title: Community-based monitoring of vector control interventions impact upon mosquito population dynamics in rural Zambia
Creators: name: Sikaala, Chadwick
Publisher: name: University of Liverpool Repository
Year: 2015

description: Over the last decade, the malaria burden has reduced drastically across many parts of sub-Saharan Africa. This is mainly due to effective implementation of integrated malaria control programmes that include large scale application of vector control in the form of long-lasting insecticidal nest (LLINs) and indoor residual spraying (IRS), both of which target the most efficient human-seeking malaria vector species. However, in spite of these efforts, malaria has yet to be eliminated from most of Africa. However, recent increases in the physiological resistance of vector populations, especially to the pyrethroids that remain the only active ingredients currently used on nets threaten these achievements. Furthermore, various forms of behavioural resilience and resistance exhibited by some vector species to LLIN and IRS delivery formats for insecticides respectively limit and undermine these valuable impacts upon malaria transmission. To monitor the impact that LLINs and IRS have on vector population dynamics and malaria transmission, more effective, practical and affordable entomological surveillance systems are required. Currently, surveillance of mosquito populations are conducted by the centralized specialist teams with limited personnel, resources and geographic outreach. None of these existing systems can adequately monitor vector population dynamics longitudinally across the vastness of entire countries. The overall goal of the study was to demonstrate how a community-based surveillance system can be applied to longitudinally monitor vector population dynamics and assess the impact that LLINs and IRS have on malaria transmission in rural Zambia. To achieve this overall goal, the following specific objectives were addressed: (1) To evaluate the efficacy of exposure-free mosquito trapping methods for measuring malaria vector density, as alternatives to human landing catch; (2) To assess the cost-effectiveness using a community-based (CB) mosquito trapping scheme for monitoring vector population dynamics; (3) To determine the extent to which a community-based mosquito trapping scheme captures trends in epidemiological indicators of malaria infection risk; (4) To determine the impact of indoor residual spraying with different classes of insecticides on malaria infection burden and vector abundances in an area of high coverage with insecticide treated nets using a community-based platform. To address objective 1, a 3 x 3 Latin square method was used to evaluate the sensitivity of the Center for Disease and Control and Prevention miniature light traps (LT), the Ifakara tent trap (ITT), window exit traps (WET) and the resting boxes (RB) using the golden standard human land catch (HLC) as the reference method. The mean catches of HLC indoor, HLC outdoor, CDC-LT, ITT, WET, RB indoor and RB outdoor, were 1.687, 1.004, 3.267, 0.088, 0.004, 0.000 and 0.008 for Anopheles quadriannulatus Theobald respectively, and 7.287, 6.784, 10.958, 5.875, 0.296, 0.158 and 0.458, for An. funestus Giles, respectively. The LT (Relative rate (RR) [95% Confidence Interval] = 1.532 [1.441, 1.628] P