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 long does it take 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 is the difference between HIV & 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.

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See Also

How Can I tell if I am affected with HIV?

What is AIDS?

How is HIV Transmitted?

HIV can be transmitted from an infected person to another through:

• Blood (including menstrual blood)
• Semen
• Vaginal secretions
• Breast milk

Blood contains the highest concentration of the virus, followed by semen, followed by vaginal fluids, followed by breast milk.

* Activities That Allow HIV Transmission

• Unprotected sexual contact
• Direct blood contact, including injection drug needles, blood transfusions, accidents in health care settings or certain blood products
• Mother to baby (before or during birth, or through breast milk)

Sexual intercourse (vaginal and anal): In the genitals and the rectum, HIV may infect the mucous membranes directly or enter through cuts and sores caused during intercourse (many of which would be unnoticed). Vaginal and anal intercourse is a high-risk practice.

Oral sex (mouth-penis, mouth-vagina): The mouth is an inhospitable environment for HIV (in semen, vaginal fluid or blood), meaning the risk of HIV transmission through the throat, gums, and oral membranes is lower than through vaginal or anal membranes. There are however, documented cases where HIV was transmitted orally, so we can't say that getting HIV-infected semen, vaginal fluid or blood in the mouth is without risk. However, oral sex is considered a low risk practice.

Sharing injection needles: An injection needle can pass blood directly from one person's bloodstream to another. It is a very efficient way to transmit a blood-borne virus. Sharing needles is considered a high-risk practice.

Mother to Child: It is possible for an HIV-infected mother to pass the virus directly before or during birth, or through breast milk. Breast milk contains HIV, and while small amounts of breast milk do not pose significant threat of infection to adults, it is a viable means of transmission to infants.

The following "bodily fluids" are NOT infectious:

• Saliva
• Tears
• Sweat
• Feces
• Urine

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See Also

How can I tell if I am Affected with HIV?

Can I get HIV from Kissing

Casual contact through closed-mouth or "social" kissing is not a risk for transmission of HIV. Because of the potential for contact with blood during "French" or open-mouth, wet kissing, CDC recommends against engaging in this activity with a person known to be infected. However, the risk of acquiring HIV during open-mouth kissing is believed to be very low. CDC has investigated only one case of HIV infection that may be attributed to contact with blood during open-mouth kissing. In this case both partners had extensive dental problems including gingivitis (inflammation of the gums). It is likely that there was blood present in both partners' mouths making direct blood to blood contact a possibility.

Can I get HIV from Oral Sex?

There is considerable debate within the HIV/AIDS prevention community regarding the risk of transmission of HIV through oral sex. What is currently known is that there is some risk associated with performing oral sex without protection; (there have been a few documented cases of HIV transmission through oral sex). While no one knows exactly what that risk is, cumulative evidence indicates that the risk is less than that of unprotected anal or vaginal sex. The risk from receiving oral sex, for both a man and a woman, is considered to be very low.

Currently, risk reduction options when performing oral sex on a man (fellatio) include the use of latex condoms, but also include withdrawal before ejaculation without a condom (avoiding semen in the mouth) and/or refraining from this activity when cuts or sores are present in the mouth.

When performing oral sex on a woman (cunnilingus), moisture barriers such as a dam (sheet of latex), a cut-open and flattened condom, or household plastic wrap can reduce the risk of exposure to vaginal secretions and/or blood.

How Can I tell if I am affected 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).

Oppurtunistic Infections

In our bodies, we carry many germs - bacteria, protozoa, fungi, and viruses. When our immune system is working, it controls these germs. But when the immune system is weakened by HIV disease or by some medications, these germs can get out of control and cause health problems.

Infections that take advantage of weakness in the immune defenses are called "opportunistic". The phrase "opportunistic infection" is often shortened to "OI".

TESTING FOR OIs

You can be infected with an OI, and "test positive" for it, even though you don't have the disease. For example, almost everyone with HIV tests positive for Cytomegalovirus (CMV). But it is very rare for CMV disease to develop unless the CD4 cell count drops below 50, a sign of serious damage to the immune system.

