The swine flu virus called the threat of a new pandemic

With 2016 in domestic pigs in China is dominated by the influenza virus, the genome of which combines the features of strains of swine flu virus H1N1 that caused the 2009 pandemic, and North American reassortant (combining the genes of several strains of the virus) strain, reported in the Proceedings of the National Academy of Sciences. Laboratory studies have shown that it is very easily inhabits the epithelial cells of the respiratory tract, and more than 10 percent of the employees of the pig farms have antibodies to it. All this indicates that the new swine flu virus (the strain got the name G4 EA H1N1) may cause a new pandemic.

In 2009-2010 occurred pandemic influenza caused by virus A/H1N1, strain H1N1pdm2009. The first cases recorded in the United States and Mexico in April 2009, and then in a few months the infection has spread throughout the world. According to the Center for control and disease prevention United States, as a result, in the first year of virus circulation was lost 151700-575400 people.

A/H1N1 was particularly contagious and dangerous, as was the result of reasontly — mixing of the genetic material of several viruses. A/H1N1 — “hybrid” of influenza viruses that infect pigs (so called swine flu), birds and people. When this happens, a new virus often gains the ability to infect species that were previously immune to it. Therefore it is necessary to examine what viruses infect animals with which people often contact such as agricultural, Pets, those who often become prey to hunters, and so on. Their pathogens are most likely due to reascertain will be human too.

Therefore, researchers from several scientific institutions in China, headed by Liu Jinhua (Jinhua Liu) from China agricultural University examined what influenza viruses circulate among pigs in Chinese farms 10 most “pork” provincial 2011-2018 years, and identified what has changed over the years of their occurrence. To do this, scientists took swabs from the noses of dead meat animals (29918 samples) and also did a lung homogenate from swine with clinical signs of respiratory infection (1016 samples). Viruses were identified by polymerase chain reaction: looked primarily at the genes of hemagglutinin (the H in the name of the flu virus) and neuraminidase (N in the name of the flu virus). Their sequences were compared with those already known for other strains.

The genome of one of 179 found strains of the virus, closely related genes H and N to H1N1pdm2009 strain, was sequenced completely. On cultures of epithelial cells of human trachea to check how easy it is linked with different versions of sialoglycoprotein SAα2,6Gal — one of the key molecules for infection with influenza viruses. In addition, the authors analyzed data from immunological tests 338 employees 15 pig farms, which in 2016-2018 revealed the presence of antibodies to specific strains of influenza viruses. They were compared with the results of similar tests 230 people not involved in animal husbandry.

It turned out that in 2016 among Chinese pigs began to spread rapidly a new strain of influenza virus H1N1, which the authors called G4 EA H1N1, and since then it is found more frequently than others. Apparently, G4 EA H1N1 was the result of reasontly Eurasian and American strains A/H1N1. In experiments with cell cultures it is preferably contacted with the “human” version of sialoglycoprotein SAα2,6Gal. An additional series of experiments on ferrets (these animals are very often used for evaluation of vaccines and drugs against influenza) showed that G4 EA H1N1 is easily transmitted from one animal to another.

Workers pig antibodies to the virus identified in 10.4 percent of cases, people not associated with agriculture, 4.4 percent of cases. The effect remained after took into account possible cross-reactivity with H1N1pdm2009 (that is an option when the antibodies were to the strain that caused the pandemic in 2009, not the new virus). All of this (proximity to person, a large proportion of people with antibodies to the strain, its ease of binding with the desired glycoprotein and transfer from one individual to another) indicates that G4 EA H1N1 in the next years cause a new pandemic. Therefore, the authors point to the need to start a periodic inspection of the employees of the pig farms, as well as themselves pigs, infection related to the flu virus.

In 2016, American scientists have foundthat the severity of influenza caused by a certain virus strain can be assessed by year of birth of the patient. It depends on what kind of virus people have encountered in childhood, and such information can be obtained, knowing their prevalence in a particular season. Influenza viruses within the same group are similar glycoproteins neuraminidase, and if the immune system has ever encountered neuraminidase specific group, it is likely to be easier to fight back the virus with the glycoproteins of the same group.

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