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As national wastewater testing expands, Texas researchers identify bird flu in nine cities

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As national wastewater testing expands, Texas researchers identify bird flu in nine cities

As researchers increasingly rely on wastewater testing to monitor the spread of bird flu, some are questioning the reliability of the tests being used. Above, the Hyperion Water Reclamation Plant in Playa Del Rey.

(Jason Armond / Los Angeles Times)

As health officials turn increasingly toward wastewater testing as a means of tracking the spread of H5N1 bird flu among U.S. dairy herds, some researchers are raising questions about the effectiveness of the sewage assays.

Although the U.S. Centers for Disease Control and Prevention says current testing is standardized and will detect bird flu, some researchers voiced skepticism.

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“Right now we are using these sort of broad tests” to test for influenza A viruses in wastewater, said epidemiologist Denis Nash, referring to a category of viruses that includes normal human flu and the bird flu that is circulating in dairy cattle, wild birds, and domestic poultry.

“It’s possible there are some locations around the country where the primers being used in these tests … might not work for H5N1,” said Nash, distinguished professor of epidemiology and executive director of City University of New York’s Institute for Implementation Science in Population Health.

The reason for this is that the tests most commonly used — polymerase chain reaction, or PCR, tests — are designed to detect genetic material from a specific organism, such as a flu virus.

But in order for them to identify the virus, they must be “primed” to know what they are looking for. Depending on what part of the virus researchers are looking for, they may not identify the bird flu subtype.

There are two common human influenza A viruses: H1N1 and H3N2. The “H” stands for hemagglutinin, which is an identifiable protein in the virus. The “N” stands for neuraminidase.

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The bird flu, on the other hand, is also an influenza A virus. But it has the subtype H5N1.

That means that while the human and avian flu virus share the N1 signal, they don’t share an H.

If a test is designed to look for only the H1 and H3 as indicators of influenza A virus, they’re going to miss the bird flu.

Marc Johnson, a professor of molecular microbiology and immunology at the University of Missouri, said he doesn’t think that’s too likely. He said the generic panels that most labs use will capture H1, H3 and H5.

He said while his lab specifically looks for H1 and H3, “I think we may be the only ones doing that.”

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It’s been just in the last few years that health officials have started using wastewater as a sentinel for community health.

Alexandria Boehm, professor of civil and environmental engineering at Stanford University and principal investigator and program director for WastewaterSCAN, said wastewater surveillance really got going during the pandemic. It’s become a routine way to look for hundreds if not thousands of viruses and other pathogens in municipal wastewater.

“Three years or four years ago, no one was doing it,” said Boehm, who collaborates with a network of researchers at labs at Stanford, Emory University and Alphabet Inc.’s life sciences research organization. “It sort of evolved in response to the pandemic and has continued to evolve.”

Since late March, when the bird flu was first reported in Texas dairy cattle, researchers and public health officials have been combing through wastewater samples. Most are using the influenza A tests they had already built into their systems — most of which were designed to detect human flu viruses, not bird flu.

On Tuesday, the CDC released its own dashboard showing wastewater sites where it has detected influenza A in the last two weeks.

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Displaying a network of more than 650 sites across the nation, there were only three sites — in Florida, Illinois and Kansas — where levels of influenza A were considered high enough to warrant further agency investigation. There were more than 400 where data were insufficient to allow a determination.

Jonathan Yoder, deputy director of the CDC’s Division of Infectious Disease Readiness and Innovation, said those sites were deemed to have insufficient data because testing hasn’t been in place long enough, or there may not have been enough positive influenza A samples to include.

Asked if some of the tests being used could miss bird flu because of the way they were designed, he said: “We don’t have any evidence of that. It does seem like we’re at at a broad enough level that we don’t have any evidence that we would not pick up H5.”

He also said the tests were standardized across the network.

“I’m pretty sure that it’s the same assay being used at all the sites,” he said. “They’re all based on … what the CDC has published as a clinical assay for for influenza A, so it’s based on clinical tests.”

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But there are discrepancies between the CDC’s findings and others’.

