Some properties of the virus of duck plague

Experiments were conducted to determine some of the physical and chemical characteristics of duck plague virus. As measured by filtration through membranes of graded porosity, the infectious particles were more than 100 mμ in diameter but less than 220 mμ The virus is sensitive to ether and chloroform and has the acridine orange-staining characteristics of DNA. Its infectivity is destroyed by heating at 50° C for 2 hours or at 56°C or 60°C for 10 minutes. At 22°C infectivity declines slowly and is no longer detectable after 30 days. Drying over calcium chloride at 22° C results in complete inactivation in 9 days. The virus is fairly stable over the pH range from 5 to 10 but is very rapidly inactivated at pH 11 or higher and pH 3 or lower. Infectivity is destroyed by trypsin, chymotrypsin and pancreatic lipase.