Dr. Thomas Frieden, director of the Centers for Disease Control and Prevention in Atlanta, talked recently about the latest Avian flu health scare to hit China. The big fear with bird flu virus is that it develops the ability to go from person to person and trigger a pandemic.
The scarier aspects of this virus (H7N9): "The first is the severity of illness. A significant proportion of the people who have been diagnosed had severe illness or have died. We expect that more mild cases will be found. The genetic sequence itself … seems to have some characteristics that suggest that it's a little bit adapted to a mammalian host — to people, pigs. So it has the risk of mutating into something that would go person to person. And it doesn't cause severe illness in birds. This again is paradoxical; we don't have the clue of sick flocks, so we're not able to cull flocks. If that persists as the pattern, the likelihood is that it could become widespread in birds in China and even neighboring countries. Even if it doesn't develop the ability to spread person to person, it would still increase the risk of infections for people who work with poultry."
Reassuring signs: "We have not seen sustained person-to-person spread. China has assessed hundreds of close contacts of (infected) cases and has not identified secondary cases. That's really encouraging, because in regular influenza, you would expect 20 or 30 percent of contacts to be infected. There has been excellent global collaboration. We're building on a decade of preparedness. We're better prepared than ever to deal with a pandemic."
China's reaction to the outbreak: "From the moment the (cases) were reported, the collaboration that we've had with China has been exemplary. We're receiving virus samples. They posted on the Internet the full genetic sequence of the viruses. We've had regular communication with them."
H7N9 samples at the CDC: "We're doing several key things with it. The first is to understand it well. We'll re-sequence the genome so we know every DNA molecule in it. The most urgent tasks are to come up with the best way of diagnosing the infection. Our laboratory is working on that. We will provide that to China so they can improve the quality of their diagnosis there. The second is to work on seed strains for a vaccine. We don't know that this will spread person to person, but we want to be prepared, and that means making a vaccine. If you look at (the) 1918-1919 (flu pandemic), more than 50 million people died. Of all the threats to health, there's none that has as much potential to do harm as influenza."
Why bird flu often hits China: We have generally anticipated influenza coming from Southeast Asia, not just China. There's a very intense animal-human interface. Lots of people, lots of chickens, lots of pigs, and all kind of mixed up together in close quarters. About 75 percent of emerging infections come from an animal source. China is … about a fifth of the world's population, so even on an average, you expect it to account for a significant portion of new infections. But you can't let down your guard anywhere. In fact, H1N1 came out of Mexico, and we didn't expect that, so one of the things we try to do in public health always is to expect the unexpected.
What CDC can do that China can't do: CDC laboratories are, in practice, the reference laboratories for the world. We have the top scientists in so many areas, including influenza. We've already sent to the Chinese some materials that will help them do blood tests to see if people have been exposed to, or infected with, this strain of flu. When they're safer, we're safer. We have the ability to create a test that's a little more accurate.
CDC's new Advanced Molecular Detection (AMD) initiative: It's the single most important thing that we can do to improve our ability to protect Americans from infectious disease threats. With AMD, we'll be able to find outbreaks that we missed before, find them sooner than before, stop them quicker, and figure out how they're spreading so we can prevent them more effectively.
AMD funding: It's a proposal in the president's budget for FY 2014, $40 million. I'm optimistic. I think there's broad bipartisan support for protecting Americans from infectious disease threats. We need to do this. Microbes are evolving all the time, and unless we keep pace with them, we will lose the arms race with drug resistance, with new strains, with globalization of travel.
