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The importance of venereal modes of B virus (cercopithecine herpesvirus 1) transmission was evaluated in 49 rhesus monkeys tested at necropsy. Antibodies to B virus were demonstrated in 19 monkeys, but no active viral shedding was detected in mucosal swabs collected at death. The polymerase chain reaction demonstrated presence of the ICP 18.5 (UL28) gene of B virus in neuronal tissues of 15 monkeys presumed to be latently infected, including 12.8% of trigeminal and 22.9% of lumbosacral ganglia pools. Two monkeys tested positive at both sites. Breeding history was predictive of B virus seropositivity (odds ratio, 1.64; 95% confidence interval, 1.21-2.23; P < .05). The population attributable risk of B virus seropositivity due to breeding was 22.7%, similar to the proportion of monkeys with B virus DNA in neuronal tissues subserving the genital region. Sexual contact is a significant, but not predominant, mode of B virus transmission between monkeys.

Three men who had worked at the same animal research facility and had had contact with macaque monkeys were infected with B virus (Herpesvirus simiae). Their clinical presentations varied from self-limited aseptic meningitis syndrome to fulminant encephalomyelitis and death. Patient 1 was treated only after a respiratory arrest and other signs of advanced brain stem dysfunction had occurred. He died 8 days after hospital admission, despite treatment with acyclovir. Patient 2 presented with subtle signs and symptoms of brain stem encephalitis. He received antiviral therapy with intravenous ganciclovir. Patient 3 had a headache without meningismus and was also treated with acyclovir. Both patients 2 and 3 survived and did not have objective sequelae. Viral culturing, ELISA and western blot antibody testing, and magnetic resonance imaging all proved useful in the diagnosis of these patients' conditions.

Rapid diagnosis of B virus (herpesvirus simiae) infection in humans followed by early antiviral treatment is essential for the patient's survival. To improve laboratory diagnosis of B virus infections, a polymerase chain reaction (PCR)-based test using synthetic oligonucleotide primers and probe was developed to detect B virus DNA in clinical samples. After the specificity of the PCR was assessed for detection of several B virus isolates, the method was used to investigate human and monkey specimens, and results were compared with those obtained by viral culture. PCR appeared to be more sensitive than conventional virus isolation and thus of practical use for a rapid identification of B virus infection when conventional viral cultures are negative.

The epidemiology of B virus infection in a large (n = 157) cohort of rhesus macaques at the California Regional Primate Research Center was evaluated prospectively from September 1989 through January 1991 by serial physical examinations, a behavioral substudy (n = 51), and repeated diagnostic testing. Half were B virus antibody-positive at baseline; subsequently, incident cases of infection were documented through serology alone (42) or with virus isolation (5). Eight recurrent infections and a single symptomatic (primary) case were observed. Risk of B virus infection increased as monkeys aged, with few > 3 years old remaining uninfected. Postpubertal monkeys and those entering sexual adolescence (2-3 years) were at greatest risk, although wounding by cagemates and breeding history (for females) were both significant predictors of time to infection. B virus was isolated from oral or conjunctival and genital tissues in equal proportions. Transmission occurred only during the breeding season, possibly coinciding with an elevation in social stressors in the population.