Touchdown PCR, ELISA and stool examination for early diagnosing of Schistosoma mansoni in mice.

A detection assay for Schistosoma mansoni DNA in mouse serum samples based on touchdown PCR was evaluated. Fifty four mice (7 weeks old) were infected with 60 +/- 10 cercariae of S. mansoni (Egyptian strain) through tail skin. Three days and 1-8 weeks post-infection (PI), six mice were randomly chosen from the infected ones and blood was collected by cardiac puncture. Sera and faeces were collected for 8 weeks PI. Antisoluble egg antigen (SEA) IgG for S. mansoni was detected in infected mice sera of at 3 weeks PI by ELISA. The earliest deposition of eggs in the small intestines was at the 5th week PI. The eggs were detected in faeces at the 8th weeks by modified Kato's thick-smear. However, S. mansoni DNA was detected by touchdown PCR in sera at 2 weeks PI. The intensity of S. mansoni DNA bands in infected mice sera detected in polyacrelamide gel electrophoresis increased gradually during the experimental period. Data recommended touchdown PCR potential tool for the early diagnosis of S. mansoni infection.