A new bug is in town. In addition to the already existing flu versions — swine, bird, equine and human — now there is a dog version: canine influenza virus.

First documented by University of Florida researchers at a Florida dog racetrack in January 2004, the dog-flu virus closely mimics infections caused by the more common Bordatella (kennel cough)/Para influenza virus that we have seen for years and vaccinate against. And because dog flu is new, we don't have any dogs with natural or vaccine-induced protection against this virus.

Therefore, virtually 100 percent of exposed dogs can become infected, with about 80 percent of those becoming clinically ill, meaning that the other 20 percent don't show signs of illness. Nevertheless, they can help spread the disease. So taking your dog to the dog park might not be advisable.

There are two types of infections: 1) the more common mild illness, and 2) the more severe less common one. Symptoms for the first one are coughing, nasal discharge and low-grade fever (normal temperature is 100 to 102 degrees).

These pets might cough for up to three weeks, but they respond to antibiotics and cough suppressants. The sicker dogs cough, too, but they exhibit more-severe signs, such as high fever (104 to 106 degrees) and bronchial pneumonia, and might die if not treated aggressively.

The incubation period is two to five days after exposure; infected dogs can shed the virus for seven to 10 days after the initial sign of clinical disease.

Prevention might be your best course, by keeping your pet at home. The virus is spread by aerosolized respiratory secretions (the neighbor's dog panting on your dog as you walk past him on the sidewalk, for example). It also can spread by contaminated objects, such as toys; and even by people or their clothing if they move back and forth between infected and non-infected dogs.