As new death
reports come in, a team of experts from
China published a scary report yesterday in the
New England Journal of Medicine (NEJM) suggesting that the new H7N9 avian flu virus is even more deadly than previously believed.
The conclusions: H7N9 causes unusually severe respiratory infection, sepsis and brain damage, and appears to be resistant to vaccination and treatment.
But here’s where it gets really worrisome. In a
commentary on “global concerns” pertaining to H7N9, also in the NEJM, influenza experts Timothy Uyeki, MD and Nancy Cox discuss the potential of H7H9 to cause a pandemic (a fast-moving global epidemic) and warn that this possibility is real.
Given the severity and speed with which H7N9 is infecting and killing people, Uyeki and Cox write, “It is possible that these severely ill patients represent the tip of the iceberg and that there are many more as-yet-undetected mild and asymptomatic infections.”
Previously, concerns about H7N9 centered primarily around whether the virus was capable of human-to-human transmission. Because cases were limited to one area of China and because this type of avian flu appeared to be transmitted solely from bird to human, experts were telling us not to worry, that it should be possible to contain.
However, as early as last week, the CDC warned about the possibility of the virus
continuing to mutate in ways that could make it more and more dangerous.
What the Researchers Found
In an analysis of the virological data and circumstances surrounding the first three fatalities, a large team of Chinese researchers found that the patients became ill quickly, developed very severe pneumonia and upper respiratory distress, and their condition deteriorated very quickly with sepsis and failure of multiple organs. Particularly worrying is that two of the three developed encephalopathy, or infection of the membrane surrounding the brain.
Some of the background information in the report also offers reason for concern. Yes, all three of the victims had previously existing health conditions; one had COPD, and two had hepatitis B. One was obese. But while one patient was 87, the other two were only 27 and 35. And while two of the three had had contact with poultry in the weeks before falling ill (one was a butcher, the other had been in a poultry shop), one had no record of contact with birds.
Why Experts Are So Worried
The NEJM report contained extensive data and analysis of the genetic sequence of H7N9 and the history of development of H7 viruses. Here are just a few of the conclusions that might make your hair stand on end:
1. Infected chickens and other birds don’t show symptoms. The H7N9 virus will infect chickens with asymptomatic illness, so that it spreads widely through poultry flocks without farmers’ knowledge. Quote: “H7N9 viruses are a low-pathogenic avian influenza A virus and that infection of wild birds and domestic poultry would therefore result in asymptomatic or mild avian disease, potentially leading to a “silent” widespread epizootic in China and neighboring countries.”
2. The H7N9 spreads more easily to people than similar viruses.Quote: “The gene sequences also indicate that these viruses may be better adapted than other avian influenza viruses to infecting mammals.”
3. Vaccines developed for other H7 viruses aren’t effective. Clinical trials so far have shown that vaccines developed against other H7 strains of influenza are showing extremely limited response against H7N9.
4. Existing flu tests in the U.S. won’t detect the H7N9 virus. Quote: “Since available diagnostic assays used in clinical care (e.g., rapid influenza diagnostic tests) may lack sensitivity to identify H7N9 virus and since existing molecular assays will identify H7N9 virus as a nonsubtypeable influenza A virus, critical public health issue is the rapid development, validation, and deployment of molecular diagnostic assays that can specifically detect H7N9 viral RNA.”
Reassuringly, the researchers go on to say that such a test has already been developed in China and is hopefully on the way here.
5. No Vaccine for months. While news reports have optimistically touted efforts to create a vaccine against H7N9, Cox and Uyeki warn that this will take many months to do. Chinese officials
announced yesterday they expect to have a vaccine ready in 7 months.
http://www.forbes.com/sites/melaniehaiken/2013/04/12/new-bird-flu-danger-worse-than-believed-says-urgent-report/
