Decrypt the secret virus causing pandemic 1918

A group of genes that help the H1N1 virus enter the lungs and cause inflammation is the way they took tens of millions of people in the pandemic 90 years ago.

Scientists from the University of Wisconsin (USA), Kobe University and Tokyo University (Japan) use ferrets - animals with mechanisms to develop flu-like humans - to study viruses that cause flu 1918.

Influenza often causes inflammation in the upper part of the respiratory system (such as the nose, throat) and causes fever, muscle pain, and health deterioration.

Some people may be seriously ill and pneumonia. Sometimes bacteria cause pneumonia, but there are also cases where the disease is caused by the direct effect of the influenza virus.

In the 1918 pandemic, a new and more dangerous strain of influenza emerged. It kills 20-100 million people worldwide - at least 100 times more than previous and future flu pandemics. Autopsy records show that many victims are healthy young people who die from severe pneumonia.

'We want to find out why the 1918 flu epidemic caused severe pneumonia,' said Yoshihiro Kawaoka, an expert at the University of Wisconsin.

They replaced each gene from the 1918 virus into modern flu viruses. Then the scientists in turn put each of the modern flu viruses into ferrets. The results showed that most viruses only cause disease in the upper part of the respiratory system. But a virus strain has successfully penetrated into the lungs and divided very quickly here.

Genetic analysis showed that this modern strain has three genes - called PA, PB1, PB2 - that the other strains do not have. That group of genes, along with a viral version of nucleoprotein in 1918, helped it kill ferrets in the same manner as humans.

Police in Seattle (USA) wear a mask produced by the Red Cross to deal with the 1918 influenza pandemic. Photo: Reuters.

The culprit responsible for the 1918 flu pandemic (commonly referred to as the Spanish flu) is the H1N1 strain of influenza A virus group. Historical and epidemiological documents do not adequately record data so that the scientific community can Identify the source of the translation. Many victims are healthy young people, while previous flu outbreaks often attack the elderly, children and people with weak health.

Pandemic flu broke out in March 1918 and ended in June 1920. The H1N1 virus spreads everywhere, to the Arctic and many remote islands in the Pacific Ocean. The death toll was one-third of the European population at the time and more than twice the number of people killed in World War I.

Most experts on influenza agree that a flu pandemic will definitely recur in the future. No one knows the exact time that a pandemic will occur or if the influenza strain will cause a disaster. The H5N1 strain of avian influenza has been placed first in the list of suspects.

H5N1 is attacking poultry in Asia, Europe and parts of Africa. It has rarely infected humans but has attacked 391 people, including 247 deaths, since 2003 until now.

Scientists are concerned that some genetic changes will turn H5N1 into a strain that can spread from person to person. At that time, it could kill tens of millions of people worldwide for several months.

The world now makes four drugs that can block influenza viruses, but they often mutate genes to resist drugs - just like how bacteria evolve to neutralize antibiotics.