Age-specific sero-prevalence of amoebiasis and giardiasis in southern Indian infants and children.

The age-specific sero-prevalence of amoebiasis and giardiasis was estimated in 91 pediatric diarrhoea and in 70 non-diarrhoeal cases from Southern India. Anti-amoeba/giardia IgG assays on 20 children with inflammatory bowel disease from the UK yielded base-line levels in a non-endemic symptomatic population. IgG, IgM, and IgA levels were estimated to E. histolytica and G. lamblia using an ELISA. Concomittant faecal examinations were done for the Indian children. There was a significant correlation between acquisition of sero-positivity and age. A rise in the IgG response to both organisms was evident between 38 and 47 and 13-24 months, respectively, in diarrhoeal and non-diarrhoeal cases. An appreciable IgM response occurred predominantly in diarrhoea cases and at a younger age (less than 24 months). IgA responses were low. Anti-protozoal IgG levels in the UK children were negligible. There was no relationship between faecal excretion and sero-positivity. The study shows an age-related antibody response to E. histolytica and G. lamblia.