04/04/2026
Thanks The Plaid Horse for such a great article. Dr Lewis is the best!
Whether returning home after a thrilling summer competing on the European circuits, traveling from a home base abroad, or importing a newly purchased equine, every horse entering the United States must follow specific guidelines based on the country of origin. Once the horse “clears customs” at the airport, satisfying United States Department of Agriculture (USDA) import requirements, there’s one more thing owners must consider before their horse reaches its final destination.
Mares and stallions remaining in the U.S. beyond the temporary stay period must undergo additional quarantine for Contagious Equine Metritis (CEM). This sexually transmitted bacterial infection can cause infertility in mares and is carried by stallions. While endemic in Europe, the disease is not currently in the U.S., so testing and quarantine for horses entering the country from areas with confirmed cases are essential to maintain that disease-free status.
Fortunately for horses traveling to Florida, Palm Beach Equine Clinic’s Jordan Lewis, DVM, works closely with Richard Faver at Ossian Ventures, one of the largest commercial CEM quarantine facilities in Florida, to oversee and conduct the rigorous testing process, which differs based on whether the animal is a mare or stallion.
“Mares are usually with us for about 15 days. They need three sets of negative cultures, 72 hours apart, and then five days of washing with chlorhexidine and applying silver sulfadiazine as a topical treatment, which we call ‘clean and pack,’ ” says Dr. Lewis, adding that they take samples from three areas of the mare and also pull a blood test, called a complement fixation (CF). The CF results and each set of cultures must be sent by mail to a lab for testing, and turnaround times are about a week for the cultures and a few days for the blood.
For stallions, the process takes about 35 days. Within the first few days, a culture is taken from the stallion and sent for testing.
“When the culture comes back negative, we have a set of mares called test mares that are cycled and ready to breed,” she said. “Those stallions live cover two test mares, which then start getting cultured on day three post-breeding. They go through the same process as the other mares: three sets of cultures, 72 hours apart. Twenty-one days after breeding, they do the CF test on those mares.”
📎 Continue reading this article at https://www.theplaidhorse.com/2026/04/02/the-last-leg-of-international-travel-cem-quarantine/
📸 Courtesy of Dr. Jordan Davis
