RESUMO
Objective To evaluate the diagnostic value of the recombinant protein Sj_Ts4 in immunodiagnosis of Schistosomiasis japonica.Methods Seventy-four blood samples of schistosomiasis japonica patients(acute, chronic and advanced)were used for evaluating the sensitivity.Blood samples from 24 Clonorchiasis patients,8 patients with hookworm infections and 30 normal persons from the areas without Schistosomiasis were used ror patients.Results The positivity rates were 97.1%(33/34),100.0%(16/16),87.5%(21/24)in rSj-Ts4-ELISA and 100%(34/34),100.0%(16/16),75.0%(18/24)in SjAWA-ELISA in acute,chmnic and advanced Schistosomiasis. respectively.Statistical analysis revealed no significant difference in sensitivity(X2=1.23,P＞0.05)between both recombinant and crude antigens.The false positive reaction was found to be 6.7%(2/30)in rSj-Ts4-ELISA and 3.3%(1/30)in SjAWA-ELISA when detected in 30 cases of normal control sera.but no statisticallv significant difference was noted(x2=0.35,P＞0.05).Twelve point five percent(3/24),20.8%(5/24)and 12.5%(1/8),37.5% (3/8),of cross-reactions were observed between rSj-Ts4-ELISA and SjAWA-ELISA for detecting the sera of patients with clonorehiasis and hookworms.There was no significant difference of cross-reaction in two parasitic infections (x2=0.60,1.33,P＞0.05)with the two tests.Conclusions The rSj-Ts4 antigen shows higher sensitivity and specificity for the diagnosis of Schistosomiasis japonica,which is helpful in the serological diagnosis of Schistosomiasis japonica in endemic areas.