Just one additional case of equine herpesvirus-1 (EHV-1) was confirmed yesterday in the outbreak that has killed a dozen horses and sickened many more. For a month, state and provincial animal health officials have been working to control the outbreak, which is believed to stem from horses that recently attended a national championship cutting competition in Utah. As the number of new confirmed cases dwindles, many believe the outbreak has reached a state of containment.

Although it’s not transmissible to humans, EHV-1 is highly contagious among horses and camelids, and it is generally passed from horse to horse via aerosol transmission (when affected animals sneeze/cough) and contact with nasal secretions. The disease can cause a variety of ailments in equines, including rhinopneumonitis (a respiratory disease usually found in young horses), abortion in broodmares, and myeloencephalopathy (EHM, the neurologic form). Myeloencephalopathy is characterized by fever, ataxia (incoordination), weakness or paralysis of the hind limbs, and incontinence.

While many states and provinces haven’t seen a new confirmed case in more than a week, officials still remain diligent in monitoring EHV-1 positive horses and those exposed to the virus after the outbreak began.

"While the number of confirmed EHV-1 cases (in Colorado) has not increased in over a week, you must all still be vigilant in caring for your horses," state Commissioner of Agriculture John T. Salazar said in a statement on the Colorado Department of Agriculture website. "Please remember to practice disease prevention within your own barns; the spread of EHV-1 is a reminder to all horse owners that disease prevention practices should be practiced as a habit and not just during times of a disease spread