You don't actually "get" AIDS. You might get infected with HIV, and later you might develop AIDS. You can get infected with HIV from anyone who's infected, even if they don't look sick and even if they haven't tested HIV-positive yet. The blood, vaginal fluid, semen, and breast milk of people infected with HIV has enough of the virus in it to infect other people. Most people get the HIV virus by:
* having sex with an infected person
* sharing a needle (shooting drugs) with someone who's infected
* being born when their mother is infected, or drinking the breast milk of an infected woman
Getting a transfusion of infected blood used to be a way people got AIDS, but now the blood supply is screened very carefully and the risk is extremely low.
There are no documented cases of HIV being transmitted by tears or saliva, but it is possible to be infected with HIV through oral sex or in rare cases through deep kissing, especially if you have open sores in your mouth or bleeding gums.