HIV is a virus that causes AIDS. The virus attacks and breaks down the body's immune system, so that the human body cannot fight off different diseases it normally would.

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.

AIDS stands for acquired immunodeficiency syndrome. An HIV-infected person receives a diagnosis of AIDS after developing one of the CDC-defined AIDS indicator illnesses. A positive HIV test does not mean that a person has AIDS. An HIV-positive person who has not had any serious illnesses also can receive an AIDS diagnosis on the basis of certain blood tests (CD4+ counts). A diagnosis of AIDS is made by a physician using certain clinical criteria (e.g., AIDS indicator illnesses).

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.

Infection with HIV can weaken the immune system to the point that it has difficulty fighting off certain infections. These types of infections are known as "opportunistic" infections because they take the opportunity a weakened immune system gives to cause illness. Many of the infections that cause problems or may be life-threatening for people with AIDS are usually controlled by a healthy immune system. The immune system of a person with AIDS is weakened to the point that medical intervention may be necessary to prevent or treat serious illness.

# The first line of protection that your body provides against infections is your skin. Your skin acts as a barrier, and the sweat glands in it get rid of waste. An injury such as a cut provides a way for germs to enter and infect your body. # The small hairs and fluids in your body openings also protect you. Nostrils have hair and mucous to keep out germs carried in the air.
# The saliva in your mouth contains enzymes that may destroy germs.
# Your eyelashes, eyelids, and tears protect your eyes.
# Your vagina, urethra (the tube you pee through), anus, and bowels (guts) are lined with mucous membranes, which protect them.

# Your body's health is protected by its immune system which is a network of chemicals, cells, tissues, and organs found throughout your body.These work together to protect you from germs.Your immune system can distinguish the difference between what belongs in your body and what does not belong.When your immune system detects something foreign, it tries ti destroy and remove it to keep you healthy.
# White blood cells (part of the immune system) called lymphocytes (B cells and T cells) protect the body from germs such as viruses, bacteria, parasites and fungi.
# The two main types of T-cells are T-4 (CD-4) cells and T-8 (CD-8) cells.
# When a germ or virus or bacterium enters your body the immune system recognises it as foreign to the body and potentially harmful. The T-4 cells begin the attack against infections by activating killer T-cells and antibody-producing B-cells while the T-8 (CD-8) cells end the immune response.
# Another way your immune system protects you is by the production of antibodies against what is not part of your body.The activated B-cells try to destroy any foreign particles not recognised as belonging to your body by creating antibodies to attack and destroy these foreign particles.This occurs when a virus such as HIV infects you.Your body recognises HIV as being foreign and potentially dangerous and therefore produces antibodies against it.Although effective at first, the antibodies do not eliminate the infection.
# Some HIV are killed but many more viruses will infect T-4 cells, the very same cells that are supposed to co-ordinate the defence against the virus.Infected T-4 (CD-4) cells become virus factories, which if activated, will produce viruses instead of triggering the production of more antibodies against it.

HIV is present in infectious quantities in:

* Blood and blood products
* Semen and possibly pre-cum
* Vaginal and cervical secretions
* Breast milk.

During invasive surgical procedures health care workers may also come into contact with the following body fluids, which contain significant amounts of HIV:

* Amniotic fluid
* Cerebrospinal fluid
* Synovial fluid around bone joints

In HIV+ persons, HIV is either not present or present in very minute amounts in:

* Saliva (only found in minute amounts in a small number of people),
* Tears and Blister fluid
* Urine, Faeces, Vomit or Sweat

Finding a small amount of HIV in a body fluid does not necessarily mean that HIV can be transmitted by that body fluid. Contact with saliva, tears, or sweat has never been shown to result in transmission of HIV.

You are at high risk

* if you have sex without condoms
* if you have many sex partners and do not use condoms
* if your sex partner(s) has/have sex with other persons without using condoms.
* if you have shared unsterilised needles for intravenous drug use
* if you have sex with only one partner who is HIV positive

The main route of HIV transmission is through:

* Unprotected sexual contact with an infected person
* By sharing needles with an infected person and
* From an infected mother to child during pregnancy, during birth or shortly after birth while breastfeeding
For HIV transmission to occur the following criteria must be met:
1. HIV must be present
2. There must be a sufficient quantity of HIV present
3. It must go into the bloodstream
Note: HIV is most concentrated in blood.

