ATLANTA -- All birds at PetSmart stores in metro Atlanta and the rest of Georgia are under a quarantine after an outbreak of a bird disease that can be transferred to humans.

The Georgia Department of Agriculture ordered the quarantine at the PetSmarts, plus a Superpetz store in Martinez outside of Augusta due to psittacosis, Commissioner of Agriculture Tommy Irvin announced Monday.

Psittacosis is a bacterial disease that primarily affects parrots, parakeets and other members of the parrot family. It is treatable but can be fatal to the birds. Only in rare cases does it infect poultry.

The disease produces flu-like symptoms in humans, but it does not respond to treatments for the flu. The disease is especially dangerous to the young, the elderly and people with weakened immune systems, such as persons with chronic disease, AIDS or HIV infection or those taking chemotherapy for cancer.

"We have had two confirmed cases of psittacosis at PetSmart stores in Hiram and Woodstock. There have also been confirmed cases at the dealer, Preferred Birds of Milton, Florida, that supplied birds to all the stores we are quarantining," said Irvin.

The pet retailer voluntarily agreed to stop selling birds from Preferred Birds at all of their stores nationwide while they checked all its birds from the disease.

"While we don’t believe there is any cause for alarm, we want our customers to be aware of this possibility," PetSmart officials said in a statement on their web site.

"Birds infected with psittacosis may appear drowsy, eat poorly, and have runny eyes or nose and diarrhea. If your bird is exhibiting these symptoms we encourage you to contact your veterinarian," the company added in its statement.

"PetSmart had already begun a quarantine, but the quarantine did not meet all state requirements. We are requiring PetSmart and Superpetz to move the birds away from the public and to begin using medicated feed to treat the birds. The quarantine will last 45 days or until released by our State Veterinarian," said Irwin.

The quarantine applies only to birds sold at the stores, not to other animals.

If you purchased a bird from PetSmart or the Martinez Superpetz and have concerns about its health, please contact your veterinarian, or if you have concerns about your health, contact your health care provider or local health department.