A framework for evaluating the costs of malaria elimination interventions: an application to reactive case detection in Southern Province of Zambia, 2014.

BACKGROUND: This paper summarizes a framework for evaluating the costs of malaria elimination interventions and applies this approach to one key component of the elimination strategy-reactive case detection (RCD)-implemented through 173 health facilities across 10 districts in Southern Province of Zambia during 2014. METHODS: The primary unit of analysis is the health facility catchment area (HFCA). A five-step approach was followed to estimate implementation costs: organize preliminary information; estimate basic unit costs; estimate activity unit costs; estimate and organize final unit cost database; and create the final costing database (one row of data per HFCA). By working through a specific application, the overall logic of the analysis and details of each step are presented. An electronic annex also provides all details of the analysis. Because population varies substantially across HFCAs, all results are reported per 1000 population in HFCAs. RESULTS: During 2014, 38.9 households per HFCA were visited for RCD services; 166.8 individuals were tested and 32.3 tested positive and were treated. The mean annual cost per HFCA was $1177 (median = $923, IQR $651-$1417). Variation in costs was driven by the number of CHWs and passive cases detected. CHW-related costs and data review meetings accounted for the largest share of costs. Rapid diagnostic tests and drugs accounted for less than 10 % of total costs. CONCLUSIONS: The framework presented here follows standard methods in applied costing of public health interventions (combining ingredients- and activity-based costing approaches into one final cost analysis). Through an application to a specific programme implemented in Zambia in 2014, the details of how to apply such methods to an actual programme are presented. Such details are not typically presented in existing costing analyses but are required for applied analysts working with national malaria control programmes and other organizations to complete such analyses as part of routine programme implementation. Obtaining data and information for implementing the approach remains complicated, in part because analysts from one organization may not have easy access to information from another organization. This basic approach is transparent and easily applied to other malaria elimination interventions being implemented in sub-Saharan Africa and elsewhere.

Targeting indoor residual spraying for malaria using epidemiological data: a case study of the Zambia experience.

BACKGROUND: In Zambia and other sub-Saharan African countries affected by ongoing malaria transmission, indoor residual spraying (IRS) for malaria prevention has typically been implemented over large areas, e.g., district-wide, and targeted to peri-urban areas. However, there is a recent shift in some countries, including Zambia, towards the adoption of a more strategic and targeted IRS approach, in coordination with increased emphasis on universal coverage of long-lasting insecticidal nets (LLINs) and effective insecticide resistance management. A true targeted approach would deliver IRS to sub-district areas identified as high-risk, with the goal of maximizing the prevention of malaria cases and deaths. RESULTS: Together with the Government of the Republic of Zambia, a new methodology was developed applying geographic information systems and satellite imagery to support a targeted IRS campaign during the 2014 spray season using health management information system data. DISCUSSION/CONCLUSION: This case study focuses on the developed methodology while also highlighting the significant research gaps which must be filled to guide countries on the most effective strategy for IRS targeting in the context of universal LLIN coverage and evolving insecticide resistance.

Open-source satellite enumeration to map households: planning and targeting indoor residual spraying for malaria.

BACKGROUND: Defining the number and location of sprayable structures (houses) is foundational to plan and monitor indoor residual spray (IRS) implementation, a primary intervention used to control the transmission of malaria. Only by mapping the location and type of all sprayable structures can IRS operations be planned, estimates of spray coverage determined, and targeted delivery of IRS to specific locations be achieved. Previously, field-based enumeration has been used to guide IRS campaigns, however, this approach is costly, time-consuming and difficult to scale. As a result, field-based enumeration typically fails to map all structures in a given area, making estimations less reliable and reducing the enumerated coverage. METHODS: Using open source satellite imagery and Geographic Information System software, satellite enumeration was conducted to guide IRS operations in 15 districts (91,302 km(2)) in northern Zambia during the 2014 spray season. Cost of satellite enumeration was compared to standard enumeration. Enumerated households were sampled to estimate sprayable surface area and wall type from the satellite enumeration using linear and logistic regression, respectively. RESULTS: In comparison to the traditional field-based enumeration procedure, satellite-based enumeration was 22 times faster, and 10 times less costly. An estimated 98 % of the satellite enumerated buildings correctly classified roof type. Predicted surface area of each household correlated at a value of 0.91 with measured surface area of each household. CONCLUSION: For IRS campaigns, high quality and high coverage enumeration data aid in planning, through informed insecticide procurement. Through the identification of geographical areas and populations to target, enumeration data guide operations and assist monitoring and evaluation of IRS through the unbiased estimation of coverage achieved. Satellite enumeration represents a quick, cheap and accurate system to provide these data, and has potential applications beyond IRS for delivery of other targeted or non-targeted interventions (e.g. net distributions, mass drug administration, immunization campaigns, or even sampling frames for field studies).

The Impact of Household and Community Indoor Residual Spray Coverage with Fludora Fusion in a High Malaria Transmission Setting in Northern Zambia.

Zambia's National Malaria Elimination Program transitioned to Fludora Fusion in 2019 for annual indoor residual spraying (IRS) in Nchelenge District, an area with holoendemic malaria transmission. Previously, IRS was associated with reductions in parasite prevalence during the rainy season only, presumably because of insufficient residual insecticide longevity. This study assessed the impact of transitioning from Actellic 300CS to long-acting Fludora Fusion using active surveillance data from 2014 through 2021. A difference-in-differences analysis estimated changes in rainy season parasite prevalence associated with living in a sprayed house, comparing insecticides. The change in the 2020 to 2021 dry season parasite prevalence associated with living in a house sprayed with Fludora Fusion was also estimated. Indoor residual spraying with Fludora Fusion was not associated with decreased rainy season parasite prevalence compared with IRS with Actellic 300CS (ratio of prevalence ratios [PRs], 1.09; 95% CI, 0.89-1.33). Moreover, living in a house sprayed with either insecticide was not associated with decreased malaria risk (Actellic 300CS: PR, 0.97; 95% CI, 0.86-1.10; Fludora Fusion: rainy season PR, 1.06; 95% CI, 0.89-1.25; dry season PR, 1.21; 95% CI, 0.99-1.48). In contrast, each 10% increase in community IRS coverage was associated with a 4% to 5% reduction in parasite prevalence (rainy season: PR, 0.95; 95% CI, 0.92-0.97; dry season: PR, 0.96; 95% CI, 0.94-0.99), suggesting a community-level protective effect, and corroborating the importance of high-intervention coverage.

Developing High-Resolution Population and Settlement Data for Impactful Malaria Interventions in Zambia.

Foundational high-resolution geospatial data products for population, settlements, infrastructure, and boundaries may greatly enhance the efficient planning of resource allocation during health sector interventions. To ensure the relevance and sustainability of such products, government partners must be involved from the beginning in their creation, improvement, and/or management, so they can be successfully applied to public health campaigns, such as malaria control and prevention. As an example, Zambia had an ambitious strategy of reaching the entire population with malaria vector control campaigns by late 2020 or early 2021, but they lacked the requisite accurate and up-to-date data on infrastructure and population distribution. To address this gap, the Geo-Referenced Infrastructure and Demographic Data for Development (GRID3) program, Akros, and other partners developed maps and planning templates to aid Zambia's National Malaria Elimination Program (NMEP) in operationalizing its strategy.