Modification of carbohydrate compositions of 31/36 kDa proteins of plerocercoids (sparganum) of Spirometra mansoni grown in different intermediate hosts

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 (χ (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.