The Presence of a Bacteriophage for B, salmonicida in River Waters

Abstract

EPIDEMICS of “Furunculosis of the Salmonicidæ” generally attributed to a well-defined bacterium— B. salmonicida (Emmerich and Weibel, 1894)—have been the cause of a high mortality among salmon and trout in England during recent years and have been difficult to deal with owing to a lack of know ledge of the epidemiology of the disease and particularly of the reservoirs of the infection during inter-epidemic seasons. The problem of following out the infection is not easy as B. salmonicida has no saprophytic existence in river water, in which it does not live for more than a few days, so that it is useless to attempt the isolation of the bacillus from the suspected water—even if this were a practical possibility. Moreover, the absence of sick or dead fish does not exclude the possibility of infection, as apparently healthy fish are known to act as carriers of the disease and to be capable of spreading the infection.