Background: Blastomyces dermatitidis, a fungus endemic to Mississippi River Valley, infects both dogs and humans. Canine blastomycosis was last characterized in Tennessee with 78 cases presenting to the University of Tennessee Veterinary Medical Center (UTVMC) during 1977-1999. A Blastomyces antigen quantitative (BdAg) test has since emerged as a less invasive yet sensitive diagnostic for blastomycosis.
Objective: The objective was to identify cases of canine blastomycosis at UTVMC and characterize the presentation, clinicopathologic and imaging abnormalities, and treatments selected during 2014-2023. Animals and
Methods: One hundred thirty-one (131) cases of canine blastomycosis were identified from a hospital population using laboratory database searches for BdAg and pathology (i.e. cytology, histopathology, and necropsy) submissions.
Results: Electronic medical record and imaging report screening confirmed clinical diagnosis in 126 cases. Clinical cases were all ages, gender, and size, yet most often < 5 years of age (n=65/126, 52%) and weighing >10 kg (n=57/126, 45%). Emergency (n=57/126, 45%), Ophthalmology (n=28/126, 22%), and Internal Medicine (n=25/126, 19.8%) services were most visited at initial presentation. Respiratory, ocular, and dermatological manifestations were most commonly involved, both as primary and total organ systems. Notable clinicopathologic abnormalities included leukocytosis, neutrophilia, hyperproteinemia, hypoalbuminemia, hyperglobulinemia, elevated C-reactive protein, and low iron. Thoracic imaging commonly revealed structured interstitial patterns (50/86, 58.1%), with miliary (20/86, 23.3%) and nodular (38/86, 44.2%) features. Itraconazole was the most frequently prescribed antifungal (89/106, 84%).
Conclusions: Veterinarians should consider Blastomyces sp. infection for a variety of clinical presentations.
