Longitudinal study of giardiasis in three day care centres of Havana City

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.