Background: To assess the usefulness of an enzyme immuno-assay test for the diagnosis of two familial outbreaks of Fasciola hepatica parasitosis in the Zamora area, where watercress are a normal part of the diet.
Patients and methods: The microbiological diagnosis of two familial outbreaks of fascioliasis was analyzed, which included the search for eggs in feces by the Kato technique and two serologic tests, one screening test by indirect hemagglutination, and a confirmatory test by enzyme-immunoassay in 12 patients.
Results: Five out of the six seropositive patients had eggs detected in their feces. To note that two of the patients with eosinophilia that excreted eggs--one asymptomatic and the other with abdominal pain--had a positive result in the EIA test only and with high titers.
Conclusions: The EIA test is useful for the diagnosis and study of fascioliasis outbreaks to interpret the significance of low titers in the screening test in patients with eosinophilia.