Non-invasive immunodiagnosis of Schistosomiasis japonica: the detection of specific antibodies in saliva

Objective To assess the feasibility of using saliva for Schistosomiasis japonica diagnosis. Methods Schistosoma japonicum infected animal model was established. Pairs of saliva and serum samples from rabbits and chronic schistosomiasis patients were collected. Anti-schistosoma specific antibodies in saliva and serum were detected by indirect ELISA. Results The specificities of antibody detection of rabbit saliva and serum were 93% (28/30) and 97% (29/30), respectively, and the sensitivities of antibody detection of rabbit serum and saliva were 100% (24/24) and 88% (21/24), respectively. A significant correlation (r = 0.5307, P = 0.0038 < 0.05) existed between anti-SEA IgG levels in serum and saliva. As with those in serum, anti-SEA IgG levels in saliva could reflect the state of infection and treatment. The sensitivity of antibody detection was 91% (29/32) for patient saliva samples and 100% (32/32) for their sera. 8 samples were positive in 140 normal saliva samples (i.e. 6% false positive rate) and 6 samples were positive in 156 normal serum samples (4% false positive rate). There was a significant correlation ( r = 0.4227, P = 0.008 < 0.05) between specific antibodies in saliva and serum. Conclusion The detection of specific antibodies in saliva can be used as a non-invasive immunodiagnosis method of Schistosomiasis japonica.