Deadly bird flu outbreak requires urgent coordinated response

Since late 2021, a deadly bird flu outbreak has been spreading in the United States. This highly pathogenic form of avian influenza (H5N1) has been decimating wild birds, severely impacting poultry, pushing up egg prices, and initiating fears that a new zoonotic pandemic may be just around the corner.

A team of scientists led by the University of Maryland (UMD) has now tracked the arrival and progression of this deadly bird flu outbreak in North America in order to clarify how this outbreak is different from previous ones, and how public health authorities should attempt to manage it.

According to the experts, the severe toll on wild birds and a marked shift from seasonal to year-round infections signal dangerous changes in the nature of bird flu outbreaks. “We’ve been dealing with low pathogenic avian influenza for decades in the poultry industry, but this is different,” said co-author Jennifer Mullinax, an assistant professor of Wildlife Ecology at UMD.

“This highly pathogenic virus is wiping out everything in numbers that we’ve never seen before. This paper illustrates how unprecedented it is, and describes what we think is coming. It’s really a call to arms saying, we can’t afford to address this from our individual silos. Federal agencies, state agencies, the agriculture sector, and wildlife management, we are all going to have to deal with this together, because we can’t afford not to.”

Although in 2015, an outbreak of highly pathogenic H5N8 in the United States led to the culling of over 50 million poultry birds, health authorities managed to eradicate the disease that same year, largely because it did not significantly impact wild birds, which made its containment relatively easy. With the current outbreak, such methods are unlikely to work.

“Unlike H5N8, this disease is heavily impacting wild birds,” explained lead author Johanna Harvey, a postdoctoral researcher in Disease Ecology at UMD. “It’s difficult to estimate how many birds are truly affected across wild populations, but we’re seeing dramatic disease impacts in raptors, sea birds, and colonial nesting birds. And we now have the highest amount of poultry loss to avian influenza, so this is a worst-case scenario.”

Moreover, while previous bird flu outbreaks typically occurred in the fall, providing the farmers the possibility to prepare for seasonal outbreaks, cull flocks to stop the spread of the disease, and have almost a full year to recover their losses, the current outbreak appears to be sustained throughout the whole year, with summertime disease detections in wild birds and poultry outbreaks in both spring and autumn. 

The scientists recommend a management approach based on a method called “Structured Decision-Making” which aims to identify and bring together relevant experts, distinguish the unknown from the known factors, and establish measurable actions and goals with quantifiable results.

“Good decision science is what you do when you don’t know what is going to happen next. This is a novel virus for North American birds, so no one knows if their immune systems will adapt, or how long that will take, or what that will look like. Where do we direct our funds for maximum benefit? Is it a vaccine? How do we track it in wild birds? Do we test the water or the soil? What are the triggers for different actions, and how do we measure if we’re succeeding? These decisions have to be made on multiple scales,” Mullinax concluded.

The study is published in the journal Conservation Biology.

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By Andrei Ionescu, Earth.com Staff Writer

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