Serodiagnosis of sparganosis by ELISA using recombinant cysteine protease of Spirometra erinaceieuropaei spargana.

The Spirometra erinaceieuropaei cysteine protease (SeCP) gene encoding a 36 kDa protein was expressed in Escherichia coli, and the potential of recombinant SeCP protein (rSeCP) as an antigen for the serodiagnosis of sparganosis was investigated by ELISA and compared with those of ELISA with sparganum excretory-secretory (ES) antigens. The sensitivity of rSeCP-ELISA and ES-ELISA was 96.67 % (29/30) and 100 % (30/30) respectively, for the detection of anti-sparganum IgG antibodies in sera of the experimentally infected mice (P > 0.05), and the specificities of both ELISA were 100 % (77/77). In heavily, moderately, and lightly infected mice (five, three, and one larvae per mouse), anti-sparganum antibodies were firstly detected by rSeCP-ELISA at 10-12 days post-infection (dpi), respectively, and then continued to increase with a detection rate of 100 % at 14-22 dpi. In three groups of infected mice, the anti-sparganum antibody levels at different times after infection were statistically different (P < 0.05). The results showed that the rSeCP might be a potential candidate antigen for early and specific serodiagnosis of sparganosis. But, it needs to be further evaluated with sera of the patients with sparganosis and other helminthiasis.