The viral samples were titrated by the TCID microculture assay after 48 h incubation for HHV-1 and EMCV and 72 h for VACV-WR and DEN-2 (Rodriguez et at.
The effective concentrations ([EC.sub.50]) were 24.6, 34.2 and 21.9 [mu]g/ml for DEN-2, VACV-WR and HHV-1, respectively.
Polar compounds are expected to be responsible for the antiviral activity of the EE extract which has disclosed significant effect against HHV-1, VACV and DEN 2.
Because reaction was also found to type-specific monoclonal antibodies such as HC1, HC2, and HC3 (1), raised against gC of HHV-1, that virus was identified as the etiologic virus type.
To discriminate between HHV-1 and HHV-2, type-specific PCR was performed according to the protocol of Piiparinen and Vaheri, using their published primers (2).
Together with the reaction with different HHV-1-specific antibodies, including subtype-specific monoclonal antibodies, this was a clear indication of HHV-1 virus's being the causative agent, excluding other possible primate herpesviruses.
Moreover, HHV-1 can naturally pass to primitive primates such as tree shrews (9).
In Old World primates, reports of human HHV-1 infections (10-12) indicate a virus-host relationship similar to that in humans, although sporadic fatal cases have been described, mainly in very young animals (13,14).
An outbreak of a fatal HHV-1 infection was observed recently in a group of common marmosets (C.