Furunculosis of Fish 



No fish disease is to be feared more by the hatchery man than 

 furunculosis, or the "great red plague" of salmon and trout. In 1935, 

 Fish stated that this disease had spread throughout regions of the 

 United States and Canada to such a degree that it threatened our entire 

 system of artificial propagation of salmon and trout. The shipping of 

 infected hatchery fish has established this disease in many American 

 trout and salmon hatcheries. Of still greater importance is the 

 possibility that furunculosis may become well established among wild 

 trout through planting of infected fish. 



Although furunculosis in wild trout of North America has by no 

 means assumed epidemic proportions., in Great Britain this disease became 

 so serious that a committee was formed to study ways of combating it 

 (Furunculosis Committee ^ 1930^ 1933;, 1935). In two rivers of Great 

 Britain, which were by no means first class, the losses over periods of 

 3 and 6 years were $63 000 and $3,600. In other rivers these figTires 

 were even exceeded (Furunculosis Committee 1933)- 



Furunculosis was originally described from hatchery fish in Germany 

 by Bnmerich and Weibel (1894), who found the causative agent to be a 

 bacterium which they named Bacterium salmonicida . After their description, 

 the disease was commonly recognized in German trout hatcheries where it 

 was believed to be strictly a hatchery disease (Fish 1937). Plehn 

 dispelled this belief in 1909 by finding furunculosis among wild fish in 

 the Province of Bavaria. Extensive studies by this author in 1909 and 

 1911 revealed the existence of the disease in wild trout taken from 25 

 rivers and streams of that Province. Shortly after this, furunculosis was 

 found in other parts of Germany, in France, Austria, Belgium, and 

 Svd.tzerland (Fuhrman 1909, Pittet 1910, Surbeck 1911). The disease was 

 first observed in Great Britain among mature salmon from four rivers 

 (Masterman and Arkwright 1911). Three years later it was found among 

 salmon in Ireland by Mettam (1914). In recent years an epizootic 

 disease occurred among trout farms in Japan which was thought to be 

 furunculosis (Furunculosis Committee 1933). 



The first definite proof that furunculosis existed in the Western 

 Hemisphere was offered by Marsh (1902) who found it to be the cause of 

 an epizootic among hatchery fish in Michigan. It has since been found 

 in many salmon and trout hatcheries throughout the United States 

 (Fish 1937), and Smith (1942) estimated that it has occurred in more 

 than one-fotorth of the United States. 



Up to 1937, furunculosis had not been reported from wild fish in 

 the United States (Fish 1937). In 1937 furunculosis was described in 

 adult Loch Leven trout ( Salmo trutta levensis ) in incoming under 

 circumstances indicating that it was not merely a hatcheiy epidemic 

 transplanted to open waters, but the true establishment of the disease 

 among wild stock (Fish 1937). 



