Dot ELISA for measuring anti-Fasciola IgG isotypes among patients with fascioliasis.

Stool examination using modified Kato thick smear method was performed to detect Fasciola eggs and other parasites. Forty-five patients were proved to have Fasciola infection by passing eggs in their stool samples. Pallor was the major presenting symptom (95.5%) followed by abdominal pain (93.3%) and fever (15.5%). Hepatomegaly was recorded in 86.6% of patients compared to 33.3% with splenomegaly. Abdominal, ultrasonography revealed hepatomegaly in 38 cases (84.4%) and common bile duct dilatation in 35 patients (77.7%). Moreover, 4 cases showed Olympic game rings which are diagnostic. All of patients had positive IgG4 levels, 40 cases were found positives for specific total IgG and 42 cases for IgG1, whereas, only 30 cases had positive IgG2 levels (66.6%). Dot-ELISA showed that IgG2 and IgG4 giving the highest specificity (>99%), followed by IgG1 (90%) and the least specific test was obtained with detection of IgG (85%). From the present work, it was concluded that detection of anti-Fasciola isotypes especially IgG4 is very specific for accurate diagnosis of fascioliasis.

Detection of E. histolytica, G. lamblia and Cryptosporidium copro-antigens in stool samples.

A double antibody sandwich ELISA technique, using a chromatography purified antisera against E. histolytica, G. lamblia and Cryptosporidium antigens, was applied to detect copro-antigens of the corrosponding parasites in 90 patients. All positive cases were diagnosed by parasitological examination and proved to have the infection solely. Beside the 90 positive cases, 40 age-matched controls were included in the study, of which 20 individuals were infected with other parasites but not Cryptosporidium, E. histolytica or G. lamblia (acted as an infected control group) and the other 20 individuals with no intestinal parasites (normal control group). The assay could detect 100% of those infected with both of G. lamblia and E. histolytica and 96.6% (29/30) of patients with Cryptosporidium infection. False positive reactions were detected in 3 cases using G. lamblia antisera (92.5%), 5 cases using E. histolytica antisera (87.5%) and 2 cases using Cryptosporidium antisera (95%). A direct increase in the mean antigen level was observed with the increasing intensity of infection in the 3 parasites, so higher mean O.D. readings was observed in heavily infected cases than moderately infected cases than lighter intensity of infection. Only those in elder age group (> 20 years) infected with E. histolytica were found to have statistically higher O.D. readings of the antigen than middle age group (10-20 years). On the other hand, no statistically significant difference was observed between different age groups and antigen level in cases with either G. lamblia or Cryptosporidium.