013 were collected and analyzed. 18 administrative villages with a history of endemic schistosomisis from 6 counties were selected for field survey. Individuals aged 6-65 years received screening test by IHA, and feces of antibody positive inhabitants were collected and tested by miracidia hatching technique. Hatching technique was conducted to determine the infection rate of schistosomiasis in cattle if there was any cattle existed. RESULTS: Various interventions were conducted with adaption to the local situation by the Departments of Agriculture, Water Conservancy, Forestry, and Health. The total number of cattle decreased from 75 388 at the beginning of 2009 to 1 805 at the end of 2013 in 6 counties with a reduction rate of 97.5%, while the prevalence in cattle reduced to 0-0.3% in 2013. Snail-infested areas were stable but areas with infected snails decreased significantly, and no infected snails were found in 2012-2013. Meanwhile, the infection rate of human beings on county level were less than 1%. No infected snails and cattle were found in 18 selected villages and the prevalence in inhabitants was in the range of 0-0.8%. CONCLUSION: Cooperation between provincial government and the Ministries of Health and Agruiculture accelerates the process to reach the criteria of transmission control of schistosomiasis in Hubei Province. However, sustainable effort in needed as the current endemic situation of schistosomiasis is stillunstable.

[Assessing the correlation between international collaboration and academic influence in parasitic diseases: a case study of National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention].

OBJECTIVE: To investigate the activity of scientific research and international collaboration in National Institute of Parasitic Diseases (NIPD), Chinese Center for Disease Control and Prevention (China CDC) from 2002 to 2012, and assess the relationship between international collaboration and academic influence at an individual level. METHODS: Non-bibliometric indicators including number and structure of scientific research personnel, number of projects and funds, visiting frequency, etc, were used to assess the activity of scientific research and international collaboration, and bibliometric indicators including publications and h index, were employed to estimate the academic influence of senior professionals in NIPD, China CDC. The relationship between the international collaboration and international academic influence in the control and research of parasitic diseases was evaluated by using analysis of covariance and generalized linear models. RESULTS: There was an increase tendency of the number of projects, funds and visiting frequency in NIPD, China CDC since the foundation of the institute in 2002, notably after 2011. The h2 index of NIPD, China was 7. Analysis of covariance and generalized linear model analysis revealed that the number of international partners (F = 81.75, P < 0.0001) , number of international projects (F = 22.81, P < 0.0001) , number of national projects (F = 7.30, P = 0.0110), and academic degree (F = 3.80, P = 0.0330) contributed greatly to individual academic influence, while visiting frequency, professional title and length of service had no significant association with h index. CONCLUSION: Elevation of international collaboration projects and development of long-term, stable international partnership may enhance the institutional and individual international academic influence in the field of parasitic diseases.

[Establishment and application of rapid assessment system of environment with high transmission risk of schistosomiasis in marshland and lake regions II establishment and application of measures for field survey].

OBJECTIVE: To establish the measures of schistosomiasis field survey and evaluate the efficacy of their application according to the content of indexes of rapid assessment system to high transmission risks in schistosomiasis endemic areas of lake regions. METHODS: In 2012, based on the analysis of Oncomelania hupensis snail situation, and schistosomiasis epidemic data of human and cattle from 2008-2010, 60 villages from Hunan, Hubei, Jiangxi and Anhui provinces were selected and investigated, and the content of the investigation included the field feces, snail status, and epidemic situation of human and cattle. The systemic sampling was applied for snail investigation; the feces collected from snail investigation field were examined by the hatching test (3 bottles for 1 sample). A cluster random sampling was carried out with more than 300 people in each village. By using the hatching test (3 bottles for 1 sample) , the human stool examination was carried out for the identification of the infected persons who were positive in the immunity test screening. The hatching test was applied for cattle of all the villages (3 bottles for 1 sample). RESULTS: A total of 65 field feces spots were surveyed in 60 villages, field feces were found in 78.46% (51/65) of spots, and the positive rate of field feces was 1.07% (9/842). There were 73.33% (44,160)of villages with cattle, and the largest amount cattle with 329 was found in Wufeng Village, Jiangxi Province. The cattle infection rate was 1.5 1% (4,913,242) in 3242 investigated cattle. The highest cattle infection rate was 4% in Tongxin Village, Jiangxi Province. The population of 47 099 was surveyed, the infection rate was 0.77% (364/47 099), and the highest was 4.37% in Xumuchang Village, Hunan Province. The infection rate was 0 in 43.33% (26/60) of villages. No acute schistosomiasis cases were reported in all the villages in 2011 and 2012. Totally, 77 snail spots in 60 villages were investigated, and 51 spots were marshland and 26 spots were ditches. The schistosome-infected snails were detected in 5.88% (3/51 )of the marshland spots and the living snails were found in 80.39%(41/51) of the spots. The highest density of living snails was 3.20/0.1 m2 in Xumuchang Village, Hunan Province. The average density of infected snails was 0.00045/0.1 m2 (4/8942). The infected snail spots were distributed in Liujiadi Village and Liuhe Village of Hubei Province, and Jiangkou Village of Anhui Province. No infected snails were detected in 26 ditches spots. The living snails were detected in 53.85% (14/26) of the ditches spots. The highest average density of living snails was 3.76/0.1 m2 in Huakou Village, Hubei Province. CONCLUSIONS: The measures of field survey for rapid assessment system of high transmission risks in schistosomiasis endemic areas of lake regions are established and applied with scientific, impersonal and rapid characteristics.

