RESUMO
The morning stools of 590 randomly selected primary school children were examined with direct smear and formol-ether concentrate technique for Giardia infection. Giardia cysts were found in the stools of 158 [26.78%] children of which 151 were asymptomatic. No significant difference was observed between the two sexes. The weight and height of the infected and non-infected children did not differ significantly. Of all the infected children 133 were treated with a full course of metronidazole 123 of which were sampled two weeks after treatment. Of these, 17 were still infected [treatment failure: 13.82%]. Altogether, 52.73% of the children were positive for Giardia cysts within six months of therapy. The annual cumulative incidence was calculated to be 97.6% which means that 97.6% of the children will be reinfected within one year after successful treatment. We conclude that it may not be beneficial to treat asymptomatic giardiasis in hyperendemic areas