Dermocystidium sp. infection in cultured juvenile southern catfish Silurus meridionalis in China

DAO Diseases of Aquatic Organisms Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials DAO 65:245-250 (2005) - doi:10.3354/dao065245 Dermocystidium sp. infection in cultured juvenile southern catfish Silurus meridionalis in China Qizhong Zhang1,2,*, Zhijian Wang1 1School of Life Sciences, Southwest China Normal University, Chongqing 400715, PR China2Institute of hydrobiology, Jinan University, Guangzhou 510632, PR China *Email: zhangqzdr@sohu.com ABSTRACT: A species of Dermocystidium was discovered on the skin and fins of reared southern catfish Silurus meridionalis Chen. The parasite only appeared and caused disease in juvenile catfish at a water temperature of 18 to 23°C. Marked external macroscopical clinical signs of the disease were sluggish movement of the fish, and the appearance of white filiform dermal cysts varying in size (3–20 mm in length and 0.15–0.35 mm in width). Examination of both fixed and fresh mounts for light microscopy and of samples for transmission electron microscopy (TEM) showed spherical spores (3.2–15 µm in diameter) with a peripheral nucleus (1.1–1.8 × 0.5–1.6 µm in diameter) and a prominent refractile body (2.08–10.83 µm in diameter) which occupied most of the volume of a mature spore. Three types of spore were identified, and are presumed to represent various developmental stages. Meanwhile, TEM showed the remnant nuclei in the residual plasmodium of a cyst, revealing its degenerative process. This paper represents the first observation and description of Dermocystidium sp. parasitizing catfishes. KEY WORDS: Dermocystidium · Protozoa · Histology · Silurus meridionalis Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in DAO Vol. 65, No. 3. Online publication date: July 18, 2005 Print ISSN: 0177-5103; Online ISSN: 1616-1580 Copyright © 2005 Inter-Research.