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PIROPLASMOSIS
and Head of Clinical Pathology at the Irish Equine Centre, County Kildare, Ireland. “We investigated a poor performance episode in a racing yard here in 2009. Three horses were anemic with no obvious cause and no history of importation. The stable contained some 60 horses in training at this time. More than 40 were shown to be piroplasmosis positive on further investigation,” Leadon recalls. “There was no evidence of spread and the outbreak was subsequently officially declared over within three months of the diagnosis.” Because Ireland does not have the tick vectors (needed to spread the disease), the presumptive causation was iatrogenic. That is, spread from humans to horses via medical or other equipment. Leadon adds, “This episode heightened our awareness of the disease.” No testing for piroplasmosis is necessary
for any horse being imported into Ireland. In contrast, all horses being imported into the U.S. (except those from Iceland and Canada) are required to be tested cELISA negative at the U.S. import center before they are granted entry. In England “There is free movement of horses throughout the European Union without restrictions,” relays Fred Barrelet, an equine surgeon from Rossdale & Partners, in Newmarket, U.K., despite the occurrence of piroplasmosis in the Republic of Ireland in 2009 and in the U.S. since 2009, Just like Ireland, horses do not require any form of testing for piroplasmosis to enter the U.K. In fact, even horses being imported to England from piroplasmosis endemic regions in Europe are moved freely to and from the U.K. Even piroplasmosis positive horses are routinely moved into the
The Troublesome Tick Most of the ticks in the United States are not able to transmit the parasites that cause piroplasmosis (B. caballi and T. equi). In the United States, only Dermacentor nitens, D. variabilis, and Amblyomma cajennense are known to transmit piroplasmosis. These ticks are only found in specific regions of the U.S., which limits the natural spread of the disease. Other ticks, however, are still capable of transmitting important infectious diseases to horses. Lyme disease, for example, is spread by ticks. Other diseases spread from ticks to horses include: Equine Ehrlichiosis; Colorado Tick Fever; Tularemia; Tick Paralysis; and Equine Granulocytic Anaplasmosis
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