IIFT detection of TsGDH in the epicuticle of different Trichinella spiralis stages. IIFT was conducted to detect the TsGDH expression on epicuticle of T. spiralis using diverse sera (anti-rTsGDH serum, infection serum, and pre-immune serum). Bright green fluorescence was observed on the outer cuticle of 12 IIL, 3 and 6 d AWs and NBL, but not in ML and 6 h IIL stages. Infection serum and pre-immune serum served as positive and negative controls. Scale bars for ML, 6 h, 12 h IIL, 3 d AWs and NBL: 200 μm; scale bar for 6 d AWs: 500 μm.