There’s some troubling influenza news starting to come out of China.
A new strain of avian influenza, H7N9, has begun infecting humans. According to Chinese news reports the latest information is that:
- There have been 14 cases in humans
- There have been six deaths
- A person who had close contact with a dead H7N9 bird flu patient now has fever
It has now been four years since the H1N1 outbreak in 2009, commonly known as swine flu. As you may recall that virus was contagious, it could be spread fairly easy from human to human, but turned out not to be lethal in most cases. It still killed at least 18,000 people worldwide.
So what the does the emergence of a new influenza strain that originates in animals but has now jumped to humans mean? Here are some questions and answers based upon an interview with Dr. Pedro Piedra, a virologist at Baylor College of Medicine, and other sources including the World Health Organization.
What is H7N9?
It’s a type of bird flu virus that normally circulates amongst avian populations with some variants known to occasionally infect humans. This is the first time this variant, H7N9 has infected humans, meaning it must have made some genetic leap that would allow it to do so.
Why is the virus infecting humans now?
We don’t know as the source for these infections has not yet been pinpointed. However, through the process of mutations, these viruses that commonly circulate in birds occasionally adapt to be able to grow in other mammals, including humans.
How bad might this get?
That’s impossible to say and it depends upon two primary factors: Is it easily passed from one human to another, and is the strain highly pathogenic.
OK, is it easily passed from human to human?
We don’t yet know this is contagious among humans, or whether the patients infected so far have all had contact with an infected animal. So far there is evidence of one human close to an H7N9 patient becoming sick, but this is not definitive. This is something we should learn within the next several days, however. Recent studies by researchers like Ab Osterhaus, head of viroscience of the Erasmus Medical Center in the Netherlands, have begun to identify the specific genetic variants that allow viruses to spread from human to human.
How pathogenic is the virus?
This, too, is unknown. In general the H7 avian viruses have been associated with milder diseases, but that is not an absolute rule. In birds this virus is not highly pathogenic, but that’s no guarantee it will be so in humans.
What do we know about this virus, then?
Scientists are rapidly working to sequence this H7N9 strain to both better understand its potential to spread among humans and to begin developing biological countermeasures.
How concerned should people be about this?
It’s really hard to say, but in the coming weeks we will have a better grasp on whether this is going to take off. However, whenever there is a virus like this that starts to impact more than a handful of individuals, it obviously becomes concerning.
Is China cooperating with international officials?
In 2003, Chinese authorities initially tried to cover up the emergence of a disease that became known as SARS. They later had to apologize for their slow response and promised to be more forthright during future pandemics. There is some evidence they are being more forthcoming with the H7N9 outbreak.
Is there any treatment for avian influenza?
For treatment (and prevention) of human infection with most avian influenza viruses, CDC and WHO currently recommend oseltamivir or zanamivir, two of four prescription antiviral medications currently licensed for use in the United States. It is unclear how susceptible H7N9 is to these drugs as some viruses have become resistant to them.
Is it safe to travel to China?
At this time the World Health Organization does not advise the application of any travel measures with respect to visitors to China nor to persons leaving China.