The United States has 1,639 cases of the new H1N1 flu in 43 states, with two deaths, Reuters quoted the U.S. Centers for Disease Control and Prevention as reporting today. U.S. officials have said they expect the swine influenza virus to spread to all 50 states and to cause many infections ranging from mild to severe. The case count on Thursday was 896 but there has been a backlog of likely cases that need extra testing to confirm.