Are we closer to a flu pandemic than ever before?
The virus is already entrenched in this part of the world, number one. Second, the number of human cases is on the rise, particularly in Vietnam. And third, the virus continues to be unpredictable and unstable. That's why we have to remain constantly on alert.
Do we have the ability to prevent a pandemic?
This is not an easy battle. The virus is everywhere and very changeable. We are dealing with billions of animals, not just human beings. But I still believe there is a window of opportunity. That's why we should implement all the necessary strategies cleaning up backyard farms, improving surveillance not just on a piecemeal basis but comprehensively and thoroughly. There is no single panacea.
Are developed countries providing sufficient aid to carry out these measures?
The international community has already provided a lot of support, and I'm very grateful. But we need an additional $250 million altogether. This sounds like a big figure, but this is a lot less than the magnitude of the economic loss that a pandemic would cause.
Studies published last week showed that the virus is now circulating in migratory birds in western China. Could these birds spread the virus?
The findings certainly confirm that the virus is very unstable. Migratory birds used to be regarded as reasonably resistant to the virus, but now we find that's not the case. We cannot rule out the possibility that these birds will carry it to other areas. The most important thing is to test more samples from animals and humans in the area, so that we know how far the virus has spread.
Are you happy with the cooperation you've received from Beijing?
Overall, I am quite happy. We found they had aggressively culled poultry, and had restricted the movement of poultry and people. That's good, but we strongly recommend that the Chinese government get more samples from humans and animals. We need to know whether the virus is spreading among asymptomatic birds and humans.
How do you respond to charges that Chinese farmers have been using the flu drug Amantadine on their chickens?
The Chinese government has officially told the WHO that the government has never encouraged [use of] this drug for prevention purposes. We're waiting for more information. It's a very serious blow to our fight against this virus if amantadine has been used in an inappropriate manner, because this drug would normally play an important role in treating influenza.
Does the WHO support Vietnam's efforts to develop its own bird-flu vaccine?
We understand why Vietnam wants to produce its own vaccine because there may not be enough vaccine from the West for developing countries. [But] if the vaccine quality is not well controlled, the vaccine will cause more problems than it solves. Our job is not to stop the Vietnamese but to make sure the vaccine produced will be safe and effective.
Vietnam has seen rising case numbers with a lower mortality rate. What does this mean for the virus?
Our investigations have concluded that, so far, there's no evidence of efficient human-to-human transmission there. But given the unpredictable nature of the virus, the longer the current situation persists, the more chance the virus will achieve efficient human-to-human transmission.
Are there any genetic changes in the virus?
The H5N1 virus has undergone significant genetic changes over the past several years, but there's no evidence so far of a specific change that makes the virus more transmissible to humans.
You've said that 100 million people could die in a worst-case pandemic. Do you still believe that?
If [a pandemic] happens, the consequences could be very serious, and the magnitude of human casualties could be in the order of millions of deaths. One hundred million is just one of so many possible figures. What's important is to understand the serious potential consequences and prepare for them.