DAO 49:165-170 (2002)  -  doi:10.3354/dao049165

Streptococcus iniae infections in Red Sea cage-cultured and wild fishes

A. Colorni1,*, A. Diamant1, A. Eldar2, H. Kvitt1, A. Zlotkin3

1Israel Oceanographic and Limnological Research, National Center for Mariculture, PO Box 1212, Eilat 88112, Israel
2Department of Poultry and Fish Diseases, The Kimron Veterinary Institute, PO Box 12, Bet Dagan 50250, Israel
3Department of Clinical Microbiology, The Hebrew University of Jerusalem, Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel

ABSTRACT: Streptococcus iniae was isolated from 2 moribund wild Red Sea fishes, Pomadasys stridens (Pomadasyidae) and Synodus variegatus (Synodontidae), both collected in shallow waters along the Israeli coast of the Gulf of Eilat. The site is approximately 2 km from a mariculture cage farm in which streptococcal infections were diagnosed in previous years in the red drum Sciaenops ocellatus. This is the first report of S. iniae in Red Sea fishes. Biochemical and molecular similarities between the isolates from cultured fishes and those from the wild specimens suggest that a single strain is involved, and that Œamplification¹ and dispersal of this pathogen from captive to feral fishes have occurred. At the molecular level, the pathogen is different from the S. iniae isolates that have been afflicting the Israeli freshwater aquaculture in recent years. Although S. iniae prevalence in the wild fish populations of the area remains to be determined, the northernmost region of the Gulf of Eilat, virtually landlocked and with generally calm seas and weak currents, seems to be particularly vulnerable to the impact of diseases that develop in this mariculture system.

KEY WORDS: Fish disease · Mariculture · Red drum · Sciaenops ocellatus · Sea bass · Dicentrarchus labrax · Tilapia · Oreochromis mossambicus · 16S rRNA · PCR

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