Earlier this week, a team of scientists from Baylor College of Medicine, the University of Texas Health Science Center at Houston, the Texas Epidemic Health Institute and the El Paso Water Utility, published a report showing high levels of bird flu from wastewater in nine Texas cities. Their data show that H5N1 is the dominant form of influenza A swirling in these Texas towns’ wastewater.

But unlike other research teams, including the CDC, they used an “agnostic” approach known as hybrid-capture sequencing.

“So it’s not just targeting one virus or one of several viruses,” as one does with PCR testing, said Eric Boerwinkle, dean of the UTHealth Houston School of Public Health and a member of the Texas team. “We’re actually in a very complex mixture, which is wastewater, pulling down viruses and sequencing them.”

“What’s critical here is it’s very specific to H5N1,” he said, noting they’d been doing this kind of testing for approximately two years, and hadn’t ever seen H5N1 before the middle of March.

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Blake Hanson, an assistant professor at the University of Texas Health Science Center at Houston School of Public Health and a member of the Texas wastewater team, agreed, saying that PCR-based methods are “exquisite” and “highly accurate.”

“But we have the ability to look at the representation of the entire genome, not just a marker component of it. And so that has allowed us to look at H5N1, differentiate it from some of our seasonal fluids like H1N1 and H3N2,” he said. “It’s what gave us high confidence that it is entirely H5N1, whereas the other papers are using a part of the H5 gene as a marker for H5.”

Boerwinkle and Hanson underscored that while they could identify H5N1 in the wastewater, they cannot tell where it came from.

“Texas is really a confluence of a couple of different flyways for migratory birds, and Texas is also an agricultural state, despite having quite large cities,” Boerwinkle said. “It’s probably correct that if you had to put your dime and gamble what was happening, it’s probably coming from not just one source but from multiple sources. We have no reason to think that one source is more likely any one of those things.”

But they are pretty confident it’s not coming from people.

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“Because we are looking at the entirety of the genome, when we look at the single human H5N1 case, the genomic sequence … has a hallmark amino acid change … compared to all of the cattle from that same time point,” Hanson said. “We do not see that hallmark amino acid present in any of our sequencing data. And we’ve looked very carefully for that, which gives us some confidence that we’re not seeing human-human transmission.”

The Texas’ team approach was really exciting, said Devabhaktuni Srikrishna, the CEO and founder of PatientKnowHow.com, noting it exhibited “proof of principle” for employing this kind of metagenomic testing protocol for wastewater and air.

He said government agencies, private companies and academics have been searching for a reliable way to test for thousands of microscopic organisms — such as pathogens — quickly, reliably and at low cost.

“They showed it can be done,” he said.

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Opinion: Most older Americans who need hearing aids don't use them. Here's how to change that

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Opinion: Most older Americans who need hearing aids don't use them. Here's how to change that

Having depended on hearing aids for nearly three decades, I’m astounded by the lack of Medicare coverage for devices that can solve a problem afflicting tens of millions of older Americans.

Nearly two-thirds of Americans over age 70 have some degree of hearing loss, and over half of those 75 and older experience impairment serious enough to be considered disabling. But most don’t wear hearing aids.

Because the legislation that created Medicare nearly 60 years ago specifically excluded hearing aids, those who rely on the program’s traditional coverage must pay for them out of pocket. That expense is among the chief barriers to wider use of the devices.

Age-related hearing loss impedes basic communication and the relationships that depend on it. Expanded access to hearing aids could therefore do no less than enable more older Americans to establish and maintain the social connections that are essential to a meaningful life.

Hearing loss is like an invisible, muffling curtain that falls in front of anyone speaking. Asking people to repeat themselves can yield irritated and hurtful responses. And it’s hopeless to ask a soft-spoken person to speak up. Sometimes it’s easier just to nod and smile.

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Many older people I know choose to avoid social gatherings altogether because they can’t hear well. Without hearing aids, I’d stay home too.

Hearing loss can harm one’s health in other ways. For example, I’ve written about the need for a comprehensive approach to reducing cancer risk at older ages, including preventive services such as colorectal cancer screening. But these services rely on conversations between patients and their healthcare providers. An older patient’s ability to hear and understand such conversations shouldn’t be taken for granted or ignored.

