The clinical picture and laboratory findings in the case of a purely systemic infection with EEE virus are described. Another case is described in which the relationship between the EEE infection and the clinical picture is problematical.
Virus was isolated from the blood of the first case, and serologic studies were carried out with paired sera from that case and a single specimen from the second case. Specific serologic diagnosis was possible by means of either neutralization or HI tests, but the CF test was found to be too insensitive to detect significant antibody levels in these sera.
Previous infection with a related virus was recognized to have occurred in one case and to have influenced the pattern of HI response. The possible protective effect of this previous infection against serious consequences of the current EEE infection is mentioned.