TABLE 1.

Number of infected cells in the gray and white matter of spinal cords of BALB/c nu/nu mice^a

Virus	No. of infected cells/longitudinal section
	Gray matter	White matter
DA	7.5	128.5
DA	20.5	205
DA	2.5	147
DA	11.5	99.5
GD-43	97	7.5
GD-43	43	2
GD-43	27.5	0
GD-43	24	0

^aBALB/c nu/nu mice were inoculated with 10² PFU of the DA or GD-43 virus and sacrificed 21 days later. For each mouse, two longitudinal sections of the entire spinal cord were processed for the detection of viral antigens. The sections were systematically scanned under a microscope, and infected cells in the gray and white matter were counted. The figures are the average for two sections.