Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

A new pathogenic Cryptobia from freshwater fishes: a light and electron microscopic study.

Abstract

C. iubilans n.sp. is described from Herichthys cyanoguttatum (type host), Cichlasoma nigrofasciatum, C. octofasciatum and C. meeki, obtained from a fish breeder who reported increased mortality of young fishes. The parasites were present in the stomach, intestine, gall bladder, spleen, ovary and liver and also intracellularly within macrophage-like cells. The trophozoites measure 5.5 to 12.5 × 3.5 to 5.5 (average 4.0 × 9.0) µm and have a short prominent rostrum, an anterior flagellum measuring 10 to 18 µm (1.5 to 2 times the body length) and a posterior flagellum measuring 11 to 19 µm (attached along the whole body length). Other features include a triangular kinetoplast, long cytopharynx reinforced with 5 + 4 parallel microtubules, preoral ridge short with a smooth profile, incomplete subpellicular corset greatly reduced, prominent polysaccharide granules. No bacterial endosymbionts were present in the cytoplasm. Cysts were not found. Cryptobia iubilans is the first record of intestinal Cryptobia from freshwater fish. It is the only endoparasitic member of the genus which is pathogenic to its host and which is known to occur intracellularly.