Onchocerciasis elimination mapping in Malawi: mapping of vector <i>Simulium</i> breeding sites using an integrated approach of community knowledge and topographical maps

Abstract

BACKGROUND: Large areas in Malawi have not been treated for onchocerciasis. To understand whether to provide treatment in these areas of unknown onchocerciasis endemicity, the Malawi Onchocerciasis Control Program conducted identification and mapping of breeding sites as a prerequisite for onchocerciasis elimination mapping (OEM). METHODS: The team employed a community knowledge approach using questionnaires and discussions, alongside the standard method of using topographical maps, to plan and implement river prospections for Simulium vector breeding sites. RESULTS: A total of 188 sites were prospected from 180 rivers, with 122 sites (67.8%) identified from community information and 58 (32.2%) from topographic maps. Of the 188 sites visited, 30 were positive for Simulium damnosum larvae/pupae and 91 were considered potential breeding sites and need to be visited in a different season for confirmation. A breeding site map for OEM areas was developed. Prospection using this approach lasted for 24 days (approximately eight rivers/day) compared with a previous prospection with the same team that used 12 days to prospect 25 rivers (approximately two rivers/day). CONCLUSION: This demonstrates the potential of using the health system structure and community knowledge for breeding site surveys, shortening the prospection time while effectively identifying fast-flowing rivers and breeding sites.