Research has shown that owning a dog can actually boost a person’s health and immune system. Just make sure you return the favor by keeping an eye on your furry friend’s own health.

Veterinarians across the country are warning pet owners to be on the lookout for a highly infectious strain of dog flu that has sickened more than 2,000 dogs in 40 states since being detected in Chicago around April of last year. Dog owners should be extremely cautious when it comes to where they take their dogs, and what kind of company their dogs keep.

“It starts and it will move through an area like wildfire. It gets into the kennels, rescues and shelters,” said Texas Veterinarian Dr. Luann Ervin. “These places can certainly be a problem because they house a large number of dogs. So these symptoms get going and before you realize you’ve got something, you have 10 or 12 dogs that have it.”

According to the American Veterinary Medical Foundation, canine influenza, also known as dog flu, refers to a highly contagious infection caused by an influenza A virus. This particular strain, H3N2 canine influenza, was thought to be limited to Korea, China, and Thailand. Health officials are unsure how dog flu made its way into the United States.

The Centers for Disease Control and Prevention reported on the dog flu outbreak in Chicago back in the spring. Since then, around 2,000 pets, including 1,000 in Chicago alone, have fallen ill due to the outbreak. Officials in Texas say dog flu has been confirmed in one dog from Austin while other potential cases are being investigated.

Although the H3N2 virus is not considered deadly unless the dog is too young, too old, or suffers from a preexisting condition, veterinarians are warning pet owners to be aware of symptoms, which can include runny nose, lethargy, coughing, sneezing, lack of appetite, and fever. Infected dogs tend to recover within 10 to 21 days of becoming sick.

Since symptoms can take up to two weeks to appear, dog owners are advised to be extra vigilant of initial symptoms, which are similar to those experienced by humans suffering from the flu. It is spread through direct contact with an infected dog, so places like kennels, dog parks, and rescue shelters would carry the highest infection risk.