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

Malaria Journal

Research

Lindsay R Townes¹  Mark L Wilson¹  Dyson Mwandama²  Don P Mathanga³ 

[1] Department of Epidemiology, School of Public Health, University of Michigan, 48104, Ann Arbor, MI, USA;Malaria Alert Centre, College of Medicine, University of Malawi, Blantyre, Malawi;Malaria Alert Centre, College of Medicine, University of Malawi, Blantyre, Malawi;Department of Community Health, College of Medicine, University of Malawi, Blantyre, Malawi;

关键词: Malaria;    Land Cover;    Rapid Diagnostic Test;    Malaria Risk;    Traditional Authority;   

DOI  :  10.1186/1475-2875-12-407

 received in 2013-07-06, accepted in 2013-11-08,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundUnderstanding 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.MethodsTen 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.ResultsOf 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 (<25-m radius), controlling for the child sex and age (in months), bed net ownership, elevation, and random effects intercepts for village and TA-level unmeasured factors. After controlling for area affects in MLLR, proximity to active agriculture remained a significant predictor of positive RDT result (OR 2.80, 95% CI 1.41-5.55). Mapping of Pearson residuals from MLR showed significant clustering (Gi* z > 2.58, p < 0.01) predominantly within TA Sitola, while residuals from MLLR showed no such clustering.ConclusionThis 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.

【 授权许可】

CC BY   
© Townes et al.; licensee BioMed Central Ltd. 2013