Serodiagnosis of experimental sparganum infections of mice and human sparganosis by ELISA using ES antigens of Spirometra mansoni spargana

We conducted a study of serodiagnosis of experimental sparganum infections of mice and human sparganosis by enzyme-linked immunosorbent assay (ELISA) using excretory-secretory (ES) antigens of Spirometra mansoni spargana and compared the sensitivity and specificity of crude and ES antigens for detecting the specific anti-sparganum IgG antibodies. By crude antigen ELISA and ES antigen ELISA, anti-sparganum IgG was detected in all of 30 serum samples of the infected mice; no cross-reactions were observed in serum samples of the mice infected with Trichinella spiralis, Schistosoma japanicum, Toxoplasma gondii, and normal mice. Anti-sparganum IgG was detected by ES antigen ELISA in sera of mice infected with one, two, four, six, and eight spargana at 3 weeks post-infection (wpi), with a detection rate of 100%, and lasted to 18 wpi when the experiment was ended. The difference in anti-sparganum antibody levels among five groups of the infected mice was statistically significant (F = 245.296, p < 0.05); the antibody levels were correlated with infecting doses of spargana (r = 0.323, p < 0.05). The sensitivity of both ELISA in detecting the serum samples of patients with sparganosis was 100% (20/20), but 96.72% (59/61) of specificity of ES antigen ELISA in detecting serum samples of patients with cysticercosis, echinococcosis, paragonimiosis, clonorchiosis, and schistosomiasis, and healthy persons was significantly greater than 72.13% (44/61) of crude antigen ELISA (chi (2) = 14.027, p < 0.05). Our finding indicates that ELISA using ES antigens of S. mansoni spargana may be applied to the specific early serodiagnosis of sparganosis.