The Facts

AIDS (acquired immune deficiency syndrome) was first recognized in North America in the early 1980s. It is caused by a virus known as HIV(human immunodeficiency virus). HIV infection has become a world wide epidemic. As of 2013, the World Health Organization (WHO) stated there were 35 million people currently infected with the virus.

HIV is more common among certain populations at risk, such as people who inject illicit drugs, and bisexual and gay men. HIV infections are also increasing among women, Aboriginal peoples, and African and Caribbean communities.

The virus can be found in the blood, semen, vaginal fluid, and breast milk of infected people. HIV is also found in saliva, sweat, and tears, though not in high enough amounts to transmit the virus to another person. There are no known cases of anyone catching HIV through sneezing, shaking hands, or from toilet seats or mosquito bites.

HIV may be transmitted through unprotected heterosexual or homosexual, vaginal, anal, or oral sex. Although the risk of infection is lower with oral sex, it is still important to use protection during oral sex, such as a dental dam (a piece of latex to cover the vagina during oral sex) or a condom. HIV can also be passed on through perinatal infection, where mothers who have HIV are at risk of giving the disease to the baby during birth. The risk of perinatal infection is declining with new treatments. Breast-feeding by an infected mother can also transmit HIV.

Symptoms and Complications

Symptoms of HIV infection appear 2 to 12 weeks after exposure. At this point the virus begins rapidly taking over immune cells in the blood. The symptoms of this phase are flu-like and include:

When the symptoms begin to appear, the person with HIV is very infectious.

The symptoms usually go away within a week to a month, and the person will feel fine again. However, the symptoms may return from time to time. The symptoms of HIV are similar to symptoms of other diseases. The only way to know for sure whether you are HIV-positive is to be tested. After infection with HIV, it can take 3 months for antibodies to the virus to be detectable in the blood. On average, it takes about 22 days to develop antibodies. This is called seroconversion. After seroconversion occurs, the virus can be detected using a blood test.

After the initial symptoms go away, the body's immune system tries to control the virus. 

The immune system can keep the virus at bay for a while, but it can't completely get rid of it. Many people will feel fine for years before their immune system weakens and they develop AIDS. Without treatment, about half of HIV-positive people develop AIDS within 10 years of infection. Some people develop AIDS within a few years of infection. A few, called long-term non-progressors, do not develop AIDS until much later. Many factors affect the time frame to develop AIDS, including medications and the person's general health and lifestyle.

Anyone can become infected with HIV. Fortunately, it can be prevented.

The main ways to prevent HIV infection are:

Unless you are in a mutually monogamous relationship (neither of you is having sex with anyone else), and you are sure neither of you is HIV-positive, make sure to use a condom every time you have sex. In some cases, couples where one partner is infected may decide to risk infection of the other partner, especially if they are trying to get pregnant. If this is the case,talk to your doctor. Your choice of sexual partner is also important, since condoms do sometimes break or leak. You may know that you practice safe sex and that you haven't used dirty needles, but you must also know that your sexual partners and all their other partners do the same. Sharing needles is very dangerous – it carries a high risk of getting HIV.

People with other sexually transmitted infections (STIs) such as herpes are much more likely to contract HIV during sex, probably because of tiny breaks in their skin or vaginal lining.Keeping free of other STIs will help reduce your risk of HIV infection, but this alone will not protect you from infection. That's why it is important to use condoms.