Canine Influenza detected in several states

Canine influenza virus is a recently emergent pathogen of dogs that has caused highly contagious respiratory disease in racing greyhounds, pet dogs and shelter animals.  The dog flu virus is currently spreading.  Canine influenza is now affecting dogs in Virginia, Colorado, New York, New Jersey, and Pennsylvania.  This virus has been documented as the cause of natural outbreaks of illness in dogs since 2004 when it was discovered in racing greyhounds in Florida.  A genetic analysis of canine influenza virus strains isolated during the first outbreak indicated that all eight genes were most similar to those of equine influenza virus of the H3N8 subtype.

Canine influenza does not affect people, cats, or other animals.  It appears to be fully adapted to and highly contagious among dogs.  Clinical signs can resemble those in other tracheobronchitis infections.  The most common signs are low fever, cough, lethargy, and nasal discharge that may be either serous or purulent.  Some dogs may develop high fever and pneumonia.  The case fatality rate is between 1% and 5%.

Canine influenza should be suspected in outbreaks of respiratory disease among dogs that are fully vaccinated with traditional vaccines.  Although serology can be used to diagnose canine influenza, it may have more diagnostic relevance if used in locations where canine influenza is not yet endemic.  In this case a positive serum antibody titer combined with compatible signs is suggestive of the disease.  Because virus isolation is rather unreliable, the use of a polymerase chain reaction (PCR)-based testing for the rapid identification of the virus is the test of choice.  Viral RNA can be detected on nasal swabs.  This test is more accurate if samples are collected from infected dogs before clinical signs appear or as early as possible from the onset of disease.  From fatal cases, lung and distal trachea specimens can also be tested by PCR.

The Texas Veterinary Medical Diagnostic Laboratory (TVMDL) is currently using an influenza matrix RT-PCR for the detection of canine influenza from samples submitted to the laboratory.  

For additional information please contact TVMDL.

http://www.cfsph.iastate.edu/Factsheets/pdfs/canine_influenza.pdf
http://www.cdc.gov/flu/canine/
http://www.sheltermedicine.com/portal/is_canine_influenza_update.shtml