Spring is here, which means both people and their pets are eager to get outside and socialize. Unfortunately, many dog parents may not realize that more puppy playdates mean more opportunities for their pup to get sick from dog flu. In fact, two highly contagious strains of dog flu – H3N8 and H3N2 – have been traveling across the country since 2007, infecting dogs in nearly all 50 states.  Dr. Kathryn Primm, owner and chief veterinarian at Applebrook Animal Hospital and co-author of “Pet Parents Guide to Infectious Disease,” discusses what every pet parent should know about dog flu and spring pet health, including: What kinds of dogs are most at risk The signs and symptoms and how to treat it Whether its preventable and how to protect dogs from it   Symptoms of canine influenza virus include: Coughing. Sneezing. Variable fever. Clear nasal discharge that progresses to thick, yellowish-green mucus. Rapid/difficult breathing. Loss of appetite. Lethargy.