An aviar flu strain has been detected before in the United States between corral birds on a California farm.
The virus, called H5N9 highly pathogen, is a type of avian influenza, also known as “avian flu.” This is not the same type of aviar flu that has already been extended on dairy farms and poultry in the US. UU., Causing at least several dozen infections in humans. That virus is called H5N1.
So what is H5N9? How does it differ from H5N1, and should we be equally worried about it?
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What is H5N9?
H5N9 is a highly pathogenic avian flu (or avian flu) virus that has some structural similarities with H5N1.
H5N9 “low pathogens” viruses have been previously detected in birds in the United States and other parts of the world, that dates from the 1960s. However, these infections are usually associated with less severe symptoms That the “highly pathogenic” strains are. This is the first time that H5N9 highly pathogen has been seen in the US also quite uncommon worldwide.
How did H5N9 arise?
New Subtypes and influenza strains may arise If the viruses collect random genetic mutations as they multiply, as well as if multiple viruses exchange genetic information with each other. This last process is known as genetic reconditioningAnd it usually happens when an organism is infected with at least two different viruses at the same time.
Some experts suspect that H5N9 may have arisen among the ducks in California due to the genetic reorganization that occurs between circulating H5N1 viruses and other flu viruses that contain the N9 protein. (“H5” and “N9” are two proteins that are on the surface of the virus that give their name to the subtype of avian flu).
H5N1 was also detected in the birds of the farm, so this could be plausible, according to a January 24 report Of the World Animal Health Organization (WOAH), which monitors disease outbreaks in animals worldwide.
Such reorganization can lead to “new unpredictable viruses”, Angela RasmussenVirologist at the University of Saskatchewan in Canada, wrote in x.
He added that ducks can be excellent host animals so that a genetic reorganization takes place because, unlike chickens, they do not get very sick from many avian flu viruses. Therefore, while an infected chicken would die quickly, ducks can survive and continue spreading the disease to new guests.
What is happening on the farm where H5N9 was detected?
In the January 24 report, the WOAH announced that H5N9 had been identified in a duck farm in Merced County, California. The current outbreak, which according to the report was confirmed on January 13, is being closely monitored by officials.
“The USDA Animal and Vegetable Health Inspection Service (APHIS), together with state health and wildlife officials of health and wildlife, is carrying out comprehensive epidemiological research and greater surveillance in response to HPAI [highly pathogenic avian influenza] Related events, “Woah wrote in the report.
To avoid a greater propagation of the infection, the almost 119,000 birds on the farm have now been sacrificed. These avian flu viruses are known as “highly pathogens” because they are Extremely deadly for certain poultry – Like chickens, and the sacrifice of a exposed flock generally is considered the best way to prevent additional flocks.
Why is avian flu?
Scientists have recently expressed growing concern that an aviar flu strain could mutate in a way that extends easily among humans, which caused a pandemic. This happened during historical pandemics, as the “Spanish flu” in 1918 and the “Asian flu” in 1957.
Humans can infect with avian influenza if the virus He gets into his eyes, nose or mouth, or if he is inhaled in the form of drops in the air. However, not all avian flu viruses are equipped to efficiently infect people and then spread among them. When they are given more opportunities to spread to new animals, viruses have greater chances of collecting that ability and damaging humans.
In particular, in recent years, H5N1 has spread to new countries, including the United States He has been widely infected poultry and poultry and has also risen to several mammals, including cattle and Domestic cats. Since its discovery, H5N1 has infected more than 900 people worldwideAnd in the last year, at least 67 people in the United States It has been infected. In December 2024, a woman in Louisiana became The first person in the United States to die as a result of an H5N1 infection.
How does H5N9 H5N1 differ?
Avian influenza viruses come in different subtypes, which are named according to subtle variations in the structure of Two key proteins on the surface of virus: hemaglutinine (H) and neuraminidase (n). Then, H5N9 and H5N1 have the same hemaglutinin protein, but a different neuraminidase protein.
The specific combination of H and N proteins of a virus Determine a variety of important featuresAs the good thing that is to spread from one animal to another, how mortal it is and if it is resistant to antiviral treatment.
In addition to the difference in its neuraminidase proteins, H5N9 differs from H5N1 in several other ways.
For example, H5N1 infections They are more common among humans and it is believed that they are the More mortal of all highly pathogenic influenza strains in humans and chickens.
H5N9 represents a risk for humans?
So far, little is known about whether H5N9 could extend to humans and potentially cause pandemic.
On their website, the Centers for Disease Control and Prevention (CDC) currently establish that the The public health risk of Aviar H5 is “low” But that the agency is “observing the situation carefully and working with the states to monitor people with animals.” The main approach of the CDC on that website is H5N1, but the agency is monitoring the H5 viruses widely, using its flu surveillance systems to monitor any case in humans.
As of January 18There has been no evidence that H5 avian flu spread from one human to another in the United States
“The H5N9 combination is not new and other versions, such as H5N5 there are also.” Florian KrammerProfessor of Vaccinology at the ICAHN School of Medicine at Mount Sinai in New York, He told CBS News. “The fact that this is now detected does not mean problems,” he emphasized.
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