terrible news, i thought i should post this and bring it to yalls attention, concerning for sure. Thanks to Science.org et al…terry
DECIPHERING D
A mysterious influenza strain infects livestock around the world. Scientists worry it can become a threat to humans as well
19 FEB 2026 2:00 PM ETBYJON COHEN
Cattle at feed lots like this one in Mexico’s Nuevo León state often huddle together, which may help the influenza D virus spread. RODO GARZA/DGPPE UANL
NUEVO LEÓN STATE IN MEXICO—At dawn one morning in December 2025, researchers in the sprawling city of Monterrey, Mexico, loaded a large passenger van with syringes, swabs, test tubes, air samplers, and coolers. They then drove through the flat countryside for 2 hours, leaving the gap-toothed Sierra Madre Oriental mountains in the distance, until they reached a feed lot that had 24,000 head of cattle. “Everywhere you look, all the way to the horizon, it’s cows,” said Gregory Gray, an infectious disease clinician and epidemiologist from the University of Texas Medical Branch.
At the farm, the team began swabbing noses and taking blood samples from the animals. Gustavo Hernández-Vidal, a veterinarian at the Autonomous University of Nuevo León, walked with Thang Nguyen-Tien, a virologist in Gray’s lab, to a long pen that held about 100 sick cattle. From a rafter, Nguyen-Tien hung a bioaerosol sampler that sucks in air and spins it to separate particles and collect viral genetic material. Curious, the farm’s head veterinarian asked what they were doing.
“We want to see what the cows are breathing,” Hernández-Vidal said.
“The cows and us,” the vet replied.
snip…
But humans may become infected by IDV as well. Several studies, including one the U.S.-Mexican team carried out earlier at the same feed lot, have found antibodies to the virus in farm workers, indicating they were exposed to it. There is no evidence yet they fell ill, but IDV could evolve to more readily infect and sicken people, says Gray, who has helped discover a half-dozen viruses in humans and animals. “We need to be ready to respond,” he says. “What appears today as a quiet livestock virus could, with little warning, ignite the next influenza pandemic,” Ohio State University (OSU) veterinarian Cody Warren and co-authors warned in an 8 February preprint that showed flu D readily infects cells found in human airways.
snip…
His team found that the virus could spread between pigs through contact. None became ill, but he worried news of the finding might harm the pork industry. It still had scars from 2009, when an influenza A subtype known as H1N1 jumped from pigs to humans, causing a pandemic initially called the “swine flu.” (The virus was later renamed “pandemic H1N1.”) Hause and Li asked Richard Webby, a renowned flu researcher at St. Jude Children’s Research Hospital, to help them study the new virus but urged him to “keep it on the down low, at least initially,” Hause remembers.
Webby discovered the virus could spread via direct contact between ferrets, a model to study flu in mammals, which suggested a risk of pig-to-human spread. But unlike the influenza A and B viruses that infect humans every year, it did not spread between the ferrets via respiratory droplets, and it didn’t sicken them.
When Hause, Li, Webby, and co-workers first published a report about their findings in 2013, they described the virus as “distantly related” to flu C, with which the new virus shared about half of its genome. “I didn’t think we had enough information to justify proposing it as a new genus,” Hause says.
The next year, Hause, Li, and colleagues found the virus in 18% of U.S. cattle with respiratory disease. Eight cattle herds in five states had antibodies to it. “That was a really big surprise,” Li says. Something else was striking: The team could not create reassortants between their new virus and flu C, which should occur if they belonged to the same type. At the suggestion of a reviewer, they proposed giving it a new name, flu D, in a 2014 paper. They contended that cows, not swine, were the virus’ main reservoir.
Researchers soon began to find flu D at cattle farms all over North America, Europe, Asia, Africa, and Australia. A study of Swedish dairy farms found IDV antibodies in bulk milk. Gray’s team has also found the virus in aerosol samples from poultry farms in Malaysia. Antibodies to flu D have turned up in sheep, goats, camels, deer, horses, wild boars, cats, and dogs, as well.
