It’s a big threat, which zoos are taking very seriously.
Across the United States, bird flu is no longer a concern only for dairy and poultry farms — it’s now knocking on the gates of zoos and wildlife sanctuaries, putting some of the nation’s rarest animals at risk.
Last month, cases of avian influenza, specifically the H5N1 strain of the virus, were reported at the Wildlife Zoo and Aquarium outside Phoenix, Ariz., claiming the lives of a cheetah, mountain lion, swamphen, kookaburra and an Indian goose. Twenty big cats also died at a wildlife sanctuary in Washington.
This month at Chicago’s Lincoln Park Zoo, a Chilean flamingo and a harbor seal both died from highly pathogenic avian influenza (known as HPAI). In Virginia, the Richmond Metro Zoo reported the deaths of a Stanley crane and African crowned crane due to bird flu, according to The Washington Post.
While the exact exposure is unknown for some of these cases, it’s believed contact with infected waterfowl, which are natural carriers of the virus, is the culprit.
No cases of bird flu have been reported at zoos and wildlife sanctuaries in the Dallas-Fort Worth area, although infected waterfowl and other wild birds like the red-tailed hawk, have been reported in Texas. Zoo officials are on high alert for even the slightest whiff of bird flu, especially since billions of birds travel through Texas during their seasonal migrations every year, said Dr. Anne Burgdorf-Moisuk, associate vice president of animal health and welfare at the Dallas Zoo.
“Although what’s happening now is a bit different — the virus has mutated a bit — HPAI is something that zoo veterinarians have had to watch out for for a really long time,” Burgdorf-Moisuk said. “We have protocols in place for disease outbreaks like HPAI, foot and mouth disease and lots of issues that could be problems for a zoo.”
Burgdorf-Moisuk and Dr. Kimberly Rainwater, veterinary services director at the Fort Worth Zoo, explained that the emergency response protocols in case of a bird flu outbreak take into account many factors. These include any alerts to bird flu in Texas, how far the reported cases are in proximity to the zoo, identifying which animals are the most vulnerable and potential points of exposure.
“The plan we’re using right now, we put together in early 2022 when this current outbreak started and when we started seeing more cases,” said Rainwater. “We use that plan continuously, looking at what level of the plan we’re at because it is a tiered plan with different responses at different levels.”
The first level of this response plan involves tracking where positive cases are being reported by the U.S. Department of Agriculture. If the virus is being reported in states bordering Texas, Burgdorf-Moisuk said, zoo staff will start planning precautionary measures and housing birds and other animals indoors to prevent exposure to waterfowl and other infected wild birds that may fly in and out of enclosures.
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If an animal catches bird flu despite the safety measures in place, Burgdorf-Moisuk and Rainwater said, no antiviral treatments are available; the only course of action is supportive care. The animal is also immediately separated from others to keep it from spreading the virus.
While there are vaccines for highly pathogenic avian influenza, none are approved for use among zoo animals, at least in the United States. In May 2023, however, USDA did grant emergency use of a shot for critically endangered California condors as part of a pilot program across three zoos in California and Oregon.
The chance of an animal surviving bird flu is challenging to predict, Rainwater said. “Survival for a lot of the birds that we see that get sick is pretty low,” she added.
See here and here for some background. I didn’t see any news related to the Houston Zoo and its response to HPAI – I did find this release from 2022 when HPAI first emerged – but I’m sure they’re taking similar precautions. With all the chaos and destruction happening in the federal government right now, I hope they’re all still able to get these reports from the Ag Department. There are far worse things to be worried about, but this is one of those situations that could break through. I’d rather that everything work as intended, but here we are.