[Field evaluation of a novel plant molluscicide "Luo-wei" against Oncomelania hupensis IV molluscicidal effect in field of river beach in Dongzhi County, Anhui Province].

OBJECTIVE: To evaluate the field effect of the plant molluscicide "Luo-wei" (tea-seed distilled saponins, TDS) against the snail Oncomelania hupensis in the river beach in Anhui Province. METHODS: The immersing and spraying experiments were carried out in the river beach in Dongzhi County, Anhui Province, to assess the molluscicidal effect of 4% TDS comparing with 50% wettable powder of niclosamide ethanolamine salt (WPN). The chi(2) test or Fish's exact test was used to examine the differences between or among the molluscicidal effects by different environments, molluscicides, application methods, or days after the intervention. Meanwhile, the cost-effectiveness of the two molluscicides was analyzed. RESULTS: After 1, 2 , 3 d and 7 d of the immersion, the snail death rates in both TDS group and WPN group increased gradually, the snail death rates in the two groups after immersing for 7 d were 94.62% and 99.24%, respectively, and there was no significant difference between them ( chi(2) = 3.30, P > 0.05). After 1 , 3 , 7 d and 15 d of spraying, the snail death rates were 70.82%, 79.75%, 85.11% and 91.65% in the TDS group, and 77.71%, 84.27%, 91.90% and 95.58% in the WPN group, respectively, and the differences among the snail death rates of the two groups at each time point were statistically significant (all P values < 0.05). The costs of spraying were 316.71 yuan per 100 m2 for TDS and 309.71 for WPN. CONCLUSIONS: The molluscicidal effect of TDS has reached the requirements of national standard on nature source pesticides in the river beach of the middle and lower reaches of the Yangtze River. It is necessary to further evaluate its cost-effectiveness in large-scale field experiments in the future.

[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.

Disability weight of Clonorchis sinensis infection: captured from community study and model simulation.

BACKGROUND: Clonorchiasis is among the most neglected tropical diseases. It is caused by ingesting raw or undercooked fish or shrimp containing the larval of Clonorchis sinensis and mainly endemic in Southeast Asia including China, Korea and Vietnam. The global estimations for population at risk and infected are 601 million and 35 million, respectively. However, it is still not listed among the Global Burden of Disease (GBD) and no disability weight is available for it. Disability weight reflects the average degree of loss of life value due to certain chronic disease condition and ranges between 0 (complete health) and 1 (death). It is crucial parameter for calculating the morbidity part of any disease burden in terms of disability-adjusted life years (DALYs). METHODOLOGY/PRINCIPAL FINDINGS: According to the probability and disability weight of single sequelae caused by C. sinensis infection, the overall disability weight could be captured through Monte Carlo simulation. The probability of single sequelae was gained from one community investigation, while the corresponding disability weight was searched from the literatures in evidence-based approach. The overall disability weights of the male and female were 0.101 and 0.050, respectively. The overall disability weights of the age group of 5-14, 15-29, 30-44, 45-59 and 60+ were 0.022, 0.052, 0.072, 0.094 and 0.118, respectively. There was some evidence showing that the disability weight and geometric mean of eggs per gram of feces (GMEPG) fitted a logarithmic equation. CONCLUSION/SIGNIFICANCE: The overall disability weights of C. sinensis infection are differential in different sex and age groups. The disability weight captured here may be referred for estimating the disease burden of C. sinensis infection.

