The swine flu gave Wall Street a reason to turn cautious on Monday, with the Dow Jones industrial average giving up a midday recovery and retreated about 0.6 percent as the death count in Mexico grew to about 150 people from 100. There have been far fewer cases reported elsewhere, including the United States, and no other fatalities. Investors were also mindful of previous health scares that had only short-term jostling effects on the market including bird flu, Mad Cow disease and the West Nile virus - none of which ever escalated to into global pandemics. Still, Wall Street decided to hedge its bets as the US cases of swine flu doubled to about 40. Airline and other travel-related stocks suffered the sharpest losses Monday. The European Union health commissioner advised Europeans to avoid nonessential travel to Mexico and the United States, but the Centers for Disease Control and Prevention in Atlanta said the recommendation was unwarranted.