Equine piroplasmosis is a tick-borne protozoal infection of horses. Piroplasmosis may be difficult to diagnose, as it can cause variable and nonspecific clinical signs. The symptoms of this disease range from acute fever, inappetence and malaise, to anemia and jaundice, sudden death, or chronic weight loss and poor exercise tolerance. Piroplasmosis is a major constraint to the international movement of equines. Although this disease was formerly endemic in Florida, the organisms were eradicated by the 1980s and piroplasmosis is considered to be an exotic disease in the United States. However, false negatives can occur in the complement fixation test, which was used for import testing until 2005, and there is a possibility that some horses in the U.S. might be inapparent carriers. In 2008, an outbreak occurred at a facility in Florida, highlighting the need to maintain constant vigilance for this disease.