In 1918, a particularly virulent strain of influenza swept the globe:

The influenza pandemic of 1918-1919 killed more people than the Great War, known today as World War I (WWI), at somewhere between 20 and 40 million people. It has been cited as the most devastating epidemic in recorded world history. More people died of influenza in a single year than in four-years of the Black Death Bubonic Plague from 1347 to 1351. Known as “Spanish Flu” or “La Grippe” the influenza of 1918-1919 was a global disaster.

If not careful, we could be looking at a repeat:

The likelihood of a human flu pandemic is very high, US Health and Human Services Secretary Michael Leavitt said as he begin a tour of south-east Asia to co-ordinate plans to combat bird flu.

Health officials world-wide are worried about the so called bird flu (avian flu) caused by the H5N1 virus. The virus is not known to be transmissible from human-to-human contact, but 60 people have succumbed to it in South-East Asia in the last 2 years (Cambodia, China, Indonesia, Japan, Laos, South Korea, Thailand, and Vietnam). According to the Centers for Disease Control and Prevention (CDC):

… most cases of bird flu infection in humans have resulted from contact with infected poultry or contaminated surfaces.

Scientists are concerned that H5N1 will mutate into a strain transmissible via person-to-person contact. If that were to happen, a world-wide pandemic is feared.

The most recent outbreak of avian flu occurred in Indonesia. Suspected outbreaks have also appeared in Romania and Turkey, though H5N1 was today ruled out as the cause in Romania.

As an World Health Organization predicts that a pandemic could kill between 5 and 150 million people, governments are taking the matter seriously:

[President Bush] met drug firm chiefs as officials from 80 countries and the UN met to try to plan a global approach to any pandemic.

Last week, the Senate released $4bn for the purchase of anti-flu drugs.

Mr Bush recently suggested that the military could enforce quarantines in affected areas in the United States.

Mr Bush’s comments are further evidence that avian flu has risen close to the top of the White House agenda, says the BBC’s James Coomarasamy in Washington.

The Department of Health and Human Services seems to be on top of bird flu situation:

CDC is taking part in a number of pandemic prevention and preparedness activities, including:

• Working with the Association of Public Health Laboratories on training workshops for state laboratories on the use of special laboratory (molecular) techniques to identify H5 viruses.
• Working with the Council of State and Territorial Epidemiologists and others to help states with their pandemic planning efforts.
• Working with other agencies such as the Department of Defense and the Veterans Administration on antiviral stockpile issues.
• Working with the World Health Organization (WHO) and Vietnamese Ministry of Health to investigate influenza H5N1 in Vietnam and to provide help in laboratory diagnostics and training to local authorities.
• Performing laboratory testing of H5N1 viruses.
• Starting a $5.5 million initiative to improve influenza surveillance in Asia.
• Holding or taking part in training sessions to improve local capacities to conduct surveillance for possible human cases of H5N1 and to detect influenza A H5 viruses by using laboratory techniques.
• Developing and distributing reagents kits to detect the currently circulating influenza A H5N1 viruses.
• Working together with WHO and the National Institutes of Health (NIH) on safety testing of vaccine seed candidates and to develop additional vaccine virus seed candidates for influenza A (H5N1) and other subtypes of influenza A virus.