Historically, most vector control efforts for malaria prevention in Africa have focused almost exclusively on adult stages, specifically indoor residual spraying (IRS) [1, 2] and insecticide-treated nets (ITN) [3–5]. However, with increasing insecticide resistance  and behavioural avoidance by mosquito vectors , development and evaluation of complementary vector control strategies remains a priority. Reviews of the early 20th century programmes in Brazil, Zambia and Egypt [8–10], have highlighted dramatic reductions of malaria burden achieved by integrated vector management generally and mosquito larval control specifically [11–14]. Application of microbial larvicides, such as Bacillus thuringensis var. israelensis (Bti), to larval habitats offers a control option that cannot be avoided by mosquitoes [15, 16] and that has low probability of developing resistance due to the complex mode of action of the larvicide [17, 18]. Furthermore, recent successes in urban Tanzania , the highland of western Kenya  and in Eritrea , suggest that larval control may be a valid option for malaria vector control in selected eco-epidemiological settings.
Rapid growth of cities, characterized by a distinctive mix of different social, economic and cultural conditions is an important feature of contemporary African countries [22–25]. High population density associated with relatively few breeding sites suggests that area-wide application of vector control strategies is more practical and affordable in urban areas [26, 27]. Moreover, stronger institutional support, governance and infrastructure offer significant advantages for establishing and sustaining vector control programmes in urban areas. However, the heterogeneity and mobility of the human population renders most urban communities less cohesive and therefore difficult to mobilize en masse to achieve impact of public health interventions. Malaria vector proliferation, transmission intensity and burden in urban areas is highly heterogeneous and focal, [23, 26, 28–30]. Despite its growing importance, it is only recently that urban malaria is receiving the attention it deserves [23, 25, 26].
Cities and large towns are regarded as some of the most favourable environments for sustainable mosquito larval control, because mosquito-breeding sites are defined and easily located. However, larval control requires quite specific ecological understanding of the major vector species and their distinctive interaction with the local environment on very fine spatial scales [11, 31, 32]. Additionally, technical understanding of the principles and practice of larvicide application or environmental management, as well as intensive labour under challenging field conditions, are essential [11, 31–33]. Sustainable systems for monitoring the abundance and distribution of aquatic mosquito stages are required to enable effective decisions and actions by managers responsible for such programmes. This represents a particular challenge in Africa where the primary vector, Anopheles gambiae, can develop from egg to adult in less than a week in habitats, which can be ephemeral and difficult to detect [34–36].
Larval control for malaria prevention, delivered primarily through human resources mobilized from within local communities, has been recommended to minimize cost and maximize sustainable scalability [31–33, 37]. However, given the technical, logistic and coverage requirements of larval control, which are probably greater than for current priority measures, such as insecticide-treated nets or indoor residual spraying, community-led rather than merely community-based vector control may be difficult to achieve [31, 35, 37]. A more sustainable approach might be the blending of vertical and horizontal strategies for the implementation of community-based systems for delivering area-wide control measures. Such an approach might rely on extensive mobilization of community-based labour integrated into vertical management systems implemented by centralized institutions [31, 35, 37]. It is important to identify and understand the social and environmental factors that influence human behaviour and consequently the effectiveness of such programs.
The Urban Malaria Control Programme (UMCP) in Dar es Salaam has been initiated by the Dar es Salaam City Council as a pilot programme to develop sustainable and affordable systems for larval control as part of routine municipal services [19, 32, 35, 37–39]. An in-depth look at the environmental and programmatic determinants of surveillance coverage in this urban environment was conducted to identify strengths, weaknesses and opportunities for improvement.