Seven years' experience with Cryptosporidium parvum in Guinea-Bissau, West Africa.

In community-based studies conducted from 1991 to 1997 in Guinea-Bissau, West Africa, stool specimens from children aged less than 5 years with diarrhoea were routinely examined for enteric parasites. Cryptosporidium parvum, found in 7.7% of 4,922 samples, was the second most common parasite, exceeded only by Giardia lamblia which was found in 14.8% of the samples. The highest prevalence of cryptosporidium was found in children aged 6-11 months, whereas the prevalence of other enteric parasites increased with age. Cryptosporidiosis showed a marked seasonal variation, with peak prevalences found consistently at the beginning of or just before the rainy seasons, May through July. By contrast, no seasonality was found for the enteric parasites Giardia lamblia or Entamoeba histolytica. We conclude that Cryptosporidium parvum is an important pathogen in children with diarrhoea.