That wide range of species is worrisome. It opens the way for two viral variants adapted to different species to coinfect the same animal and reassort, creating progeny that is better at dodging existing immunity in the human population. The H1N1 strain that caused the 2009 pandemic, for example, combined gene segments from flu A viruses in swine, birds, and humans.
snip…
The Chinese team also suggested the virus was better at spreading between people than assumed. Unlike Webby, they found it was capable of airborne spread between ferrets—a factor that “may have facilitated [its] ability to spill over into humans,” the researchers wrote. Webby, unsure of what to make of those data as well, notes the team used a viral strain recently isolated in China. “Maybe this particular version of flu D has a little bit more zoonotic potential than others,” he says. “We’re fishing in the dark.” Gao and co-authors did not respond to repeated interview requests from Science.
snip…
AT THE MEXICAN feed lot, which raises cattle trucked in from many different farms, it was easy to see how respiratory viruses could move rapidly between mingling cattle. “Cows are very affectionate animals and tend to huddle together,” said Jessica Rodriguez, who grew up on a Texas cattle ranch and is working on a Ph.D. in epidemiology with Gray.
Two days of work at the Mexican farms yielded 155 samples that were flown to Gray’s lab in Texas. Researchers found IDV in nasal samples from six sick and eight apparently healthy cattle—35% of the cattle sampled. One cow had an influenza C infection. The researchers plan to screen the samples for other novel viruses that might harm humans or livestock, including a new coronavirus that Gray and Hernández-Vidal discovered in sick cows on this farm in 2024.
Looking up at large flocks of barn swallows wheeling around the corrals and perching on rafters and gates, Hernández-Vidal wondered whether they might move influenza D from place to place, which routinely happens with A. “That would be a very big deal,” he said.
“Nobody’s testing for it,” Gray added.
see full text:
https://www.science.org/content/art...sickening-cattle-around-world-are-humans-next
Efficient replication of influenza D virus in the human airway underscores zoonotic potential
The copyright holder for this preprint this version posted February 8, 2026. ; https://doi.org/10.64898/2026.02.07.704474
ABSTRACT
Influenza D virus (IDV), primarily found in livestock species, has demonstrated cross-species transmission potential, yet its threat to humans remains poorly understood. Here, we curated a panel of IDV isolates collected during field surveillance from 2011 to 2020 from swine and cattle to assess their ability to infect human airway cells as a proxy for zoonotic threat assessment. Using lung epithelial cell lines, primary well-differentiated airway epithelial cultures, and precision- cut lung slices, we demonstrated that IDV efficiently propagates in cells and tissues from the human respiratory tract, reaching titers comparable to human influenza A virus (IAV). Infection kinetics in primary porcine airway cultures and respiratory tissues mirrored those from human, suggesting similar infectivity across species. To define host responses to IDV infection, we evaluated innate immune sensing and downstream interferon signaling in human respiratory cells. IDV infection resulted in markedly reduced activation of interferon regulatory factor (IRF) signaling and diminished induction of interferon lambda 1 and interferon-stimulated genes compared to IAV, indicating inefficient activation of innate immune sensing pathways. However, IDV replication was potently restricted in interferon-pretreated cells, demonstrating sensitivity to interferon- mediated antiviral effector mechanisms once an antiviral state was established. Together, these findings show that IDV can efficiently infect the human airway while limiting innate immune sensing, a feature that may facilitate zoonotic spillover. Our study highlights the need for enhanced surveillance of IDV at the animal-human interface and provides a foundation for further investigation into its biology and potential for causing human infection and disease.
SIGNIFICANCE STATEMENT
Influenza D virus (IDV) is a poorly understood virus type in the Orthomyxoviridae family. Although initially considered incapable of infecting humans, high seropositivity rates among cattle and
swine workers suggest that zoonotic infections may already be occurring. However, the extent of human compatibility—and the potential for spillover—remains poorly understood. Our study demonstrates that IDV replicates efficiently in multiple human respiratory models while largely evading innate immune defenses, raising concern that only minimal evolutionary changes may be required for sustained human transmission. These findings underscore the need for further investigation into IDV biology and zoonotic risk. Such studies are critical for identifying viruses with the potential to adapt to humans before they become public health threats.
