Epidemiology of diarrhoeal disease in rural Malawi - a case study of cryptosporidiosis

A rural community based case control study was conducted in Malawi, over a 23 month period, to identify determinants influencing human cryptosporidiosis in under fives. 96 home interviews were conducted in 24 communities (cases n=24; unmatched controls n=72). 61 risk factors were investigated by questionnaire, combined with quantitative data from drinking water and domesticated animal stool samples. Cryptosporidium oocysts were not detected in either sample type. Multivariate logistic regression of questionnaire data revealed an increased risk of cryptosporidiosis associated with ownership of pigs (OR7.2, 95%CI 1.9–27.5, p=0.004), presence of diarrhoea in the household (OR8.8, 95%CI 1.8–53.4, p=0.008), bathing in the river (OR76.7, 95%CI 1.1–23.8, p=0.037) and no education within the household (OR3.6, 95%CI 1.1–11.8, p=0.038). Bacteriological results indicating faecal contamination of both drinking water stored within the home, and the surface of guardians’ hands were indicative of poor hygienic practices and potential sources of infection.