Bird flu threat means suburban zoo, rehabilitation centers must hide their precious birds

Peacocks are generally free to roam the grounds of Brookfield Zoo, making courtship displays at this time of year.

This seasonal ritual, when male birds unfurl their jewel-colored feathers to impress females, will not have a visiting audience at the zoo this spring.

Brookfield moved the peacocks and guinea fowl indoors to isolate them from contact with wild birds that can spread a highly contagious and deadly form of bird flu. Storks, cranes, crows and Cape Barren geese also stay in their indoor waiting areas out of sight of the public.

The bird flu epidemic that has swept through poultry farms and backyard flocks across much of the United States has put zoos and animal rehabilitation centers on high alert.

“We want to take every precaution possible,” said Dr. Sathya Chinnadurai, senior vice president of animal health and welfare at the Chicago Zoological Society, the nonprofit organization that runs the Brookfield Zoo. .

As of Monday, 28.2 million birds on commercial and backyard flocks died from the disease or were euthanized to prevent the virus from spreading, according to the US Department of Agriculture. The first US case appeared in a wild American duck in South Carolina in January.


Visitors to Brookfield Zoo will not be able to see the peacocks, along with several other bird species, as they have been moved indoors due to concerns about the spread of bird flu.
– Courtesy of Brookfield Zoo

The last major outbreak of highly pathogenic avian flu wiped out 50.5 million commercial birds, mostly chickens and turkeys, from December 2014 to June 2015, costing the US economy an estimated $3.3 billion, it said. USDA in a final report.

“Now this outbreak has primarily hit the poultry system. This outbreak is hitting the poultry system 100 percent. But it seems to be hitting wild populations harder than the previous one,” said Dr. Sarah Reich, chief veterinarian at the Willowbrook Wildlife Center. at Glen. Ellyn.

Cook County Forest Preserve biologists suspect bird flu caused the recent deaths of more than 200 double-crested cormorants at a lake and man-made colony in Barrington, though federal authorities have yet to confirm the cases positive.

So far, 763 cases have been detected among wild birds in more than 30 states. The outbreak has claimed at least 41 bald eagles from Maine to Florida.

“It’s really bigger, and in 2014-15 I don’t recall any large-scale mortality events in wild birds,” said David Stallknecht, director of the Southeastern Cooperative Wildlife Disease Study, an organization from research at the University of Georgia. “There were raptors affected and other species and geese, but nothing like the numbers we’re seeing now.”

Virus Precautions

Two US zoos have had cases of highly pathogenic avian flu in birds in their collection, according to the USDA. Avian influenza viruses are classified as low pathogenic or highly pathogenic based on their genetic characteristics and the severity of disease in poultry.

The USDA does not track or report cases in zoos, but the agency’s Animal and Plant Health Inspection Service tests and confirms samples upon request. Zoos then work with state animal health officials to determine quarantine or isolation requirements, a USDA spokeswoman said.

A hawk flies over intern Manny Gonzales as he clears the raptor area last Thursday at the Willowbrook Wildlife Center in Glen Ellyn.  Raptors are likely to show clinical signs of illness if infected with bird flu, wildlife experts say.

A hawk flies over intern Manny Gonzales as he clears the raptor area last Thursday at the Willowbrook Wildlife Center in Glen Ellyn. Raptors are likely to show clinical signs of illness if infected with bird flu, wildlife experts say.
– Brian Hill | Personal photographer

Infected birds can shed the virus through feces and respiratory secretions. Zoos have taken strict measures to avoid inadvertently transmitting the virus through contaminated equipment and supplies. Brookfield has added boot washing and sanitizing stations for indoor housed bird keepers.

“We really want to make sure that we reduce the risk of feces or anything else being carried by wild geese or any other wild birds into indoor buildings,” Chinnadurai said.

The condors and some of the other larger birds in the zoo stay outside. The zoo has put tarps or covers over their outdoor enclosures to try to keep wild birds out.

“These are animals that we believe are in their best welfare to stay in their greatest outdoor access habitats,” Chinnadurai said.

Although the disease is often fatal in chickens and turkeys, wild waterfowl and migratory shorebirds can carry the virus without becoming ill.

“They can almost look like Typhoid Marys where they can spread disease, but they don’t necessarily show clinical signs of disease,” Reich said.

Willowbrook cares for injured and orphaned wildlife, and is one of the few rehabilitation centers licensed to accept injured migratory birds in the Chicago area.

“We haven’t reduced capacity or stopped taking certain species like some other centers have,” Reich said.

Veterinary tech Mariah Faiola works with a raven, which is one of the bird species at high risk for bird flu last Thursday at the Willowbrook Wildlife Center in Glen Ellyn.

Veterinary tech Mariah Faiola works with a raven, which is one of the bird species at high risk for bird flu last Thursday at the Willowbrook Wildlife Center in Glen Ellyn.
– Brian Hill | Personal photographer

But if cases start to rise in Illinois, experts at Willowbrook worry they may need to limit the consumption of certain species before peak migration season.

“We are also at the dawn of orphan gosling and duckling season, and we are taking in hundreds and hundreds of goslings and ducklings,” Reich said. “And the first species or the first group of animals that we would limit intake for would be waterfowl because they are most at risk, and that would be devastating because it could mean that hundreds to thousands of birds would not get of potential care.”

The public health risk from H5N1 avian flu viruses remains low, but occupational exposures to birds may put people at higher risk of infection, the Centers for Disease Control and Prevention said.

Willowbrook employees who deal with vulnerable species wear personal protective equipment and do “lots, lots, lots of disinfection,” Reich said.

“We don’t really have a lot of different areas that we can isolate animals in, so we’re really trying to limit the spread of things early on,” she said.

If high-risk species are brought to Willowbrook with neurological or respiratory problems – potential signs of bird flu – and these problems cannot be attributed to another cause, the birds will be euthanized. A great blue heron and a lesser scaup are among the handful of birds that died alone or were euthanized in Willowbrook, which did not pursue testing.

“If we had some sort of event where multiple birds arrived showing clinical signs from the same area,” Reich said, “or God forbid, animals already in our care started showing those signs as they didn’t have them before, that’s when we would choose to send those people for testing.”

“Expect Anything”

Some wildlife experts say it’s unclear when the outbreak might subside or if this form of bird flu might continue to circulate.

“Our caseload, at least the number of cases submitted, is going down, at least from the southeast, which can be a good sign. But I guess we’re just sitting here waiting for anything,” said Stallknecht. “I don’t know how else to put it.”

Transmission of low pathogenic strains of bird flu in North America typically resumes in late summer or early fall, he said.

“That’s what we have to wait to see what will happen. In Europe, this virus is obviously maintained in wild waterfowl populations,” Stallknecht said. “That’s definitely a possibility here.”

Bird flu tends to come in cycles, Brookfield’s Chinnadurai said.

“As the birds migrate north, we are watching their movements closely,” he said. “Probably depending on the seasonality of wild bird migration, it might be another month or two before we start to see a decline.”

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