H7N9 flu may have evolved from at least four other flu viruses

The deadly H7N9 avian bird flu may have evolved from at least four other existing flu viruses in poultry, ducks and wild birds, according to a recent study.

According to the U.K. National Health Service, the study was conducted by researchers from the Chinese Academy of Sciences in Beijing and the Chinese Center for Disease Control and Prevention. The genetic analysis of the H7N9 bird flu virus used information from global virus databases to track the origins of the virus.

The researchers concluded that the H7N9 virus appears to have originated from at least four different reassortment events. A reassortment event occurs when two different types of bird flu infect the same cell at the same time, mixing the RNA particles from each virus and generating a new virus.

The scientists suggest that the haemagglutinin protein coding genes of the H7N9 strain come from a virus circulating in the East Asian fly way and the neuraminidase protein coding genes may have been introduced by birds migrating from Europe. Other RNA segments of the virus may have come from two different groups of H9N2 viruses infecting ducks and chickens in eastern China.

By tracing the origins of the new H7N9 bird flu virus, scientists can obtain clues about how the virus could behave in the future. Additional mutations to the virus could lead to enhanced human transmissibility.

The results of the study were published in The Lancet.

As of April 18, the virus infected 87 people in China and caused 17 fatalities.