DAO 37:13-21 (1999)  -  doi:10.3354/dao037013

Gill lamellar pillar cell necrosis, a new birnavirus disease in Japanese eels

Nam-Sil Lee1, Yukihiro Nomura2, Teruo Miyazaki1,*

1Faculty of Bioresources, Mie University, 1515 Kamihama, Tsu, Mie 514-8507, Japan
2Biotechnology Research Laboratories, Takara Shuzo Co., LTD. 3-4-1Seta, Otsu, Shiga 520-2193, Japan
*Addressee for correspondence. E-mail:

ABSTRACT: Since the late 1980s, a birnaviral gill disease has been occurring in Japanese eels Anguilla japonica reared in warmwater ponds in western regions in Japan. Diseased eels mostly displayed marked formations of aneurysmal hematomas within gill lamellae and high mortalities. Histological examination revealed necrosis of pillar cells and subsequent aggregation of erythrocytes inside the lamellar capillaries, and proliferation of interlamellar epithelia onto the lamellae. Gastric gland cells were also necrotized. Electron microscopy revealed birnavirus infection in lamellar pillar cells. The causative birnavirus was isolated and cultured in fish cell lines and was found to be related to an infectious pancreatic necrosis virus (IPNV) Sp serotype by neutralization tests. The viral pathogenicity was confirmed by the results of histopathological examinations and infectivity experiments.

KEY WORDS: Sp serotype birnavirus · Japanese eel · Aneurysm in gill lamellae · Pillar cell necrosis · Gastric gland necrosis

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