The prevalence, incidence and reinfection of giardiasis were studied in 365
children attending three day care centres (DCCs) in Havana City. Three sto
ol samples were obtained from each child every 6 months during an 18-month
period. We identified three distinct groups of children according to their
patterns of infection. In the largest group (51%) children were never found
infected. In the second group, they were found infected once or twice duri
ng the study period, and in the third and the smallest group (9%) they were
found infected in most or all the study periods. This last group seems to
be children 'predisposed' to Giardia lamblia infection. The prevalence of g
iardiasis (20%) remained almost constant throughout the study period. The i
ncidence declined from 16 to 11%, and reinfection increased from 36 to 49%.
All the children had normal nutritional status and the only clinical manif
estation that correlated strongly with the frequency of cross-sectional sur
veys positive to Giardia was the number of diarrhoeal episodes recorded dur
ing the last 6 months of the study period. Further studies will be necessar
y to ascertain the causes that determine the 'predisposition' to giardiasis
in children. (C) 1999 Elsevier Science B.V. All rights reserved.