To see if you're infected with an OI, your blood might be tested for antigens (pieces of the germ that causes the OI) or for antibodies (proteins made by the immune system to fight the germs). If the antigens are found, it means you're infected. If the antibodies are found, you've been exposed to the infection. You may have been immunized against the infection, or your immune system may have cleared the infection, or you may be infected. If you are infected with a germ that causes an OI, and if your CD4 cells are low enough to allow that OI to develop, your health care provider will look for signs of active disease. These are different for the different OIs.

OIs AND AIDS

People who aren't HIV-infected can develop OIs if their immune systems are damaged. For example, many drugs used to treat cancer suppress the immune system. Some people who get cancer treatments can develop OIs.

HIV weakens the immune system so that opportunistic infections can develop. If you are HIV-infected and develop opportunistic infections, you might have AIDS.

In the US, the Center for Disease Control (CDC) is responsible for deciding who has AIDS. The CDC has developed a list of about 24 opportunistic infections. If you have HIV and one or more of these "official" OIs, then you have AIDS. The list is available at http://www.aidsmeds.com/lessons/StartHere8.htm.

WHAT ARE THE MOST COMMON OIs?

In the early years of the AIDS epidemic, OIs caused a lot of sickness and deaths. Once people started taking strong antiretroviral therapy (ART), however, a lot fewer people got OIs. It's not clear how many people with HIV will get a specific OI.

In women, health problems in the vaginal area may be early signs of HIV. These can include pelvic inflammatory disease and bacterial vaginosis, among others.

The most common OIs are listed here, along with the disease they usually cause, and the CD4 cell count when the disease becomes active:

• Candidiasis (Thrush) is a fungal infection of the mouth, throat, or vagina. CD4 cell range: can occur even with fairly high CD4 cells.
• Cytomegalovirus (CMV) is a viral infection that causes eye disease that can lead to blindness.CD4 cell range: under 50.
• Herpes simplex viruses can cause oral herpes (cold sores) or genital herpes. These are fairly common infections, but if you have HIV, the outbreaks can be much more frequent and more severe. They can occur at any CD4 cell count.
• Malaria is common in the developing world. It is more common and more severe in people with HIV infection.
• Mycobacterium avium complex (MAC or MAI) is a bacterial infection that can cause recurring fevers, general sick feelings, problems with digestion, and serious weight loss. CD4 cell range: under 75.
• Pneumocystis pneumonia (PCP) is a fungal infection that can cause a fatal pneumonia. CD4 cell range: under 200. Unfortunately this is still a fairly common OI in people who have not been tested or treated for HIV.
• Toxoplasmosis (Toxo) is a protozoal infection of the brain. T-cell range: under 100.
• Tuberculosis (TB) is a bacterial infection that attacks the lungs, and can cause meningitis. CD4 cell range: Everyone with HIV who tests positive for exposure to TB should be treated.

PREVENTING OIs

Most of the germs that cause OIs are quite common, and you may already be carrying several of these infections. You can reduce the risk of new infections by keeping clean and avoiding known sources of the germs that cause OIs.

Even if you're infected with some OIs, you can take medications that will prevent the development of active disease. This is called prophylaxis. The best way to prevent OIs is to take strong ART.

TREATING OIs

For each OI, there are specific drugs, or combinations of drugs, that seem to work best. Refer to the Fact Sheets for each OI to learn more about how they are treated.

Strong antiretroviral drugs can allow a damaged immune system to recover and do a better job of fighting OIs.

Wha is AIDS?

WHAT DOES "AIDS" MEAN?

AIDS stands for Acquired Immune Deficiency Syndrome:

* Acquired means you can get infected with it;
* Immune Deficiency means a weakness in the body's system that fights diseases.
* Syndrome means a group of health problems that make up a disease.

AIDS is caused by a virus called HIV, the Human Immunodeficiency Virus. If you get infected with HIV, your body will try to fight the infection. It will make "antibodies," special molecules to fight HIV.

