Pulmonary Fibrosis - Latest & Greatest From The AAEP Forum
The American Association of Equine Practitioners (AAEP) is currently having their annual forum in San Diego, California. Veterinarians from all over the world come to this conference to learn about the latest advances and techniques in veterinary medicine, with the goal of promoting and improving the health and well-being of horses everywhere.
A very popular session at the AAEP convention is the Kester News Hour, which covers some of the most recent reports in the veterinary literature. One of the topics that was discussed this year was pulmonary fibrosis in horses. This is a very severe condition that tends to occur in older horses (average 14.5 years old) but can occur in horses as young as four years old. Affected animals may have a severe cough and a lot of trouble breathing, and they can also have a fever and an increased number of white blood cells in their bloodstream. These signs can also be seen in horses with pneumonia, so it’s important for a veterinarian to carefully examine the horse, the horse’s medical history, and the results of diagnostic tests in order to tell the difference. In horses with pulmonary fibrosis, tough fibrous connective tissue forms throughout the lungs, which interferes with the ability of the lungs to expand and collapse with normal breathing. Pulmonary fibrosis is a devastating condition that has a very poor prognosis for recovery.
There are several known causes of pulmonary fibrosis, including a condition known as silicosis, and injection of certain immunomodulatory drugs. However, the cause in the majority cases still remains unknown. Through the persistent and meticulous work of some dedicated researchers (Williams et al. 2007), it has been found that a virus, equine herpesvirus type 5 (EHV-5), may be involved in many of these cases. In their study, the virus was found in 19/24 affected horses, and only 2/23 control horses (horses without pulmonary fibrosis). There is not yet enough information to be able to say that EHV-5 infection is a cause of pulmonary fibrosis, but there does appear to be an association. More work will certainly be done to determine what roll EHV-5 may play in this terrible disease. If there is an infectious component, then preventing transmission of pathogens through basic infectious control practices that we always talk about (e.g. preventing nose-to-nose contact between horses, washing your hands between handling different horses, isolating “stressed”/sick horses that may be shedding virus, etc.) may be beneficial for preventing pulmonary fibrosis as well. Keep watching for more information from the conference!
