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Academics find bird flu similar to deadliest virus of early last century
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[Author: Leng Jian Source: China Medical News Time: 2005-10-14 Editor: Roland]
The results of a series of studies published in the recently published American journals Science and Nature show that the bird flu virus has a similarity to the deadliest historical virus in history. The virus, which sparked fears of a global pandemic that killed 150 million people at the turn of the last century, was further heightened on Oct. 5 by scientists' concerns about the virus.
Scientists studying the "Spanish flu" virus, which killed 50 million people in 1918-1919, found that it shared characteristics with the H5N1 bird flu virus. Analysis of the reemerging pathogen showed that, like its modern "cousins," the virus began to appear in birds, spread across species to humans through mutations, and became highly contagious and deadly.
Another related study has determined that a similar set of mutations has occurred in the H5N1 virus, which has killed at least 60 people in Thailand, Vietnam, Cambodia and Indonesia. That could mean that the virus humans are now experiencing is beginning to evolve along the path that turned a 1918 avian virus into a human killer.
Jeffrey Taubenberger, of the U.S. Army Institute of Pathology, worked on both studies. He said, "This suggests that the H5N1 virus may have the ability to infect humans and, by extension, increase the risk of its widespread pandemic." The work could help develop drugs to target this highly lethal strain of influenza virus and could provide a "checklist" of dangerous genetic traits that could improve researchers' surveillance of harmful strains of the virus.
The study also showed that the Spanish flu virus was transmitted directly from birds to humans across species. The less serious 1957 and 1968 influenza pandemics began when the bird flu virus first combined its genes into a species of virus that was already spreading in humans, a mutation that occurs either in humans or in animals, and both viruses can be present in humans or animals at the same time.
Since a direct crossing between species has already happened, it will happen again, and modern-day avian influenza could evolve into a form capable of spreading between humans by a new path." With H5N1, it could go in either direction," Dr. Taubenberger said." It's possible that H5N1 could spread in the form of a modern human influenza virus, or it could become fully adapted to humans like the 1918 virus."
A week before this study was published, David Nabarro, who was appointed as the U.N. coordinator for avian and human influenza, said avian flu had the potential to kill 150 million people. Indonesia, the fourth country to be hit by the H5N1 flu virus, reported its seventh human death from the flu on May 5 - a 23-year-old male patient. Although only three of those cases have been confirmed to be caused by the virus.
Dr. Taubenberger's study, published in a recent issue of the journal Nature, released their resulting genetic map of the H1N1 Spanish flu virus, using viral material from the well-preserved remains of a female patient from that year in the Alaskan permafrost. Another team at the CDC, under the direction of Dr. Taubenberger, used this information to "recreate" the H1N1 virus. The results were published in a recent issue of the U.S. journal Science. The vials containing the reconstructed virus are stored in a secure laboratory at the U.S. Centers for Disease Control. The virus is so devastating that it can kill even the young and healthy.
Dr. Taubenberger said, "In the case of the H5N1 virus, we found some of the same characteristics. This suggests that it is possible that the H5 family of viruses is in the process of undergoing changes that can spread to humans. If these changes were to occur, they would be heading toward an evolutionary path similar to the 1918 influenza pandemic."
Related:
Flu outbreaks of the last centuryThe 1918 "Spanish flu" is known to have killed 50 million people. It began in early 1918 and peaked at the end of the year. it quietly disappeared in 1919. The cause of the disease was not known at that time. 1933 The influenza virus was identified and the Spanish flu virus is now known as the H1N1 variant. It is extremely pathogenic, causing pneumonia and hemorrhage in infected people, and has the highest mortality rate among adults aged 18 to 34.
The 1957 "Asian flu" pandemic killed about 4 million people.
The 1968 "Hong Kong flu" pandemic killed about 1 million people.