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WHO promotes the implementation of a comprehensive strategy to control and eliminate schistosomiasis through preventive chemotherapy, snail control, clean water supply, improved sanitation, behaviour change interventions, and environmental management. The transmission of schistosomiasis involves infected definitive hosts (humans or animals) excreting eggs that hatch (miracidia), which infect freshwater snail vectors (also referred to as intermediate snail hosts) living in marshlands, ponds, lakes, rivers, or irrigation canals. Infective larvae (cercariae) develop within the snail, which, when released, may infect humans and/or animals in contact with the water. Snail control aims to interrupt the transmission cycle of the disease by removing the vector snails and, by so doing, indirectly improves the impact of the preventive chemotherapy by reducing reinfection. Snail control was, for many years, the only strategy for the prevention of schistosomiasis before preventive chemotherapy became the primary intervention. Snails can be controlled through various methods: environmental control, biological control, and chemical control. The chemical control of snails has proven to be the most effective method to interrupt the transmission of schistosomiasis. The current review aims to describe the vector snails of human schistosomiasis, present the chemicals and strategies for the control of snails, the challenges with the implementation, and the future needs. Snail control can play a key role in reducing schistosomiasis transmission and, thus, complements other interventions for disease control. There is a need to develop new molluscicide products or new formulations and methods of applications for existing molluscicides that would target snail vectors more specifically.

Abstract Background Through a nationally representative household survey in Afghanistan, we conducted an operational study in two relatively secure provinces comparing effectiveness of computer-aided personal interviewing (CAPI) with paper-and-pencil interviewing (PAPI). Methods In Panjshir and Parwan provinces, household survey data were collected using paper questionnaires in 15 clusters, and OpenDataKit (ODK) software on electronic tablets in 15 other clusters. Added value was evaluated from three perspectives: efficient implementation, data quality, and acceptability. Efficiency was measured through financial expenditures and time stamped data. Data quality was measured by examining completeness. Acceptability was studied through focus group discussions with survey staff. Results Survey costs were 68% more expensive in CAPI clusters compared to PAPI clusters, due primarily to the upfront one-time investment for survey programming. Enumerators spent significantly less time administering surveys in CAPI cluster households (248 min survey time) compared to PAPI (289 min), for an average savings of 41 min per household (95% CI 25–55). CAPI offered a savings of 87 days for data management over PAPI. Among 49 tracer variables (meaning responses were required from all respondents), small differences were observed between PAPI and CAPI. 2.2% of the cleaned dataset’s tracer data points were missing in CAPI surveys (1216/ 56,073 data points), compared to 3.2% in PAPI surveys (1953/ 60,675 data points). In pre-cleaned datasets, 3.9% of tracer data points were missing in CAPI surveys (2151/ 55,092 data points) compared to 3.2% in PAPI surveys (1924/ 60,113 data points). Enumerators from Panjsher and Parwan preferred CAPI over PAPI due to time savings, user-friendliness, improved data security, and less conspicuity when traveling; however approximately half of enumerators trained from all 34 provinces reported feeling unsafe due to Taliban presence. Community and household respondent skepticism could be resolved by enumerator reassurance. Enumerators shared that in the future, they prefer collecting data using CAPI when possible. Conclusions CAPI offers clear gains in efficiency over PAPI for data collection and management time, although costs are relatively comparable even without the programming investment. However, serious field staff concerns around Taliban threats and general insecurity mean that CAPI should only be conducted in relatively secure areas.