The Food and Drug Administration did improve access to hearing aids by making some of them available without a prescription in 2022, but the over-the-counter devices are inadequate for serious hearing loss like mine. My private health insurance, meanwhile, started covering hearing aids a few years ago, providing up to $2,500 for them every five years. One hearing aid alone can cost that much or more, however.

Despite its limitations, my private coverage for hearing aids is better than nothing, which is what traditional Medicare provides.

Hearing loss is more common among lower-income people and those without advanced education. The toll from noisy workplaces compounds age-related hearing loss for some. One analysis found that most Americans with a serious hearing disability can’t afford the typical price of hearing aids.

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Many of the older adults who can’t come up with these significant out-of-pocket expenses spent their working years in low-wage jobs that our country depends on. Denying them treatment for their hearing loss is a lousy way to treat people who gave years of service to our society.

Although some older adults with hearing loss won’t benefit from hearing aids, Medicare coverage for the devices might encourage more beneficiaries to get their hearing tested so they can get the treatment that’s right for them. And while Medicare coverage alone won’t address the stigma some people associate with hearing aids, the availability of newer, more comfortable and less obvious technology might win over some refuseniks.

Legislation reintroduced with bipartisan support last year would finally correct this glaring gap in Medicare coverage by removing the hearing aid exclusion from the law. There’s no reason to delay action on this any longer. Are our representatives listening?

Mary C. White is an adjunct professor of environmental health at Emory University’s Rollins School of Public Health, a Public Voices fellow at AcademyHealth in partnership with the OpEd Project and a former federal epidemiologist.

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Second human case of bird flu detected in Michigan dairy worker

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Second human case of bird flu detected in Michigan dairy worker

A second human case of bird flu in a diary worker has been confirmed in Michigan, state and federal health officials announced Wednesday.

The symptoms were mild, consisting of conjunctivitis. The Texas dairy worker who contracted the virus in March also came down with pink eye.

At a press call on Wednesday, Nirav Shah, principal deputy director of the U.S. Centers for Disease Control and Prevention, said the finding was “not unexpected” and that it was a scenario “that we had been preparing for.”

He said that since the discovery of H5N1 in dairy cattle, state and federal health officials have been closely monitoring farmworkers and slaughterhouse workers and urging farmers and farmworker organizations to “be alert, not alarmed.”

Federal officials say they still believe the human health risk of bird flu is low; however, it underscores the need for people who are interacting with infected or potentially infected farm animals or birds to take precautions, including avoiding dead animals and wearing personal protective equipment (PPE) if there’s a need to be in close contact.

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Though a nasal swab from the person in Michigan tested negative for influenza, an eye swab from the patient was shipped to the CDC and tested positive for influenza A(H5N1) virus.

This is the third case of H5N1 reported in the United States. A poultry worker in Colorado was identified in 2022.

Although the symptoms in the three farmworkers in the U.S. have been mild, people elsewhere in the world have suffered more severe illness, including death. According to the World Health Organization, between Jan. 1, 2003, and March 28, 2024, there have been 888 cases of human infection from 23 countries; 463 were fatal.

In preparation for a more widespread outbreak, the CDC updated its guidance for PPE in dairies and issued a nationwide order for healthcare providers to be on the lookout for novel influenza.

On Tuesday, the CDC asked clinical laboratories and health departments to increase the number of influenza samples being analyzed “to maximize the likelihood of catching a case of H5N1 in the community,” Shah said.

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The US Department of Agriculture is also expanding its surveillance and support by providing $1500 to non-infected farms to beef up biosecurity, and $100 to producers who want to buy inline samplers to test their milk. The agency will also provide $2000 per farm to cover veterinary fees for testing, as well as shipping costs to send those tests to laboratories for analysis.

There have been no cases of H5N1 detected in California’s dairy herds.

Officials said ongoing analysis of the nation’s dairy supply suggests it is safe to consume, Despite the risk to human health being low, an official with the Administration for Strategic Preparedness and Response said it will make Tamiflu available upon request “to jurisdictions that do not have their own stockpile and are responding to pre-symptomatic persons with exposure to confirmed or suspected infected birds, cattle or other animal exposures.”

Dawn O’Connell, assistant secretary of the preparedness agency, said it started the “fill and finish” process for approximately 4.8 million doses of vaccine “that is well matched to the currently circulating strain of H5N1 through the national pre-pandemic influenza vaccine stockpile program.”

