Scientists are getting creative in monitoring the bird flu outbreak – by testing stool

Amid widespread gaps in U.S. testing for H5N1, a type of bird flu, and now that a second case has been discovered in humans, scientists are turning to more creative ways to monitor the outbreak — especially in human and animal feces.

Scientists and officials are expanding wastewater monitoring across the U.S. and engaging community members to collect waste samples from birds. They hope to keep an eye on this outbreak as they prepare for the next pandemic.

A new dashboard to monitor influenza A in wastewater across the country was launched last week by the Centers for Disease Control and Prevention (CDC). H5N1 is not specifically monitored, but the highly pathogenic variant of bird flu is part of the influenza A family.

The dashboard helps identify hotspots in the US where influenza A is becoming more common – and since flu rates among people are low this time of year, such an increase could alert scientists and the public to possible outbreaks of H5N1.

“I’m really happy to see them sharing the data they have,” said Marc Johnson, a professor at the University of Missouri School of Medicine and laboratory leader for wastewater monitoring in Missouri.

Another project turns to citizen scientists – high school students in New York City – to examine bird droppings for infectious diseases.

Volunteers, clad in personal protective equipment, are trained to collect fecal samples from local parks, then work with scientists from the Icahn School of Medicine at Mount Sinai to analyze what pathogens are present.

This is how H5N1 was first discovered in New York City in late 2022, according to a new study.

“There is a lot of potential for citizen science, especially to expand the scope of pathogen surveillance,” said Philip Meade, lead author of that study and a researcher at the Mount Sinai laboratory.

“It is very difficult to gain a complete understanding of the viruses circulating in our environment,” he said.

The citizen science program, called Virus Hunters, could be expanded to other flyways for migratory birds along the West Coast and the Midwest, Meade said.

“The more people you have on the ground helping us generate the data now and understand what’s happening, the better it is for us and also for nature,” said Christine Marizzi, co-author of the study and director of Community science for BioBus, the mobile research laboratory that works with students.

Citizen science programs don’t just increase the number of people collecting samples, Marizzi said. They also build trust in science among communities.

“We do this together with the community. We actively involve the community from the start,” she says. “Getting information out there so we can build the trust you really need when the next pandemic comes along. That will be very, very important.”

Part of the challenge in monitoring the emergence of viruses in animals is the sheer scale of the task. Normally, animals (and people) are only tested when they are sick – but scientists are now learning that H5N1 can circulate asymptomatically in cows and possibly other animals as well.

This type of non-invasive sampling can monitor for pathogens even when no symptoms are present.

During this bird flu outbreak, there have been gaps in testing as farms and workers face negative consequences if they test positive. Testing wastewater allows officials to understand what pathogens are circulating without directly testing animals and humans.

“If any of the farms are on municipal sewage, we can test it – we don’t have to go to the farms,” Johnson said. “I think this is a really good idea, not just for dairy, but especially downstream from meat processing plants so we can keep an eye on whether it’s spreading” to non-dairy animals.

Infections in dairy cows are usually detected by testing their milk, as udders have been proven to contain high levels of the flu virus – but in other non-lactating animals it can be difficult to know where to test the animal to get accurate results. get results. . “Testing downstream of meat processing plants is a great idea because it doesn’t matter what part of the cow it’s in,” Johnson said.

H5N1 was detected in the wastewater of nine of the ten Texas cities surveyed recent pre-print study. Most of the virus likely originated in animals, but human infections cannot be ruled out, the authors concluded.

“Whether it’s from livestock or people or birds or whatever, let’s get an idea of ​​how much is there so if there’s a change we know to pay attention,” Johnson said. “We need a baseline of what’s going on so we can see if things are getting worse or better.”

If national influenza A monitoring had taken place a few months ago, he said, officials might have discovered the H5N1 outbreak in cows much sooner. Scientists believe the current outbreak started in late 2023, but was only discovered in late March.

Wastewater monitoring can also help detect onward transmission from farms, especially to new species.

This cow-adapted flu strain could continue to acquire mutations as it returns to bird populations or transitions into new species.

“When viruses spend time in different hosts, they evolve to become better at replicating in those hosts. So any time a virus like this enters a mammalian host and remains there and circulates in that host, that is something that is of great concern to us,” Meade said.

“If this gets to pigs, we should be nervous,” Johnson said. Typically, pigs are not checked for these types of diseases until they become ill, but asymptomatic infections can go unnoticed. “If the pigs don’t get sick, they could already be in pigs and we wouldn’t know.”

Undetected infections among humans would also be a major concern.

“If we missed it by five months in dairy cattle, we could miss it in something else. And it could be something much more concerning than dairy cows,” Johnson said.