Community-based surveillance and control of malaria vectors in urban Dar es Salaam, Tanzania

Recent increase in political and funding commitments to malaria control have resulted in rapid scale up of indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) as priority vector control interventions. Despite this increasing coverage and consequent substantial reductions of malaria burden, residual malaria transmission by outdoor-biting mosquitoes in particular, necessitates complimentary vector control strategies such as larval source management. More sensitive and scalable entomological surveillance tools are required to monitor the resultant lower transmission levels that persist across much of the tropics. The Urban Malaria Control Program (UMCP) in Dar es Salaam, Tanzania, implements a large-scale community-based (CB) larviciding programme with the aim of demonstrating operational feasibility of integrating larval control into routine municipal services, while utilizing community-owned resource personnel (CORPs) for its implementation. The goal of this study was to a better understanding of community participation in larval-stage vector surveillance and control, and to develop a practical, safe and affordable prototype for routine programmatic adult mosquito surveillance. Qualitative methods involving administering a set of unstructured interviews to CORPs were used to investigate their performance and demographic characteristics, their perceptions and reasons for participating in the UMCP. Ethnographic and historical resources were used to examine how ‘participation in’ and ‘responsibility for’ larval control is inter-articulated through scientific protocols, development practices, and the specific political history of Tanzania. Cross-sectional surveys were later used to assess the effectiveness of operational, community-based larval habitat surveillance systems within the UMCP by estimating the respective detection coverage and sensitivity levels by CORPs. Additionally, an intensive and extensive CB system for routine, longitudinal, programmatic surveillance of mosquitoes using the Ifakara Tent Trap (ITT) was developed and evaluated in comparison with quality assurance (QA) surveys using either ITT or human landing catches (HLC) and with malaria parasite prevalence from the cross-sectional surveys. Overall, CORPs’ individual detection coverage and sensitivity levels were poor, influenced by his/her unfamiliarity with the area, habitat type, fencing and inclusion within larviciding roll out. These indicators were particularly low among CORPs recruited through programme management staff, compared to those recruited by local government officials or health committees, and among staff living outside their areas of responsibility. The CORPs perceived their role to be professional rather than voluntary, with participation being a de facto form of employment. In spite of all challenges, the central coordination role played by the city council, coupled with catalytic donor funding and technical support from expert research partners, enabled institutionalization of strengthened management and planning and improved community mobilization. Capacity to exploit national and international funding systems was enhanced and a sustainable implementation program was ultimately established with funding from the Ministry of Health and Social Welfare, overseen by the National Malaria Control Programme and implemented by the City and Municipal Councils. Management of this program is currently supported by a spatially extensive and temporally intensive community-based longitudinal adult mosquito vector surveillance system with predictive power for parasite infection risk