The most common strains begin their journey in Southeast Asia and continue to circulate throughout the year following cyclical patterns.
Every year flu viruses, those that spread around the world in the autumn winter season, are born around large cities such as Hong Kong and Bangkok.
In practice, they are born in a populous and chaotic cradle, such as the dense and crowded cities of the Far East and Southeast Asia.
From these places, in a period of time ranging between 8 and 12 months, they wander around the Earth and then disappear. And reappear “different” the following year.
From East to West
The life cycle of influenza viruses has been accurately reconstructed by genetic research involving two international teams.
Experts have focused on the viruses that reach Europe each year around November or December.
The first team, led by Edward Holmes of Pennsylvania State University (USA) focused the study on the H3N2 and H1N1 viruses that seem to appear in the tropical belt of the Far East.
The second team, from the University of Cambridge (Great Britain), led by Colin Russell, analyzed 13,000 samples of the H3N2 virus collected since 2002 in different parts of the planet.
It has thus been shown that the birthplace of viruses is always in Southeast Asia, although the precise area can vary by a few hundred kilometers from one year to the next.
They also found that when a virus is born in the Far East, usually during the rainy season, where it stops for about a month, it takes 6-7 months to reach Europe and, subsequently, North America.
Finally, after about a year, it closes its world tour in South America. This is the latest region of the planet to be infected, because it is less connected with Asia than other countries.
This research will allow us to intervene to create the strongest vaccines for each individual flu and predict when each of them will arrive in different areas of the planet.
According to the World Health Organization, 5 to 15 percent of people worldwide contract influenza viruses each year, of which about 4 million become seriously ill and as many as 250 to 500,000 die from complications.
Joycelyn Elders is the author and creator of EmpowerEssence, a health and wellness blog. Elders is a respected public health advocate and pediatrician dedicated to promoting general health and well-being.
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