The detection of IgM antibodies for Schistosoma mansoni
using gut-associated antigens (IgM-IFT) was compared to the
parasitological Kato-Katz method for study of the transmission of
schistosomiasis in an urban area in Campinas. About 400 schoolchildren
whose ages ranged from 6 to 18 years, were observed for a period of
two years. Blood samples on filter paper and fecal samples were
collected, at intervals of six months. Serological (IgM-IFT)
prevalence rates of 1.2%, 4.3%, 3.6%, 2.9% and 3.4% were obtained in
five surveys carried out. S. mansoni eggs were detected in only
one child out of the 225 children (0.4%) who were submitted to the
Kato-Katz method (three slides for each fecal sample) in the 1st
survey. Sixty eight children who submitted five blood samples, one for
each survey, were found IFT negative throughout the study. No child
was found to be IFT positive in all five surveys, and only four
children showed IFT positive results in at least four surveys.
Seroconversion from IFT negative to positive was observed from the 1st
to the 2nd survey in six chidren, from the 2nd to the 3rd survey in
three children, from the 3rd to the 4th survey in four children, and
from the 4th to the 5th survey in two cases. However, confirmation of
S. mansoni infection using the fecal examination was not
possible in any of the cases. Also, in most of them the IFT result
oscillated from negative to positive and vice versa. Our data implied
that recent transmission of schistosomiasis in the study area was not
possible.
