Elevated dry-season malaria prevalence associated with fine-scale spatial patterns of environmental risk: a case–control study of children in rural Malawi

Abstract Background Understanding the role of local environmental risk factors for malaria in holo-endemic, poverty-stricken settings will be critical to more effectively implement- interventions aimed at eventual elimination. Household-level environmental drivers of malaria risk during the dry season were investigated in rural southern Malawi among children < five years old in two neighbouring rural Traditional Authority (TA) regions dominated by small-scale agriculture. Methods Ten villages were randomly selected from TA Sitola (n = 6) and Nsamala (n = 4). Within each village, during June to August 2011, a census was conducted of all households with children under-five and recorded their locations with a geographic position system (GPS) device. At each participating house, a nurse administered a malaria rapid diagnostic test (RDT) to children under five years of age, and a questionnaire to parents. Environmental data were collected for each house, including land cover within 50-m radius. Variables found to be significantly associated with P. falciparum infection status in bivariate analysis were included in generalized linear models, including multivariate logistic regression (MLR) and multi-level multivariate logistic regression (MLLR). Spatial clustering of RDT status, environmental factors, and Pearson residuals from MLR and MLLR were analysed using the Getis-Ord Gi* statistic. Results Of 390 children enrolled from six villages in Sitola (n = 162) and four villages in Nsamala (n = 228), 45.6% tested positive (n = 178) for Plasmodium infection by RDT. The MLLR modelled the statistical relationship of Plasmodium positives and household proximity to agriculture ( 2.58, p < 0.01) predominantly within TA Sitola, while residuals from MLLR showed no such clustering. Conclusion This study provides evidence for significant, dry-season heterogeneity of malaria prevalence strongly linked to peridomestic land use, and particularly of elevated risk associated with nearby crop production.http://deepblue.lib.umich.edu/bitstream/2027.42/112703/1/12936_2013_Article_3017.pd

Clinical outcomes among febrile children aged 2 to 59 months with negative malaria rapid diagnostic test results in Mchinji District, Malawi

BackgroundMalawi malaria treatment guidelines recommend a definitive diagnosis, using a malaria rapid diagnostic test (mRDT), for all patients with fever or history of fever. Improving the management and outcomes of febrile children with negative mRDT results should be a priority.MethodsThrough a prospective cohort study designed to investigate clinical outcomes of children treated at the community level, we followed, for 7 days, children aged 2 to 59 months, who had negative mRDT results and were treated with antipyretic medication. Clinical outcomes were assessed on days 3 and 7 post-recruitment.ResultsThe median age of recruited children was 19 months. Of the 285 children enrolled, 139 (48.8%) were females. Of the children for whom data were available for analysis, 95/236 (40.3%) had fever (temperature ≥ 37.5°C) at enrolment, and almost half of the sick children (125/268; 46.6%) had symptoms of upper respiratory tract infection. Most sick children (89.6%; 95% confidence interval, CI = 84.2 to 93.3) recovered, while 10.4% (95% CI: 6.7 to 15.8) were still sick by day 7 of follow-up. There were no deaths reported during the 7 days of follow-up. Being afebrile at enrolment (odds ratio, OR = 2.5; 95% CI = 1.1 to 6.0; P = 0.027) and sleeping under an insecticide-treated net (ITN) (OR = 2.7; 95% CI = 1.2 to 6.2; P = 0.011) were associated with recovery by day 7. In multivariable analysis, sleeping under an ITN the previous night was the only factor associated with recovery by day 7. Microscopy did not detect any malaria parasites in the blood of recruited children, at recruitment or on day 7.ConclusionsIn this community-level study, the majority of febrile children with negative mRDT results recovered within 7 days of health worker consultation for a febrile illness, having only taken antipyretics

Impact of health facility-based insecticide treated bednet distribution in Malawi: progress and challenges towards achieving universal coverage.

High levels of insecticide treated bednet (ITN) use reduce malaria burden in countries with intense transmission such as Malawi. Since 2007 Malawi has implemented free health facility-based ITN distribution for pregnant women and children <5 years old (under-5s). We evaluated the progress of this targeted approach toward achieving universal ITN coverage.We conducted a cross-sectional household survey in eight districts in April 2009. We assessed household ITN possession, ITN use by all household members, and P. falciparum asexual parasitemia and anemia (hemoglobin <11 grams/deciliter) in under-5s.We surveyed 7,407 households containing 29,806 persons. Fifty-nine percent of all households (95% confidence interval [95% CI]: 56-62), 67% (95% CI: 64-70) of eligible households (i.e., households with pregnant women or under-5s), and 40% (95% CI: 36-45) of ineligible households owned an ITN. In households with at least one ITN, 76% (95% CI: 74-78) of all household members, 88% (95% CI: 87-90) of under-5s and 90% (95% CI: 85-94) of pregnant women used an ITN the previous night. Of 6,677 ITNs, 92% (95% CI: 90-94) were used the previous night with a mean of 2.4 persons sleeping under each ITN. In multivariable models adjusting for district, socioeconomic status and indoor residual spraying use, ITN use by under-5s was associated with a significant reduction in asexual parasitemia (adjusted odds ratio (aOR) 0.79; 95% CI: 0.64-0.98; p-value 0.03) and anemia (aOR 0.79; 95% CI 0.62-0.99; p-value 0.04). Of potential targeted and non-targeted mass distribution strategies, a campaign distributing 1 ITN per household might increase coverage to 2.1 household members per ITN, and thus achieve near universal coverage often defined as 2 household members per ITN.Malawi has substantially increased ITN coverage using health facility-based distribution targeting pregnant women and under-5s, but needs to supplement these activities with non-targeted mass distribution campaigns to achieve universal coverage and maximum public health impact

MOESM1 of The effect of holes in long-lasting insecticidal nets on malaria in Malawi: results from a case–control study

Additional file 1: Table S1. Sensitivity analysis: Association between malaria and total hole area quartiles

MOESM3 of Assessing bed net damage: comparisons of three measurement methods for estimating the size, shape, and distribution of holes on bed nets

Additional file 3: Figure S2. Circularity of holes measured using image analysis

Household characteristics in eight districts, Malawi, 2009 (N = 7,407).

a<p>Data from 2008 Malawi census.</p>b<p>95% confidence interval.</p

Insecticide treated bednet (ITN) use by persons who reside in any household and in a household that owns an ITN in eight districts, Malawi, 2009 (N = 29,806).

a<p>95% confidence interval.</p