History
01-13-2025 1:24:31pm -- Zane, a 1 year old Arabian Tennessee Walking Horse cross, was presented to the NC State Equine Medicine Service on 1/13/25 for evaluation of a chronic intermittent cough and elevated respiratory rate.

Zane has had an intermittent dry cough since his owners acquired him in September.
Zane has been otherwise normal with no history of fevers, nasal discharge, or lymphadenopathy. Zane has previously had no increased respiratory rate or effort before 1/12 (day prior to presentation). Zane is up to date on vaccines, and has been treated with SMZ, ceftiofur crystalline free acid (Excede) as well as flunixin meglumine prior for his cough and for post-castration discharge. His SAA has repeatedly been normal (<20 mg/L).
Zane came from a farm where he lived with all species including donkeys, and is currently pastured with donkeys. He has been dewormed once in September with Zymecterin Gold but has not been dewormed since.
Zane's hay was being soaked and his grain at this time but this has not changed his cough. All medications were discontinued 1/12 prior to presentation.

Relevant Diagnostics & Results

Physical Exam
Respiratory:    Tachypneic (50 brpm) with increased abdominal effort on expiration. Diffusely increased bronchovesicular sounds and expiratory wheezes auscultated bilaterally, right > left. Intermittent dry cough/ coughing fits.

Clinical Diagnostics
Fecal Bearmann:    No Nematode Larvae Observed

Broncho-Alveolar Lavage & Transtracheal wash:
Chronic inflammation with eosinophilic component.
Increase in small lymphocytes is part of the chronic inflammation. Considerations given the eosinophilic component include hypersensitivity (e.g. inflammatory airway disease, recurrent airway obstruction) and migrating parasite larvae.
Active Nematode collected:    Dictyocaulus arnfieldi confirmed.    VIDEO

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Male: Copulatory bursa with rudimentaty bursal rays and wedge-shaped grainy spicules

Notes
Dictyocaulus arnfieldi are patent but asymptomatic in Donkeys. (Note that donkeys are this horse's pasture mates. Could use a baermann to check the donkeys to find the culprit.)

Horses show pathology but have weak patency. (This explains why the Baermann was negative for D. arnfieldi larvae; and why Broncho-Alveolar Lavage & Transtracheal wash are recommended for horses when D. arnfieldi are suspect.)