A recent report in the magazine of the Texas Equine Veterinary Association is by Dr. Claire Freeman on the subject of a fairly new respiratory disease in horses called equine multinodular pulmonary fibrosis, or EMPF. This disease was first described only five years ago and there have only been 42 documented cases since that time. However, there are probably many more cases that have gone undiagnosed due to a lack of complete testing. Dr. Freeman’s case was a 20-year old quarter horse that was having difficulty breathing, an increased temperature for over a month, and decreased appetite and weight loss. The horse was treated with antibiotics and responded while on medication but relapsed when antibiotics were stopped.

This horse appeared to have pneumonia but because he did not respond to antibiotics, he was referred to LSU. Further testing included getting a sample out of the airways in the lungs as well as an ultrasound of the lung area. No bacteria or fungi were found in the lungs but an unusual herpes virus called equine herpes virus 5 was found. This virus has been associated with EMPF and the condition is characterized by pulmonary fibrosis or scarring in the lungs. Unfortunately, the disease changes in the lungs are mostly permanent as most horses do not survive. The horse in this case did not survive in spite of therapy with steroids and antiviral drugs. Both of these therapies are questionable as the cause of the syndrome is still not proven and therefore this makes the treatment difficult. This case illustrates that if a horse does not respond to routine treatment in a short period, further testing should be sought quickly.