Multinodular pulmonary fibrosis in five horses.
METHODS
5 horses were evaluated because of decreased appetite, weight loss, fever, cough, tachypnea, and respiratory distress.


RESULTS
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.


RESULTS
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).


CONCLUSIONS
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.
Wong
David M
DM
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
Belgrave
Rodney L
RL
Williams
Kurt J
KJ
Del Piero
Fabio
F
Alcott
Cody J
CJ
Bolin
Steven R
SR
Marr
Celia M
CM
Nolen-Walston
Rose
R
Myers
Ronald K
RK
Wilkins
Pamela A
PA
D000212:Acyclovir / Q000627:therapeutic use; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000818:Animals; D000998:Antiviral Agents / Q000627:therapeutic use; D003937:Diagnosis, Differential; D017809:Fatal Outcome; D005260:Female; D006566:Herpesviridae Infections / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy / Q000662:veterinary*; D006734:Horse Diseases / Q000175:diagnosis* / Q000188:drug therapy; D006736:Horses; D008297:Male; D011658:Pulmonary Fibrosis / Q000175:diagnosis / Q000188:drug therapy / Q000662:veterinary* / Q000821:virology; D012307:Risk Factors; D016896:Treatment Outcome; D018140:Varicellovirus / Q000302:isolation & purification*
D000305:Adrenal Cortex Hormones; D000998:Antiviral Agents; D000212:Acyclovir