How you can become infected with HIV (idea)

I could not find all these information on E2, so I'll fill the hole. Note that this node deals with HIV transmission (AIDS itself appears after you have been infected.)

The important thing to know is that HIV is transmitted through some human body secretions generated by mucous membranes, but not all human body secretions. This is the list of the secretions that may transmit AIDS, and the situations in which you may be in contact with them.

• Semen, vaginal or anal secretions. Vaginal or anal sexual intercourse is one the most common ways to be infected, as well as oral sex at least for the one who is in contact with the other person's sex. Female-to-female transmission is rare. Of course, the risk almost completely disappears using latex condoms.
• Blood. This may typically happen when sharing needles or syringes with an infected person, whether these needles are used for drugs, steroids, tattoo, etc. It also used to happen during blood transfusions before 1985 (depending on your country), but blood transfusions and donations should be safe nowadays since blood is tested and the needles are used only once. The situation may be different in some countries though.
• Pregnancy. A mother infected with HIV may pass the virus to her baby, with a probability of 1/4.
• Milk. In some case, breastfeeding may transmit the HIV to the baby (or to anyone who is suckling...)
• Saliva. This is not sure. While a simple (mouth closed) kiss will not transmit HIV, safety of long, deep kisses (French kiss) is not completely established. However there is no known case of HIV transmission through kissing.

Therefore, the following situations will not infect you:

• using clothes, phones, toilet seats that were used by an infected person.
• having everyday contact with an infected person, including kissing her/him on the cheeks or on the (closed) mouth. Sweat and tears do not transmit AIDS.
• Being bitten by a mosquito. Insects cannot transmit AIDS.