CIRCULATING SCHISTOSOMAL ANTIGENS IN MONITORING
PRAZIQUANTEL EFFICACY IN CHILDREN WITH SCHISTOSOMIASIS
Hassan MM, Hegab MHA, Abd El-Aziz; O, Afify H,
Department of
Parasitolgy, Faculty of Medicine, Zagazig University, Zagazig, Egypt
To monitor the efficacy
of praziquantel therapy by egg count and circulating antigen
Stool, urine and
blood samples were collected from 900 S. mansoni-infected children before
and at 1, 3 and 5 months after praziquantel (PZQ) treatment. Three
different doses of 2 PZQ formulae (Distocide and Biltricide) were used for
treatment. EGF was counted by examining 3 slides for every child for 3
consecutive days. The double sandwich ELISA was conducted using monoclonal
antibody 128C3 to detect circulating schistosomal antigens in children
serum samples. The antigen assay sensitivity was 91.7% and specificity was
>99% with no evidence of cross-reactivity with other parasites. A
significant correlation was observed between the egg count and the antigen
level before treatment (r= 0.82, p <0.001).
The egg count and
antigen levels before treatment appear to be key variables in determining
the most suitable drug dose for an individual. A single 40-mg dose appears
to be adequate for those in either the baseline egg count (1-30 EGF) or the
baseline antigen level (80-184 ng/ml). However, the cure rate decreases
with an increase in either the baseline egg count or the baseline antigen
level. A higher doses (a single 60-mg or double 40-mg dose) and continued
follow-ups appear to be needed in such cases