A new method for monitoring subclinical virus infections of the central nervous system in mice.
The course of a subclinical virus infection of the central nervous system (CNS) of mice has been followed by measuring spontaneous motor activity using Animex equipment. A significant drop in activity occurred on the 5th and 6th day after inoculation with the A774 (avirulent) strain of Semliki Forest virus (SFV) before histological changes were apparent but at the same time as maximum brain virus titre. The relationship of the fall in activity to changes in the pattern of weight gain, food and water intake was also investigated.