A blood test for HIV looks for these antibodies. If you have them in your blood, it means that you have HIV infection. People who have the HIV antibodies are called "HIV-Positive."

Being HIV-positive, or having HIV disease, is not the same as having AIDS. Many people are HIV-positive but don't get sick for many years. As HIV disease continues, it slowly wears down the immune system. Viruses, parasites, fungi and bacteria that usually don't cause any problems can make you very sick if your immune system is damaged. These are called "oppurtuniatic infections".

HOW DO YOU GET AIDS?

You don't actually "get" AIDS. You might get infected with HIV, and later you might develop AIDS. You can get infected with HIV from anyone who's infected, even if they don't look sick and even if they haven't tested HIV-positive yet. The blood, vaginal fluid, semen, and breast milk of people infected with HIV has enough of the virus in it to infect other people. Most people get the HIV virus by:

• having sex with an infected person
• sharing a needle (shooting drugs) with someone who's infected
• being born when their mother is infected, or drinking the breast milk of an infected woman

Getting a transfusion of infected blood used to be a way people got AIDS, but now the blood supply is screened very carefully and the risk is extremely low.

There are no documented cases of HIV being transmitted by tears or saliva, but it is possible to be infected with HIV through oral sex or in rare cases through deep kissing, especially if you have open sores in your mouth or bleeding gums.

WHAT HAPPENS IF I'M HIV POSITIVE?

You might not know if you get infected by HIV. Some people get fever, headache, sore muscles and joints, stomach ache, swollen lymph glands, or a skin rash for one or two weeks. Most people think it's the flu. Some people have no symptoms.

The virus will multiply in your body for a few weeks or even months before your immune system responds. During this time, you won't test positive for HIV, but you can infect other people.

When your immune system responds, it starts to make antibodies. When this happens, you will test positive for HIV.

After the first flu-like symptoms, some people with HIV stay healthy for ten years or longer. But during this time, HIV is damaging your immune system.

One way to measure the damage to your immune system is to count yourCD4 cells you have. These cells, also called "T-helper" cells, are an important part of the immune system. Healthy people have between 500 and 1,500 CD4 cells in a milliliter of blood.

Without treatment, your CD4 cell count will most likely go down. You might start having signs of HIV disease like fevers, night sweats, diarrhea, or swollen lymph nodes. If you have HIV disease, these problems will last more than a few days, and probably continue for several weeks.

HOW DO I KNOW IF I HAVE AIDS?

HIV disease becomes AIDS when your immune system is seriously damaged. If you have less than 200 CD4 cells or if your CD4 percentage is less than 14%, you have AIDS. If you get an opportunistic infection, you have AIDS. There is an "official" list of these opportunistic infections put out by the Centers for Disease Control (CDC). The most common ones are:

• PCP (Pneumocystis pneumonia), a lung infection;
• KS (Kaposi's sarcoma), a skin cancer;
• CMV (Cytomegalovirus), an infection that usually affects the eyes
• Candida, a fungal infection that can cause thrush (a white film in your mouth) or infections in your throat or vagina

AIDS-related diseases also includes serious weight loss, brain tumors, and other health problems. Without treatment, these opportunistic infections can kill you.

The official (technical) CDC definition of AIDS is available at http://www.cdc.gov/mmwr/preview/mmwrhtml/00018871.htm AIDS is different in every infected person. Some people die a few months after getting infected, while others live fairly normal lives for many years, even after they "officially" have AIDS. A few HIV-positive people stay healthy for many years even without taking antiretroviral medications (ARVs).

IS THERE A CURE FOR AIDS?

There is no cure for AIDS. There are drugs that can slow down the HIV virus, and slow down the damage to your immune system. There is no way to "clear" the HIV out of your body.

Other drugs can prevent or treat opportunistic infections (OIs). In most cases, these drugs work very well. The newer, stronger ARVs have also helped reduce the rates of most OIs. A few OIs, however, are still very difficult to treat.

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