On several farms in China, microbiologists have found a new strain of swine flu. Mutations in it allow this strain to spread from one person to another. The description of the study was published in the scientific journal Proceedings of the National Academy of Sciences.
“The G4 virus has all the traits of a pathogen that could cause a new influenza pandemic. It differs in profile from modern seasonal influenza strains and can be transmitted from person to person. However, it has all the characteristics of the H1N1 virus that caused the global swine flu pandemic in 2009, "the scientists write.
At the end of the last decade, outbreaks of avian and swine flu occurred in the world, which claimed the lives of several thousand people. From this, physicians and biologists concluded that humanity could face a new influenza pandemic, similar in scale to the Spanish flu epidemic, which claimed millions of lives in the first half of the 20th century.
So far, such epidemics of influenza have not occurred for a simple reason - swine and bird flu are not yet able to spread by airborne droplets and quickly spread from person to person. On the other hand, as the infamous experiments of Yoshihiro Kawaoka and Ron Fouche showed in 2011, the bird flu virus only needs three small mutations to do this. One of them, as Chinese scientists later found out, had already acquired natural versions of the H7N9 strain.
Conducting a kind of census of viruses that circulate on animal farms in China, Microbiologists under the leadership of the Director of the Center for Disease Control and Prevention of the People's Republic of China, George Gao, discovered that something similar has recently happened with swine flu.
New swine flu
Over the past two decades, according to Gao and his colleagues, the H1N1 strain, a close relative of the pdm / 09 virus, which caused a pandemic in 2009, began to dominate among pigs. After its completion, this virus "returned" to the pig population and began to spread among them. Therefore, scientists are closely monitoring the types of influenza that were present in the bodies of animals on Chinese farms between 2011 and 2018.
It turned out that the emergence of pdm / 09 and natural evolutionary processes led to the fact that H1N1 was split into several separate lines, each of which had its own set of mutations. Recently, one of them, G4, began to dominate among pigs and supplant other varieties of the virus.
This strain is a cross between H1N1 and pdm / 09. Presumably, it arose after the pig became infected with both variants of the flu. The result is a new virus, G4. From pdm / 09, he inherited the M gene, which is responsible for the assembly of new viral particles and is considered the main cause of the high lethality of this virus.
As shown by subsequent experiments on cultures of human cells and ferrets, this strain can penetrate the cells of the lungs of people and be transmitted by airborne droplets, like seasonal varieties of this disease. In addition, the G4 virus caused much more severe infections in ferrets than either of its ancestors did.
As subsequent experiments on these animals showed, all existing influenza vaccines could not protect them from infection. This is because G4, unlike H1N1 and pdm / 09, belongs to a different antigenic group. As biologists note, this suggests that this pathogen is very dangerous for the human population. Therefore, it is necessary to strictly control the epidemiological situation on the farms.
This is also supported by the fact that tests for antibodies to G4, which scientists conducted among employees of 15 such enterprises, showed that 10-15% of them had already been in contact with this form of flu. Therefore, Gao and his colleagues do not exclude that this virus could cause a new influenza pandemic in the coming years. You need to be prepared for this, scientists conclude.