
Worrying Signals Emerge As Bird Flu Gains Resistance Mutation
Two new studies released in 2025 provide a mixed picture of how well our current antivirals are holding up against H5N1, the highly pathogenic bird flu virus that continues to spill over into mammals and humans. The good news: H5N1 viruses from recent human cases remain susceptible to frontline antiviral drugs. More concerning is a resistance mutation that emerged and spread rapidly during a poultry outbreak in Canada, raising flags about the virus's potential to evolve past our defenses.
The antiviral oseltamivir (commonly known as Tamiflu) is currently recommended for treating and preventing H5N1 infections. It works by inhibiting neuraminidase, a surface protein the virus uses to release itself from infected cells and spread through the body. But this treatment only works if the virus remains sensitive to the drug.
Tamiflu, the same antiviral used to treat ordinary seasonal influenza, is the front line medication ... More recommended for treating highly pathogenic bird flu (Photo by Rui Vieira/PA Images via Getty Images)
In a study published in the CDC's journal Emerging Infectious Diseases, researchers tested H5N1 viruses from human infections reported in Cambodia, Chile, and the United States during 2023–2024. These viruses belonged to two clades (genetic lineages): 2.3.2.1c and 2.3.4.4b. All tested viruses were susceptible to oseltamivir and other neuraminidase inhibitors, including zanamivir and peramivir, as well as baloxavir, a newer drug that targets a different viral protein. Most also remained sensitive to older M2-blocking antivirals—except for two viruses isolated in Cambodia. These results support continued use of oseltamivir as the first-line treatment and for post-exposure prophylaxis in close contacts of infected individuals.
Computer generated 3D model, showing a cross-section of the green RNP spirals, blue hemagglutinin, ... More red neuraminidase, and purple m2 ion channels that constitute the structure of the Influenza A Virus (Orthomyxovirus family) image courtesy CDC/Douglas Jordan, 2009. (Photo by Smith Collection/Gado/Getty Images)
However, not all recent developments are reassuring. A separate study published in Emerging Microbes & Infections documented a large outbreak of H5N1 in poultry in British Columbia, Canada. Genetic sequencing of the virus revealed the presence of the H275Y mutation in the neuraminidase gene—well-known to confer resistance to oseltamivir. This mutation had previously rendered the majority of seasonal H1N1 viruses resistant to the drug during the 2008–2009 flu season.
What makes the Canadian case notable is how quickly the resistant virus spread. Within 27 days of detection, it had jumped across 44 farms. While resistance mutations like H275Y are often associated with reduced viral fitness, the Canadian outbreak strain spread quickly between farms, suggesting that this particular virus was able to transmit efficiently despite carrying the mutation. The mutation appears to have arisen through reassortment, a genetic mixing process that occurs when influenza viruses exchange segments. In this case, the virus acquired its neuraminidase segment from a different influenza lineage circulating in North American birds.
These findings illustrate how resistance can arise in animal populations, well before human outbreaks begin. They also highlight the importance of genomic surveillance—not only in people but also in poultry and wild birds, where the virus continues to evolve.
Combination therapies may offer a way to slow resistance. Studies in animals have shown that using multiple drugs with different mechanisms simultaneously can reduce viral load more effectively and lower the chances of resistance emerging. But in the real world, access to such treatments remains limited.
For now, Tamiflu still works—but the virus is changing. Our response must keep pace.
Hashtags

Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
33 minutes ago
- Yahoo
It Sure Seems Like One Key GOP Vote Regrets Appointing RFK Jr.
Senator Bill Cassidy promised the American people that Robert F. Kennedy Jr. would not make any changes to the CDC's vaccine advisory committee when he cast his decisive confirmation vote for the HHS secretary. But on Monday RFK Jr. scrapped the board entirely, leaving Cassidy scrambling to explain himself and his vote. 'Of course, now the fear is that the ACIP will be filled up with people who know nothing about vaccines except suspicion,' Cassidy posted on X after Kennedy explained his rationale in a Wall Street Journal op-ed. 'I've just spoken with Secretary Kennedy, and I'll continue to talk with him to ensure this is not the case.' When asked what he said specifically to Kennedy to 'ensure' that the immunization advisory committee wouldn't be run by anti-vaxers, Cassidy went mum. 'I'd rather just characterize it as: we had a conversation,' he told Semafor's Burgess Everett on Tuesday. When Burgess asked if Cassidy was 'still comfortable' with voting to confirm RFK Jr. in February, Cassidy replied 'I'd rather not comment on that.' During the confirmation process Cassidy explicitly guaranteed that 'If confirmed, [RFK Jr.] will maintain the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices without changes.' Either Cassidy was lying, or RFK Jr. was lying to Cassidy. Now all of the other promises that Cassidy made on RFK's behalf—like not making false claims about vaccines causing autism, or even appearing before Congress on a quarterly basis—are moot. Cassidy claimed that he studied his decision to confirm Kennedy 'exhaustively' and took it 'very seriously.' It's clear that Cassidy's words meant nothing as Kennedy guts a key institution of our national health apparatus.


