Genetic basis of Chronic respiratory tract infections in dogs - encompass persistent infections affecting the upper and/or lower respiratory system. These infections can arise from various factors such as infectious agents (bacteria, viruses), anatomical abnormalities, or underlying diseases that predispose dogs to impaired airway clearance and recurrent infections.
Common Causes - Infectious Agents: Dogs can be infected by multiple respiratory pathogens causing chronic infections. The canine infectious respiratory disease complex (CIRDC), also known as kennel cough, involves agents like Bordetella bronchiseptica, canine parainfluenza virus, canine adenovirus type 2, canine influenza virus, and others. Mixed infections can prolong the disease course. Chronic Bronchitis: A non-infectious chronic inflammatory respiratory condition that can predispose to secondary infections. Frequently seen in small and toy breeds such as West Highland White Terriers and Cocker Spaniels. Anatomical Predispositions: Brachycephalic breeds (English Bulldog, French Bulldog, Pug), and breeds prone to tracheal collapse (Yorkshire Terrier, Pomeranian, Chihuahua) have an increased risk for chronic respiratory problems due to airway obstruction, leading to repeated infections. Other Conditions: Anatomical syndromes such as brachycephalic obstructive airway syndrome (BOAS) increase susceptibility.
Clinical Signs - Persistent or chronic cough. Nasal discharge or chronic sneezing. Exercise intolerance and increased respiratory effort. Voice changes or honking cough associated with tracheal collapse. Possible secondary complications like pneumonia in severe or untreated cases.
Why This Matters to Breeders and Vets - Breeders: Knowledge of breed predisposition helps guide responsible breeding and selection, aiming to reduce chronic respiratory issues in offspring. Genetic counseling and screening for anatomical traits such as brachycephaly or tracheal collapse can aid in breeding decisions. Vets: Early identification and management improve quality of life and reduce complications. Veterinarians must be vigilant in breeds prone to chronic respiratory infections, tailor diagnostics, and recommend long-term treatment and environmental management.