More than 25 people have died in China from avian influenza since January, and last week, a study in The Lancet reported that a third strain of avian flu—in addition to H5N1 and H7N9—has mutated to jump from birds to people.
The first woman to be diagnosed with H10N8, the newest mutation, died Dec. 6th. The authors of the study explained that this version of the flu hasn’t been widely reported within bird flocks, meaning it’s transmission might spread quietly. So far, human to human transmission has not been diagnosed. Still, the tone of the report is cautious, saying, “The pandemic potential of this novel virus should not be underestimated.”
This season alone, more than 113 people in China have been infected with avian flu, which is primarily contracted from exposure to birds. According to an unofficial tally documented by the Center for Infection Disease Research and Policy, there have been 67 deaths per 300 documented cases since the resurgence of the strain, which since 2003 has killed about 67 percent of its victims.
More frighteningly, last week the Ministry of Health in Malaysia reported their first case of H7N9, a 67 year-old tourist from China who was sick upon arrival. The official press release from the World Health Organization was calm about the spread, saying “Until the virus adapts itself for efficient human-to-human transmission, the risk of ongoing international spread of H7N9 virus by travelers is low.”
Still, a study published this week in Nature analysed more than 80,000 gene sequences and determined that the deadly 1918 pandemic virus — which killed an estimated 100 millon people — was also avian in origen. Because the real fear when discussing viruses is rapid mutations, it’s useful to know that the 1918 virus was likely in circulation in human hosts for two to 15 years before the pandemic occurred, but it’s still enough to give epidemiologists pause. Research in laboratories in Wisconsin and the Netherlands recently proved that a more contagious strain of H5N1, one that would allow easy airborne transmission between humans, could be reached in only a few mutations.
Fortunately since 1918, technology for monitoring pandemics has dramatically increased. Recently, new research technique called phylogeography was developed to trace the spread of a virus across Egypt. By feeding the viral genetic sequence and geographical information into a complex program, phylogeography helps researchers better understand how viruses spread and the amount of time it takes, helping doctors prevent further transmissions.
The Chinese authors of the study in The Lancet called for similarly active monitoring of the spread of the most recent avian flu, writing, “Whether cases of avian influenza A H10N8 virus infection are going to increase is unknown, because how widely these viruses are circulating in poultry is unknown.” It continued, “More surveillance will be needed to establish the origin of H10N8 and to monitor potential future transmission events.
In the meantime, it seems the appetite for bird meat in China has decreased dramatically; Tyson said demand for its chicken is down as much as 30 percent –that´s a lot of freezer burn.
Image credit: Avian influenza (WHO@PHOTO)