4 reasons not to worry about “new” swine flu in the news

When the world does not end with the current pandemic, it may seem strange to think ahead of the next potential pandemic. However, the report, which provided hints that the newly identified swine flu virus could spread to humans, caused that fear. However, public health officials say it is not an imminent threat.

The virus, found in pigs in some parts of China, has characteristics similar to the strain that caused the virus 2009 H1N1 Swine Flu Pandemic (SN: 12/18/09), a new study was found. But just because you’ve identified an influenza virus that is endemic in swine does not mean that it poses an immediate threat to people. Rather, it informs researchers that they should monitor sick people for similar viruses.

“It’s not an urgent threat of an infectious disease,” said Anthony Forch, director of the National Institute of Allergy and Infectious Diseases in Bethesda, Maryland, at a hearing in the Senate on June 30. I said. To keep our eyes on it, just like when the swine flu emerged in 2009.”

Influenza virus enters cells by binding to a protein called sialic acid. Birds and humans have different types of this protein in the upper respiratory tract, but pigs have both. As a result, pigs are more vulnerable to the swine-specific influenza strains as well as bird and human influenza viruses. As a result, animals are often mixed pots of flu.

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Infection with swine, bird, swine, human influenza virus Exchange genetic material -Called reclassification-creates a new lineage (SN: 2/12/10). If some of these new strains can infect people and make them sick, the virus can cause an even greater outbreak.

Like the 2009 H1N1 virus, the newly identified porcine virus, called G4 EA H1N1, or G4 for short, can attach to the type of sialic acid that covers the human respiratory tract. It can also replicate in human cells grown in dishes, The researchers said on June 29 Minutes of the National Academy of Sciences.. Infected ferrets-ferrets, which are often used in flu studies because they exhibit symptoms similar to humans, can also get sick and transmit the virus to other ferrets. Findings suggest that the virus can cause illness and spread among people.

“We really point out the fact that we have to keep an eye on the influenza virus,” said Marie Kulhane, a swine veterinarian who had been studying influenza at the University of Minnesota in St. Paul and was not involved in the study. say.

Here are four things you need to know about the G4 swine flu virus:

The virus began to spread in pigs in 2013.

So the new virus is not new at all.

Jinhua Liu, an influenza researcher at the China Agricultural University in Beijing, and his colleague have found more than 30,000 nasal swabs from 10 pigs in 10 provinces in northern and central China for the seven-year influenza virus from 2011 to 2018. Or lung samples were analyzed. G4 virus appeared in pigs in 2013 and became more prevalent in the years that followed. By 2016, it was the predominant form of the influenza virus circulating in tested pigs.

“That said, the virus is very good at pig-to-pig transmission,” Culhane said. “And it’s probably good that it doesn’t cause a very serious illness in pigs.

It is unclear how widespread the virus was. So far, scientists have only tested a small percentage of pigs in China.

The virus has infected some people, but it is unknown if they became ill.

Ten percent of the 338 people tested who worked with pigs had antibodies or immune proteins that recognized the virus. This was a sign that recovery from a previous infection had been observed, Liu et al.

It is not known when the worker was exposed to the virus, because the antibody can spread for years after the infection. It is also unknown if there were any symptoms during the infection. The infection went unnoticed because the virus may not cause serious illness. If the worker is symptomatic, the symptoms of the disease may be indistinguishable from regular flu.

This test may have detected an immune protein that recognizes another influenza virus, but not G4. Searching for antibodies is like searching for smoke, says Culhane. “You see smoke, but you don’t know where the fire is.”

Other influenza antibodies that bind closely related virus strains did not recognize the newer virus. This is because the part of the virus that the antibody binds to has changed sufficiently that people are not protected from previous influenza outbreaks, and if the virus begins to spread, it may not be immune. Means

There is no evidence that the virus spreads easily among people.

When monitoring a variety of influenza strains and determining the risk of a pandemic, “people need to be aware of person-to-person transmission,” Culhane says. If many people unrelated to pigs and other infected animals get the virus, it will be more worrisome.

The study found that only 4% of the general population had antibodies to G4. People who are regularly exposed to pigs are more likely to be positive. The paper also cites two cases of influenza caused by G4-like viruses in people whose neighbors have pigs. However, there is no evidence that someone working with a pig transmitted the virus to anyone else.

There is no evidence of virus elsewhere.

The World Health Organization coordinates a global influenza surveillance and response system that collects data from Member States to monitor seasonal and pandemic influenza. The United States has its own surveillance system within the US Department of Agriculture and Centers for Disease Control and Prevention.

Currently, only Chinese pigs are infected with G4 influenza. There is no evidence of G4 or similar viruses in other countries. Especially for the United States, “I have no evidence of that, and I’m always looking at the data,” Culhane says.