This is the height of the flu season in the northern hemisphere. But there is concern a new, more deadly strain of flu is on the horizon.
In Southeast Asia, where the flu season has only just begun, the bird flu is rapidly spreading through the region. Now, there is concern among health officials the avian virus could mutate into a strain that can be transmitted from human to human - a strain that scientists may not have the tools to fight.
Dr. Julie Gerberding, Director of the U.S. Center for Disease Control and Prevention, said there is no crisis - yet.
"We are not imminently on the brink of an avian flu pandemic," she said.
However, Dr. Gerberding emphasized the importance of catching the first such case of human-to-human transmission quickly. She cited the 1918 avian flu pandemic as an example.
"When avian virus evolved to form the 1918 flu strain that caused the global pandemic, it didn't happen overnight. It happens in a series of progressive steps where you'll see local outbreaks, and the virus gradually evolves to become more efficiently transmitted from person to person. That's why it's important we have a two million dose supply of H-5 vaccine and the ability to produce more quickly. That's why it's important we have a stockpile of antiviral drugs that we can get to the region of emergence," says Dr. Gerberding.
The 1918 flu pandemic, also known as "Spanish flu," killed between 20 to 40 million people worldwide. So far, according to the World Health Organization, there have been 42 human deaths from bird flu, all in Asian countries.
Hundreds of thousands of infected birds have been killed in an effort to stem the flu's spread. Dr. Gerberding said it will take a global effort to defeat the bird flu.
"It would be difficult for any one country, including ours, to do this alone. But together, we do have an extraordinarily strong network of capability, and that's what we need to foster and develop and rely on," she said.
Dr. Julie Gerberding pointed out it was this same global network of health organizations that led to the containment of SARS, the pneumonia-like disease that swept through Asia last year, killing approximately 800.