A negative piroplasmosis test is starting to be a requirement at horse events across the country. In 2011, AQHA issued a statement saying ” all horses entering the grounds for any AQHA world championship show – in Oklahoma City, Amarillo or Houston – will be required to present a certificate of a negative blood test for equine piroplasmosis.” At the writing of this article, racetracks in 11 states also require a negative piroplasmosis certificate, and the number is expected to increase.
Piroplasmosis is a tick-born infectious disease that is transmitted by ticks or contaminated needles. Piroplasmosis attacks and destroys a horse’s red blood cells. The mortality rate can be as high as 20% The only known treatments for the disease are are antitheilericidal drugs and chemotherapy. Unfortunately, chemotherapy is not always effective and can cause serious side effects. Once a horse has contracted piroplasmosis, even though it may be symptom-free, it can be a carrier of the disease for life.
According to the Missouri Department of Agriculture, “an infected horse will show symptoms in mild forms such as weakness and lack of appetite. More acute cases include fever, anemia, jaundice, a swollen abdomen and labored breathing. Horses that survive the acute phase of infection may continue to carry the parasites for long periods of time. There is no cure for equine piroplasmosis.” Once a horse is exposed to the disease it can start showing symptoms in 10-30 days.
You may be asking why events are just now beginning to require a negative piroplasmosis certificate. Up until 2005, the Unites States was one of only 7 countries where piroplasmosis was not found. In 2004, a newly developed test was used to screen horses being imported to the United States. This test, competitive enzyme-linked immunosorbent assay (CELISA), was said to be a more sensitive test but it was discovered later that the test resulted in an unacceptable amount of false negatives. This resulted in the importation of infected horses into the United States.