Disseminated necrotizing myeloencephalitis: a herpes-associated neurological disease of horses.

The research paper discusses a neurological disease in horses that is associated with the equine viral rhinopneumonitis type I virus, causing widespread tissue death in the spinal cord and brain. The disease was observed in several horses who had been paralysed or weak for several weeks and showed symptoms after exposure to a respiratory disease.

Isolation of Equine Viral Rhinopneumonitis Type I Virus

• The researchers isolated the virus from the spinal cord and brain of a horse that was suffering from paraparesis, a condition characterized by partial paralysis or weakness in the limbs. This horse also had disseminated necrotizing myeloencephalitis, a severe brain and spinal cord disease characterized by widespread inflammation and tissue death.

Presence of Necrotic Arteriolitis and Gasserian Ganglioneuritis

• Upon investigation, the researchers also discovered necrotic arteriolitis in the horse, a condition where the small arteries undergo necrosis, leading to tissue death.
• Gasserian ganglioneuritis, an inflammation of the gasserian ganglion which is a cluster of nerve cell bodies, was also present in the horse. This condition can cause severe pain and sensory disturbances.

Evidence from Previous Cases

• Historical data revealed twelve additional cases of horses with similar lesions. These horses had been suffering from ataxia (lack of muscle control) or paralysis for several weeks, similar to the initial case. This added evidence supports the conclusion that the equine viral rhinopneumonitis type I virus is linked to the severe, necrotizing neurological disease in horses.

Field Survey and Connection to Respiratory Disease

• A significant finding from a field survey was that out of 24 horses showing signs of acute myelitis (inflammation of the spinal cord), 14 had developed these symptoms after recent exposure to a respiratory disease. This connection suggests that the respiratory disease could play a role in the development of the neurological condition or that the two illnesses may have a common causative agent, such as the equine viral rhinopneumonitis type I virus.