The flu outbreak, alongside declining exports and the existing economic crisis, could send Mexico's peso falling to as low as 15 to the dollar, said Pedro Tuesta, an economist at the consulting company 4Cast.

"We believe it will end the year between 14 and 15 to the dollar," Tuesta said, saying that the loss of foreign exchange from tourists was not the only reason.

The ratings given by agencies like Moody's Investors Service, Standard and Poor's, and Fitch Ratings influence whether foreign investors are willing to hold Mexican debt.

On Monday, Standard and Poor's became the latest agency to place the country on watch for downgrade, although the rating remains at BBB+, one of the highest emerging market ratings.

Foreign investors have a substantial chunk of Mexico's domestic debt and if they sell, they would probably sell their peso proceeds for dollars.

Mexico's overall exports have been hurt even more than tourism. They declined 30.5 percent to 31.4 billion dollars during the same period.

Mexico's biggest export, oil, has fallen by more than two-thirds in value year on year, in line with the general slump in oil prices.

Meanwhile, industrial exports have plummeted as a US recession has hit demand for durable goods. A substantial chunk of Mexico's exports are so-called maquila goods, that is, intermediate goods imported for conversion into finished goods for export.

(Xinhua News Agency May 14, 2009)