Experimental propagation of lymphocystis disease of fishes

The agent of lymphocystis disease has been propagated under laboratory conditions for more than 2 years. Although several hatchery-propagated centrarchids are susceptible, the bluegill (Lepomis macrochirus) is the host of choice because it is most easily maintained. At 12.5° the disease was transmitted by implantation and by injection, but there was no evidence of fish-to-fish spread, nor seasonal change in host susceptibility. The infective agent was clearly demonstrated to be filterable (Millipore HA). It retained infectivity in storage at −20° for almost two years, and its viability after desiccation was confirmed. These facts support its postulated viral nature. The virus was glycerol- and ether-sensitive and did not induce formation of giant lymphocystis cells in monolayer cultures of bluegill ovary cells.