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Diseases of in Japan Total 15,000

ton Taiwan Total 60,000 ton from Taiwan Japan 74,000 ton

13,000 ton

Tanaka, M.* and M. Yoshimizu** 40,000 ton (in Japan)

*1: Fuji Trout Farm, Shizuoka Prefectural Research Institute of Fishery, 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 Fujinomiya, Shizuoka 418-0108 Japan *2: Laboratory of Bio-Technology and Microbiology, Faculty of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041-8611, Japan Fig. 1. Eel products in Japan and amount of imported eel from 1985 to 2010.

Shift of diseases by changing a culture condition Green-house aquarium

Outside pond Outside pond (～1970’s) Vibriosis : Vibrio anguillarum, Red spot disease : Pseudomonas anguilliseptica Red disease : Aeromonas hydrophila Head ulcer disease : atypical A. salmonicida Saprolegniasis : Saprolegnia diclina Type I i 3% Water temperature is 28～30 ℃. White spot disease: Ichthyophthirius multifilis j Heterosporiosis : Heterosporis anguillarum 5% VECNE 30% Green house (1980’s～) Viral endothelial cell necrosis of eel (VECNE) Others Edwarssiellosis : Edwardsiella tarda 39%

Columnaris disease : Flavobacterium columnare c Edwarsiellosis Others (not infectious diseases) 8% 10% g f e d 0% 1% 1% 3%

Vibriosis: Vibrio anguillarum Red spot disease : Pseudomonas anguilliseptica

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Red disease : Aeromonas hydrophila Fungal disease : Saprolegnia diclina

White spot disease: Ichthyophthirius multifilis Heterosporiosis : Heterosporis anguillarum

Viruses isolated or observed in eel fry Viral endothelial cell necrosis of Japanese eel (VECNE) (Pathogenicity does not confirmed.) (Photo: provided by Dr. H. Fukuda) = “intense congestion of the gill”

EVA EVEX

Adenovirus Picornavirus Gill filaments of diseased fish; dilatation of the central venous sinuses was observed.

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・In the liver, hemorrhage and destruction of blood vessels were observed. ・In the kidney, hemorrhage in the hematopoietic tissue and destruction of Intense congestion in central venous sinuses of blood vessels were observed. gill filaments was found.

Paracolo disease = Edwardsiellosis : Edwardsiella tarda (Paracolobacterium anguillimortiferum)

Japanese eel endothelial cell (JEEC) and CPE of causative virus. (Photo provided by Dr. Ono.)

Virus particles of 75 nm in diameter were observed in the hypertrophied nuclei.

Eel herpesvirus disease at “Tateba”(in the market) Columnaris disease : Flavobacterium columnare (Photo：provided by Dr. T. Miyazaki)

TATEBA

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Eel culture (Breeding) Treatment and Control of VECNE ・Increasing temperature of rearing water 1972： Prof. Yamamoto, Hokkaido University 2010： Dr. Tanaka, National Inst. with non-feeding. had succeed to hatch out and to get succeed to get eggs from culture grown

a fry. eel and to hatch out.

250 37 死亡数1 ) 200 Ded fish ℃ 水温 34 死 Te 150 亡 m 水 31 尾 温 100 数

( Temp Water 28 50 fish died of Number 0 25 0 5 10 15 20 25 30 35 40 45 経過日数 Days Fig. . Results of increasing temperature of rearing water at private farm .

・Poly (I:C) immunization; dsRNA injection to matured fish to prevent viral infection (plan is carrying out).

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