A sign in a Singapore hospital warns patients of key swine flu countries. Singapore has not yet reported any infections. (AP Photo/Wong Maye-E)

U.S. health officials declared swine flu a public health emergency Sunday. According to an article in the New York Times, Homeland Security Secretary Janet Napolitano quantified that move by comparing it to preparations for a hurricane: The storm might not hit, but everyone needs to be prepared. The World Health Organization (WHO) has also stressed that the situation is still very much evolving — but into what?

As of last night, officials had confirmed 20 cases in the United States. This came on the heels of an estimated 1,300 infected in Mexico City — 81 of whom were reportedly dying.

Weirdly enough, U.S. President Barack Obama was just in Mexico City a couple of weeks ago, according to the L.A. Times.  On April 16, distinguished archeologist Felipe Solis received the president, then died a week later from flu-like symptoms.

According to the WHO, there is currently no vaccine for swine flu. Should the situation escalate to pandemic proportions, there won’t be enough time to develop and mass-produce one. However, it’s essential to stress that we’re just talking vaccines here — there are plenty of prescription medications on the market capable of treating it. In the meantime, the organization is advising frequent hand washing and avoiding touching suspect surfaces. Officials in Mexico City have taken the added precaution of canceling large gatherings, such as sporting and entertainment events.

Swine flu isn’t a new illness. According to the Centers for Disease Control and Prevention (via CNN), 12 cases were reported in the U.S. between 2005 and January 2009. In 1976, 200 people in New Jersey contracted the illness, though only one died. This time, however, the transmission stats are higher from person to person.

The most devastating epidemic and pandemic disease in history have inflicted the most damage when jumping from one human population to another, or from one species to another.

To learn everything you need to know about swine flu and its implications, visit the CDC’s Swine Flu page, as well as Allison’s previous ScienceStuff posts about the outbreak, here and here.

To learn more about the vaccines and diseases, check out these HowStuffWorks.com articles:
How the Flu Works
How Vaccines Work
10 Worst Epidemics