DAO 36:227-231 (1999)  -  doi:10.3354/dao036227

Lactococcus garvieae and Streptococcus iniae infections in rainbow trout Oncorhynchus mykiss: similar, but different diseases

A. Eldar1, C. Ghittino2,*

1Department of Poultry and Fish Diseases, Kimron Veterinary Institute, POB 12, 50250 Bet-Dagan, Israel
2Fish Disease Laboratory, IZS - State Veterinary Institute, Via Bologna 148, I-10154 Turin, Italy
*Addressee for correspondence. E-mail:

ABSTRACT: Clinical and macroscopic findings (anorexia, lethargy, loss of orientation and exophthalmia) indicate that Streptococcus iniae and Lactococcus garvieae infections of trout share some common features, but histopathology reveals notable differences between the 2 diseases. Meningitis and panophthalmitis are the main lesions among S. iniae infected trout, whereas L. garvieae infection results in a hyperacute systemic disease. Differences in the LD50s of the 2 pathogens and the sudden onset of signs and death correlate with the histopathological findings, indicating the severity of L. garvieae infection of trout.


KEY WORDS: Trout ยท Streptococcus iniae · Lactococcus garvieae · Pathology · Experimental disease


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