Iron supplementation increases small intestine permeability in primary schoolchildren in Lusaka, Zambia.

Elevated intestinal permeability, measured as an increased lactulose:mannitol (L:M) ratio, indicates injury of the small intestinal mucosa. As part of a randomized iron and multi-micronutrient (without iron) supplementation trial (Nchito et al., 2004), we determined intestinal permeability in a subgroup of schoolchildren at 10 months' follow-up to assess the effect of the interventions. Among 153 children (mean age 10.2 years and 53.6% girls) iron supplementation resulted in a higher L:M ratio compared with placebo (0.29 vs. 0.21, P=0.025). There was no effect of multi-micronutrient supplementation, and no interaction between the interventions. The finding could be one of the mechanisms explaining the negative effects of medicinal iron supplementation on morbidity found in some other studies.

Cryptosporidiosis in urban Zambian children: an analysis of risk factors.

In four crowded townships of Lusaka, Zambia, the prevalence of cryptosporidiosis in 222 children with diarrhea was 18%, with marked temporal and geographic variation over the course of one rainy season. Using data on the finding of oocysts of Cryptosporidium parvum in urban water supplies, the areas under study were categorized as high or low risk. Prevalence of cryptosporidiosis in children with diarrhea was higher in high risk areas after stratification by early/late stage of the rains (Mantel-Haenszel odds ratio [OR] = 2.9, 95% confidence interval [CI] = 1.3, 6.7; P = 0.008). Cryptosporidiosis was not associated with keeping animals, nutritional status, or parental education, but was apparently more common in breast fed children (OR = 2.7, 95% CI = 1.1, 6.9; P = 0.01), although the proportion of exclusively breast fed children was not measured. Since most of these infections were of short duration, we conclude that transmission of C. parvum can vary dynamically within one city and over short periods of time, and that water-borne contamination may be a substantial influence.

Cryptosporidiosis in adults in Lusaka, Zambia, and its relationship to oocyst contamination of drinking water.

In Lusaka, where human immunodeficiency virus seroprevalence in young adults is approximately 25%, four townships were studied to establish the prevalence of persistent diarrhea in adults and the etiologic importance of cryptosporidiosis in adults with persistent diarrhea. Cryptosporidium parvum oocyst contamination of urban water supplies was measured and the results used to categorize these populations into high or low exposure. In total, 506 adults were reported as having had diarrhea in the 2 weeks prior to the survey; 101 of these episodes were persistent. Adults with persistent diarrhea in the high-exposure areas were more likely to have cryptosporidiosis (odds ratio, 5.14; 95% confidence interval, 1.57-17.2; risk ratio, 1.83; 95% confidence interval, 1.04-3.21; P = .003) although overall prevalence of persistent diarrhea was not greater in these areas. This association was not confounded by animal exposure, travel, or boiling water. Within these urban populations, water contamination with C. parvum was a major influence on the prevalence of infection.