Human Immunodeficiency Virus.

What is AIDS? What causes AIDS?

AIDS stands for Acquired Immune Deficiency Syndrome.

An HIV-positive person receives an AIDS diagnosis after developing one of the CDC-defined AIDS indicator illnesses. An HIV-positive person can also receive an AIDS diagnosis on the basis of certain blood tests (CD4 counts) and may not have experienced any serious illnesses. A positive HIV test does not mean that a person has AIDS. A diagnosis of AIDS is made by a physician according to the CDC AIDS Case Definition.

Over time, infection with HIV (Human Immunodeficiency Virus) can weaken the immune system to the point that the system has difficulty fighting off certain infections. These types of infections are known as opportunistic infections.

Many of the infections that cause problems or that can be life-threatening for people with AIDS are usually controlled by a healthy immune system. The immune system of a person with AIDS has weakened to the point that medical intervention may be necessary to prevent or treat serious illness.

What is the Difference Between HIV and AIDS?
HIV is the virus that causes AIDS.

H - Human: because this virus can only infect human beings.
I - Immuno-deficiency: because the effect of the virus is to create a deficiency, a failure to work properly, within the body’s immune system.
V - Virus: because this organism is a virus, which means one of its characteristics is that it is incapable of reproducing by itself. It reproduces by taking over the machinery of the human cell.
A - Acquired: because it’s a condition one must acquire or get infected with; not something transmitted through the genes
I - Immune: because it affects the body’s immune system, the part of the body which usually works to fight off germs such as bacteria and viruses
D - Deficiency: because it makes the immune system deficient (makes it not work properly)
S - Syndrome: because someone with AIDS may experience a wide range of different diseases and opportunistic infections

How long does it take for HIV to cause AIDS?

Currently, the average time between HIV infection and the appearance of signs that could lead to an AIDS diagnosis is 8-11 years. This time varies greatly from person to person and can depend on many factors including a person’s health status and behaviors. Today there are medical treatments that can slow down the rate at which HIV weakens the immune system. There are other treatments that can prevent or cure some of the illnesses associated with AIDS. As with other diseases, early detection offers more options for treatment and preventative health care.

What’s the connection between HIV and other sexually transmitted diseases?

Having a sexually transmitted disease (STD) can increase a person’s risk of becoming infected with HIV, whether or not that STD causes lesions or breaks in the skin. If the STD infection causes irritation of the skin, breaks or sores may make it easier for HIV to enter the body during sexual contact. Even an STD that causes no breaks or sores can stimulate an immune response in the genital area that can make HIV transmission more likely.

Where did HIV come from?

The most recent presentation on the origin of HIV was presented at the 6th Conference on Retroviruses and Opportunitistic Infections (Chicago, January 1999). At that conference, research was presented that suggested that HIV had “crossed over” into the human population from a particular species of chimpanzee, probably through blood contact that occurred during hunting and field dressing of the animals. The CDC states that the findings presented at this conference provide the strongest evidence to date that HIV-1 originated in non-human primates. The research findings were featured in the February 4,1999 issue of the journal, Nature.

We know that the virus has existed in the United States, Haiti and Africa since at least 1977-1978. In 1979, rare types of pneumonia, cancer and other illnesses were being reported by doctors in Los Angeles and New York. The common thread was that these conditions were not usually found in persons with healthy immune systems.

In 1982 the Centers for Disease Control and Prevention (CDC) officially named the condition AIDS (Acquired Immune Deficiency Syndrome). In 1984 the virus responsible for weakening the immune system was identified as HIV (Human Immunodeficiency Virus).

How many people have HIV and AIDS?

Worldwide: UNAIDS estimates that as of December 2000, there were an estimated 36.1 million people living with HIV/AIDS (34.7 million adults and 1.4 million children under 15). Since the epidemic began, an estimated 21.8 million people have died of AIDS (17.5 million adults and 4.3 million children under 15).

An estimated 5.3 million new HIV infections occurred in 2000. During 2000, HIV- and AIDS-associated illnesses caused deaths of an estimated 3 million people, including 500,000 children under the age of 15.

In the United States: According to the Centers for Disease Control and Prevention (CDC), there are between 800,000 and 900,000 people living with HIV. Through December 2000, a total of 774,467 cases of AIDS have been reported to the CDC; of this number, 448,060 persons (representing 58% of cases) have died.  (Source: Centers for Disease Control - CDC)

Latest U.S. AIDS Trends
Download the most recent CDC HIV/AIDS Surveillance Reports


How can I tell if I’m infected with HIV?

The only way to determine whether you are infected is to be tested for HIV infection. You can’t rely on symptoms to know whether or not you are infected with HIV. Many people who are infected with HIV don’t have any symptoms at all for many years.

Similarly, you can’t rely on symptoms to establish that a person has AIDS. The symptoms associated with AIDS are similar to the symptoms of many other diseases. AIDS is a diagnosis made by a doctor based on specific criteria established by the Centers for Disease Control and Prevention (CDC).

What are the Symptoms of HIV?

Primary HIV infection is the first stage of HIV disease, when the virus first establishes itself in the body. Some researchers use the term acute HIV infection to describe the period of time between when a person is first infected with HIV and when antibodies against the virus are produced by the body (usually 6- 12 weeks).

Some people newly infected with HIV will experience some “flu-like” symptoms. These symptoms, which usually last no more than a few days, might include fevers, chills, night sweats and rashes (not cold-like symptoms). Other people either do not experience “acute infection,” or have symptoms so mild that they may not notice them.

Given the general character of the symptoms of acute infection, they can easily have causes other than HIV, such as a flu infection. For example, if you had some risk for HIV a few days ago and are now experiencing flu-like symptoms, it might be possible that HIV is responsible for the symptoms, but it is also possible that you have some other viral infection.

What are the Symptoms of AIDS? There are no common symptoms for individuals diagnosed with AIDS. When immune system damage is more severe, people may experience opportunistic infections (called opportunistic because they are caused by organisms which cannot induce disease in people with normal immune systems, but take the “opportunity” to flourish in people with HIV). Most of these more severe infections, diseases and symptoms fall under the Centers for Disease Control’s definition of full-blown “AIDS.” The median time to receive an AIDS diagnosis among those infected with HIV is 7-10 years.

Provided by ArmMed Media
Revision date: June 21, 2011
Last revised: by Tatiana Kuznetsova, D.M.D.