FILE - In this file photo... Pictures
FILE - In this file photo taken Sunday, Dec. 4, 2011, runners stream southward on Las Vegas Boulevard during the Rock 'n Roll Las Vegas Marathon. After health officials investigated a stomach illness following last year's marathon and Half-Marathon, organizers are promising several changes to this year's races _ including strict sanitation rules and a contractor supplying water to runners. (AP Photo/Julie Jacobson, File)
