The most important infectious disease occurring in the fish of the lakes and rivers of the Soviet Union are infectious dropsy of carps and the disease of the carp aid bladder.
The first evidence of the occurrence of carp infectious dropsy on the territory of the USSR, however, low its reliability is, reaches back to the year 1915. The disease was reported to occur in one of the carp fisheries of the Vitebsk region (Dormachev, 1916).
In the year 1932, apparently due to the import of foreign fish by the Soviet producers, a heavy dropsy infection broke out in the USSR, and its occurrence was soon common in the pond carp farms. It was at this moment that the Soviet scientists came to devote themselves to an all-round and thorough study of this disease, concentrating their efforts namely on the etiology of infectious dropsy and on the working out of good diagnostic methods and measures for its supression.