https://www.biorxiv.org/content/10.64898/2026.02.07.704474v1.full.pdf
DECIPHERING D
A mysterious influenza strain infects livestock around the world. Scientists worry it can become a threat to humans as well
19 FEB 2026 2:00 PM ETBYJON COHEN
Cattle at feed lots like this one in Mexico’s Nuevo León state often huddle together, which may help the influenza D virus spread. RODO GARZA/DGPPE UANL
NUEVO LEÓN STATE IN MEXICO—At dawn one morning in December 2025, researchers in the sprawling city of Monterrey, Mexico, loaded a large passenger van with syringes, swabs, test tubes, air samplers, and coolers. They then drove through the flat countryside for 2 hours, leaving the gap-toothed Sierra Madre Oriental mountains in the distance, until they reached a feed lot that had 24,000 head of cattle. “Everywhere you look, all the way to the horizon, it’s cows,” said Gregory Gray, an infectious disease clinician and epidemiologist from the University of Texas Medical Branch.
At the farm, the team began swabbing noses and taking blood samples from the animals. Gustavo Hernández-Vidal, a veterinarian at the Autonomous University of Nuevo León, walked with Thang Nguyen-Tien, a virologist in Gray’s lab, to a long pen that held about 100 sick cattle. From a rafter, Nguyen-Tien hung a bioaerosol sampler that sucks in air and spins it to separate particles and collect viral genetic material. Curious, the farm’s head veterinarian asked what they were doing.
“We want to see what the cows are breathing,” Hernández-Vidal said.
“The cows and us,” the vet replied.
snip…
But humans may become infected by IDV as well. Several studies, including one the U.S.-Mexican team carried out earlier at the same feed lot, have found antibodies to the virus in farm workers, indicating they were exposed to it. There is no evidence yet they fell ill, but IDV could evolve to more readily infect and sicken people, says Gray, who has helped discover a half-dozen viruses in humans and animals. “We need to be ready to respond,” he says. “What appears today as a quiet livestock virus could, with little warning, ignite the next influenza pandemic,” Ohio State University (OSU) veterinarian Cody Warren and co-authors warned in an 8 February preprint that showed flu D readily infects cells found in human airways.
snip…
His team found that the virus could spread between pigs through contact. None became ill, but he worried news of the finding might harm the pork industry. It still had scars from 2009, when an influenza A subtype known as H1N1 jumped from pigs to humans, causing a pandemic initially called the “swine flu.” (The virus was later renamed “pandemic H1N1.”) Hause and Li asked Richard Webby, a renowned flu researcher at St. Jude Children’s Research Hospital, to help them study the new virus but urged him to “keep it on the down low, at least initially,” Hause remembers.
Webby discovered the virus could spread via direct contact between ferrets, a model to study flu in mammals, which suggested a risk of pig-to-human spread. But unlike the influenza A and B viruses that infect humans every year, it did not spread between the ferrets via respiratory droplets, and it didn’t sicken them.
When Hause, Li, Webby, and co-workers first published a report about their findings in 2013, they described the virus as “distantly related” to flu C, with which the new virus shared about half of its genome. “I didn’t think we had enough information to justify proposing it as a new genus,” Hause says.
The next year, Hause, Li, and colleagues found the virus in 18% of U.S. cattle with respiratory disease. Eight cattle herds in five states had antibodies to it. “That was a really big surprise,” Li says. Something else was striking: The team could not create reassortants between their new virus and flu C, which should occur if they belonged to the same type. At the suggestion of a reviewer, they proposed giving it a new name, flu D, in a 2014 paper. They contended that cows, not swine, were the virus’ main reservoir.
Researchers soon began to find flu D at cattle farms all over North America, Europe, Asia, Africa, and Australia. A study of Swedish dairy farms found IDV antibodies in bulk milk. Gray’s team has also found the virus in aerosol samples from poultry farms in Malaysia. Antibodies to flu D have turned up in sheep, goats, camels, deer, horses, wild boars, cats, and dogs, as well.
