TABLE 1.

Quantification of the number of infected neurons detected by immunofluorescence labeling of viral antigens^a

Time after inoculation	Virus	Total no. of neurons counted	No. (%) of antigen-positive neurons	No. (%) of antigen-positive round cellsb
18 h	GDVII	154	136 (88)
	DA		0 (0)
24 h	DA	386	6 (1.5)	18 (4.7)
48 h	DA	460	10 (2.1)	32 (6.9)
72 h	DA	561	6 (1)	40 (7)
6 days	DA	568	13 (2.2)	83 (14.6)

^aAn average of 20 fields per slide were chosen at random. Total neurons and antigen-positive neurons were counted. At 18 h postinoculation, many neurons have already been lysed by GDVII, which explains why fewer neurons could be counted. 

^bAs described in the text, antigen-positive round cells, with no morphological characteristics of neurons, were observed in cultures infected with DA virus.