PetSmart has suspended bird sales in 775 stores in 44 states, including nine stores in the Pittsburgh area, because a number of cockatiels have tested positive for psittacosis, also known as parrot fever.

Psittacosis is an infection caused by bacteria. Birds can transmit the disease to other birds and to people.

There were no confirmed cases of psittacosis locally in 2007, according to a spokesman for the Allegheny County Health Department. But Dave Zazac yesterday said he could find no indication that PetSmart, headquartered in Phoenix, had notified health officials about company concerns.

Sales were suspended Dec. 19 when birds in PetSmart stores, including those in Allegheny County, were put into quarantine in the stores. They are being treated with antibiotics, said a spokesman at the company's 24-hour media hot line.

"We suspended sales as a precaution," the PetSmart spokesman said. "Employees wear gloves and gowns" when they feed and care for the birds, and there have been no reports of employees or customers contracting psittacosis.

Random tests conducted at PetSmart stores across the country indicated that a number of birds tested positive for the infection. Positive results were returned from 23 stores, according to a company Web site.

PetSmart has sent letters to people who purchased birds after Oct. 1. The letter says, in part, "we don't believe there is any cause for alarm." Customers are advised to consult their veterinarian if pet birds appear drowsy or have poor appetites, runny eyes, runny noses or diarrhea.

Humans who contract parrot fever will exhibit flu-like or cold symptoms, according to a fact sheet from the Allegheny County Health Department. Symptoms include chills, fever, cough, fatigue, vomiting and diarrhea. Fatal cases are rare, the sheet says.

People would need to have a lot of direct contact with a bird to get parrot fever, Mr. Zazac said. The disease can be spread to people who inhale dust or fumes from bird droppings or by being bitten by an infected bird.

The infection is treated with antibiotics.

Go to www.achd.net/factsheet/psit.htm or www.petsmartfacts.com for more information.