Is Mass Treatment the Appropriate Schistosomiasis Elimination strategy?/Le Traitement De Masse Est-Il Une Strategie Appropriee Pour L'elimination De la schistosomiase?/?Es El Tratamiento Masivo la Estrategia Apropiada Para Eliminar la Esquistosomiasis?

Introduction Schistosomiasis remains a major public health problem in the Philippines. Some 6.7 million people distributed in 1212 villages (barangays), predominantly in the islands of Leyte, Samar and areas of Luzon and Mindanao, are at risk of the disease. (1) In 2000, the Philippines' Department of Health adopted mass treatment as its schistosomiasis control strategy with the aim of disease elimination. (2) Mass chemotherapy with praziquantel has proven cost-effective in high-prevalence areas such as China. (3) The rationale and strategies for global schistosomiasis mass treatment were recently reviewed by the Schistosomiasis Control Initiative. (4) In the Philippines, mass treatment is offered to all residents [greater than or equal to] 5 years of age, in barangays with prevalence [greater than or equal to] 15%, without the need for stool examination. Even though annual mass treatment is recommended, its frequency depends largely on the availability of praziquantel nationwide. When the drug stock is insufficient, priority is given to highly endemic areas. This study is a secondary analysis of data collected as part of a research project entitled Schistosomiasis Transmission Ecology in the Philippines (STEP) which aimed to develop a dynamic model of the influence of anthropogenic changes due to rice farming on the transmission of Schistosoma japonicum parasitic worms. Results of the baseline part of this project have been published elsewhere. (5,6) The design of STEP included the mass treatment of all residents of the 50 participating barangays to compare the l-year risk of reinfection in irrigated and rain-fed barangays. Our intent was to treat all barangay residents including those who were not STEP participants. STEP participants were involved in intensive data collection activities. The conduct of the mass treatment was expected to be relatively uncomplicated, but coverage was much less than expected. Thus, here we describe in detail the mass-treatment activities and conduct secondary analyses to explore correlates of participation and coverage in 50 barangays in Western Samar province, the Philippines. Methods Study population Prior to 2004, no schistosomiasis mass treatment had been offered in Western Samar. Health services in the Philippines are delivered through a hierarchy of health centres. The 50 study barangays did not have any main health centres but there were 12 barangay health stations (BHS) and 145 barangay health workers (BHWs). Neither stool examination for schistosomiasis nor its treatment are offered in BHS. Patients suspected of being infected are referred to the Schistosomiasis Control Unit (SCU) offices in the capital Catbalogan. Hence, before the mass treatment described here, only a very small proportion of the Western Samar population had ever been treated for schistosomiasis. Based on information from STEP, less than 1% of participants had been treated with praziquantel in the previous 12 months (data not shown). All residents were offered praziquantel treatment. Selected residents from each barangay had participated in the STEP cohort study. The STEP project had a defined sample of 5995 individuals [greater than or equal to] 5 years who consented to participate in the research. (5,6) Detailed descriptions of research design, sample selection and baseline epidemiological findings appear elsewhere. (5-7) The study design involved a follow-up assessment of human and animal infection 1 year after mass treatment of all willing residents, not just the STEP study participants. Mass treatment advocacy and mobilization activities Before the mass treatment, the STEP research team conducted six focus group discussion sessions among farmers, women and teachers of six barangays from different municipalities and with SCU team members. The focus groups were used to obtain community perceptions and beliefs about the cause, transmission, signs and symptoms, diagnosis, perceptions of severity and treatment of schistosomiasis. …