5. B. salmonicida is aerobic and facultatively anaerobic, grows 

 well on agar and in broth, but poorly on potato. It produces a brown 

 pigment on culture media only under aerobic conditions. 



6. The organism liquefies gelatin and serum media. It does not 

 produce indole but ferments glucose, mannite, galactose, levulose, 

 maltose, and salicin. Sucrose, lactose, dulcite, and raffinose are not 

 fermented. 



7. The organism gives rise to complement fixation and 

 agglutination with specific antisera. 



8. Smooth (S), rough (R), and G-type colonies of B. salmonicida 

 have been demonstrated. The smooth type organism is pathogenic and 

 rough nonpathogenic. The organism falls into two groups with respect 

 to R and S phases s Group I, R = S plus n; Group II, S-j_ = R^ plus n-|_. 



9. A bacteriophage has been demonstrated, but it is difficult 

 to correlate it with tlie distribution of the disease. It has been 

 associated with infected organs of fish and is quite specific. Its origin 

 is obscure. 



10. The disease is a general infection, affecting the kidney, 

 spleen, liver, and muscular tissues. There may be congestion of blood 

 vessels in the abdominal cavity and a discharge of blood and mucus from 

 the vent. Topical lesions are areas of necrosis. No active toxin has 

 been demonstrated, but the organism is proteolytic. Leucocytic 

 infiltration is not outstanding in furunculosis. 



11. In the Salmonidae the order of susceptibility is brown trout, 

 brook trout, and rainbow trout. Many other fresh water fish are also 

 susceptible. 



12. The disease is spread by water and food. Carriers of the 

 disease are an important reservoir. Migratory Salmonidae, however, are 

 not thought to be important in the spread of the disease. 



13. High temperature and low water levels favor the prevalence 

 of the disease. The temperature must be within 55° to 66° F. before 

 an important epizootic will take place in nature. The role of water 

 pollution in the spread of the disease is undecided, 



14-. Diagnosis depends on culturing the causative organism. 

 Confirmation may be obtained by injecting the organism into a fish or 

 frog. 



15. Furunculosis differs from ulcer disease in several respects. 

 The lesions of ulcer disease are clear-cut, and their contents easily 

 washed away. Ulcers of furunculosis are ragged and deep red in color. 



71 



