MELBOURNE, Fla. — The Brevard Zoo has closed its free-flight walk-through aviaries to the public until further notice to try to protect its bird residents from the avian flu, zoo officials announced Thursday.

This week, state wildlife officials reported that several ducks in Brevard County have tested positive for avian influenza (HPAI), a highly pathogenic illness.

“Given the seriousness of this disease and the close proximity to the animals in our care, we have implemented our avian influenza plan,” Brevard Zoo Executive Director Keith Winsten said.

The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service reported cases of avian flu, commonly known as “bird flu” on a farm in Indiana on Feb. 9. Since then, cases of wild birds testing positive for HPAI in parts of South Carolina, North Carolina, Virginia and Kentucky.

As far back as January, samples collected by USDA-Wildlife Services from a hunter-harvested blue-winged teal in Palm Beach County, Fla., tested positive for the strain as well.

Zoo birds susceptible to HPAI include macaws, black swans, Osceola turkeys and whistling ducks. They will be moved to indoor habitats, while other species will receive habitat modifications to prevent contact with wild birds. All Zoo animal care staff will use personal protective equipment while caring for the zoo’s birds.

Avian influenza, a viral infection that occurs naturally in birds, can infect wild birds, but they may not always get sick from it. Some domesticated birds such as chickens, ducks and turkeys, can become infected, often fatally.

Avian influenza does not present an immediate public health concern, and no human cases of avian influenza viruses have been detected in the United States, the USDA said.