What is the Spanish Flu?

Spanish influenza is the second deadliest infectious disease in human history. It infected about 1 billion people worldwide and killed between 25 and 40 million people (at that time, the world population was about 1.7 billion people). ); Its global average lethality is about 2.5% -5%, compared with 0.1% of general influenza, which is more lethal, and the infection rate has reached 5%.

Spanish influenza

The Spanish influenza can be simply divided into three waves. The first wave occurred in the spring of 1918, which is basically just an ordinary influenza; the second wave occurred in the fall of 1918, the highest mortality rate; the third wave occurred in 1919 Between winter and spring of 1920, the mortality rate was between the first and second waves. The first recorded flu occurred in the United States on March 4, 1918

The current death toll is inconclusive, and the most conservative estimate is more than 20 million. Because it was at the end of the First World War and the war, most countries did not have detailed statistics.

Death toll

1.076 million in North America

327,000 South America

2.163 million in Europe

In Asia, 15.57 million, of which India has the largest number of deaths globally, about 12.5 million.

Oceania 965,000

1.353 million in Africa

21.642 million worldwide

Reconstructed Spanish flu virus

No virus was found in the medical community at the time. The medical community at the time thought it was an infectious disease caused by bacteria, so it did not understand why the flu was so deadly. It was not until 1933 that British scientist Smith Andenwes isolated the virus from humans for the first time and named it H1N1. Many scientists later wanted to know why the virus was so deadly, but were unsuccessful; one was because of its danger, and the other was that all the remains at the time had been disposed of with fire.

In 1997, American scientist J. Taubenberger published in the Science weekly the results of research he and his colleagues made using genetic technology, suggesting that the 1918 influenza virus and swine influenza virus Very similar, a virus closely related to the influenza A (H1N1) virus. To this day, the virus can still be found in pigs in some countries.

In February 1998, the molecular pathology department of the American Defense Pathology Center (AFIP) found the body of an Eskimo woman that had been frozen for nearly 80 years near the Brevig Mission in Alaska. Brevig Mission lost 85% of the population in November 1918 due to the flu. One of the four samples contained some genetic material from the 1918 virus. This sample gave scientists first-hand knowledge to study the virus.

According to British media reports in October 2001, British scientists are trying to find the samples or fragments of the virus that caused the flu based on the remains of 10 Londoners who died of the 1918 flu, analyze its genomic characteristics, and study why it is so strong Lethal and contagious.

In October 2002, the U.S. Centers for Defense Pathology collaborated with a microbiologist at Mount Sinai Medical School in New York to begin an attempt to rebuild the virus. In one experiment, they successfully created a virus with two 1918 virus genes. Compared to other influenza viruses, this virus is more lethal to mice.

On February 6, 2004, Science reported two teams, the National Institute for Medical Research and the Scripps Research Institute in the United States, which reconstructed the red blood cell agglutination of the 1918 flu. Hemagglutinin (HA glycoprotein) and learn how the protein molecule changes shape to allow it to move from birds to humans.

On October 5, 2005, researchers announced that the gene sequence of the 1918 virus had been recombined. The H5N1 virus that occurred in Asia in 2005 is similar to the 1918 virus in some places, but it is currently difficult to turn it into a human. ^[1]

On July 5, 2014, foreign media reported that Professor Yiyu Kawaoka of the University of Wisconsin-Madison has recently developed a deadly virus, 2009 swine flu virus. If this virus spreads from the laboratory, it may cause hundreds of millions of people Lost, no effective preventive vaccine has been developed.