A condom is the only barrier that is now available to prevent the transmission of HIV and other sexually transmitted infections, during sexual intercourse.

# It is possible to become infected with HIV through oral sex, however the risk of becoming infected in this way is lower than for unprotected sexual intercourse with a man or woman. # When giving oral sex to a man (sucking or licking a man's penis) a person could become infected with HIV if infected semen gets into any cuts, sores or receding gums they might have in their mouth. # Giving oral sex to a woman (licking a woman's clitoris or vagina) is considered relatively low risk. Transmission could take place if infected fluids from a woman get into the mouth of her partner. The likelihood of infection occurring might be increased if there is menstrual blood involved or if the woman is infected with another STI, which causes breaks in the skin, therefore increasing exposure to blood.

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). Oral sex: 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. 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.

# Deep or open-mouthed kissing is a very low risk activity in terms of HIV transmission. # There has been only one documented case of someone becoming infected with HIV through kissing; a result of exposure to infected blood during open-mouthed kissing. # If you or your partner have open wounds in your mouth, you should avoid kissing until the wound has healed.

# Whilst research suggests that high concentrations of HIV can sometimes be detected in pre-cum, it is difficult to judge whether HIV is present in sufficient quantities for infection to occur. To guard against the possibility of infection with HIV or any other STI it is best to practise safer sex i.e. sex with a condom from start to finish. # Note that if there is an open wound on the penis then the risk for transmission is greatly increased.

# No. This is because HIV is not an air-borne, water-borne or food-borne virus. # Therefore ordinary social contact such as kissing, shaking hands, coughing and sharing cutlery does not result in the virus being passed from one person to another.

# When visiting the barber there is no risk of infection unless the skin is cut (which may occur if the barber accidentally cuts you) and if there is a transfer of infected blood. # If the instruments are contaminated with infected blood and are not sterilised between clients there is a risk of HIV transmission. # To reduce the risk of blood-borne infections such as hepatitis and HIV ensure that the razor/instruments used are new or have been properly sterilised. # However, people who carry out body piercing, tattoos, or hair-dressing should follow procedures called "universal precautions", which are designed to prevent the transmission of blood-borne infections such as HIV and hepatitis B.

# HIV is transmitted sexually regardless of your sexual preference. Note however, that world wide there is a higher prevalence of the virus in certain groups because of their sexual practices and therefore having unsafe sex with someone from one of these groups places you at a higher risk of contracting the virus.
# Men who have sex with men, commercial sex workers, and people who have a sexually transmitted infection are examples of such groups.
# By following safe sexual practices (using a condom every time) you can reduce your chances of becoming infected.

# Generally the fragile nature of the virus prevents it from surviving for a substantial amount of time in the open air. The length of time HIV can survive outside the body is dependent on the amount of HIV present in the body fluid and the conditions the fluid is subjected to.
# Note that HIV is fragile and many common substances such as hot liquid, soap, bleach, alcohol, and the gastric juices found within your stomach can destroy the virus.
# The only studies on the survival of HIV outside the body have been conducted in the laboratory under controlled scientific conditions. These studies found HIV is not affected by extreme cold, but it is inactivated by heat and is destroyed after 30 minutes at 60oC.
# Scientific studies have found that HIV can sometimes survive in dried blood at room temperature for up to six days. It is extremely difficult to assess exactly the length of survival of HIV outside the body in a non- laboratory setting.

# The symptoms of initial HIV infection are not very specific. Initial symptoms include a dry cough, shortness of breath and a flu-like illness. # During this very early period of infection only a small minority of people experience symptoms, which are serious enough to require a doctor's attention. # During this stage, which is also called acute infection, the virus multiplies rapidly. You might test negative for HIV antibodies during this stage, but you can still pass HIV on to someone else. This is called the window period of roughly three months from the time of infection to the time when you will show antibodies against HIV. HIV antibodies begin to show in an infected person's blood when they seroconvert.

The "window period" is the time it takes for a person who has been infected with HIV to seroconvert (test positive) for HIV antibodies. The Centers for Disease Control (CDC) says about the window period: "Antibodies generally appear within three months after infection with HIV, but may take up to six months in some persons." The three month window period is normal for most of the population. Many people will have detectable antibodies in three or four weeks. Very, very rarely (i.e., only a few cases ever), a person could take six months to produce antibodies.