Cases of Dog Flu Are On the Rise. Here's How to Tell if Your Dog Has It

The number of cases of the canine flu are surging in dogs. Cats as well.

The illness has closed shelters and doggy day-care businesses in Texas and elsewhere, mostly across the South, and forced some groups to suspend adoptions until they could stop its spread. 

Exactly how many dogs have gotten sick is not known because there is no official tally of cases across the country, according to the American Veterinary Medical Association. Dog flu is not a disease that must be reported.

Cases have also been found this year in Alabama, North Carolina, Oklahoma, South Carolina and Tennessee, the association says.

Although highly contagious among pets, dog flu does not pose a danger to humans, and most animals recover.

But if you want try to spare your pets, here’s what to watch for.

What is Dog Flu?

Like the human variety, canine or dog flu is a contagious respiratory disease caused by a virus. One type of virus, H3N8, was first reported in horses and then, in 2004 in Florida, in racing greyhounds. It is thought to have jumped from horses to dogs, and since then has been found in most states and the District of Columbia, according to the American Veterinary Medical Association. 

Another type, H3N2, caused a rash of cases in Chicago kennels in 2015. Before being discovered in the United States, it was seen in dogs in 2006-2007 in Asia and probably was the result of an avian or bird flu virus that was transmitted to dogs, the veterinary medical association says. In 2016, a group of shelter cats in Indiana was diagnosed with it. The following year it also was found in dogs in Florida, Georgia, Kentucky, Louisiana, Missouri, North Carolina, South Carolina, Tennessee and Texas.

How Is It Spread?

Dog flu is transmitted by coughing, barking and sneezing, through droplets or aerosols, the veterinary medical association says. Dog in shelters, day-care centers and at groomers are especially at risk. The virus can spread on food and water bowls and on collars and leashes, or through people that have had contact with a dog that was infected. 

How Long Can the Virus Survive?

The virus can remain alive and able to infect dogs for up to 48 hours on surfaces, 24 hours on clothing and 12 hours on someone’s hands. Most cases of H3N8 appear two to three days after exposure though the virus has an incubation period of up to five days. For H3N2, dogs may show signs of infection between two to three days afterward. Dogs are most contagious during the incubation period.

What Are the Symptoms of Dog Flu?

The most common symptom is a cough that can persist for 10 to 21 days, even with treatment with antibiotics and cough suppressants, according to the veterinary medical association. Coughs can be moist or a dry. Other symptoms: nasal or eye discharges, sneezing, lethargy, loss of appetite or fever. Almost all dogs exposed to the viruses become infected, with about 80% showing symptoms. The other 20% can still spread the virus.

Dogs can become shows signs of pneumonia and although most dogs recover, some deaths have been reported.

Cats also have nasal discharges, congestion and excessive salivation. 

Tests can identify which strains of the virus are present. 

How is Dog Flu Treated?

Most dogs recover in two to three weeks, but pneumonia, dehydration and other infections might require additional treatment. Those could include antimicrobials for bacterial infections, medications to reduce fevers and fluids for dehydration. 

Infected dogs should be isolated for four weeks. 

Antiviral drugs that are used to treat flu are approved only for humans. 

Are There Vaccines?

Yes, vaccines are available for dogs both H3N8 and H3N2. A bivalent vaccine protects against both strains.

But there are no vaccines approved for cats. 

This article originally included Michigan as one of the states where canine influenza had been reported but although there were outbreaks of an unidentified respiratory illness earlier in the year, there have been no confirmed cases in the state in 2022, according to the American Veterinary Medical Association.