According to an inaugural, multi-center report, equine herpesvirus-5 (EHV-5) is associated with a newly recognized, potentially fatal lung disease in horses called equine multinodular pulmonary fibrosis, or EMPF.

“EMPF is an important emerging disease in horses that was first recognized in 2002”, said lead author Kurt Williams, DVM, PhD, Dipl. ACVP, assistant professor in the Department of Pathobiology and Diagnostic Investigation at Michigan State University’s College of Veterinary Medicine. “EMPF is characterized by a low grade fever, weight loss, and gradual exercise intolerance.”

In this study, EHV-5 was identified in 100% of the 24 horses affected with EMPF, but in none of the horses included in the control group.

Williams explained, “This is the first published study describing EMPF and these results implicate EHV-5 as a contributor to the development of EMPF, but not necessarily as the cause of this disease.” Ongoing research is attempting to characterize the precise role of EHV-5 in this disease.

EMPF causes striking lung tissue changes in affected horses that are often quite advanced by the time of diagnosis, thereby requiring aggressive medical treatment.

“Affected horses treated appropriately have a fair to guarded prognosis, but can recover and return to training or a previous level of performance,” said Belgrave.

Williams’ study, “Equine multinodular pulmonary fibrosis: A newly recognized herpesvirus-associated fibrotic lung disease,” was published in Veterinary Pathology and has previously been covered by The Horse based on a pre-publication presentation of the study results (article #10077).

 A case series by Wong, Belgrave, and colleagues is scheduled to be published in an upcoming edition of the Journal of the American Veterinary Medical Association