Recognizing and Preventing Equine Herpesvirus (EHV)

Who passed on the message to Pennsylvania horse owners? An unwanted visitor: Equine Herpesvirus (EHV). Recently, a horse in Cambria County tested positive. Unfortunately, this led to the animal's euthanization. Everyone wants to prevent an encore of this heart-breaking event. So, let's delve into the facts behind this contagious, multifaceted virus. The horse owned by Cambria County residents tested positive for EHV, shedding light on the need for further awareness and preventative measures. The other four horses on the same farm were exposed, leading to an imposed quarantine.[1]

Understanding the Enemy: EHV

EHV, notorious for being a highly communicable virus, can trigger several health complications in horses. From rhinopneumonitis, a common respiratory illness in juvenile horses, to abortions in expecting mares and Equine Herpes Myeloencephalopathy (EHM), the virus rears its ugly head with different symptoms.[2] Typically, the first and often unnoticed sign of EHV-1 infection is fever. Although it can go unnoticed, the presence of other symptoms like cough, reduced appetite, despair, and nasal discharge, particularly in young horses, should serve as warning signs. Mares usually display no apparent signs of infection before they miscarry. The time-frame for an abortion can vary, often occurring late - around the eighth month of gestation - but can sometimes take place earlier. Abortions can happen anytime, from two weeks to a few months following an EHV-1 infection. Horses with EHM initially show signs of fever and may portray symptoms of a respiratory infection. A few days later, however, they may exhibit neurological signs such as ataxia or incoordination, limb weakness, urine retention and dribbling, loss of tail tone, and recumbency or an inability to rise.

How EHV Spreads and Preventative Measures

EHV is transmitted through close or nose-to-nose contact with an infected horse, sharing of contaminated equipment, or through people's clothing, hands, or equipment used with an infected horse. Therefore, habitual cleanliness, basic disinfection practices, and general biosecurity measures should always be in place to control disease spread. Current EHV-1 vaccines may curtail viral shedding but do not offer protection against the neurologic EHM form. The greatest defense against disease spread is disease prevention through routine biosecurity practices. Breeding a healthy and happy horse isn't a walk in the park. It comes with numerous trials, including the threats posed by diseases like EHV. But by staying informed and implementing solid preventative measures, we can lessen the risk our equine companions face. References: [1] The Horse: Your Guide to Equine Health Care ( [2] American Association of Equine Practitioners ( Please consult a qualified veterinarian to guide diagnosis, therapy, and treatment.