What is HIV?

HIV is a virus. A virus is a very small living thing that can reproduce and spread. Viruses cannot survive on their own - they need an animal or person to live within. When a virus finds a home within a living organism, it replicates (begins to make copies of itself) within this organism's cells. A virus can damage the cells it replicates in, which is one of the things that can make the infected creature become ill.

The immune system is a group of cells and organs which protect your body by fighting viruses and infections. In humans, the body's immune system usually finds and kills viruses fairly quickly.

People can become infected with HIV from other people who already have it, and, when they are infected they can then go on to infect other people. Basically, this is how HIV is spread.

HIV stands for the 'Human Immuno-deficiency Virus'. Someone who is infected with HIV is said to be 'HIV+' or 'HIV positive'.

Why is HIV so dangerous?

Different viruses attack different parts of the body - some may attack the skin, others the lungs, and so on. The common cold is caused by a virus. What makes HIV so dangerous is that it attacks the immune system itself, the very thing that would normally get rid of a virus. It particularly attacks a special type of immune-system cell - without these, the immune system's ability to fight off the virus is weakened, and HIV spreads throughout the body.

This process isn't visible, and there isn't any way to tell just by looking if someone's been infected by HIV. But a blood test can detect the virus in the blood from about three months after infection first occurred. A person infected with HIV may look and feel perfectly well for many years and they may not even know that they are infected. Then, as the person's immune system weakens they become increasingly vulnerable to illnesses, many of which they would normally fight off easily.

Where does HIV come from?

The first recognised cases of AIDS occurred in the USA in the early 1980s. A number of gay men in New York and San Francisco suddenly began to develop rare opportunistic infections and cancers that seemed stubbornly resistant to any treatment. At this time, AIDS did not yet have a name, but it quickly became obvious that all the men were suffering from a common syndrome. The discovery of HIV, the Human Immunodeficiency Virus that causes AIDS was made soon after. While some were initially resistant to the connection (and indeed remain so today), there is now clear evidence to prove that HIV does cause AIDS.

HIV is a lentivirus, and like all viruses of this type, it attacks the immune system. Lentiviruses are in turn part of a larger group of viruses known as retroviruses. The name 'lentivirus' literally means 'slow virus' because they take such a long time to produce any adverse effects in the body. They have been found in a number of different animals, including cats, sheep, horses and cattle. However, the most interesting lentivirus in terms of the investigation into the origins of HIV is the Simian Immunodeficiency Virus (SIV) that affects monkeys.

In February 1999 a group of researches from the University of Alabama announced that they have found a type of SIV virsu that was almost identical to HIV. Their final findings were published two years later in Nature magazine. In this article, they concluded that wild chimps had been infected simultaneously with two different simian immunodeficiency viruses which had "viral sex" to form a third virus that could be passed on to other chimps and, more significantly, was capable of infecting humans and causing AIDS.

There are several theories about how humans could have contracted the virus.

How long can HIV live outside the human body?

Scientists and medical authorities agree that HIV does not survive well outside the body, making the possibility of environmental transmission remote. HIV is found in varying concentrations or amounts in blood, semen, vaginal fluid, breast milk, saliva, and tears. To obtain data on the survival of HIV, laboratory studies have required the use of artificially high concentrations of laboratory-grown virus. Although these unnatural concentrations of HIV can be kept alive for days or even weeks under precisely controlled and limited laboratory conditions, CDC studies have shown that drying of even these high concentrations of HIV reduces the amount of infectious virus by 90 to 99 percent within several hours. Since the HIV concentrations used in laboratory studies are much higher than those actually found in blood or other specimens, drying of HIV-infected human blood or other body fluids reduces the theoretical risk of environmental transmission to that which has been observed - essentially zero. Incorrect interpretations of conclusions drawn from laboratory studies have in some instances caused unnecessary alarm.

Results from laboratory studies should not be used to assess specific personal risk of infection because (1) the amount of virus studied is not found in human specimens or elsewhere in nature, and (2) no one has been identified as infected with HIV due to contact with an environmental surface. Additionally, HIV is unable to reproduce outside its living host (unlike many bacteria or fungi, which may do so under suitable conditions), except under laboratory conditions; therefore, it does not spread or maintain infectiousness outside its host (CDC: National Center for HIV, STD and TB Prevention Divisions of HIV/AIDS Prevention

Can anything 'create' HIV?

No. Unprotected sex, for example, is only risky if one partner is infected with the virus. If your partner is not carrying HIV, then no type of sex or sexual activity between you is going to cause you to become infected - you can't 'create' HIV by having unprotected anal sex, for example.

You also can't become infected through masturbation - nothing you do on your own is going to give you HIV - it can only be transmitted from another person who already has the virus.

What are the symptoms of HIV-infection?

Many of those infected with HIV have no problems for several years.

However, some may show

What if I test HIV-positive?

