The new swine flu virus apparently spreads just like regular flu. You could pick up germs directly from an infected person, or by touching an object they recently touched, and then touching your eyes, mouth, or nose, delivering their germs for your own infection. That's why you should make washing your hands a habit, even when you're not ill. Infected people can start spreading flu germs up to a day before symptoms start, and for up to seven days after getting sick, according to the CDC.
The swine flu virus can become airborne if you cough or sneeze without covering your nose and mouth, sending germs into the air.
The U.S. residents infected with swine flu virus had no direct contact with pigs. The CDC says it's likely that the infections represent widely separated cycles of human-to-human infections.