Horse Rhino Flu

Information on the symptoms of rhinovirus (herpes virus) in horses.

Addison's disease symptoms in dogs and cats

Select a Topic

  1. What is Rhino Flu?
  2. What Causes Rhino Flu?
  3. Diagnosing Rhino Flu
  4. Help for Rhino Flu
  5. More Information on Rhino Flu

What is Rhino Flu?

Rhino flu, also known as rhinopneumonitis in horses, is an upper respiratory disease caused by the equine herpes virus. It affects the mucous membranes of the nasal cavities and lungs. Although this disease is not life-threatening, it can cause serious health complications which affect the respiratory, reproductive and nervous system of the horse.

What Causes Rhino Flu?

Most adult horses are exposed to the equine herpes virus during their first months of life. The virus usually affects the horse’s respiratory system but remains dormant for the rest of his life with the help of the immune system.

If the immune system is compromised in any way, the virus will cause respiratory symptoms. Rhino flu can also cause abortion in a pregnant mare if infected with the virus. The virus can also attacks the spinal cord and cause neurological symptoms. If treated early, symptoms can be reduced and managed.

Diagnosing Rhino Flu

The diagnosis of rhino flu is based on the symptoms, a complete physical examination and review of the horse’s medical history. Certain diagnostic tests such as x-rays, thoracic ultrasound, endoscopic examination, fine needle aspiration and lung biopsy may be performed to confirm the diagnosis.

Symptoms and signs

The common symptoms and signs of rhino flu include:

  • Fever
  • Loss of appetite
  • Lethargy
  • Nasal membranes and eyes redden and tear
  • Nasal discharge
  • Dry, hacking cough
  • Stocking up and heat in the lower legs
  • Swollen, enlarged lymph nodes in the neck


Help for Rhino Flu

Treatment of rhino flu involves certain medications, supportive care and adequate rest. Medications such as antibiotics may be prescribed to treat secondary infections. A vaccination program is very important to protect against infection.

Pregnant mares require the rhinopneumonitis vaccine at least three times during the gestation period (months 5, 7 and 9) to prevent abortion. If your horse lives in isolation, an annual vaccination is usually sufficient.

Young horses should also receive the vaccine every 2 to 3 months while horses that move around a lot should be vaccinated at least 4 times per year. These vaccinations, however, are not that effective and cannot protect against neurological disease.

Avoid giving your horse human cough syrups or decongestants as these are potentially dangerous. In order to speed recovery, a comfortable, dry but well ventilated barn or stable, adequate rest, palatable foods as well as plenty of fresh, clean water and tender loving care are essential.

More Information on Rhino Flu

Tips to prevent rhino flu

There are a number of things that horse owners can do to prevent an episode of rhino flu affecting their horse and these include:

  • Feed your horse high quality hay or grain
  • Always ensure that your horse has access to fresh, clean water
  • Make sure that your horse’s stable is well ventilated – always keep the top half of the stable door open
  • Reduce exposure to dust and allergens to facilitate easier breathing
  • Boost your horse’s immune system with immune-boosting supplements and antioxidants
  • Separate young horses from older horses if rhino flu has developed amongst the herd
  • Change bedding regularly and check for bedding soaked with urine – use fresh shavings or shredded paper in peat instead of straw
  • Ensure that horses are kept warm and dry in cold and wet conditions as well as after exercise
  • Make sure that your horse’s vaccinations are updated to prevent infections
  • De-worm your horse regularly


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