H3N2 Isolation Time Longer Than Anticipated

According to a recent article from the Journal of the American Veterinary Medical Association, dogs that are infected with influenza A H3N2 may need to be isolated at least 3 weeks to avoid spreading the virus. This is due, in part, to the fact that some animals can spread the virus for up to 20 days; in rare cases, up to 30 days after primary clinical signs have abated.

Influenza A H3N2 is a relatively new influenza virus that first emerged in the United States in the spring of 2015 with outbreaks in Chicago. Outbreaks in Atlanta and Texas soon followed, and now, about half of the United States has seen outbreaks. This new strain of the virus is thought to have entered from Southeast Asia, where it originated in 2006.

According to The New York State Animal Diagnostic Laboratory at Cornell, both the new H3N2 strain and the H3N8 strain (in the United States since 2004), “can cause high fever, loss of appetite, coughing, nasal discharge, and lethargy. Symptoms may be more severe in cases caused by the H3N2 virus. Some infected dogs may not show symptoms at all. H3N2 has caused infection and respiratory illness in cats.”

Dr. Keith Poulsen, a diagnostic case and outreach coordinator for the Wisconsin Veterinary Diagnostic Laboratory at University of Wisconsin-Madison, is quoted in the article as stating that he recommends “testing dogs that present with respiratory signs to determine whether an influenza virus is present and, if so, which virus is causing the illness.” He also said, “This approach will help veterinarians know which vaccines are needed in their communities and how long dogs with signs of illness should be kept away from dog parks or boarding facilities.”

The Cornell Chronicle reported that Dr. Edward Dubovi, a virologist at Cornell who helped identify the virus, is urging dog owners to vaccinate their animals against this new strain since it is highly contagious. The article states, “The vaccine may be given to healthy dogs age 6 weeks and older. It is delivered in 2 doses spaced a few weeks apart