The Royal Caribbean ship "Serenade of the Seas" arrives at port in San Diego April 30, 2009. Cruise operators are now diverting ships to the Port of San Diego, suspending calls to Mexican ports due to the influenza A (H1N1), formerly referred to as swine flu, scare. At least 12 unscheduled cruise ships will stop in San Diego, bringing a boost to the local economy. REUTERS/Mike Blake (UNITED STATES HEALTH TRAVEL BUSINESS)