Urban/rural differences in prevalence and risk factors for intestinal helminth infection in southern Malawi

Urbanization may increase the risk of human infection with intestinal helmi nths. A cross-sectional survey was conducted to investigate the prevalence, intensity and potential risk factors of acquiring such infection, among ch ildren aged 3-14 years in similar urban and rural communities in southern M alawi. Stool samples were collected from 553 children (273 urban and 280 ru ral). The overall prevalence of helminth infection was significantly higher in the urban subjects than in the rural (16.5% v. 3.6%; P < 0.001), mostly because of differences in the prevalence of Ascaris lumbricoides infection . Living in an urban community was associated with a significantly higher r isk of infection [odds ratio (OR) = 5.3; 95% confidence interval (CI) = 2.6 -12.1], even after controlling for potential confounding factors. In the ur ban community, risk factors included having pools of water/sewage around ho uses (OR = 3.0; CI = 1.4-6.5), not wearing shoes (OR = 7.1; CI = 2.7-19.2), not attending school (OR = 2.8; CI = 1.2-6.5), having mothers with 4-8 yea rs of education (OR = 5.2; CI = 2.0-14.0), and having mothers below 35 year s of age (OR = 4.09; CI = 1.39-16.28). In this part of Africa, efforts to r educe helminth infections may best be focused on reducing geohelminth burde n in urban areas.