Ultrasonographic examination was used to define the severity of injuries to the superficial digital flexor tendon in 73 National Hunt or point-to-point racehorses and the factors influencing the outcome of the cases were examined. Thirty-four of the horses (46 per cent) returned to work with an average time out of training of 13.5 months. The rate of recurrence of the injury was 35 per cent. The severity of the lesions was related to the outcome; all the mildly affected horses returned to work, with 63 per cent of them racing and an average time out of training of 10.2 months; 50 per cent of the moderately affected horses returned to work, and 30 per cent raced with an average time out of training of 11.3 months; 30 per cent of the severely affected horses worked, and 23 per cent raced with an average time out of training of 18.3 months. The differences in outcome between unilateral and bilateral injuries within each severity group were not statistically significant. Seventy-six per cent of horses treated with polysulphated glycosaminoglycans returned to work, compared with 46 per cent of conservatively managed horses and 50 per cent of horses treated with laser therapy. However, these differences were not statistically significant and the rate of recurrence of the injury in the horses treated with polysulphated glycosaminoglycans was 50 per cent compared with only 31 per cent in the conservatively managed horses. Seventy per cent of the mares and 47 per cent of the geldings were retired from racing.

Case Description—5 horses were evaluated because of decreased appetite, weight loss, fever, cough, tachypnea, and respiratory distress. Clinical Findings—Tachycardia, tachypnea, increased respiratory effort, lethargy, fever, poor body condition, and nasal discharge were detected in various combinations on initial physical examination. Evaluation of the lower portion of the respiratory tract via radiography and ultrasonography revealed a severe nodular interstitial pattern. Histologic examination of lung tissue revealed interstitial expansion of alveolar parenchyma with collagen, intraluminal accumulation of neutrophils and macrophages within the alveoli, and occasional intranuclear inclusion bodies within alveolar macrophages. Equine herpesvirus type 5 was detected in samples of lung tissue, bronchoalveolar lavage fluid, or both via polymerase chain reaction assay in all cases. A diagnosis of equine multinodular pulmonary fibrosis (EMPF) was established. Treatment and Outcome—Horses were provided supportive treatment and were administered a variety of medications including corticosteroids and acyclovir. Two horses survived and returned to their previous level of activity. Three horses were euthanized because of either deterioration of clinical condition (n = 2) or failure to improve within 4 weeks of initiation of treatment (1). Clinical Relevance—EMPF should be considered as a differential diagnosis for adult horses with interstitial pneumonia and should be suspected on the basis of characteristic radiographic, ultrasonographic, and histopathologic findings. Equine herpesvirus type 5 is found in association with EMPF; although the exact pathogenic role this virus plays in EMPF is unknown, equine herpesvirus type 5 may be an etiologic agent or cofactor in the development of EMPF.

A total of 1235 tracheal aspirates taken from 724 thoroughbreds in race training, aged from two to 10 years, were examined cytologically and bacteriologically. An inflammation scoring system on a scale of 0 to 9 was devised to allow the severity of lower airway disease to be assessed from the cytological results. The inflammation scores were closely related to the isolation of bacteria (P<0.001), and the most common bacterial isolates were Streptococcus zooepidemicus , Streptococcus pneumoniae and Pasteurella/Actinobacillus ‐like species. Lower airway disease was less common in older horses (P=0.031), and the groups at highest risk were the two‐ and four‐year‐olds. Lower airway inflammation was more common in the four‐year‐olds at National Hunt yards than in the four‐year‐olds at flat racing yards (P=0.040, odds ratio=3.80).