She said the decision to get started on H5N1 vaccines was not a response to any heightened concern, but since it takes several months to fill and finish vaccine doses, the agency “thought it made sense given what we were seeing.”

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Gas stoves may contribute to early deaths and childhood asthma, new Stanford study finds

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Gas stoves may contribute to early deaths and childhood asthma, new Stanford study finds

Lung-irritating pollution created by cooking with gas stoves may be contributing to tens of thousands of premature deaths and cases of childhood asthma in the United States, according to a new study published in the journal Science Advances.

For decades, scientists have known the flames from a gas stovetop produce nitrogen dioxide, a pungent gas that can inflame a person’s lungs when inhaled. But for the first time, a team of researchers from Stanford University and Oakland-based research institute PSE Healthy Energy published a nationwide estimate of the long-term health consequences associated with cooking with natural gas and propane stoves.

Researchers concluded that exposure to nitrogen dioxide emissions alone may contribute to nearly 19,000 premature deaths in the United States each year. It has also resulted in as many as 200,000 current cases of pediatric asthma compared with cooking with electric stoves, which do not produce nitrogen dioxide.

Aggressive and impactful reporting on climate change, the environment, health and science.

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Stanford researcher Yannai Kashtan noted higher levels of pollution were correlated with the amount of gas that was burned. But pollution also accumulated at higher levels inside smaller homes.

“If you live in a smaller house, you’re exposed to more pollution, and that can lead to income and racial disparities in exposure,” Kashtan said. “In general, folks living in neighborhoods with higher levels of outdoor pollution also tend to have higher indoor pollution. So this environmental injustice extends indoors as well.”

The American Gas Assn., a trade organization representing more than 200 local energy companies nationwide, dismissed the findings as “misleading and unsupported.”

“Despite the impressive names on this study, the data presented here clearly does not support any linkages between gas stoves and childhood asthma or adult mortality,” the association’s president and CEO, Karen Harbert said in a statement earlier this month.

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The study is the latest examining the serious health effects associated with breathing fumes from gas stoves, which release planet-warming carbon emissions and a variety of air pollutants. In recent years, the popular household appliance has become a political hot-button issue as policymakers and regulators have weighed environmental impacts against consumer choice.

Many large cities in California, including Los Angeles, have moved toward phasing out gas stoves in newly constructed residences. Earlier this month, the California Assembly advanced a bill to the Senate that would require gas stoves to come with warning labels detailing the pollution and health effects that can arise from cooking with gas.

Gas stoves emit a variety of pollutants, including asphyxiating carbon monoxide, cancer-causing formaldehyde and benzene. The flame also creates nitrogen dioxide, a precursor to smog and a pollutant that can cause difficulty breathing.

Environmental groups say consumers should be notified about these pollutants and the potential harm they can cause.

“Gas stoves create pollution in our homes, increasing the risk of childhood asthma and other respiratory problems for our families,” said Jenn Engstrom, state director for California Public Interest Research Group. “However, this risk has largely been hidden from the public. Consumers deserve the truth when it comes to the danger of cooking with gas. Warning labels will give consumers what they need to make informed decisions when they purchase appliances for their homes.”

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Kashtan and other researchers had previously discovered cooking with gas stoves presented a similar cancer risk as inhaling second-hand cigarette smoke. They also found some gas stoves leaked contaminants even when the burners were off.

The effects are especially devastating to children, whose smaller and still-developing lungs need to take more breaths than adults, Kashtan said. Older adults, especially those with cardiovascular or respiratory illness, are also more vulnerable to pollution from gas stoves.

To alleviate indoor air pollution, experts recommend using ventilation hoods and opening windows while cooking,

Starting in 2008, California required new and redeveloped homes to have ventilation that could prevent pollution from building up indoors. But during their research, measuring emissions in more than 100 households across the country, Yannai said they found many kitchens didn’t have ventilation hoods at all.

Although the health effects of breathing these pollutants are clear, researchers still wonder to what degree these conditions could be reversible. As communities take steps to mitigate their exposure or transition away, he said we could soon see the results.

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“It’s never too late to stop breathing in pollution,” he said.

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