Age-related rate of seropositivity of antibody to Giardia lamblia in different age groups in Cairo.

: Two hundred and twenty normal individuals were subjected to Giardia lamblia antibody IgG analysis. All subjects were of low socioeconomic standard using Indirect Immunofluorescent Antibody Test (IFAT). According to age the study persons were divided into 4 groups : group I with age in between 6 to 35 months, group II with age in between 3 years and less than 6 years, group III with age group ranged between 6 years and 16 years old and group IV with age above 16 years. The Seropositivity to Giardia infection was (37%) in all age groups, while it was 23%, 52%, 32% and 40% in each of the four age groups respectively. It is a noteworthy that infants after 12 months of age showed seropositivity to Giardia infection which meant that they caught actual infection in this early period of life while infants younger than 12 months were all seronegative to Giardia antibody. Different patterns of age associated acquisition of antibody levels were noted in the study groups. Infants and children showed a progressive acquisition of antibody titre which arrived to the highest level at the adult age group greater than 16 years that was significantly higher than other age groups.