Lymphocystis disease of fish.

Viruses are submicroscopic absolute parasites which are utterly dependent upon living cells for their reproduction and which in fact cannot be propagated in the absence of living cells. Lymphocystis is a virus-caused disease of fishes. It is a chronic disease and is seldom, if ever, fatal. Lymphocystis is easily transmitted between species, but less between genera. Topics discussed are: (1) identification, (2) cause of the disease, (3) source and reservoir of infection, (4) mode of transmission, (5) incubation period, (6) period of communicability, (7) susceptibility and resistance, (8) range, (9) occurrence, and (10) methods of control.