Evaluating the efficacy, impact, and feasibility of community-based house screening as a complementary malaria control intervention in southern Africa: a study protocol for a household randomized trial

Abstract

Background Concerted effort to control malaria has had a substantial impact on the transmission of the disease in the past two decades. In areas where reduced malaria transmission is being sustained through insecticide-based vector control interventions, primarily long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), non-insecticidal complementary tools will likely be needed to push towards malaria elimination. Once interruption in local disease transmission is achieved, insecticide-based measures can be scaled down gradually and eventually phased out, saving on costs of sustaining control programs and mitigating any unintended negative health and environmental impacts posed by insecticides. These non-insecticidal methods could eventually replace insecticidal methods of vector control. House screening, a non-insecticidal method, has a long history in malaria control, but is still not widely adopted in sub-Saharan Africa. This study aims to add to the evidence base for this intervention in low transmission settings by assessing the efficacy, impact, and feasibility of house screening in areas where LLINs are conventionally used for malaria control. Methods A two-armed, household randomized clinical trial will be conducted in Mozambique, Zambia, and Zimbabwe to evaluate whether combined the use of house screens and LLINs affords better protection against clinical malaria in children between 6 months and 13 years compared to the sole use of LLINs. Eight hundred households will be enrolled in each study area, where 400 households will be randomly assigned the intervention, house screening, and LLINs while the control households will be provided with LLINs only. Clinical malaria incidence will be estimated by actively following up one child from each household for 6 months over the malaria transmission season. Cross-sectional parasite prevalence will be estimated by testing all participating children for malaria parasites at the beginning and end of each transmission season using rapid diagnostic tests. CDC light traps and pyrethrum spray catches (PSC) will be used to sample adult mosquitoes and evaluate the impact of house screening on indoor mosquito density, species distribution, and sporozoite rates. Discussion This study will contribute epidemiological data on the impact of house screening on malaria transmission and assess the feasibility of its implementation on a programmatic scale. Trial registration ClinicalTrials.gov PACTR202008524310568. Registered on August 11, 2020.

House Screening Reduces Exposure to Indoor Host-Seeking and Biting Malaria Vectors: Evidence from Rural South-East Zambia

“…This study had several limitations. First, due to logistical challenges and resource limitations, the initial number of households targeted in the original study protocol [ 24 ] was not achieved. We experienced a large loss of CDC-LT batteries in the year before collections took place after the screens were installed.…”

“…Two neighboring health facility catchment areas were selected for this study: Mkopeka and Nyimba Urban. The study area has been described in detail as part of an entomological baseline study [ 22 ] and elsewhere [ 23 , 24 ].…”

“…This study was a cluster randomized controlled trial using a generalized randomized block design, with the village as the block. This study was part of a larger community-based house screening trial, and the protocol has been reported previously [ 24 ]. A total of 89 villages were included in the main study [ 23 ].…”

Optimizing Routine Malaria Surveillance Data in Urban Environments: A Case Study in Maputo City, Mozambique

“…Maputo City, the capital of Mozambique, is located in the southern area of the country on the west side of Maputo Bay, with a climate alternating between a cool, dry season extending from approximately April through October and a hot rainy season from November through March each year. 13 Malaria burden in Maputo City is low, with Plasmodium falciparum being the predominant species and an estimated prevalence in children aged 2 to 10 years of 5.2% (PfPR 2-10 ) in 2019. 14 Because Maputo City and Maputo Province have very low transmission, this urban region has been excluded from the mass distribution of long-lasting insecticide-treated bed nets (LLINs) in the eight of the 10 provinces with endemic malaria.…”

Community perceptions, acceptability, and the durability of house screening interventions against exposure to malaria vectors in Nyimba district, Zambia

“…This study was part of a larger randomized controlled study evaluating the effectiveness and impact of community-based house screening as a complementary malaria vector-control tool, conducted in rural south-east Zambia [ 27 , 28 ]. As part of that trial, the intervention group consisted of 400 households provided with LLINs and fine wire mesh screens to stop mosquito entry.…”