Characterization of a herpesvirus, isolated from a calf, with nervous signs and no specific humoral immune response

Abstract

An herpesvirus, isolated from a nine month old calf, with neurological clinical signs, unilateral ocular and nasal discharge was characterized as Bovine Herpes Virus-1.1 (BHV-1.1). Nasal, ocular and prepucial swabs were collected and supernatants were inoculated in Madin Derby Bovine Kidney cells. Only the nasal and ocular inoculates from the first three days after clinical signs appeared, produced herpesvirus characteristic citopathic effect. The isolate (Uy-1999) was identified as herpesvirus by direct immunofluorescence, characterized by restriction enzyme genomic profile, polymerase chain reaction and immunohistochemistry. Even though the isolate Uy-1999 is immunogenic for other bovines, the animal from ehich the isolation was made, never produced BHV specific antibodies, while it did to other pathogens as bovine viral diarrhea virus. The results obtained up to now suggest that the lack of humoral immune response is not due to an antigenic variation of the isolate. If the existence of BHV-1 latently infected bovine is not an isolated issue, the tests used in the control campaigns should be reviewed.