March 28, a month before information about swine flu flooded headlines all over the world, a 9-year-old girl in Imperial County, California, had a fever of 104.3 degrees Fahrenheit. flu that year, but that day she took a sample of mucus from her throat with a cotton swab. This mucus sample is taken to the Naval Health Research Center in San Diego, where experts test and classify the virus in this form as 'unsubtypable' influenza A - this is a new virus.
The laboratory transferred the mucus sample to the Centers for Disease Control and Prevention in Atlanta, Georgia on April 17, four days after Mexico confirmed the first case of swine flu. Lying in the girl's mucus is a virus that is spreading globally. Until now, 41 countries have confirmed more than 11,000 cases of swine flu, a fact not as serious as scientists fear.
CDC (Centers for Disease Control) found that the virus is a combination of human, bird and pig flu genes - a type of flu sausage. Some come from viruses commonly found in North America, originating from pigs in 1999. But some gene combinations have never been found in humans or pigs.
For many years scientists have predicted the possibility of a hybrid virus forming from pigs. Now, the biggest swine flu outbreak in history may be the first evidence that this is possible. In the past 10 years, many new types of flu have appeared in pigs on farms and scientists do not know the reason for this phenomenon. However, they had predicted for years before this phenomenon began.
Juergen Richt, a virologist at Kansas State University, said: 'I have warned that there may be viruses originating from pigs and then turning to humans and creating diseases' . Richt and colleagues summarized a series of studies on flu viruses from humans and some animals in the last few decades. They published the results in January in the article 'The Pig as a Mixing Vessel for Influenza Viruses' published in the Journal of Molecular and Genetic Medicine.
Pigs are often susceptible to influenza, and can synthesize human and bird viruses that can cross barriers between different species. The 1957 to 1968 Asian flu epidemic was caused by mixed and synthesized viruses. Richt contends that the virus spreads from birds to humans and transmits within the new host's body, or the virus passes from birds to a mammal, such as pigs, where they change genes and form new influenza viruses. For years, the 1918 flu epidemic infected 20 to 40 million people worldwide believed to be caused by pigs. The researchers then conducted a number of genetic studies that raised doubts about the swine flu theory. Scientists now suspect that birds infect us, and ourselves, infect pigs.
Pigs used to infect people with previous mixed viruses, even with the synthesis of flu genes from pigs, birds and humans. If the internal organs of the pigs are viral plates, where the gene is combined, it is possible that the pandemic flu virus has been hidden in pig farms for decades. Richt said: 'Everyone looks at bird flu in Southeast China, and we say,' You forget that it can happen right in your backyard. '
Not all flu viruses can infect all animals. For example, birds do not have receptors for human flu. Two different lines can only be combined in one body with receptors of both. Pigs are a suitable host - they can be sick from human and bird flu strains.
To reproduce, flu viruses get into the host's cells and replicate themselves, Gene Erickson, a microbiologist at Rollins Animal Disease Laboratory in North Carolina. The virus genome has eight parts, each of which is copied and damaged into a new virus. When two different viruses invade a cell, they start copying themselves. In this case, there are not only 8 but 16 viral parts on the 'assembly line', and the genes start mixing in a process called recombination. That way a new virus is formed, like a virus is infecting humans. If there are 3 different viruses in the same cell, many other combinations can be formed.
Until now, swine flu has always been ignored. Pigs do not easily infect humans, and when the virus is infected, it often fails in the new body and cannot infect others. When entering a person's body, the virus from pigs often meets the 'bottom line'. According to a study published in the journal Clinical Infectious Diseases, swine flu has infected only a few dozen people worldwide since its discovery in 1930. By 2006, only about 50 cases were reported worldwide. gender. Plus 12 schools that CDC has written, a total of 62.
Then in the last 10 years, something has changed. Since the late 1990s, influenza viruses have recombined in pigs at a faster rate. Pigs start to cough up new viruses into the air.
Christopher Olsen, professor of public health at the University of Wisconsin-Madison and co-author of the study, said: 'The change we observe is a completely different change. In fact, we see the formation of a new virus through recombination. This virus is a combination of swine flu, bird flu and human flu. We have yet to find out exactly why this is happening. '
With the current epidemic, Olsen is worried: 'This virus is completely different from what we have seen in the past and is capable of transmitting from person to person .'