A Kuwaiti health official says all 18 US soldiers infected with swine flu have recovered and left this oil-rich US ally. The official, Youssef Mandakar, said today that the soldiers entered Kuwait by air and did not have any contact with the local population. He said their cases were "mild" and they have all left the country. He would not say where they came from or their destination. Kuwait announced on Saturday that a number of American soldiers passing through the country were infected, but it did not say how many. The US Embassy and the military also had declined to give any details other than they were being treated. Kuwait is a major ally of Washington and a logistics base for US military personnel serving in Iraq.