What would a swine flu pandemic do to the economy?

As the swine flu epidemic has moved from Mexico to Canada, the United States, New Zealand, and Spain, global financial markets are already feeling the effects of the outbreak. In the United Kingdom, several stocks have fluctuated based on speculation about the disease's effects, and American indexes started lower on flu concerns. (BloggingStocks takes a look at stocks that could be affected by the epidemic.)

At its heart, swine flu is a fairly traditional respiratory disease. It has an incubation period of one to two days, and causes fevers, lethargy, loss of appetite, coughing, runny nose and sore throat. In some cases, it can have a gastric component, leading to nausea, vomiting and diarrhea. In the past, swine flu has been passed from animal to human, but not from human to human. The current strain, however, appears to be making the human-to-human leap.