DIAGNOSTIC VALUE OF SCHISTOSOMA MANSONI SERUM DNA BY POLYMERASE CHAIN REACTION IN PATIENTS WITH INTESTINAL SCHISTOSOMIASIS
Shawky Abd Elhamid Fouad1, Maha Mohamed Abou El-Magd2 and Marwa Fathy Amer3
Departments of Internal Medicine1, Parasitology2 and Biochemistry3 Faculty of Medicine, Cairo University
Background: Schistosomiasis mansoni is a major health issue in the tropics and subtropics. Direct parasitological methods are definitive for diagnosis of schistosomiasis. However, their sensitivity is poor even with concentration techniques.Also serodiagnostic assays cannot discriminate between active and old infections.Aim of study: To study the value of PCR technique as a method for detection of Schistosoma mansoni DNA in human serum and its value in diagnosis of active schistosomiasis mansoni infection.Materials and methods: The present study included 92 individuals; 69 patients infected with S. mansoni, 13 with other parasitic infections and 10 normal individuals. The studied individuals were categorized into 4 groups: Group I, active intestinal schistosomiasis, group II, cases with past history of intestinal schistosomiasis, group III (parasitic control group) and group IV (healthy control group). Stool samples collected from all groups were subjected to examination by direct smear, formol-ether sedimentation methods and Kato-Katz technique. Rectal snip examination was done only for group II patients to exclude the presence of viable Schistosoma mansoni ova. Serum samples from all subjects were analyzed using PCR technique for detection of Schistosoma mansoni DNA. Results: All cases of active intestinal schistosomiasis were positive by Kato-Katz technique (56 cases), of them, only 27 cases (48.2%) were positive by direct smear method and 32 cases (57.14%) were positive by formol-ether sedimentation method. Serum examination using PCR detected DNA of S.mansoni in 96.4% of patients with active intestinal schistosomiasis. Conclusion: PCR is a highly sensitive test for diagnosis of S.mansoni infection particularly that, PCR gave this high sensitivity with single serum sample as compared to three or more stool samples required for Kato-Katz technique.