Thelazia rhodesi (Spirurida, Thelaziidae), bovine eyeworm: morphological study by scanning electron microscopy.

Abstract

Thelazia rhodesi (Spirurida, Thelaziidae) is a parasite of ruminants, which causes ocular infections. Scanning electron microscopy was used to study the surface ultrastructure of adult worms of this nematode. At the anterior end of both sexes, the buccal opening was orbicular. Around the mouth, four pairs of cephalic papillae and two lateral amphids were seen. A pair of lateral cervical papillae was present. In the female, the vulva was located at the anterior part of the body, and the tail end was stumpy with two phasmids near its extremity. In the male, the tail was blunt, without caudal alae, and curved ventrally. There were 14 paired preanal papillae, one single papilla directly anterior to cloaca, one paired postanal papilla, and two phasmids at the posterior end. The spicules were unequal and dissimilar. The cuticle was transversally striated and appeared serrated.