Today was just a weird day as we sold off, but marginally compared to elsewhere. Parts of Asia and Europe, as well as Latin America, saw their equity markets hit hard over fears of a pandemic swine flu outbreak. Many traders feel this is a notion that will pass as a footnote rather than as a catastrophe, and this was a very light day for data. Sheila Bair at FDIC did manage to call the bank liquidity crisis over.

Here are today's unofficial closing bell levels:

Dow 8,025.00 -51.29 (-0.64%)
S&P 500 857.51 -8.72 (-1.01%)
Nasdaq 1,679.41 -14.88 (-0.88%)

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Just as investors were beginning to feel somewhat positive -- the economy was at least bottoming, and possibly showing early signs of turning around -- swine flu has appeared and put the global economy under its own stress test.

The Obama administration declared a public health emergency Sunday because of the flu outbreak. So far officials have confirmed cases in New York, Texas, California and Kansas. Globally there have been cases of the same strain of the deadly flu, which is suspected in the deaths of 103 people in Mexico, as far as New Zealand.

One after another, sectors, markets and companies affected by the flu's consequences have exhibited symptoms -- good or bad.

BloggingStocks and DailyFinance have more:

• Don't fear the swine flu . . . trade it
• Airlines could suffer thanks to a potential swine flue epidemic
• Analyst warns Visa/Mastercard could be smacked by swine flu
• Swine flu: Outbreak takes its toll in the oil patch
• Fear of flu epidemic hurts stocks, helps some drug companies
• What would a swine flu pandemic do to the economy?

I remember Toronto during SARS. As one of the harder hit areas, it was not a happy place. It was the end of winter, but that miserable, cold winter just didn't want to end. People walked the streets in a gloomy haze, afraid to take the subway and giving dirty looks to anyone brazen enough to cough in public. Worse, I couldn't even visit a friend in the hospital. All things considered though, in global pandemic terms, it was over relatively quickly. Let's hope swine flu will be the same.

In the meantime, let's put on our investors hats and see what's in store for some stocks:

Travel and tourist stocks
This is one of the worst hit areas, especially airlines, as people may cancel their travel plans. For example, AMR Corp. (NYSE: AMR) traded over 9 percent lower an hour after the open. Royal Caribbean Cruises (NYSE: RCL) was down over 15 percent. In fact UBS downgraded these airlines and hotels this morning: AMR, Continental Airlines (NYSE: CAL), Host Hotels and Resorts (NYSE: HST), Lasalle Hotel Properties (NYSE: LHO), Marriott (NYSE: MAR), United Airlines (NASDAQ: UAUA), US Airways (NYSE: LCC). Carnival Cruise Lines (NYSE: CCL) also declined considerably. Best to stay away from the sector.

Earlier I took a look at the obvious impact that the pig pig flu outbreak could have on airlines, but I was surprised to see the profound impact it has had in the oil patch.

Black gold futures are 5% lower this morning because of global economic recovery concerns that have surfaced thanks to the "deadly swine flu." In early morning trading, June-dated crude was trading below $50 per barrel and recently dipped below $49 per barrel.

Pork producers aren't the only stocks getting hammered by swine flu fears. Brokerage JPMorgan observed today that "concerns over the swine flu outbreak could weigh on MasterCard Inc. (NYSE: MA - option chain) / Visa Inc. (NYSE: V - option chain) shares due to fears that cross-border fees may suffer from reduced cross-border travel related to the virus," sending shares of both companies lower at the sound of the opening bell.

Although JPMorgan added that it's too early to tell what impact the swine flu will have on MasterCard and Visa, the firm asserted that "the risk is worth monitoring in our view."

What more could go wrong for airlines, right? The swine flu outbreak has reminded some investors of the SARS epidemic in Asia, and it has taken its toll on airlines. With the Mexican government closing schools and stores because of a public health emergency, we await a worldwide reaction. With fears of human-to-human transmission of the disease, no doubt we are going to see airlines suffer again.

Swine flu cases have reached as far as New Zealand, and cases were found in Spain, America and Canada, In the country of origin, Mexico, there have also been deaths, making this a worldwide outbreak. These concerns resulted in battered airline stocks in foreign trading. In Chinese trading, Air France KLM, Deutsche Lufthansa, British Airways, and Iberiea were all more than 7% lower. Cathay Pacific and Air China were both sharply lower as well.