H1N1, also known as the swine flu virus, may be on our minds at the moment, but it is hardly the first pathogen to trigger fear and panic. From the avian flu to the bubonic plague, disease outbreaks have been a constant in human history. Scientists are locked in a perpetual struggle to ward off the latest and most virulent forms of pathogenic bacteria, viruses, and protists.

Swine flu was first diagnosed in the U.S. by the CDC in San Diego County, California, on April 14 of this year. The virus, the result of a reassortment of four strains of influenza A virus subtype H1N1 (one endemic in humans, one in birds, and two in pigs), has claimed around a hundred lives and been reported in over 50 countries.