With concerns about a possible global avian flu pandemic on the rise, U.S. employers, especially those with multinational operations, may need to grapple with complex and unprecedented legal issues raised by the illness.

To date, no human influenza pandemic has broken out, and according to recent World Health Organization data, there have been no reports of the avian flu in the United States. Nevertheless, the H5N1 strain of the influenza has reportedly infected more than 200 individuals worldwide and has been found in birds that can infect humans. And concerns about possible mutations of the virus have been widely reported.