A-I: IFT with intact worm of different T. spiralis phases probed by anti-rTsSP serum. The apparent immunostaining is observed on cuticles of ML (A), 6 hpi IIL (B), 24 hpi IIL (C), 3 dpi female adult (D), 6 dpi female adult (E), and NBL (F). The ML probed by infection serum (G) was utilized as a positive serum control; the ML incubated with normal mouse serum (H) and PBS (I) were applied to negative controls. When worm sections were incubated by anti-rTsSP serum, positive staining is seen in cuticles and stichosomes of ML (J), IIL (K) and female adult at 3 dpi (L). The ML probed by infection serum (M) was employed as a positive serum control; ML reveals no staining with normal mouse serum (N) and PBS (O) as a negative control. Scale-bars: 100 μm.