Several laboratory tests are available to detect outbreaks of canine influenza.

CIV infection should be suspected in dogs with respiratory signs.

Diagnostic Methods

Because of the increasing prevalence of canine influenza virus (CIV) infection, the rapid spread of the infection among dogs, and the potential for up to 20% of dogs to have a severe disease course, veterinarians and other pet care professionals should have a high index of suspicion in dogs presenting with cough, nasal discharge, and fever. CIV infection should be suspected in dogs with persistent cough and those with pneumonia or other clinical signs of more severe respiratory illness.⁶

It is important for diagnostic tests to be performed to determine the cause of canine cough outbreaks because canine influenza cannot be distinguished from other respiratory infections based solely on clinical signs.²

Several laboratory testing methods are available for detection of influenza infection, including:

1. Virus isolation
2. Virus antigen detection by immunoassays
3. Virus nucleic acid detection by polymerase chain reaction (PCR)
4. Serology for virus-specific antibody

Each of these tests has strengths and limitations, and accurate results are impacted by the timing of sample collection in relation to the phase of CIV illness. Therefore during outbreaks, it is important to use several diagnostic approaches to determine the etiology rapidly and accurately.²

The table below summarizes diagnostic testing options for CIV. A veterinarian should be contacted for guidance on appropriate testing, as well as isolation precautions and treatment.⁶ It is also important to note that positivity for other respiratory pathogens does not rule out infection with canine influenza, as secondary infections are common.^2,6,8,12