[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.

[Evaluation indices of social burden caused by advanced schistosomiasis].

OBJECTIVE: To study the evaluation indices and their weights of social burden caused by advanced schistosomiasis so as to provide scientific basis for control of the disease. METHODS: Primary indices of social burden evaluation for advanced schistosomiasis were summarized based on literature review. Secondary indices were put forward by a brainstorming process of experts. After the first round Delphi method, the secondary indices that needed were chosen, and the importance of primary indices was prioritized. Through the second and third round Delphi method, the weight of each secondary index was obtained. RESULTS: Four primary indices and 16 secondary indices consisted the index system of social burden induced by the disease. According to the significance, the 4 primary indices were arranged as social economy, government image, public psychology and social security. The weight of "funding for schistosomiasis control from central and local governments" in "social economic" stood the largest (14.063), while that of "equity to patients" in "government image", the smallest (3.125). CONCLUSION: The study covers all major aspects and their significance in social burden of advanced schistosomiasis, and an evaluation index system has been established for field validation.

Assessment of the age-specific disability weight of chronic schistosomiasis japonica.

OBJECTIVE: To estimate the age-specific disability weight of chronic schistosomiasis japonica in China. METHODS: Between October 2004 and January 2005, residents from two schistosome-endemic counties were screened for Schistosoma japonicum infection using an enzyme-linked immunosorbent assay. Disability and morbidity were assessed in seropositive individuals using the European quality of life questionnaire with an additional cognitive dimension (known as the "EQ-5D plus") and ultrasonography. The age-specific disability weight of chronic schistosomiasis was estimated based on participants self-rated health scores on the visual analogue scale of the questionnaire; the relationships between health status, morbidity and disability weight were explored using multilevel regression models. FINDINGS: Of 2843 seropositive individuals, 1419 (49.9%) were classified as having chronic schistosomiasis. Hepatomegaly was found in 76.3% (1082/1419); hepatic fibrosis was found in 73.3% (1040/1419); and splenomegaly was found in 18.6% (264/1419). Diarrhoea was the most common self-reported symptom (46.0%; 653/1419), followed by abdominal pain (32.6%; 463/1419), impaired capacity to work or study (30.7%; 436/1419), and blood in the stool (11.1%; 157/1419). More than half of the respondents reported impairments in at least one dimension of the EQ-5D plus questionnaire, particularly pain or discomfort (47.9%; 675/1410) and anxiety or depression (39.4%; 555/1410). The overall disability weight was 0.191, and age-specific weights ranged from 0.095 among those aged 5-14 years to 0.246 among those aged > 60 years. Multilevel regression models indicated that the disability weight was significantly associated with the participants sex, grade of hepatic fibrosis, the presence of hepatomegaly, abdominal pain, blood in the stool, impaired capacity to work or study, and cognition. CONCLUSION: The disability weight attributable to chronic schistosomiasis japonica is high and increases with age. Our findings call for a reappraisal of the disability weights due to chronic schistosomiasis mansoni and schistosomiasis haematobia as well as a re-estimation of the global burden of schistosomiasis.

Strategy formulation for schistosomiasis japonica control in different environmental settings supported by spatial analysis: a case study from China.

With the aim of exploring the usefulness of spatial analysis in the formulation of a strategy for schistosomiasis japonica control in different environmental settings, a population-based database was established in Dangtu county, China. This database, containing the human prevalence of schistosomiasis at the village level from 2001 to 2004, was analyzed by directional trend analysis supported with ArcGIS 9.0 to select the optimum predictive approach. Based on the approach selected, different strata of prevalence were classified and the spatial distribution of human infection with Schistosoma japonicum was estimated. The second-order ordinary kriging approach of spatial analysis was found to be optimal for prediction of human prevalence of S. japonicum infection. The mean prediction error was close to 0 and the root-mean-square standardised error was close to 1. Starting with the different environmental settings for each stratum of transmission, four areas were classified according to human prevalence, and different strategies to control transmission of schistosomiasis were put forward. We conclude that the approach to use spatial analysis as a tool to predict the spatial distribution of human prevalence of S. japonicum infection improves the formulation of strategies for schistosomiasis control in different environmental settings at the county level.