Cystatin capture-dot-enzyme-linked immunosorbent assay for immunodiagnosis and assessment of cure of experimental trichinellosis in mice.

Cystatin capture dot enzyme-linked immunosorbent assay (CC-dot ELISA) was evaluated as a new version of ELISA for diagnosis of trichinellosis by the detection of anti-Trichinella spiralis cysteine proteinase (CyP) IgG, using nitrocellulose membrane sensitized with cystatin as a capture reagent for CyP from T. spiralis muscle larvae excretory secretory products (ESP) without purification, compared to the detection of anti-T. spiralis IgG by conventional (conv.) ELISA, using whole ESP. Experimentally infected mice with light (100 larvae/mouse) and heavy (300 larvae/mouse) infections by T. spiralis larvae at 7, 14, 21 and 56 days post infection, and after flubendazole treatment were examined. As early as one week post infection CC-dot ELISA gave high positive rates of 86.6% and 100% in light and heavy infections, respectively, in contrast to negative results by conv. ELISA. CC-dot ELISA showed in light and heavy trichinellosis a higher efficiency in comparison to conv. ELISA (97.7% versus 67.7% and 98.8% versus 80%, respectively) and a higher overall sensitivity (96.6% versus 55% and 98.3% versus 73.3%, respectively). No cross reactions with sera of other parasitic infected or non infected control mice were recorded by CC-dot ELISA giving 100% specificity compared to 93.3% by conv. ELISA. After treatment, CC-dot ELISA gave positive results only in uncured mice with remaining muscle larvae, while conv. ELISA was positive in mice with and without remaining muscle larvae. CC-dot ELISA used lower quantities of antigen, was performed at room temperature, and read by naked eye in less than 2.5 hours.