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.

Pattern analysis of schistosomiasis prevalence by exploring predictive modeling in Jiangling County, Hubei Province, P.R. China.

BACKGROUND: The prevalence of schistosomiasis remains a key public health issue in China. Jiangling County in Hubei Province is a typical lake and marshland endemic area. The pattern analysis of schistosomiasis prevalence in Jiangling County is of significant importance for promoting schistosomiasis surveillance and control in the similar endemic areas. METHODS: The dataset was constructed based on the annual schistosomiasis surveillance as well the socio-economic data in Jiangling County covering the years from 2009 to 2013. A village clustering method modified from the K-mean algorithm was used to identify different types of endemic villages. For these identified village clusters, a matrix-based predictive model was developed by means of exploring the one-step backward temporal correlation inference algorithm aiming to estimate the predicative correlations of schistosomiasis prevalence among different years. Field sampling of faeces from domestic animals, as an indicator of potential schistosomiasis prevalence, was carried out and the results were used to validate the results of proposed models and methods. RESULTS: The prevalence of schistosomiasis in Jiangling County declined year by year. The total of 198 endemic villages in Jiangling County can be divided into four clusters with reference to the 5 years' occurrences of schistosomiasis in human, cattle and snail populations. For each identified village cluster, a predictive matrix was generated to characterize the relationships of schistosomiasis prevalence with the historic infection level as well as their associated impact factors. Furthermore, the results of sampling faeces from the front field agreed with the results of the identified clusters of endemic villages. CONCLUSION: The results of village clusters and the predictive matrix can be regard as the basis to conduct targeted measures for schistosomiasis surveillance and control. Furthermore, the proposed models and methods can be modified to investigate the schistosomiasis prevalence in other regions as well as be used for investigating other parasitic diseases.

[Cost-effectiveness evaluation on comprehensive control measures carrying out in schistosomiasis endemic areas with regard to different layers of administrative villages stratified by infection situation of human and domestic animals. II Correlation analysis of costs and inputs with changes of schistosomiasis endemic situation in inner embankment of marshland and lake regions from 2006 to 2013].

OBJECTIVE: To investigate the correlations between inputs and costs and endemic situation of schistosomiasis in inner embankment, so as tb provide the references for the strategy optimization of schistosomiasis control. METHODS: Jiangling County was selected as the study field. The correlatibn and regression analyses were applied to analyze the endemic situation of schistosomiasis in Jiangling County from 2006 to 2013. The methods of two-stages least squares and path analysis were applied to analyze the impacts between costs and inputs and endemic situation of schistosomiasis. RESULTS: The adjusted infection rate of population, number of bovines and Oncomelania hupensis snail areas reduced by 77.42%, 76.34% and 19.43%, respectively in Jiangling County from 2006 to 2013. The correlations between the infection rate of snails and the population positive rates of blood and fecal exams, and the infection rate of bovines were significant (all P < 0.05); and there was a significant linear regression between the infection rates of snails and bovines (P < 0.05). There were statistically significant regressions between inputs at different levels and the population positive rates of blood and fecal exams, and the infection rates of bovines and snails, as well as between the costs and the population positive rate of fecal exams and the infection rates of bovines and snails (all P < 0.05), whereas there was no statistically significant regression between the costs and the population positive rate by blood exams (P > 0.05). The inputs at county level had an impact on the population positive rate of blood exams; the costs of comprehensive treatment had an impact on the population positive rate of fecal exams; the costs of human labor and measures for exams and treatments had an impact on the infeiction rate of bovines; the inputs at national level and the costs of measures for exams and treatments had an impact on the infection rate of snails (all P < 0.05). CONCLUSION: The inputs and costs of schistosomiasis control were related to the epidemic situation of schistosomiasis in Jiangling County from 2006 to 2013; therefore, it is necessary to develop a comprehensive surveillance system as substitute for the current indexes on schistosomiasis control.

[Construction and operation of network laboratory for schistosomiasis diagnosis in Jianglin County].

OBJECTIVE: To build a high quality diagnosis system for schistosomiasis surveillance in the situation of low infection in Jianglin County. METHODS: The network laboratory for schistosomiasis diagnosis was built according to the national criteria in Jianglin County in 2012. RESULTS: The network laboratory for schistosomiasis diagnosis was established successfully and the operation was quiet well. CONCLUSION: The establishment and operation of the laboratory play an important role in the realization of schistosomiasis elimination.

[Efficacy of routinely used patterns for schistosomiasis diagnosis in lake and marshland regions].

OBJECTIVE: To evaluate the efficacy of routinely used pattern for schistosomiasis diagnosis in lake and marshland regions. METHODS: A historically heavy endemic village of schistosomiasis named Jinggan Village from Jiangling County was selected for field survey. The residents aged 6-65 years were screened by indirect hemagglutination assay (IHA) and dipstick dye immunoassay (DDIA) in parallel. The serological positives were examined by Kato-Katz technique and miracidium hatching technique to determine the infection of schistosome. The consistency of the two serological methods was evaluated. In addition, the schistosome infection rates were estimated accordingto the 3 detection patterns namely IHA, DDIA, IHA+DDIA combined with the etiologic examination. RESULTS: A total of 530 individuals were examined by the serological tests. The positive rate of DDIA was 46.98% (249/530), significantly higher than that of IHA (28.49%, 151/530) (χ2 = 59.55, P < 0.01). Totally 279 individuals were serological positives determined by IHA or DDIA, while 252 of them were detected by stool examination, and 22 cases were determined as parasitological positives, while 7 and 3 cases were diagnosed as antibody negatives by IHA and DDIA, respectively. The estimated infection rates determined by IHA, DDIA, IHA plus DDIA combined with stool examination were 3.14%, 3.97%, 4.60%, respectively. CONCLUSIONS: Under the condition of endemic situation becoming more and more waning, the current routinely used pattern for schistosomiasis detection may lead to missed diagnosis. So, more sensitive and effective diagnostic tools or appropriate detection patterns need to be explored.

[Analysis of schistosomiasis endemic situation in Jiangling County from 2004 to 2013].

OBJECTIVE: To analyze the schistosomiasis endemic situation and understand its transmission trend in Jiangling County from 2004 to 2013, so as to improving the schistosomiasis control. METHODS: The relevant data of schistosomiasis were collected and analyzed statistically in Jiangling county from 2004-2013. RESULTS: The human prevalence of schistosomiasis was decreased from 10.22% in 2004 to 0.63% in 2013 with the descend rate of 93.84%, and the notable descend rate was 76.92% from 2009-2013. The cattle infection rate was decreased yearly from 7.59% in 2004 to 0 in 2013. The appearance rate of frames with living Oncomelania hupensis snails and the infection rate of snails reduce by 17.53% and 100% respectively. CONCLUSIONS: After 10-year control, the endemic situation of schistosomiasis in Jiangling County decreases and is at a low level. However, the risk factors of transmission still exist. Therefore, the comprehensive control measures still should be enhanced continuously.