Hey readers,
It's Kenny Torrella.
Nothing, it appears, can stop the bird flu.
Since early 2022, wild birds have spread the virus — known as H5N1, a highly pathogenic avian influenza — to farmed birds, resulting in the death of more than 90 million turkeys, egg-laying hens, and chickens in the US. Most birds haven't died from the disease but have been brutally killed to slow the spread. The culling has already cost US taxpayers north of a billion dollars.
The virus has also killed wild mammals, including tens of thousands of seals and sea lions, and a number of pet cats. Despite commitments from the poultry industry and the US Department of Agriculture (USDA) to enhance biosecurity on farms and increase disease surveillance, bird flu has charged ahead to infect over 60 dairy cow herds and two dairy farmworkers in recent months.
Infectious disease experts worry that the federal government's anemic response is giving the virus ever more opportunities to circulate and mutate among animal populations, which could help it adapt to more easily infect us.
"This virus is not going away," Carol Cardona, a veterinary professor at the University of Minnesota, recently told Vox's Jess Craig. "And I'm not sure how sustainable this approach that we're using is."
Cardona and other experts have called for vaccinating farmed birds to slow the spread of the disease. USDA has tested vaccines for farmed birds, but the agency has long been reluctant to deploy existing vaccines because poultry industry groups say it will disrupt trade and hurt the industry's bottom line.
With existing methods insufficient to stop the virus, some experts and technologists are beginning to advocate for another option to snuff out the bird flu: ultraviolet light.
Artificial sunlight could be bird flu's best disinfectant
Exposure to ultraviolet (UV) radiation from the sun can damage our skin and eyes, which is why we wear sunscreen and shouldn't stare at the sun — even during solar eclipses. But it can also kill pathogens.
In the 1930s, researchers found that placing UV "irradiation chambers" under the ceilings of classrooms reduced the spread of measles. But it never took off, and for decades, UV light for disease prevention in public settings remained a niche technology, as it also came with two major limitations. For one, it's dangerous to install and requires highly trained specialists. It can also be harmful if placed too close to people, so the UV lights are hung from ceilings — known as "upper room UV" — which reduces their effectiveness.
But in the early 2010s, Columbia University medical physicist David Brenner discovered that a type of UV light with a shorter wavelength than what had previously been used, known as far-UVC or far-UV, can be safely placed closer to humans. It also requires little to no installation expertise.
The discovery of far-UV has sparked a renaissance in the field of UV technology, as Vox's Dylan Matthews recently reported. Its proponents say it has the potential to halt the spread of everything from the common cold to Covid-19, ushering in a new era of disease prevention. And unlike vaccines, which must be tailored to specific strains, far-UV is effective at killing pretty much any pathogen that comes its way.
Far-UV lamps have been slowly popping up in school buses, churches, military buildings, and more. In theory, they could also be installed in poultry farms to stop the spread of bird flu.
"It seems a no-brainer to try this," Brenner told me, when I asked him about the idea. It's "not so expensive to install — certainly in the context of the cost of this whole problem."
But questions remain about how well it would work on farms.
UV vs. bird flu sounds good on paper. The reality is more complicated.
Inside farms, bird flu spreads from bird to bird through two means: in the air and through infected birds' bodily fluids — feces, saliva, and nasal secretions.
Far-UV light should be especially good at killing the virus when it's in the air, Brenner said. But bodily fluids appear to be the primary means of transmission among chickens and turkeys, according to USDA.
If that's true, then far-UV's effectiveness in slowing H5N1 would be limited.
To squash pathogens that have been spread through bodily fluids onto a surface, like a barn floor or a bird's feathers, far-UV light needs a direct line of sight to the germs. But most poultry birds are raised in overcrowded farms with tens of thousands of other birds, with layers of feces and litter on the barn floor. That density and complexity would make it hard to shine far-UV light on each nook and cranny where the virus lives.
"If you've got a complicated surface, which you of course have [on poultry farms], you're only going to get a limited amount of UVC-based decontamination," Brenner said.
"There has to be a level of airborne transmission — why wouldn't there be?" Brenner added. "But the balance between surface and airborne transmission, in my view, is not known." This same question — airborne versus surface spread — made for fierce debate in the early days of the Covid-19 pandemic.
On dairy farms, where some evidence suggests the virus is spreading from cow to cow through milking machines, some scientists believe it could also be airborne. Either way, far-UV could help provide protection to farmworkers.
"Bird flu has jumped to cows … and is now jumping from cows to people," said P.J. Piper, founder and CEO of the UV lamp company Far UV Technologies. "Having UV in barns where those people are interacting with the cattle is a really good idea."
USDA policy presents another complication. If a single poultry bird is infected with bird flu, the federal government mandates that farmers must kill the entire flock, because the virus spreads rapidly and is nearly 100 percent fatal to birds. That creates a high bar for far-UV — it can't just eradicate some of the virus, but must destroy all or nearly all of it. Otherwise, farmers will still need to kill flocks.
But combined with other prevention measures, far-UV could still help reduce the number of farms hit with an outbreak.
The beginnings of testing far-UV on the farm
The USDA, along with a number of leading poultry companies and trade groups, didn't respond to inquiries about whether the government or industry is testing far-UV as part of its bird flu response.
Aviagen Turkeys Ltd. — a major turkey breeding company based in the UK — has tested a small number of far-UV lights on a farm and is looking at installing lights in another facility as a proof of concept, according to the company.
Others in the livestock sector are also testing far-UV. Danish company UV Medico is looking at whether far-UV can reduce the spread of African swine fever on pig farms, which has ravaged the pork industry over the last decade. Iowa State University researchers have investigated its potential against porcine reproductive and respiratory syndrome (PRRS), an airborne disease that's also costly to the pork industry.
If far-UV can prove effective in a farm setting, it could be a win-win for business and public health. The global meat, dairy, and egg sectors lose $358 billion to disease annually, according to Health for Animals, a livestock vaccine trade group.
Many farms already require employees to place items like phones, tools, and lunch pails into UVC chambers, which are about the size of a small oven, as a disinfection measure before entering the farm. Signify — the parent company of the lighting giant Philips and a manufacturer of UVC chambers — told Vox sales have been up due to the bird flu outbreak.
UV-emitting lamps could be the next step in the evolution of ultraviolet light on the farm.
"The cost of not using far-UVC is really the question, or not systematically investigating it," said Ashok Chaudhari, CEO of far-UV company Baldr Light ApS. "The safety so far for humans has been shown to be extremely compelling; the same ought to apply to animals, but we just don't have enough data."
Given the threat H5N1 poses to public health, agriculture, and animal welfare, testing far-UV is the least the government and the poultry industry could do. There's too much at stake not to shine some light on bird flu.
—Kenny Torrella, staff writer
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