Experts are warning that a strain of dog influenza has quickly spread through Brooklyn and now is in Manhattan.

"This is a strain of flu that can spread very quickly among dogs. In the city, in the boroughs, we're all so close together and a lot of dogs go to daycare, walk in packs, go to dog parks," Dr. Alison Mason of Hope Animal Hospital said Wednesday about the H3N2 virus. "So those are dogs that are going to be more susceptible to getting the flu."

CAN HUMANS CATCH CANINE INFLUENZA?

No case of a human being infected has ever been reported.

WHAT ARE SIGNS OF CANINE INFLUENZA?

Cough, runny nose, fever, lethargy, eye discharge, and reduced appetite are symptoms. Not all dogs will show symptoms, though.

Most dogs recover within two to three weeks.

HOW SERIOUS IS CANINE INFLUENZA?

Few dogs die from the virus, but some may develop secondary bacterial infections that may lead to more severe illness and pneumonia.

Contact your veterinarian if you have concerns about your pet's health, or if it is showing signs of canine influenza.

HOW IS DOG FLU SPREAD?

Humans can spread canine flu through their hands and clothes if they come in contact with a dog who contracted the virus, and can remain contagious for up to a day.

Clothes, equipment, surfaces, and hands should be cleaned and disinfected after exposure to dogs showing signs of respiratory disease.

Almost all dogs are susceptible to canine flu infection, and it tends to spread among dogs in kennels and shelters. It is believed to be spread mainly among dogs through droplets created during coughing and sneezing from infected dogs, or through contact with contaminated surfaces.

Dog owners are advised to make sure their dogs are not exposed to other dogs or to cats if they are coughing or showing other signs of respiratory disease.

HOW IS DOG FLU TREATED?

Keep your dog well-hydrated as it recovers. Your veterinarian may recommend antibiotics if a secondary bacterial infection is suspected.

IS THERE A TEST FOR CANINE INFLUENZA?

Yes, testing is available.

IS THERE A VACCINE?

Vaccines to protect dogs against canine flu are available.

HOW QUICKLY DOES THE VACCINE TAKE EFFECT?

The vaccine needs to be given in two boosters. Dogs, however, are not protected until two weeks after that final booster, Mason said.