There is no greater expert on the threat of bird flu than Dr. Rob Webster of St. Jude Children's Research Hospital.
"We're due, and it could happen his year," he says.
Webster, a New Zealander by birth, first discovered that human flu is related to bird flu in 1957, but few paid attention to what he saw as a great danger.
"The veterinarians said, 'Not a problem.' The medical people said, 'Not a problem,'" recalls Webster.
We've met up with Webster before. An energetic 73-year-old, he travels the world taking samples from animals and humans to document the growing threat.
"The most exciting and potentially dangerous thing that I've prepared for all my life is going on right before my eyes," says Webster.
Webster's ideas got a lot of attention when bird flu first infected humans in Hong Kong in 1997. On his advice, the government there killed all the chickens and stopped the outbreak. But since then, Webster has identified the virus in migrating birds.
"And the virus that's in the migrating birds has got a characteristic that we associate with the ability to transfer and kill humans," says Webster. "So far, we have been fortunate. The virus hasn't got the characteristic of transmitting from me to you."
Could that be happening right now?
It could happen," he insists. "It could be one mutation."
Webster has infected lab animals with the virus and says it's very dangerous.
"This virus spreads outside the lungs to the central nervous system," he says. "[The animal] gets hind-leg paralysis and dies. This is the first influenza virus we've seen that does this in a mammal."
A vaccine developed in Webster's lab is undergoing initial tests in people today, but difficulties in manufacturing flu vaccine means it is still years away.
"It's a crying shame," admits Webster.
Still, he's glad the world is at least starting to prepare for a threat he has been warning about for years.