Detection of schistosoma mansoni DNA in human blood as a diagnostic method for schistosomiasis

Schistosomiasis is a major health problem, the diagnosis of which relies on direct examination for ova, and/or serological assays for specific antibodies and circulating antigens. The present study aimed at evaluating the detection of Schistosoma mansoni DNA by polymerase chain reaction [PCR] versus the detection of antibodies by indirect haemagglutination test [IHAT] as means for diagnosis of Schistosomiasis in human blood. The individuals under study were categorized into four groups. Group I included 36 patients with active intestinal Schistosomiasis. Group II included 20 patients with past history of intestinal Schistosomiasis. Group III included 20 patients with Schistosoma haematobium and other parasitic infections, and finally group IV which included 15 individuals serving as negative controls. For all groups under study stool and urine were examined for parasitic ova; serum was examined for S. mansoni circulating DNA by PCR and for the detection of bilharzial antibody by IHAT. PCR proved highly significant in diagnosis of active intestinal Schistosomiasis with a sensitivity of 97.2%, specificity of 100%, predictive value of positive [PVP] of 100%, predictive value of negative [PVN] of 98.2% and a diagnostic accuracy of 98.9%. All cases in group II, III, and IV were negative. IHAT results showed a sensitivity of 77.8% in group I, 90.0% in group II, 25% in group III and in group IV all cases were negative. The specificity of IHAT in the diagnosis of active intestinal Schistosomiasis was 85.7%, with PVP 84.8% and PVN 78.9%; the diagnostic accuracy was 81.6%.S. mansoni DNA detection may be used as a valuable and species specific test for diagnosis of early infection or in situations of low worm burden in which other diagnostic methods show low sensitivity and specificity. Early treatment of such cases avoids the occurrence of irreversible pathological damage by the deposited eggs

Host and parasite determinants of morbidity in Egyptian children with schistosomiasis

The relation of morbidity due to schistosomiasis in Egyptian children to egg count, eosinophilic count, antibodies mediating eosinophil damage to schistosomula, total immunoglobulins and specific antischistosomal antibodies IgG and IgM anti-cercarial antigen preparation [CAP], anti-soluble worm antigen preparation [SWAP] and anti-soluble egg antigen preparation [SEA] was evaluated. The behavior of the immune parameters after treatment was also determined. From the results obtained, it was concluded that high intensity of infection may be one of the determinants of morbidity due to Schistosoma mansoni infection in Egypt. The elevated response of antibodies mediating adherence and damage to schistosomula may be associated or play a role with morbidity. Eosinophilic count, total IgA, IgG, IgM, IgE and specific antischistosomiasis IgG and IgM [anti- CAP, anti-SWAP and anti-SEA] are not related to morbidity

Evaluation of cercarien hullen reaction [CHR] as a diagnostic test in chronic schistosomiasis and as a parameter for reinfection in acute cases

CHR was evaluated as a serodiagnostic test in relation to stool analysis, rectal snip and indirect hemagglutination test [IHA] in 25 cases with chronic active mansonian schistosomiasis. Sensitivities of CHR, IHA, rectal snip and stool analysis, respectively, proved to be 68%, 48%, 84%, and 52%. Rectal snip showed higher diagnostic efficacy 90% followed by CHR [77.5%], while IHA showed 67.5% diagnostic efficacy. To study CHR as parameter for pattern of reaction after treatment, 120 school children with acute mansonian schistosomiasis were examined. CHR was done before and one month after treatment. These children were followed up for one year by stool examination. Results of CHR test after treatment showed that the children who were not reinfected gave the highest degree of reaction, while those of high reinfection showed decrease in reaction. This denotes that anticercarial antibodies may play a role in resistance to reinfection and CHR test could be used as parameter for reinfection in such cases

Comparative evaluation of antigens used in immunofluorescence [IFAT] antibody test for serodiagnosis of schistosomiasis

The diagnostic value of antigens used in the IFAT for serodiagnosis of schistosomiasis has been evaluated. Cryosections of Schistosoma mansoni adults, formaline fixed cercariae and cryosections of infected liver, from gold hamster, which contained granuloma were used as antigens in this evaluation. The cryosections of adult worm were more reliable and more specific as an antigen for immunofluorescence [diagnostic efficacy was 95.52%]. The cercarial antigens gave the same results as the cryosection of adults. The IFAT using cryosection of infected liver contains granuloma was less reliable due to autofluorescence of eggs in the granuloma with negative sera [diagnostic efficacy was 49.01]

Treponemal reagin antibody in bilharzial patients

Venereal disease research laboratory test [VDRL] was carried out for 140 schistosomiasis patients in different stages of the disease and 20 normal individuals as control. Each group was classified according to the age [<15 years and >15 years] and sex. As bilharziasis is one of the most famous endemic diseases in Egypt, this study aimed to look for treponemal reagin in sera of bilharzial patients during the different clinical stages of the disease. From the obtained results, it could be concluded that treponemal reagin antibody is insignificantly found in schistosomiasis patients