The swine flu (H1N1) pandemic first caused a panic in March and is once again threatening to become a preoccupation among the American public.
But you’d think we be getting used to this type of scare by now.

The World Health Organization says infectious diseases are spreading faster than ever before, and new diseases are emerging at the historically unprecedented rate of one per year. Epidemics -- in short, when the number of people infected rises to an unexpected level within a country -- have become more common and are spreading with greater ease and speed. More pandemics -- basically an epidemic covering a wider geographic area, often worldwide -- are predicted as the natural extension of this trend.

From an economic standpoint, the impact of this new era could be devastating. Global trade and travel connect the world but, at the same time, facilitate the spread of infectious diseases. The reaction to outbreaks is crucial -- both to contain a disease and its associated costs. With the 2003 outbreak of SARS, for instance, the response had staggering financial implications, totally disproportionate to the number of people infected. From SARS we learned that public perception and media responses to pandemics are nearly as important as the actual disease.

Click on the icons below to read about five infectious diseases (some from the past that could still stage a comeback; some current and one future threat) and how they may impact you and the economy.