Earlier this month, reports coming out of the Chicago area have indicated a number of dogs coming down with canine influenza virus (CIV), aka dog flu, some with deadly consequences. A known type of canine flu, H3N8, had been identified in U.S. dogs since 2004; the first vaccine created for it in 2009. Currently there are two vaccines for H3N8, one by Merck Animal Health and one by Zoetis.
It wasn’t until April 13th, 2015 via press release from Cornell University was it made known that this current outbreak is actually to blame on a different strain of the influenza virus, not previously seen in the U.S. called H3N2. At this time it is unclear if dogs vaccinated for H3N8 will have any protection again H2N2.
H3N2 is a sub-type of influenza that has been widely circulating in Chinese, Korean, and Thai dogs since at least 2006. Having never previously been found in North America, it is thought this strain is a recent import from Asia as dogs are being flown worldwide more and more with sometimes minimal precautions being taken. This has raised red flags for some, calling for tighter border security.
H3N2 is extremely contagious (80% of dogs exposed to it will come down with symptoms), particularly in shelters, grooming salons, dog boarding facilities, dog parks, and dog day-cares. Less than 10% have proved fatal however. So prevention and control of this illness is largely in the hands of those professionals to put protocols in place to keep those environments clean with commonly used disinfectants.
The way this flu spreads is much like the human versions, aerosolized respiratory secretions (like sneezes, coughs) and objects contaminated by it like surfaces, food & water bowls, collars & leashes, as well as human clothes and hands. It usually takes 2 days from the time of exposure to when symptoms develop; this is when they are most contagious but it can be spread up to 10 days after infection. It’s thought some 20-25% of dogs exposed will not develop symptoms but can spread the illness.
Both viruses (H3N8 and H3N2) can cause high fever, loss of appetite, nasal discharge, coughing, and lethargy. Treatment at this time can involve antibiotics but is largely supportive care like fluids for dehydration, medications to reduce fever/inflammation, and treatment of secondary infections such as pneumonia. Currently, neither virus is known to affect humans but H3N2 has caused some illness in cats.
Diagnosis has been tricky, only a few labs have the capability to test for H3N2 since it can’t be diagnosed by symptoms alone. If you’re worried, contact your veterinarian.
The outbreak starting in the Chicago area has already been seen in Wisconsin and Indiana with an estimated 1,300 dogs being affected with at least 6 deaths. But the numbers of cases in Chicago have already begun to subside however.
Should the average dog owner be worried about this? Without precautions, the virus could be easily spread beyond the Midwest but the more you know, the better you can be prepared to take precautions like avoiding inter-state travel and communal dog areas when possible.
A H3N2 vaccine is currently in the works by animal health company Zoetis.