Influenza is a viral disease that affects numerous animals, including birds, pigs, horses, and humans. It also can affect dogs, and epidemiologists are increasingly concerned about the potential transmission of the influenza virus from these animals to humans. Canine influenza (dog flu) is caused by specific type A strains of the influenza virus. It is a contagious respiratory illness in dogs that resembles kennel cough. Although canine influenza first appeared in greyhound dogs, the respiratory illness has been observed in a variety of breeds, and all dogs are considered to be at risk of infection. However, no cases of transmission of the influenza virus from dogs to humans have been identified. Still, scientists are aware that public health conditions could deteriorate rapidly, possibly leading to a pandemic (an epidemic occurring over a widespread geographic area), if this type of transmission were to take place. See also: Animal virus; Canine influenza; Dogs; Epidemic; Infectious disease; Influenza; Kennel cough; Public health; Virus
Human cases of the flu have been described throughout recorded history. In contrast, there were no reported instances of influenza among dogs prior to the early 2000s. Since then, the canine influenza virus has been detected in dogs living in many areas of Asia, including China, South Korea, and Thailand, as well as Canada and the United States. In particular, investigators have determined that mutations in previously existing equine (H3N8), bird (H3N2), and swine (H1N1) influenza virus strains allowed those strains to infect dogs and to be subsequently transmitted among dogs. However, interspecies transmission—that is, the jumping of a virus from one animal to another—is an especially problematic situation, particularly if it involves humans. For example, the transmission of the swine flu (H1N1) from pigs to humans caused a pandemic in 2009 that killed more than 17,000 individuals worldwide. Similar types of mutations and exchanges of genes that occurred during the 2009 pandemic have been observed in dogs infected with canine influenza. Therefore, scientists acknowledge that the likelihood of canine influenza strains jumping to humans is plausible. See also: Avian influenza (bird flu); Epidemiology; Gene; H1N1 influenza; Mutation; Zoonoses
In order to prevent the potential of influenza transmission within canine pet populations, surveillance and careful monitoring of the animals are key actions. Vaccination is another preventative measure, with vaccines being available to protect dogs against the H3N8 and H3N2 strains of the canine flu. Moreover, as a result of the close proximity of people and their pet dogs, and their daily interactions with each other, any influenza outbreak needs to be monitored to minimize the risk that the virus might jump to humans, leading to the possibility of its spread within the human population. See also: Vaccination
