Antibodies against equine herpesvirus 1 in the cerebrospinal fluid in the horse.

Neutralizing antibodies against equine herpesvirus 1 were measured in serum and cerebrospinal fluid of 16 horses and ponies from a closed herd both before and after vaccination with modified live equine herpesvirus 1. These titers were also measured in 22 neurologically normal and 15 neurologically abnormal horses at a teaching hospital. Animals from the closed herd had prevaccination serum titers up to 1:8 and postvaccination serum titers up to 1:128. Horses from the teaching hospital had serum titers up to 1:64. Cerebrospinal fluid titers were not detected in the vaccinated horses or the neurologically normal horses but a low titer (1:8) was noted in one neurologically abnormal horse. This titer probably resulted from hemorrhage into the cerebrospinal fluid following trauma.