you can also get it from transfer of blood/bodily fluids (not saliva), and it can be passed down through birth
/justsaying
You can't catch or spread AIDS.
You can catch and spread HIV however, which causes AIDS.
Did OP make sure he back-washed into the drink?
This is the only way to ensure you don't catch anything nasty.
You can't absorb stuff from the drink if you put some of it back in the bottle.