Characteristics and case fatality factors of atypical canine infectious respiratory disease: an observational survey using dog owners' data in the United States.

Abstract

OBJECTIVE: To investigate the characteristics and factors associated with case fatality in atypical canine infectious respiratory disease (aCIRD) in the US, which presents unique clinical challenges, unexpected frequency of death, and limited antibiotic effectiveness. METHODS: We conducted a retrospective observational study from November 2023 to January 2024 using an online survey distributed via snowball sampling, starting in a Facebook group with 56,000 members tracking aCIRD. The study included US dog owners whose pets had persistent respiratory illness diagnosed as suspected aCIRD by a licensed veterinarian. Responses were excluded if these criteria were unmet. Eligible responses were analyzed using descriptive, univariable, and multivariable methods. RESULTS: Among 415 responses, the Southeast had the highest case rate (26.3%), and the Southwest had the lowest (9.4%). Case fatality ranged from 6.7% (Northeast) to 17.9% (Southwest). Dogs under 5 years were most affected (41.3% to 56.8%) across regions. Home exposure was most common in the Southeast (27.5%), and boarding facilities were most common in the Southwest (18.8%). Doxycycline was the most used treatment (30.8% to 50.0%), and single vaccine coverage (Bordetella/influenza) was the highest (35.1% to 48.7%). Multivariable analysis showed that clinical signs, such as lethargy, fever, difficult breathing, and sneezing, were associated with 8.06 times higher odds of death (95% CI, 2.4 to 26.6) compared to coughing, vomiting, lethargy, fever, nasal discharge, and difficult breathing. Other factors showed no significant association. CONCLUSIONS: This study provides a broad overview of aCIRD, supporting future research on pathogen detection and treatment. CLINICAL RELEVANCE: Veterinarians should monitor for lethargy, fever, difficult breathing, and sneezing as indicators of poor prognosis in dogs with aCIRD.