School WASH intervention — DTM&H MCQ

Correct answer: D — Integrated WASH improvements with hygiene education

C, integrated WASH improvements with hygiene education, is correct because the stem describes environmental drivers of transmission: open defecation, contaminated water and absent handwashing facilities, all of which sustain faecal-oral spread of diarrhoeal pathogens and soil-transmitted helminths. WHO guidance on soil-transmitted helminth control states that provision of adequate water, sanitation and hygiene services is fundamental to break the cycle of infection and reinfection and sustainably control these infections, with collaboration between deworming programmes and WASH programmes considered essential. Fixing the sanitation infrastructure and teaching hygiene behaviour interrupts the transmission pathway at its source rather than only treating existing cases, which is what makes it the single most important measure in this scenario. Chemotherapy and other clinical interventions have a role but cannot substitute for correcting the underlying environmental exposure. Why the other options are wrong: A. Single antibiotic course for pupils each term: treats bacterial diarrhoea retrospectively and has no effect on helminths or on the contaminated water and open defecation that drive reinfection; repeated unnecessary antibiotic use also risks resistance. E. Annual chest radiographs for pupils: screens for pulmonary disease such as TB, which is irrelevant to the diarrhoeal and helminth problem described and does nothing to address transmission. B. Indoor residual spraying of classrooms: this is a vector control measure for insect-borne disease such as malaria, not relevant to faecal-oral transmission of diarrhoea and helminths. C. Routine antimalarial treatment for teachers: addresses malaria, an unrelated disease process, and does not touch the sanitation and water contamination issues causing this outbreak pattern. Key point: When outbreaks are driven by open defecation, unsafe water and absent handwashing, the priority public health action is structural WASH improvement with hygiene education, not downstream drug treatment or unrelated interventions.

Reference: World Health Organization, Guideline: Preventive Chemotherapy to Control Soil-Transmitted Helminth Infections in At-Risk Population Groups, 2017 (executive summary), https://www.ncbi.nlm.nih.gov/books/n/who258983/executivesummary/