Henneguya lateolabracis sp. n. (Myxozoa: Myxosporea), the causative agent of cardiac henneguyosis in Chinese sea bass Lateolabrax sp.

Abstract

A new myxozoan parasite was found from net-pen-cultured Chinese sea bass, Lateolabrax sp. in Japan. Diseased fish exhibited chronic mortalities with clinical signs of anemic gills and enlarged bulbus arteriosus. Irregular-shaped plasmodia developed in the bulbus arteriosus, with released mature spores accumulating in the lumen. Massive influx of spores into the gills caused local occlusion and congestion of gill capillaries, lamellar hypertrophy, and degeneration of the gill epithelium. Spores were ovoid with two equal caudal appendages. Average spore size was 10.7 μm in length, 7.5 μm in width and 6.2 μm in thickness. Average caudal appendage length was 37.7 μm. A new species name, Henneguya lateolabracis, is proposed as the causative agent of cardiac henneguyosis in Chinese sea bass.