Equine coital exanthema (ECE) is a highly-contagious, venereally transmitted disease of breeding horses caused by the equine herpes virus 3 (EHV-3). ECE is found in breeding mares and stallions worldwide. ECE is characterized by the development of lesions on the external genitalia of horses. Lesions might also occur on teats of mares and muzzles of nursing foals.

Clinical signs
During the early stages of the disease, circular lesions appear on the horse's genitals. Vesicles are initially present which rupture and result in small, crater-like lesions, often with a pustular center.

Transmission
ECE is transmitted through direct skin-to-skin contact during breeding activities between horses, during artificial insemination, from the hands of people interacting with horses, or from the lips and nose of horses interacting with one another. There is also a risk of the virus spreading by either fresh or frozen semen as well as by artificial insemination and embryo transfer.

Incubation period
ECE has an incubation period between 7 to 10 days.