Bovine herpesvirus type 5 (BHV-5) is an alphaherpesvirus associated with meningoencephalitis, a disease highly prevalent in South America. In this study, we investigated the distribution of BHV-5 DNA in the brains of latently, experimentally infected calves by using a PCR for the glycoprotein B gene. Twelve calves inoculated intranasally with a Brazilian BHV-5 isolate were divided into two groups: group A calves (n = 4) were euthanized 55 days postinoculation (p.i.) for tissue collection; group B calves (n = 8) were submitted to dexamethasone administration at day 60 p.i. for reactivation of latent infection and were euthanized 50 days later. Latent infection was reactivated in all group B calves, as demonstrated by virus isolation from nasal secretions and/or seroconversion. Three calves developed neurological disease and died or were euthanized in extremis. For group A calves, viral DNA was consistently detected in the trigeminal ganglia (4/4), midbrain (4/4), thalamus (4/4), and olfactory cortex (4/4) and less frequently in the pons (3/4), cerebellum (3/4), anterior cerebral cortex (2/4), and olfactory bulb (2/4). For calves previously submitted to reactivation (group B), viral DNA was detected with roughly the same frequency in the same areas as for the group A calves. In addition, viral DNA was detected in the posterior (5/5) and dorso-lateral cortex (3/5). All DNA-positive tissues were negative for infectivity and viral antigens. These results demonstrated that latent BHV-5 DNA is present in several areas of the brain during latent infection and that virus reactivation may result in the establishment of latent infection in additional sites of the brain.
ASJC Scopus subject areas
- Microbiology (medical)