It is the role of the Centers for Disease Control and Prevention (CDC) to block the introduction of communicable diseases into the U.S. from abroad. What is less well known is that the commander of any aircraft destined for a U.S. port of entry has the same legal obligation.
Centers for Disease Control and Prevention
Regulation may be in the air for the cabins of commercial aircraft, though it is unclear which is more infectious: airborne particles or hysterical legislation. On April 6, the House subcommittee on aviation, chaired by John Mica (R-Fla.), discussed efforts to prevent a pandemic–an epidemic across international boundaries affecting masses–and debated whether the problem can best be addressed through legislation or common sense.