EHV-1 (Equine Herpes Virus) is a common virus in the equine industry.  There are other herpes virus’s, but these are the most common and often misunderstood. EHV-1 shows up clinically in two major forms, the common respiratory form and the less common but much more severe neurological form. We will examine both forms of the disease in this article and take a holistic approach to dealing with these infections. Herpes virus’s can also cause abortion.

Herpes viruses do have a special trait that is different than many other viruses. The virus can hide inside the body, waiting for the immune system to become weak, when the virus comes out and causes an illness. Stress is one factor that can suppress or reduce the immune system, so horses that travel are usually more susceptible. Any other illness and many drugs can also suppress the immune system. Pay attention to things that can stress your horse, since each horse is different. 

Respiratory form

EHV-1 in the respiratory form is called Rhinopneumonitis, and is an upper respiratory infection that looks a lot like the common cold. Horses run a fever, usually have a runny nose and may go off their feed. It is contagious between horses. 

Horses most affected by “Rhino” as it is commonly called are young horses whose immune system has not been exercised by exposure to different organisms. Older or immune-compromised horses are also susceptible. Horses with a healthy immune system may get the infection, but are able to fight it off with minimal ill effects, though they become carriers. 

Neurologic form

The neurologic form of this disease can easily be fatal. Horses may show a mild upper respiratory infection before they begin to show neurologic signs. In some cases neurologic problems such as ataxia (weak and wobbly movement) are the first signs. Horses can rapidly go down and have trouble standing. If this happens, the prognosis is often poor, no matter how you treat them.

Prevention

Infectious diseases such as EHV-1 are best dealt with by having a strong immune system in the horse to fight the virus. However, not every horse has a strong immune system, and many horses have quite a bit of stress in their life. This suppresses the immune system. Horses on a show circuit traveling frequently are often very susceptible and may come home from a show with an upper respiratory infection despite conventional efforts to protect them with vaccination. 

Conventionally we are told to vaccinate, yet horses seem to acquire infections anyway when competing regularly. This is because the immune system is weakened by the stress and the overuse of vaccines. Vaccines themselves present a stress to the immune system. Show horses are often vaccinated on a quarterly basis, since immunity is thought to not last long. This frequent vaccination schedule actually weakens the immune system, leaving horses more susceptible.

Vaccines are NOT available for the neurologic form of the disease. It is not well understood why the neurologic form occurs and why the incidence of it is increasing. However, there is some evidence that over vaccinating for the respiratory form is not helpful and could possibly contribute to a worse neurologic case. Even the experts are noticing this, and it really supports the holistic thinking of improving the immune system rather than increasing the vaccinations. (http://www.vetmed.ucdavis.edu/ceh/ehv1_vaccination.cfm).

To help prevent the disease on your farm, it is good management practice to quarantine every new horse for at least 10-14 days before putting it in contact with your horses. Keep your horse away from strange horses at events, wash your hands and change clothes if you have been near infected animals. If a horse on the farm shows signs of the neurologic form, your veterinarian will help with planning a quarantine program until the danger of spread is past. 

Strengthening the immune system

The best way to prevent the infection is have your horse as healthy as possible by feeding whole foods rather than processed grains, managing stress and giving your horse as natural a lifestyle as possible. 

Supplements that support good immune system health can be used on a regular basis, or at selective times of the year when your horse is going to be under stress or exposed to outside horses, such as at a show, trail ride or clinic. Vitamin  C is well known to help support the immune system for upper respiratory infections and is quite cheap to feed. Use pure vitamin C, without filler added and feed 4-6 gm per day for an adult horse. This can be done all year long, or just for about 10 days before, during and 10 days after a stressful event.

The basis for a healthy immune system (even in the respiratory tract) is to have a healthy gut. Use pre and probiotics if there is any question about good gut health. Do not use products with preservatives and fillers as they decrease the effectiveness of the good bugs.

Echinacea is an herb that is helpful to support the immune system and is safe for long term use or during the time surrounding an event. Depending on your source for the herb, use about 2-4 times the human dose on the label, or use a quality brand labeled for horses.

Omega 3 essential fatty acids (found in flax, hemp and chia seeds) is excellent for overall immunity and is easy to feed. Many products are sold as being high in Omega 3’s but if they are processed heavily, the amount of Omega 3 may be reduced. If feeding the seeds, use about 4 ounces twice a day for an average horse. The dose can be increased very safely. 

Minerals such as zinc and selenium are used in the immune response to viral infections. Be sure your supplements contain absorbable forms of these minerals.

Treatment

If your horse becomes ill with respiratory symptoms, in most cases homeopathic remedies or a few herbs can help him recover. An experienced homeopath may need to help you decide on a remedy if you have no response to one or two remedies you select. 

If there is some nasal discharge, Pulsatilla 30C or 30X is an excellent starting point. Give 6-8 tabs twice a day for 2-3 days. The horse should be recovering in that time. If you are in a situation where you catch the fever early, before too many symptoms are showing up, often several doses of Aconite can prevent an infection or help it to be milder than it would have been. 

Antibiotics many be offered by a veterinarian, but they have no effect on a viral infection and so should not be used. The homeopathics will stimulate the immune system to do its job. A holistic veterinarian can help you get through  most infections quite easily.

The neurologic form of the disease is much more serious and requires the help of a holistic veterinarian, often along with a conventional vet to give some supporting treatments such as fluids. Do not try to treat one of these your self. 

Conclusion

Most cases of EHV-1 are preventable or mild respiratory diseases, similar to the common cold. In young horses, the disease is often just a nice bit of exercise for the immune system, in older horses it may be insignificant. Horses under stress or with a poor immune system are more likely to become sick. The neurologic form is rare and very serious. The take-home lesson for this disease is to work on the immune system of your horse.