Cases of highly pathogenic avian influenza (HPAI) have increased in flocks of backyard and wild birds in dozens of states in recent months, forcing zoo officials to temporarily close bird exchanges.
“This strain of the disease is highly contagious and deadly to birds,” the Maryland Zoo in Baltimore said in a statement on its website. “As a precaution, we have closed our cages and moved many of our bird species to behind-the-scenes facilities with limited human contact until the threat of avian flu subsides.”
Birds in zoos can become infected by wild birds, humans, or a new bird introduced to the facility.
The spread has led zoos in Pennsylvania, Colorado, Michigan, Wisconsin, Texas and Ohio, as well as Maryland, to take precautions, including closing outdoor bird shows and moving birds indoors for their safety.
The Association of Zoos and Aquariums (AZA) has established the Zoo and Aquarium All-Hazard Partnership Program, which works with zoos to develop a plan before outbreaks occur.
Preventive measures include placing tarps or nets around exhibits, closing cages to the public and implementing strong quarantine protocols, according to Rob Vernon, senior vice president of communications and strategy at AZA.
“Facilities will be in full response mode to protect their birds for at least the next two months until transmission subsides,” Vernon told CNN in a statement.
Zoos take precautions
In an effort to prevent infection, zoos have taken several measures to protect their birds.
The Pittsburgh Zoo and Aquarium PPG has banned the public from accessing birds, including ostriches, chickens and owls. Visitors can see flamingos and penguins through the glass of their indoor enclosure.
dr. Ann Duncan, chair of animal health for the Detroit Zoological Society, said moving birds indoors is a critical preventative measure.
In a statement, she said the Maryland Zoo is adhering to a multi-level response plan that has been reviewed by the United States Department of Agriculture and other government agencies.
The zoo, which has the largest colony of African penguins in North America, has not detected any cases, but the number of cases is close enough to keep the birds indoors, according to Mike Evites, senior communications director.
“We are hatching penguin chicks as part of a plan to increase their numbers with the Association of Zoos and Aquariums breeding program as part of global conservation efforts,” he said.
Ohio’s Columbus Zoo has also closed some bird habitats while they’re being monitored and assessed, according to communications director Jane Fields.
Gregory Wallace of CNN contributed to this report.