Serodiagnosis of herpesvirus infection in primates

The presence of herpesviruses in various animal tissues used for vaccine production is of importance, inasmuch as these viruses may go unrecognized, residing in latent form. Of greatest concern is Herpesvirus simiae (B virus) present in the majority of macaca species, one of the more extensively used laboratory nonhuman primates. The close antigenic relationship of B virus to human herpes strains (H. hominis) and SA8 (a baboon herpesvirus) makes serologic differentiation extremely difficult, but necessary. Complicating the differential diagnosis is the frequent infection of simian species with human strains. The present study clearly shows that many animal sera negative to herpes simplex will be negative to B virus in the neutralization test. However, a sufficient number of sera will be negative to simplex, but positive to B virus, indicating that the assumed one-way cross is invalid. Also, if antibody to simplex is present, and this antibody is present in most adult macaques, then differentiation requires testing with B virus. At least 50% of these positive sera may appear to be negative for B virus if only tested with H. hominis. Approximately 25% of the remaining positive sera will have higher titers to B virus than to herpes simplex and 25% will have the same titers to both viruses. Further, complement is required by many of the test sera to detect the presence of antibodies to B virus.