That wide range of species is worrisome. It opens the way for two viral variants adapted to different species to coinfect the same animal and reassort, creating progeny that is better at dodging existing immunity in the human population. The H1N1 strain that caused the 2009 pandemic, for example, combined gene segments from flu A viruses in swine, birds, and humans.
snip…
The Chinese team also suggested the virus was better at spreading between people than assumed. Unlike Webby, they found it was capable of airborne spread between ferrets—a factor that “may have facilitated [its] ability to spill over into humans,” the researchers wrote. Webby, unsure of what to make of those data as well, notes the team used a viral strain recently isolated in China. “Maybe this particular version of flu D has a little bit more zoonotic potential than others,” he says. “We’re fishing in the dark.” Gao and co-authors did not respond to repeated interview requests from Science.
snip…
AT THE MEXICAN feed lot, which raises cattle trucked in from many different farms, it was easy to see how respiratory viruses could move rapidly between mingling cattle. “Cows are very affectionate animals and tend to huddle together,” said Jessica Rodriguez, who grew up on a Texas cattle ranch and is working on a Ph.D. in epidemiology with Gray.
Two days of work at the Mexican farms yielded 155 samples that were flown to Gray’s lab in Texas. Researchers found IDV in nasal samples from six sick and eight apparently healthy cattle—35% of the cattle sampled. One cow had an influenza C infection. The researchers plan to screen the samples for other novel viruses that might harm humans or livestock, including a new coronavirus that Gray and Hernández-Vidal discovered in sick cows on this farm in 2024.
Looking up at large flocks of barn swallows wheeling around the corrals and perching on rafters and gates, Hernández-Vidal wondered whether they might move influenza D from place to place, which routinely happens with A. “That would be a very big deal,” he said.
“Nobody’s testing for it,” Gray added.
see full text:
https://www.science.org/content/art...sickening-cattle-around-world-are-humans-next
Efficient replication of influenza D virus in the human airway underscores zoonotic potential
The copyright holder for this preprint this version posted February 8, 2026. ; https://doi.org/10.64898/2026.02.07.704474
ABSTRACT
Influenza D virus (IDV), primarily found in livestock species, has demonstrated cross-species transmission potential, yet its threat to humans remains poorly understood. Here, we curated a panel of IDV isolates collected during field surveillance from 2011 to 2020 from swine and cattle to assess their ability to infect human airway cells as a proxy for zoonotic threat assessment. Using lung epithelial cell lines, primary well-differentiated airway epithelial cultures, and precision- cut lung slices, we demonstrated that IDV efficiently propagates in cells and tissues from the human respiratory tract, reaching titers comparable to human influenza A virus (IAV). Infection kinetics in primary porcine airway cultures and respiratory tissues mirrored those from human, suggesting similar infectivity across species. To define host responses to IDV infection, we evaluated innate immune sensing and downstream interferon signaling in human respiratory cells. IDV infection resulted in markedly reduced activation of interferon regulatory factor (IRF) signaling and diminished induction of interferon lambda 1 and interferon-stimulated genes compared to IAV, indicating inefficient activation of innate immune sensing pathways. However, IDV replication was potently restricted in interferon-pretreated cells, demonstrating sensitivity to interferon- mediated antiviral effector mechanisms once an antiviral state was established. Together, these findings show that IDV can efficiently infect the human airway while limiting innate immune sensing, a feature that may facilitate zoonotic spillover. Our study highlights the need for enhanced surveillance of IDV at the animal-human interface and provides a foundation for further investigation into its biology and potential for causing human infection and disease.
SIGNIFICANCE STATEMENT
Influenza D virus (IDV) is a poorly understood virus type in the Orthomyxoviridae family. Although initially considered incapable of infecting humans, high seropositivity rates among cattle and
swine workers suggest that zoonotic infections may already be occurring. However, the extent of human compatibility—and the potential for spillover—remains poorly understood. Our study demonstrates that IDV replicates efficiently in multiple human respiratory models while largely evading innate immune defenses, raising concern that only minimal evolutionary changes may be required for sustained human transmission. These findings underscore the need for further investigation into IDV biology and zoonotic risk. Such studies are critical for identifying viruses with the potential to adapt to humans before they become public health threats.
https://www.biorxiv.org/content/10.64898/2026.02.07.704474v1.full.pdf
