Canine infectious respiratory disease can be caused by many different viruses and bacteria.  Dogs at most risk for any infectious disease, including respiratory infections, would be those in close proximately to other dogs, such as kennels, doggie day cares, groomers, dog shows, training classes, doggie social events, and shelters. 

Clinical signs of infectious respiratory disease can include coughing, sneezing, ocular or nasal discharge, lethargy, fever, and pneumonia. Since various pathogens can cause similar symptoms, the responsible pathogen cannot be diagnosed by clinical signs alone. The best approach to diagnose cases of infectious respiratory diseases is through nasal swabs (PCR or viral isolation and bacterial culture) and serology.

Prevalence of Pathogens

In a diagnostic sampling program sponsored by Merck Animal Health, nasal and pharyngeal swabs were taken from dogs showing clinical signs of infectious respiratory disease in the United States throughout 2015 and submitted for analysis to the New York State Animal Diagnostic Laboratory at Cornell University.  Of the over 1,500 screened sick dogs, 316 dogs tested positive for Canine Influenza H3N2 using a broadly cross-reactive matrix targeted assay.[1]

Other results showed that 178 dogs were positive for canine parainfluenza virus, 148 positive for respiratory coronavirus, 140 positive for pneumovirus, 69 positive for B. bronchiseptica, 22 positive for adenovirus type 2, and 11 positive for canine distemper virus. [2] Twelve percent of dogs that tested positive for any pathogen were infected with two or more pathogens with 5.5% co-infected with parainfluenza.[1]

Disease Prevention

Infectious respiratory disease prevention should be aimed at vaccination strategies and increased sanitation methods.  The 2016 Pet Business Consensus Statement notes that dogs that are boarded, groomed, group trained, or group walked are at higher risk for infectious respiratory diseases; these dogs should be vaccinated against infectious respiratory diseases caused by Canine Distemper, adenovirus type 2, Bordetella bronchiseptica, parainfluenza virus, and both types of canine influenza virus (H3N2 and H3N8).[2]

Sanitation and isolation procedures may help stop the spread of disease but have no effect on the shedding.  Canine Influenza H3N2 is considered to be especially infectious and according to a study conducted by the University of Wisconsin, dogs have been shown to shed H3N2 virus for up to 24 days.[3] Dogs suspected to be infected should be isolated immediately.  Afterwards, the floors, walls, and tables in the room should be thoroughly disinfected.  

Staff should wash their hands frequently with soap and water or disinfect them with an alcohol-based hand sanitizer after handling dogs and also change clothing and shoes after caring for sick dogs.

For more information, please visit: www.doginfluenza.com

About the author: Melissa Bourgeois, DVM, PhD, DACVM (Virology, Immunology) graduated from the University of Florida, College of Veterinary Medicine in 2007 with a DVM, and in 2010 with a PhD in veterinary medicine, focusing on gene expression in the equine host following West Nile virus infection. Dr. Bourgeois became a diplomate of the American College of Veterinary Microbiologists (ACVM) in virology (2011) and immunology (2013). Since July 2015, Dr. Bourgeois has worked for Merck Animal Health as a senior drug safety specialist.

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