Swine Flu Dangers

The so-called "swine flu" is actually the 2009 H1N1 virus, also known as the novel H1N1 flu or virus, the 2009 swine flu and the H1N1 flu. Whatever it's called, the flu is a new type of influenza that appeared in the spring of 2009, a virus that combined genes from swine, human and avian influenza viruses.

Type A

• Swine flu is an influenza A virus, the most dangerous kind. The Spanish flu, which killed 20 to 40 million people worldwide in 1918, was a type of influenza A virus.

Severity

• The 2009 H1N1 virus has caused mild to severe illnesses, and some victims have required hospitalization. Causes of death include bacterial pneumonia--bacterial infections sometimes occurring with or after flu infection.

Increased Danger from Medical Conditions

• The 2009 H1N1 virus is more dangerous to people with certain medical issues, including pregnancy, heart problems, asthma and diabetes. According to the Centers for Disease Control, 70 percent of 2009 H1N1 virus hospital patients had medical conditions that put them at risk of complications from seasonal flu.

Pandemic

• The H1N1 swine flu quickly became a pandemic (a global outbreak) after emerging in Mexico in spring 2009, outside the normal flu season. Flu season occurs in the late fall and winter in the Northern Hemisphere, a time when flu strikes suddenly, causing epidemics during which up to 50 percent of a community's population can become infected.

Reemergence

• Influenza A and B are responsible for seasonal flu epidemics. Since the 2009 swine flu is type A, it will circulate as a seasonal flu, perhaps in a more virulent form. However, as of September 2009, cases occurring during the Southern Hemisphere's flu season are similar to those that previously struck the U.S.

Not Fully Understood

• As a new strain, the 2009 H1N1 virus is not completely understood as of September 2009 and is, therefore, not completely predictable.