In tropical countries, there is a striking contrast between the high p
revalence of asymptomatic carriers of intestinal parasites and the low
prevalence of diarrhea directly caused by parasitic infections in chi
ldren with normal growth. Several studies conducted in Gabon in infant
s under two years of age have demonstrated that digestive tract coloni
zation by parasites occurs at a very early age regardless of nutrition
al status. Children with malnutrition have an increased likelihood of
developing parasite-induced diarrhea, which is usually a chronic disor
der caused by Giardia lamblia, Strongyloides, or Cryptosporidium. Maln
utrition-related immunosuppression may cause a host-parasite imbalance
which may exacerbate the pathogenic potential of intestinal parasites
.