Investigating the effect of a multi-component intervention program on the burden of intestinal worms and liver fluke in the Lower Mekong Basin

Our intervention will include the following components: 1. Chemotherapy: chemotherapy will be administered for soil-transmitted helminths (STH) and opisthorchis viverrini (OV) to animals (cats and dogs) and humans. Praziquantel (40mg/kg oral tablet single dose) will be administered to treat OV, and Albendazole 400mg (oral tablet single dose) will be administered to treat STH infections in humans. Animals will receive praziquantel 40mg/kg to treat OV and pyrantel 10mg/kg to treat STH infections. These medications will be delivered on the spot by health workers. Those who refuse the drug treatment will be recorded. Cats and dogs in intervention villages will be treated with pyrantel and praziquantel at baseline (after stool samples are collected), and 6 months after baseline. Cats and dogs in control villages will be treated after the completion of the study (i.e. 12 months after baseline). 2. School health promotion: the school health promotion will consist of the "Magic Glasses", an educational cartoon that has successfully improved water, sanitation and hygiene (WASH) practices in previous studies. The Magic Glasses cartoon will be adapted to the Lower Mekong Basin (LMB) following Knowledge, Attitudes and Practices (KAP) surveys with local schoolchildren in the region and/or a literature review of KAP and risk factors associated with OV and STH in the LMB region. Magic Glasses will include information on the transmission of OV and STH, and prevention strategies. 3. Community intervention: the community intervention will largely be based around the distribution of information regarding transmission dynamics, risk factors and prevention methods for STH and OV in community. The main format for this health education will be participatory community meetings led by research team members, and local ‘village health volunteers’ (VHVs). These community meetings will incorporate interactive discussions around STH and OV between research staff, VHVs and community. As well as these community meetings, brochures will be distributed to all village households addressing STH, OV. These brochures will be distributed by the VHVs who also communicate more information to householders at the same time. VHVs are the key health promotion actors at the village level. In our intervention villages these volunteers will be provided with a one-day training program addressing STH and liver fluke transmission and prevention of infection. They will also gain skills communicating this information to the community. 4. Active surveillance: active surveillance of fish, human, cat, and dog stool samples. We will use the modified formalin-ether concentration technique (mFECT) for human and animal stool examination, which our experienced teams have applied extensively for the assessment of OV and STH infection rates and intensities. Human stool samples (one sample per person) will be collected at baseline, prior to chemotherapy being administered. Follow-up stool samples will be collected one-year after the baseline collection (approximately 12 months after chemotherapy). Stool samples will be collected from cats and dogs at baseline, 6 months (Cambodia only), and 12 months. Stool samples will be analysed using mFECT. Quality control will be carried out by independent microscopists on 20% of slides mFECT. Fish collected in rivers, ponds/lakes and dams in proximity to study sites will be identified, counted, weighed, and digested using pepsin-HCl, and then examined for OV by a compression/sedimentation method, and metacercariae identified under a stereomicroscope.