A New Myxozoa Thelohanellus kitauei, the Cause of Intestinal Giant Cystic Disease of Carp

Abstract

A description is given of a new myxozoan parasite located in the intestinal wall of the cultured carp Cyprinus carpio from Japan. The name Thelohanellus kitauei n. sp. is suggested for this parasite whose spores are characterized by an egg-shaped balloon-like sack, 33.4 pm by 15.0 μtm in size in average. Spores measure 26.3 pm in length and 9.2 pm in breadth and thickness in average in water. The polysporous vegetative form which forms a giant polyp-like swelling in the intestine is inferred to be a single winding tube based on histological observations of the serial paraffin sections of the swellings. A mass of minute spherical disporous form is exceptionally observed in a small visible lesion lying under the mucosa, too. © 1981, The Japanese Society of Fish Pathology. All rights reserved.