Major cruise lines, including Carnival, Royal Caribbean, Norwegian, and MSC, will suspend cruises to and from U.S. Ports of call for 30 days. The temporary suspension announced by President Trump in a tweet in conjunction with CLIA, the world's largest cruise industry trade association, will begin at midnight Friday. Viking and Disney cruises announced similar measures Thursday. The State Department advised Sunday against any travel on cruise ships, particularly for those with underlying health conditions. Ref. USAToday.