Fecal specimens were obtained on 3 occasions at 10-12 wk intervals from 315 children in 3 rural villages in Zimbabwe and from 351 children in the high-density suburbs of an adjacent small town. Specimens were examined qualitatively and quantitatively for eggs of Hymenolepis nana, and these were found in 142 (21%) children. Infections occurred more frequently in younger children in the urban area but in older children in rural areas. The prevalence in urban areas (24%) was higher than in rural areas (18%), and in urban areas infection correlated with low "hygiene scores" (determined by observation) and with the presence in the household of an infected sibling. The prevalence of infection in the 3 rural communities did not correlate with availability of water, number of households per toilet, with low "hygiene scores," or with the presence of an infected sibling. Treatment with a single oral dose of 15 mg/kg praziquantel cured 84% of the infected children. New or reinfections occurred more frequently in households that had an infected sibling in an urban but not rural setting. The study demonstrates distinct differences in the transmission of H. nana infection in rural and urban communities. The data suggest intrafamily transmission in urban areas, particularly in households with poor hygiene behavior, leading to primary infection early in life. In rural areas, the prevalence of infection and the incidence of reinfection were highest in children of school age, and there was little evidence for intrafamily transmission of the parasite.
Stool specimens, obtained from 1813 schoolchildren from communal lands, commercial farms and urban areas in Zimbabwe, were examined for helminth and protozoan parasites. The findings were collated with anthropometric data on the same children to investigate the relationship between intestinal parasitism and nutritional status. Protozoan infections were common with Giardia lamblia being identified in 17.4% of children. There was a strong association between giardial infection and undernutrition, wasting and stunting in these children. There was no evidence of an association between helminth infection and undernutrition. In view of the known impairment of absorption from the gut in giardiasis, it is suggested that giardial infection may be an important factor contributing to the low nutritional status of many primary schoolchildren in Zimbabwe.
Lymphocytes from patients with active trichomoniasis showed a proliferative response when incubated in the presence of secretory and cellular products of either pathogenic or non-pathogenic Trichomonas vaginalis. Maximal responses were detected using 50 micrograms per ml protein after 5 days incubation. Lymphocytes from non-infected laboratory workers showed no response to these antigens. This indicates that delayed hypersensitivity reactions may act to modulate inflammatory responses in trichomoniasis.
The prevalence of intestinal parasitism in primary schoolchildren in three areas, communal (peasant farm) lands, commercial farms and urban townships, was assessed by examination of concentrated and stained stool specimens to determine the effect of water supply on intestinal parasitism. Piped water in communal lands was associated with decreased frequency of schistosomiasis and hymenolepiasis, but not with decreased frequency of protozoa. Schistosomiasis was very common in commercial farm labour communities, particularly on farms adjoining the local river, despite the availability of stored borehole water supplied through communal taps. The prevalence of intestinal parasitism in children from urban areas with municipal water supplied to taps in each household was similar to that of children in communal areas who obtained water from surface streams. The frequency of Giardia lamblia infection was higher in urban than in rural schoolchildren, and within communal areas was higher in children with access to protected borehole water. The provision of piped water was, therefore, not found to be associated with reduced prevalence of intestinal parasitism, though additional factors such as frequency of contact with infected water, the provision of ancillary improvements and the actual usage of available water supplies would need to be more closely assessed.
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