Detection of G1 genotype of human cystic echinococcosis in Egypt

The first trial to detect G1 genotype in Egyptian human isolates of hydatid cysts [HC] and serum samples to approach diagnosis of cystic echinococcosis [CE] using human sera by PCR. Using strain specific primers, 27/36 confirmed CE patients [75%] showed G1 specific band in their sera at 254 bp. Specificity was 100% without detecting bands for either other parasitosis, or mass occupying lesions. Using PCR, G1 genotype was detected in 83.3% of HC samples, without significant difference between types of human isolates [pulmonary, hepatic, or multi-organ]. G1 genotype detection in human sera was in 75% of CE patients compared to 83.3% in HC samples of the same group of patients proved satisfactory, simple and safer than HCF sampling. IHAT gave sensitivity of 58.3% compared to histopathological examination of surgically removed cysts or examination of hydatid cyst fluid [HCF] for pro-toscolices [gold standards]. The specificity was 70% with false positive reactions with other parasitic infections and mass occupying lesions. PCR detection of G1 genotype in Egyptian animal hydatid cysts showed 90% in camel isolates and 80%; in sheep isolates, but pig isolates were negative. The presence of this genotype in a high percentage in camel isolates incriminated sheep strain as the source of CE camel infection. The results may give an explanation to the contradicting results of other studies that did not relay upon molecular aspects

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