If you test positive, the sooner you take steps to protect your health, the better. Early medical treatment, a healthy lifestyle and a positive attitude can help you stay well. Prompt medical care may delay the onset of AIDS and prevent some life-threatening conditions. It is important to know that a positive HIV test should always be confirmed, to be sure that it is a true positive. If your test result is positive, there are a number of important steps you can take immediately to protect your health:

What is AIDS?

A damaged immune system is not only vulnerable to the HIV attack that first damaged it, but also to the attacks of other infections - it won't always have the strength anymore to fight off things that wouldn't have bothered it before.

As time goes by, a person who has been infected with HIV is likely to become ill more and more often until, usually several years after infection, they become ill with one of a number of particularly severe illnesses. It is at this point that they are said to have AIDS - when they first become seriously ill, or when the number of immune system cells left in the body drops below a particular point. Different countries have slightly different ways of defining the point that a person is said to have AIDS rather than HIV.

AIDS (Acquired Immune Deficiency Syndrome) is an extremely serious condition, and at this stage the body has very little defence against any sort of infection.

How long does HIV take to become AIDS??

Without drug treatment, HIV usually progresses to AIDS in an average of ten years. This average, though, is based on a person having a reasonable diet. Someone in a resource-poor area who might not be adequately nourished may well progress to AIDS and death much more rapidly.

HIV antiretroviral medication can prolong the time between HIV infection and the onset of AIDS. New medicines are being developed, and theoretically, someone with HIV can live for a long time before it becomes AIDS. These medicines, however, are not available in many poor countries around the world, and millions of people who cannot afford or access medication continue to die.

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.

How does HIV infection lead to AIDS?

HIV destroys a certain kind of blood cells--CD4+ T cells (helper cells)--which are crucial to the normal function of the human immune system. In fact, loss of these cells in people with HIV is an extremely powerful predictor of the development of AIDS. Studies of thousands of people have revealed that most people infected with HIV carry the virus for years before enough damage is done to the immune system for AIDS to develop.

However, recently developed sensitive tests have shown a strong connection between the amount of HIV in the blood and the decline in CD4+ T cell numbers and the development of AIDS. Reducing the amount of virus in the body with anti-HIV drugs can slow this immune destruction.

Is there a vaccine for AIDS?

Worryingly, surveys show that many people think that there's a 'cure' for AIDS - which makes them feel safer, and perhaps take risks that they otherwise shouldn't. These people are wrong, though - there is still no cure for AIDS.

There is antiretroviral medication which slows the progression from HIV to AIDS, and which can keep some people healthy for many years. In some cases, the antiretroviral medication seems to stop working after a number of years, in other cases people can recover from AIDS and live with HIV for decades. But they have to take powerful medication every day of their lives, sometimes with very unpleasant side-effects.

But there is still no way to cure HIV, and at the moment the only way to remain safe is not to become infected.

What do the therapies against HIV/AIDS do?

Antiviral therapy means treating viral infections like HIV with drugs. The drugs do not kill the virus. However, they slow down the growth of the virus. When the virus is slowed down, so is HIV disease. Because HIV is a retrovirus, these drugs are sometimes called antiretroviral therapy.

There also is an option of so-called "alternative" or "complementary" therapies - health treatment that does not fit into standard western medical practice. These include:

Why does it take so long to find a vaccine agaist AIDS?

Opportunistic retroviruses, such as HIV are capable of rapid mutation. Vaccines usually act on a certain property of a virus, but no vaccine can capture a single property of a virus that undergoes dramatic changes so rapidly. There have been cases, when a person would be infected with one HI-virus and after several years thousands of mutated viri would be found in the blood. That is why until now there no vaccine for HIV/AIDS has yet been found.

First traces of HIV

During the last few years it has become possible not only to determine whether HIV is present in a blood or plasma sample, but also to determine the particular subtype of the virus. Studying the subtype of virus of some of the earliest known instances of HIV infection can help to provide clues about the time it first appeared in humans and its subsequent evolution.

Three of the earliest known instances of HIV infection are as follows:

1. A plasma sample taken in 1959 from an adult male living in what is now the Democratic Republic of Congo.

2. HIV found in tissue samples from an American teenager who died in St. Louis in 1969.

3. HIV found in tissue samples from a Norwegian sailor who died around 1976.  

A 1998 analysis of the plasma sample from 1959 has suggested 7 that HIV-1 was introduced into humans around the 1940s or the early 1950s; much earlier than previously thought. Other scientists have dated the sample to an even earlier period - perhaps as far back as the end of the 19th century.

In January 2000 however, the results of a new study presented at the 7th Conference on Retroviruses and Opportunistic Infections, suggested that the first case of HIV-1 infection occurred around 1930 in West Africa . The study was carried out by Dr Bette Korber of the Los Alamos National Laboratory. The estimate of 1930 (which does have a 15 year margin of error) was based on a complicated computer model of HIV's evolution. If accurate, it means that HIV was in existence before many scenarios (such as the OPV and conspiracy theories) suggest.