Source: Texas Animal Health Commission
Texas Animal Health Commission (TAHC) confirmed equine herpes myeloencephalopathy (EHM) in a mare at a breeding farm in Cooke County on May 24. The affected farm was placed under quarantine and restricted from moving animals and semen.
Since the original EHM-positive horse, six additional horses on the premises have tested positive for the neuropathogenic strain of EHV-1. One of the test positive horses exhibited neurologic signs consistent with EHM, bringing the total number of EHM cases at this facility to two.
TAHC staff worked closely with the facility management and veterinarian to implement testing protocols and biosecurity measures. All affected horses (seven) on the premises were removed to an isolation area after being diagnosed. The remaining animals in the barn were monitored for elevated temperatures twice daily. Movement restrictions on these horses were lifted once they tested negative on nasal swabs taken 14 days after the affected horses were removed.
The seven affected horses are recovering and doing well at this time. They will remain under quarantine until all test negative on nasal swabs.
The equine industry is encouraged to obtain the latest information on this outbreak and other disease events across the country by visiting the Equine Disease Communication Center at equinediseasecc.org.
Equine herpes myeloencephalopathy (EHM) is a neurologic disease of horses linked to the equine herpes virus (EHV-1). EHV-1 in horses can cause respiratory disease, abortion, and neonatal death. Neurological signs appear as a result of damage to blood vessels in the brain and spinal cord.
EHV-1 is easily spread and usually has an incubation period between 2-10 days. Respiratory shedding of the virus generally occurs for 7-10 days, but may continue longer in infected horses. For this reason, a 21-day isolation period of con rmed positive EHM cases is suggested.
Clinical signs of EHM in horses may include:
- Fever of 102°F or greater. Fever most often comes before neurologic signs
- nasal discharge
- lack of coordination
- hindquarter weakness
- leaning or resting against a fence or wall to maintain balance
- urine dribbling
- head tilt
- diminished tail tone
- penile paralysis
Consult your veterinarian if your horse exhibits any of these signs. Click here to download an informational brochure about EHM. (pdf)