HIV has been found in blood, semen, saliva, tears, nervous system tissue, breast milk, and female genital tract secretions; however, only blood, semen, female genital tract secretions, and breast milk have been proven to transmit infection to others.  

It pass from a person who has the infection to another person. For the most part, the virus is spread by sexual contact or by sharing drug needles and syringes and also infect  through the placenta from the mother to the fetus, and rarely through breast feeding.

Other transmission methods are rare and include accidental needle injury, artificial insemination through donated semen, and kidney transplantation through the donated kidney.

High risk groups include homosexual or bisexual men, intravenous drug users who share needles, the sexual partners of those in high risk groups, infants born to mothers with HIV, and persons who received blood transfusions or clotting products between 1977 and 1985 (prior to standard screening for the virus in the blood).

Otherwise, HIV is not easy to catch. It is not spread by mosquito bites, using a public telephone or restroom, being coughed or sneezed on by an infected person, or touching someone with the disease.

The Centers for Disease control (CDC) compile statistics on many different diseases. See the picture for a summary of the AIDS statistics for U.S. states. HIV carrier rate in the United States now is 1 carrier for every 100 to 200 people.