A virus that was identified as the H3N2 strain of influenza, first seen in the Chicago area in early 2015, underwent a resurgence in the United States this year. Infected dogs experience a respiratory disease which lasts for a few days, accompanied by a fever and cough as seen with influenza in humans, and are infectious to other dogs for about a week.
One focus of the Parrish laboratory is to study how viruses emerge and spread among animals and humans, and then use that information to identify new ways to control them. Parrish and his group figured out that the new flu virus had originally jumped from birds to dogs in Asia circa 2005 and that the strain in Chicago came from Korea, where it had been circulating in dogs for several years.
A new outbreak of canine influenza was reported in Los Angeles earlier this year. Parrish and his group were able to use the methods they have developed to examine the genetic fingerprint of this virus and identify it as an H3N2 variety. However, they discovered that it was a different strain than the one that originated in southern China, and was probably brought to the United States by dogs that were rescued from dog markets. The infected dogs were quarantined until they were no longer contagious, thus preventing the spread of a new strain of influenza virus in the United States.