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In Nevada recently has a genetic change in the new form of dairy cattle infected Avy influenza that is thought to have a copy of the virus itself in animals – including humans – more easily, according to a new Technical short US Department of Agriculture from Animal and Plant Health Inspection Service.
However, it is unclear whether the virus poses a major threat to people. The CDC says the risk of H5N1 is still low for the public, though those who work in the fields or whose back herd are high.
The USDA report has surfaced when a dairy farm worker in Nevada has positively exhibited H5N1, which is the first human infection identified in the state. The symptoms of the worker include red, swollen eyes, or cinnamon, according to sources familiar with the details that did not have the option of talking to the media. US centers are working to confirm the initial positive tests for the control and prevention of diseases.
Scientists are closely watching new infections in Nevada because the setting of infected cattle gene shows that it is a sub -type of H5N1 virus, D1.1, which is associated with two severe human infections in North America, Including a death.
Churchill is the first famous example of Splore in cattle in the same valley in the same valley, D1.1. This tension was previously found only in birds and people.
Most of the bird flu infections in dairy cattle in the United States are in different conditions, or is known as “cattle cleaned”. Researchers are not sure how D1.1 was transferred to New Dahida cows. According to the USDA, dairy farmers informed the affected herd and informed the large dye office of the wild birds before their cows became ill near their fields.
Because of this, investigators assured that the cow suffered the affected birds, or perhaps their fall, and thus caught the virus. Wild birds are difficult to control the fields, where a grain -filled feed trough can look like a large bird feeder.
The sequence of the genes of these D1.1 virus has been found that helps to copy the virus more effectively to the cells, including people.
According to the USDA, this change has not been seen in wild birds or other D1.1 infections in poultry. This increases the possibility that another animal, maybe a cat or fox, brings the virus into these fields.
“This variation … provides a better copy of the virus, which gives humans to these cows,” said Dr. Sima Lakdwala, a microbiologist and immunologist at the University of Emuri. Dairy is spreading in the flock.
When the viruses change, or change, they do it in one of the two ways: grow or shift.
Flow refers to a small change in the genome, usually an error, when the virus copies itself to the cell. Most of the time, these changes are harmful to the virus or have no effect. Occasionally, a small change can help people get more fit and get out of it, which helps it to become more dominant.
A shift is a major change. The flu virus has eight parts of their genome. When two different flu viruses affect a cell at the same time, they can change the entire class of their genome to create a hybrid virus, which can have different properties dramatically.
D1.1 is a new cleaned created by a shift, so it is a hybrid virus. Half of it, including its “H” segment, comes from a highly pathogenic H5N1 virus that travels from Asia some time after April 2022 by wild birds in North America. The other half comes from the “N” class, including. The low pathogenic flu virus, which was already in the birds in North America.
According to the USDA, in September 2024, D.11 was found for the first time in wild birds, and now it is the dominant line of H5N1 in North America.
At the end of October, D1.1 Sub -type confirmed Washington states in the state of birds on a farm with the affected poultry. Although these workers allegedly developed respiratory symptoms, their infection was described as light.
A few weeks later, in early November, a 13 -year -old girl in Canada’s British Columbia also tested positively for the D1.1 stress of H5N1 and experienced serious ill and numerous organ failure. She survived, but only after weeks Of intensive care. Public health officials conducted a wide range of investigations, but they do not yet know how to come to the virus.
When scientists recognized the genome of the H5N1 virus, which affected it, they received a sign that it had begun to promote such variations that needed to become a more effective human pathogen.
Then, in December, a man over 65 years old in Louisiana who came in front of a sick bird in his backyard was also seriously ill with D1.1 and was admitted to the hospital. The man eventually died, the country’s first bird flu death became.
The genome continuity of the samples collected from this patient also revealed the changes in the virus, which potentially helped break human cells.
Researchers are looking for indicators to immediately try to understand why D1.1 was associated with two severe human infections.
“H” Part Codes for Virus Hemagglatin Protein, which helps to affect cells, while its “N” codes for an enzyme called Neurominidice, which helps break the virus from cells and spread to others Is
Scientists call the bird flu virus high or low pathogenic, which depends on how sick they make birds. However, how hard or mild in humans with these infections is rarely associated with these positions.
For example, a theory of why B3.13 infections are lightening is that experiments in feries show that people may have some cross -protection against B3.13 infection because our immune systems The virus has faced the “N” section. Seasonal flu stress.
Dr. Louis Monkla, scientists at the University of Pennsylvania’s School of Veterinary Medicine who study the study on how the virus emerges and transmits between the human population, says the D1.1 virus is the N -N. N is completely different from the section. 13 Viruses. “It’s really, really different,” he said.
It may be that this change in the N virus section helps prevent any immunity that causes people to suffer a seasonal flu virus, which increases the capacity of more severe infection. This theory is currently being investigated.
Dr. Scott Hansley, a micro -biologist at the University of Pennsylvania, is another theory.
After seeing similar changes in virus H. Proteins, which created two severe humanitarian cases in Canada and Louisiana, scientists surprised that it could be a shot of the H5N1 virus that more easily with humans Can be adapted.
Hansley says the H and N parts of the virus will have to work together in a critical dance. H. Protein helps break the virus in a cell, while N -Protein code codes for an enzyme that helps him escape and release all of his own copies that he returned to the body Is Generally, changes to N protein are at the cost of H, which makes the virus -affecting cells less efficient. Hansley believes that D1.1 may be an exception.
Its lab is experimenting to see if the D1.1 virus is a N section of the N virus to change HH protein and influence humans more easily.
“It may be very well that this particular gene type of virus is more likely to be compromised by human cells,” Hansley said. “We don’t know yet.”
CNN’s Meg Terral participated in the report.
