Respiratory disease in performance horses

Respiratory diseases are a common problem for horses worldwide that can prevent them from functioning athletically. A year long study of U.S. horses which resided at operations other than racetracks found that an estimated 1.5% (SE = 0.2) of the horses in 28 states developed acute infectious upper respiratory tract disease (IURD) and 0.3% (SE = 2.3) exhibited signs of strangles, a type of IURD caused by Streptococcus equi subspecies equi.; Equine influenza virus is one of the most common causes of IURD in performance horses, but the effect that exercise has on these infected horses has not been well documented. Moderate exercise of horses following aerosol. challenge with equine influenza virus (H3N8) did not prolong the clinical course of disease in our study. Resolution of clinical signs occurred by 14 days post challenge (PC) in horses that continued in training following infection (n = 4) and those that were confined to their stalls (w = 4). However horses that continued to exercise demonstrated slightly more severe clinical disease. All horses developed signs of pneumonia, but there was no detectable difference between groups in the severity or number of lung lesions visible on ultrasonographic examination.; During an outbreak of equine influenza virus, naturally infected horses exhibiting clinical signs of disease had a greater risk of lung consolidation and peripheral pulmonary irregularities visible on ultrasound examination of their thorax when compared to normal horses. There was no association between the duration of clinical signs and the results of the ultrasound examination.; Exercise-induced pulmonary hemorrhage (EIPH) occurs frequently in horses that exercise strenuously and prophylaxis is often attempted by treating horses with furosemide prior to racing. Examination of race records for all Thoroughbreds racing on dirt in the U.S. and Canada between June 28 to July 13, 1997 in jurisdictions that allowed the use of furosemide found that 74% of the horses received furosemide prior to racing and these horses exhibited superior performance when compared to horses that did not receive furosemide. The furosemide treated horses raced faster, earned more money, and were more likely to win, earn money or finish in the top 3 positions.