Abstract 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.
Modified agglutination test (MAT) was applied to 150 chicken sera (90 were farm-bred and 60 house-bred chickens). The prevalence of Toxoplasma antibodies was 18.7%. In house-bred chickens positive cases were 18 out of 60 (30.0%), while in farm-bred chickens positive cases were 10 out of 90 (11.1%). Histopathological sections of the seropositive chickens showed tissue lesions which were most likely to be induced by T. gondii. Tissue cysts of T. gondii were demonstrated in the liver, brain, heart and skeletal muscles of 22 (78.6%) out of 28 positive chickens. These tissue cysts were found mostly in the brain of seropositive chickens. Epidemiological implications of these data for public health significance were discussed.