The Human Immunodeficiency Virus (HIV) is not spread easily. You can only get HIV if you get infected blood or sexual fluids into your system. You can't get it from mosquito bites, coughing or sneezing, sharing household items, or swimming in the same pool as someone with HIV.
Some people talk about "shared body fluids" being risky for HIV, but no documented cases of HIV have been caused by sweat, saliva or tears.Blood can come from flossing your teeth, or from sores caused by gum disease, or by eating very hot or sharp, pointed food.
To infect someone, the virus has to get past the body's defenses. These include skin and saliva. If your skin is not broken or cut, it protects you against infection from blood or sexual fluids. Saliva contains chemicals that can help kill HIV in your mouth.
If HIV-infected blood or sexual fluid gets inside your body, you can get infected. This can happen through an open sore or wound, during sexual activity, or if you share equipment to inject drugs.
HIV can also be spread from a mother to her child during pregnancy or delivery. This is called "vertical transmission." A baby can also be infected by drinking an infected woman's breast milk. Adults exposed to breast milk of an HIV-infected woman may also be exposed to HIV.
HOW CAN YOU PROTECT YOURSELF AND OTHERS?
Unless you are 100% sure that you and the people you are with do not have HIV infection, you should take steps to prevent getting infected. People recently infected (within the past 2 or 3 months) are most likely to transmit HIV to others. This is when their viral load is the highest. In general, the risk of transmission is higher with higher viral loads. This fact sheet provides an overview of HIV prevention, and refers you to other fact sheets for more details on specific topics.
Drug Use
If you're high on drugs, you might forget to use protection during sex. If you use someone else's equipment (needles, syringes, cookers, cotton or rinse water) you can get infected by tiny amounts of blood. The best way to avoid infection is to not use drugs.
If you use drugs, you can prevent infection by not injecting them. If you do inject, don't share equipment. If you must share, clean equipment with bleach and water before every use.
Some communities have started exchange programs that give free, clean syringes to people so they won't need to share.
Vertical Transmission
With no treatment, about 25% of the babies of HIV-infected women would be born infected. The risk drops to about 4% if a woman takes AZT during pregnancy and delivery, and her newborn is given AZT. The risk is 2% or less if the mother is taking combination antiviral therapy. Caesarean section deliveries probably don't reduce transmission risk if the mother's viral load is below 1000.
Babies can get infected if they drink breast milk from an HIV-infected woman. Women with HIV should use baby formulas or breast milk from a woman who is not infected to feed their babies.
Contact with Blood
HIV is one of many diseases that can be transmitted by blood. Be careful if you are helping someone who is bleeding. If your work exposes you to blood, be sure to protect any cuts or open sores on your skin, as well as your eyes and mouth. Your employer should provide gloves, facemasks and other protective equipment, plus training about how to avoid diseases that are spread by blood.
WHAT IF I'VE BEEN EXPOSED?
If you think you have been exposed to HIV, talk to your health care provider or the public health department, and get tested.
If you are sure that you have been exposed, call your doctor immediately to discuss whether you should start taking anti-HIV drugs. This is called "post exposure prophylaxis" or PEP. You would take two or three medications for several weeks. These drugs can decrease the risk of infection, but they have some serious side effects.
THE BOTTOM LINE
HIV does not spread easily from person to person. To get infected with HIV, infected blood, sexual fluid, or mother's milk has to get into your body. HIV-infected pregnant women can pass the infection to their new babies.
To decrease the risk of spreading HIV:
Use condoms during sexual activity
Do not share drug injection equipment
If you are HIV-infected and pregnant, talk with your doctor about taking anti-HIV drugs
If you are an HIV-infected woman, don't breast feed any baby
Protect cuts, open sores, and your eyes and mouth from contact with blood.
If you think you've been exposed to HIV, get tested and ask your doctor about taking anti-HIV medications
AIDS Factsheet 