New York Post
42 minutes ago
- New York Post
Welcome to the best month of the year for stargazing — expect killer views of the Milky Way, experts say
'Core season,' as the pros at NASA have dubbed it, is officially upon us. While the 'core' of the Milky Way galaxy is visible in the night sky across the Northern Hemisphere almost all summer long, experts have long recognized June as the ultimate time of year for stargazers. Preston Dyches, messaging strategist at NASA, confirms this astronomical phenomenon in the June release of his monthly video series. The Milky Way core 'is best observed from dark sky locations far from bright city lights, and appears as a faint, cloud-like band arching across the sky toward the south,' he informed viewers. Advertisement This summer, skyward sights are particularly spectacular, partially thanks to the major lunar standstill impacting the moon's orbit. Paulista – The best news? Viewers in these prime locations don't need high-tech telescopes or even binoculars to stargaze this summer, though a closer view is often preferable for serious skygazers. The monumental sights spread across the cosmos this summer include several major constellations, ultra-bright stars, and seldom-seen planets. Advertisement Remarkable as this year's full strawberry moon, visible on June 10 and early June 11, is slated to be, the new moon on June 25 offers the darkest night sky — which makes for the most vibrant stars and planets. Early risers can catch a glimpse of Venus and Saturn, which rise around 2 hours before the Sun. Venus casts low, intense light across eastern skies throughout mornings in the month of June, while Saturn can be identified by its massive size and characteristic rings alone. Meanwhile, Mars can be spotted towards the west, and remains a striking sight around sunset, as well as the hours that follow. According to experts, the best places to stargaze in the Northern Hemisphere this summer are far, far away from major city lights. Anadolu via Getty Images Advertisement Jupiter and Mercury continue to appear a bit more elusive, even in June. Jupiter is typically visible early in June, but it is expected to return as a fixture of the morning sky in July. In the last week of June, keep your eyes out for Mercury, which, per NASA, appears 'greyish-brown to the human eye,' and will be discernible as a fixture of the evening sky, around sunset, in late June. Advertisement Other cosmic sights to behold include a slew of striking stars. Some seasoned stargazers take up viewing challenges during June and try to catch unique formations of stars alongside different planets. Regulus, the ultra-bright white 'heart' of the constellation Leo, will trail alongside Mars on June 16, while stars Castor and Pollux will form a line with Mercury on June 24, according to charts from EarthSky. Other visible constellations include the notable 'Summer Triangle,' which is made up of stars Vega, Deneb, and Altair. Longtime astronomer Patrick Moore originally coined the term, and said that not even the most 'myopic observer' could miss the cluster, which makes it a great starting point for beginner stargazers. By following these three bright stars, Milky Way viewers can spot Cygnus, Lyra, Aquila, Boötes, and Ursa Major. Observers on the East Coast of the United States are also expected to have especially unique skyward views as a result of recent Saharan dust movement, while stargazers closer to the northern border may have their sights obscured by drifting Canadian wildfire smoke.


Newsweek
an hour ago
- Newsweek
Map Shows 2 States Where Children Warned of Breathing Difficulties
Based on facts, either observed and verified firsthand by the reporter, or reported and verified from knowledgeable sources. Newsweek AI is in beta. Translations may contain inaccuracies—please refer to the original content. Air quality alerts continued on Tuesday, with children in two states being warned of "breathing difficulties" if they are exposed to poor air quality. Weather conditions such as light winds and higher temperatures are causing smoke from Canadian wildfires to settle in Ohio, pushing air quality into the unhealthy range, National Weather Service (NWS) observing program leader Brian Mitchell told Newsweek. Why It Matters Smoke from Canadian wildfires prompted widespread air quality alerts across the Upper Midwest, Great Lakes, and Northeast regions over the past few weeks. As of Tuesday, most of the smoke has moved out of the region. However, air quality alerts remain in parts of Ohio and Arizona for fine particulate matter and ozone pollution, respectively. The Air Quality Index (AQI) is expected to be Unhealthy for Sensitive Groups, which includes children and the elderly, in the affected regions. What to Know When inhaled, particles can lodge deep in the lungs and trigger inflammation, while ozone irritates the respiratory system and can exacerbate asthma. Children are particularly vulnerable to the impacts because of their developing respiratory systems and tendency to spend more time outdoors. In Ohio, the air quality alert was issued by the Northeast Ohio Areawide Coordinating Agency and warns of ground-level fine particles affecting the air quality in Ashtabula, Cuyahoga, Geauga, Lake, Lorain, Medina, Portage and Summit Counties. A stock image shows a child coughing while outside. A stock image shows a child coughing while outside. AaronAmat/Getty "Air quality levels will be unhealthy for sensitive groups during this period. If you are in the sensitive groups category of children, the elderly and those with breathing difficulties, please monitor your outdoor activity and check air quality readings at In Arizona, an Ozone High Pollution Advisory was in place for Maricopa County, including more than a million people who live in the Phoenix metropolitan area. Sunlight can contribute to higher ozone levels, making these alerts more common in the summertime. "This means that forecast weather conditions combined with existing ozone levels are expected to result in local maximum 8-hour ozone concentrations that pose a health risk. Adverse health effects increase as air quality deteriorates," the alert said. "Ozone is an air contaminant which can cause breathing difficulties for children, older adults, as well as persons with respiratory problems. A decrease in physical activity is recommended." In both states, people were urged to avoid worsening air quality levels by driving less, not idling in their vehicles, refilling their gas tanks after sunset, and waiting to mow the lawn. An air quality alert also was in place for parts of Michigan, although people in that state were not warned of breathing difficulties. What People Are Saying Air quality alert in Arizona: "You are urged to car pool, telecommute or use mass transit. The use of gasoline-powered equipment should be reduced or done late in the day." Air quality alert for Michigan: "Surface temperatures well into the 80s, ample sunlight, and west-southwest winds will create a conducive environment for Ozone development along the Lake Michigan shoreline. Residual wildfire smoke in the region may also enhance Ozone development over Lake Michigan." What Happens Next Both alerts are in place throughout Tuesday. More air quality alerts could be issued as smoke is expected to return on Wednesday.