2015 ACVIM Forum Research Abstract Program

The vessel diameter may influence the sample population of circulating cells. Collection of blood from both sites is non-invasive and dramatically increases the yield of EPCs. Consistent yield of EPCs from peripheral blood will allow future studies evaluating diagnostic and therapeutic uses in horses. Previous work by the authors showed that erythromycin-associated hyperthermia is caused by impaired sweating. Whether or not the macrolides clarithromycin and azithromycin also induce anhidrosis is unknown. This study evaluated the sweat response in foals treated with azithromycin, clarithromycin and erythromycin. In serial experiments, 12 foals (four females, eight males), aged 1 month, were treated orally for 5 days with erythromycin (25 mg/kg, 3 times daily), azithromycin (10 mg/kg, once daily) and clarithromycin (7.5 mg/kg, twice daily) according to a masked, duplicated, 6 9 3 counterbalanced design. Quantitative intradermal terbutaline sweat tests were performed on 3 successive days before treatment (baseline) and on days 1, 2, 5, 9, 24, and 39 after treatment began. There was significant (P < 0. 05) suppression of sweating when foals were given any of the 3 macrolides. Compared with terbutaline-induced sweating at baseline, values were significantly lower on all evaluation days when foals were given erythromycin, on days 2 and 5 after beginning treatment when given clarithromycin, and on days 1, 2, and 5 when given azithromycin. Overall suppression of sweating by erythromycin at the dose used in the study was significantly greater than that induced by either clarithromycin or azithromycin; however, there was no difference between the effects of clarithromycin and azithromycin. Results show that all of the macrolides commonly used for treating or preventing Rhodococcus equi pneumonia in foals suppressed sweating responses to varying degrees. Foals treated with any of these antibiotics should be considered at risk for hyperthermia. Lower airway inflammatory diseases (Inflammatory Airway Disease and Heaves) are common conditions of variable severity in horses. While alterations in bronchoalveolar lavage fluid (BALF) cytology is a characteristic finding in affected horses, the degree of lower airway inflammation is not correlated with the severity of lung function impairment. Furthermore, currently, little is known of the inflammatory and remodeling processes affecting the central airways in these horses. We developed a semiquantitative scoring system for the assessment of endobronchial biopsy morphology and hypothesized that it would allow differentiating horses with heaves from controls, independently from their clinical status (exacerbation or remission).