In the spring of 1997 a three year old boy in Hong Kong began the disease, all the symptoms resembling the common cold. Cough and high fever were not six days, which the little patient was taken to the Queen Elizabeth Hospital.
Despite intensive treatment, the boy’s condition only worsened, and save him and failed. About a month virologists analyzed sputum samples of a boy trying to figure out what was the cause of sudden death, but all in vain. In the end, the Chinese experts decided to send biological material to his American colleagues, who were able to determine that the culprit is the influenza virus H5N1, or bird flu.
That year’s bird flu was diagnosed in 18 people, six of whom died. The mortality rate from H5N1 were higher than the “Spanish flu”, which caused the death of over 50 million people in the early XX century.
At that time humanity was very lucky, because the bird flu virus did not acquire the ability to spread from person to person. But it could be different if the H5N1 virus was found with the seasonal flu virus, for example, in the body of a pig. In such cases, when multiple viruses enter a cell, they reassortation — exchange of genetic material resulting in new variants of viruses.