New Flu Strain Sickens Thousands Of Dogs, Threatens Midwest

Apr 17, 2015 at 12:57 PM ET

College students weren’t the only ones to come back from Spring Break worse for wear. In Chicago, more than 1,100 dogs—many in daycare or kennels while their humans took vacation for a week—were infected by the H3N2 dog influenza virus, and six have died. The virus has also been reported in pups in Indiana, Ohio and Wisconsin.

According to a recent CDC report, state veterinary laboratories in New York and Wisconsin have identified similarities between this H3N2 strain and the Asian H3N2 dog flu virus that was found in China and South Korea in 2006—both strains are likely an adaptation of a bird flu virus. H3N2 has since been reported in Thailand, and has also affected cats.

Though symptoms—cough, runny nose and fever—are exactly the same, the CDC does note that the dog version of H3N2 is different than the H3N2 human flu virus that causes yearly illnesses during the winter months. And there have been no cases of dog flu viruses spreading to humans. There’s no vaccine for H3N2.

Dr. Donna Alexander, administrator of the Cook County Department of Animal and Rabies Control, recommends that dog owners should avoid places where their pets might interact with other dogs, until the threat passes. This includes dog parks, training classes and boarding/daycare facilities.

A Timeline of Dog Flu in the U.S.

  • 2004: Influenza A H3N8 virus, believed to be an adaptation from horses, is first seen in January in several Greyhounds at a dog track in Florida.
  • 2006-2007: Cases of dog flu, identified as Influenza A H3N2, are found in pet dogs in southern China. The virus is later reported as circulating in farmed dogs in Guangdong, China. An outbreak of H3N2 is detected in South Korea, and phylogenetic analysis shows the Korean and Chinese viruses are similar—both originating from an avian strain.
  • 2009: A vaccine to protect dogs against Influenza A H3N8, which had spread via dog tracks to 30 states and Washington, DC, is made available.
  • 2012: A small vet hospital in Bangkok, Thailand, reports several clinical cases of dogs with flu-like symptoms. Analysis determines it is related to the H3N2 virus in Korea.
  • 2015: An April dog flu outbreak in Chicago—initially attributed to the H3N8 virus—is found to be caused by a new strain, and suggests a recent introduction of the H3N2 virus from Asia.

Read More:

Update on Canine Influenza (Dog Flu) Outbreak Reported in Chicago Area (CDC)
Canine Influenza: A Pet Owner’s Guide (American Veterinary Medical Association)