Formol-ether concentration method in the diagnosis of active schistosoma mansoni in patients with detectable IHA.

Schistosomiasis is a world wide human infection. In Saudi Arabia there are multiple endemic foci. Various methods have been used to diagnose Schistosoma mansoni. We studied 1410 patients coming from S. mansoni endemic areas with detectable antibodies by indirect hemagglutination (IHA). Stool specimens were tested for S. mansoni ova by direct smear and formol-ether concentration (FEC) methods. The objective of the study was to identify patients with active schistosomiasis using FEC method and a single direct smear. Twenty percent of IHA positive patients had active infection detected by FEC, while a single direct stool smear diagnosed only 2.4% (P< 0.0001). The percentage of positive FEC was significantly increasing in linear trend with IHA level. This trend wasn't observed with direct smear examination. The current data suggest that FEC is helpful to diagnose active schistosomiasis, therefore it is recommended in IRA positive individuals.