Published May, 2014

The University of Kentucky Veterinary Diagnostic Laboratory sent a reminder recently that all contagious equine metritis (CEM) samples should be collected by a veterinarian and in accordance with a United States Department of Agriculture protocol (Version 9 CFR 93.301). CEM is a sexually transmitted disease in horses.

The guideline said that, per USDA guidelines, veterinarians must use a rayon-tipped swab of small diameter (~.1 cm) during collection from the clitoral sinuses. The UKVDL requests that future submissions from clitoral sinuses for CEM culture should be collected in this manner. Other types of swabs might be rejected as the sample may not be of high quality.

Stallions are asymptomatic (showing no clinical signs) carriers of Taylorella equigenitalis, CEM's causative agent, while mares show distinct clinical signs when exposed to and infected with CEM.

When a mare has CEM, about a week after breeding she will begin to show distinct clinical signs, including a noticeable vaginal discharge. The economic impact of a mare with CEM is that she will not become pregnant.

The first CEM outbreak occurred in Ireland and England in 1978 through natural breeding in the Thoroughbred industry. In 1979 the first CEM outbreak occurred in Lexington, Kentucky, when two stallions were imported from Europe. This triggered a response from the United States on regulation control of imported stallions. Today, imported stallions and mares are tested for CEM.

The swab can be purchased from Difco Laboratories at 313/442-8800. For more information, contact Erdal Erol, DVM, PhD, head of diagnostic microbiology at the UKVDL.

Jenny Evans, MFA, is the marketing and promotion specialist senior at the Gluck Equine Research Center.