Due to the exposure of horses on the West Coast to Equine Herpesvirus at the NCHA Western Nationals in Ogden, Utah, the PCCHA announced this afternoon that they have cancelled the PCCHA Tejon Ranch Cutting, May 19-22, held at Lebec, Calif. A horse at Ogden died and three horses died at the Bakersfield cutting, which was held just prior to the Tejon cutting.
A press release from the Animal Health Division of the California Department of Food and Agriculture says the outbreak of Equine Herpes Myeloencephalopathy (EHV-1) has been traced to horses who attended the NCHA Western National Championships in Ogden, Utah, on April 30-May 8, where many of the horses who participated in the event may have been exposed.
They encourage owners of horses who participated in Ogden to isolate and monitor their horses for clinical signs of disease. A rectal temperature in excess of 102F commonly precedes other clinical signs and they are urging owners to take temperatures twice a day. If temperatures are above 102F, owners are urged to contact their veterinarians. Laboratory submission of nasal swabs and blood samples collected from the exposed horse can be utilized for virus detection and isolation.
The EHV-1 organism spreads quickly from horse to horse and the neurologic form of the virus can reach high morbidity and mortality rates. The incubation period of EHV-1 is typically 2-10 days. In horses infected with the neurologic strain of EHV-1, clinical signs may include: nasal discharge, incoordination, hind-end weakness, recumbency,lethargy, urine dribbling and dimished tail tone. Prognosis depends on severeity of signs and the period of recumbency.
There is no specific treatment for EHV-1 but it could include intravenous fluids and anti-inflammatory drugs. Currently there is no equine vaccine that has a label claim for protection against the neurological strain of the virus.
Horse-to-horse contact, aerosol transmission and contaminated hands, equipment, tack and feed all play a role in disease spread. However, horses with severe clinical signs of neurological EHV-1 illness are thought to have large viral loads in their blood and nasal secretions and, therefore, present the greatest danger for spreading the disease. Immediate separation and isolation of identified suspect cases and implementation of appropriate biosecurity measures are key elements for disease control.