Malaria prevalence and long-lasting insecticidal net use in rural western Uganda: results of a cross-sectional survey conducted in an area of highly variable malaria transmission intensity

Abstract

Background Long-lasting insecticidal nets (LLINs) remain a cornerstone of malaria control, but strategies to sustain universal coverage and high rates of use are not well-defined. A more complete understanding of context-specific factors, including transmission intensity and access to health facilities, may inform sub-district distribution approaches and tailored messaging campaigns. Methods A cross-sectional survey of 2190 households was conducted in a single sub-county of western Uganda that experiences highly variable malaria transmission intensity. The survey was carried out approximately 3 years after the most recent mass distribution campaign. At each household, study staff documented reported LLIN use and source among children 2 to 10 years of age and performed a malaria rapid diagnostic test. Elevation and distance to the nearest health facility was estimated for each household. Associations between parasite prevalence and LLIN use were estimated from log binomial regression models with elevation and distance to clinic being the primary variables of interest. Results Overall, 6.8% (148 of 2170) of children age 2–10 years of age had a positive RDT result, yielding a weighted estimate of 5.8% (95% confidence interval [CI] 5.4–6.2%). There was substantial variability in the positivity rates among villages, with the highest elevation villages having lower prevalence than lowest-elevation villages (p < .001). Only 64.7% (95% CI 64.0–65.5%) of children were reported to have slept under a LLIN the previous night. Compared to those living < 1 km from a health centre, households at ≥ 2 km were less likely to report the child sleeping under a LLIN (RR 0.86, 95% CI 0.83–0.89, p < .001). Households located farther from a health centre received a higher proportion of LLINs from government distributions compared to households living closer to health centres. Conclusions LLIN use and sourcing was correlated with household elevation and estimated distance to the nearest health facility. The findings suggest that current facility-based distribution strategies are limited in their reach. More frequent mass distribution campaigns and complementary approaches are likely required to maintain universal LLIN coverage and high rates of use among children in rural Uganda.

Private sector antimalarial sales a decade after “test and treat”: A cross-sectional study of drug shop clients in rural Uganda

“…The tropical climate allows for year-round malaria transmission interspersed with semi-annual peaks after the rainy seasons ( 33 ). Malaria prevalence from the most recent Malaria Indicator Survey in the mid-western region of Uganda, which encompasses Bugoye, was estimated at 18% among children under 5 years of age ( 34 ), although more recent studies in the sub-county demonstrate substantial geographic heterogeneity ( 35 ).…”

Comparing field-collected versus remotely-sensed variables to model malaria risk in the highlands of western Uganda

“…However, it has also been suggested that sufficient biting still occurs late at night within households with LLINs for transmission to occur [ 4 , 5 ]. The high prevalence of LLIN during this study was almost certainly the result of a national LLIN mass distribution campaign in 2020–21 [ 40 ] and was significantly higher than observed in the region in January-March 2020, when coverage was found to be 64.7% [ 17 ]. In addition, utilization of protective measures within the household (e.g., LLIN and installation of screening) may reflect both actual risk and the perceived risk of the homeowner.…”

“…The area is characterized by its varied geography, with deep river valleys and steep hillsides reaching elevations reaching 2500 m. The climate in western Uganda permits year-round malaria transmission with semi-annual peaks after the rainy seasons in May and November [ 14 , 15 ] driven by a mixture of Anopheles gambia e, Anopheles arabiensis , and Anopheles funestus , among others [ 16 ]. The most recent MIS in the Tooro subnational region (2018–2019), which includes the sub-county, reported a PfPR of 7.3% although rates of 30% are reported in low-lying villages located along the river basins [ 11 , 17 ].…”

“…The three participating villages were purposefully selected to achieve diversity in geography and malaria transmission intensity as determined by a previous survey of all 35 villages [ 17 ]. One village, Rwakingi 1A (PfPR 2-10 18.6%) was chosen because of its generally flat, flood-prone terrain adjacent to the Mubuku River.…”

Permethrin-treated baby wraps for the prevention of malaria in children: Protocol for a double-blind, randomized placebo-controlled controlled trial in western Uganda

“…falciparum parasitemia rates (PfPR) of 17.4% and 7.3%, respectively [ 39 , 40 ]. However, in a recent cross-sectional survey of more than 2,100 households in the Bugoye Sub-County, we found that the PfPR among children 2 to 8 years of age was upwards of 30% in many of the low-elevation villages [ 41 ]. We will recruit and enroll participants from these high transmission villages located along the river basins.…”