Canine Influenza in Pet Dog

Canine influenza (CI) is a highly contagious respiratory infection of dogs that is caused by an influenza A virus. Canine influenza caused by two influenza strains, the first strain reported in the United States, beginning in 2004, was an H3N8 influenza A virus. This strain is closely related to the virus that causes equine influenza, and it is thought that the equine influenza virus mutated to produce the canine strain. In 2015, an outbreak that started in Chicago was caused by a separate canine influenza virus, H3N2. The strain causing the 2015 outbreak was almost genetically identical to an H3N2 strain previously reported only in Asia specifically, Korea, China and Thailand. In Asia, this H3N2 strain is believed to have resulted from the direct transfer of an avian influenza virus possibly from among viruses circulating in live bird markets to dogs. Two clinical syndromes have been seen in dogs infected with the canine influenza virus, a mild form of the disease and a more severe form that is accompanied by pneumonia. This book illustrates the history, rapid diagnosis, prevalence, risk factors and epidemiological determinants of canine influenza in domestic dogs.