Scanning electron microscopy of the tegumental surface of adult Haplorchis pumilio (Looss)

The surface structure of adult Haplorchis pumilio from experimentally infected hamsters was studied in detail using scanning electron microscopy. Almost the entire surface of the worm was covered with scale-like spines regularly arranged in transverse rows. Most spines were pectinate. The size of the spines and the number of the teeth in each individual were largest in the spines around the middle region of the worm. The area surrounding the excretory pore was free of spines displaying a slightly wrinkled appearance. Many ciliated papillae were present on the anterior two-thirds of the body. The papillae on the oral sucker were more abundant than those elsewhere. The body papillae were distributed in a bilaterally symmetrical arrangement, appearing in groups, pairs or singly between the spines.