• Whole Body 05.09.2009


    A few days ago it was announced that Scientists were able to isolate two antibodies responsible for resistance to the disease in an African patient. What does this mean, exactly?

    We will cover the new discovery in an article here in a couple of days, but first, what is AIDS and what causes it?

    Danger level: High

    What is it?

    AIDS is a disease caused by the human immunodeficiency virus (HIV), causing your body to be susceptible to infections.

    Who gets it?

    In the US, there are about 1.1 million people living with an HIV infection, with 250,000 more infected and not knowing about it. About 56,000 new infections occur each year.

    Around the world, more than 33 million people are infected, most of them in developing countries, mainly in Africa and Southeast Asia. More than 20 million people have died of AIDS worldwide.

    In terms of sex, most infections occur in men through homosexual contact, but the frequency of infection in women is rising (worldwide 50% of infected people are women, while in the US only 25%).

    Age-wise, most cases occur between the ages 25-49.

    There are certain risk factors which put you at a greater risk of getting infected. They include:

    1. Having unprotected sex with multiple partners – This means not using a condom every time. This is because the HIV virus is transmitted through semen.

    2. Having unprotected sex with someone who’s HIV-positive – Meaning they are infected with the virus.

    3. Having another sexually transmitted disease – These tend to raise your risk of acquiring HIV.

    4. Sharing needles during intravenous drug use – Since the virus can also be transmitted through the blood.

    What causes it?

    As mentioned above, AIDS is caused by an infection with a virus called HIV (or by its long name, human immunodeficiency virus), shown in this picture:

    hiv

    HIV – This is how the virus looks

    The process of infection with the virus goes like this:

    1. The virus is transmitted from person to person – As mentioned above, this can happen when having sex, when sharing needles while using IV drugs, when getting blood transfusions, and from a mother carrying the virus to her child during pregnancy (there are 15-40% chances of that happening).

    2. The virus sticks to cells in our body – Our immune system (the system that protects us from infections) has many types of cells. One of these types is called T cells or CD4 cells. The HIV virus recognizes these cells and sticks to them and then enters the cells.

    After entering the cells, the virus combines its own DNA with the human DNA in the cells. That’s actually the main problem with HIV infection – Once the DNA is inside our own DNA, the virus can rest there undetected, with no way of destroying it.

    3. The virus replicated itself within the cells -- This causes both a larger number of viruses in the body, and also destroys the cells the virus was in.

    Soon after infection, the virus replicates itself rapidly, but the body usually can fight this. Unfortunately, this fighting isn’t very effective, and leaves enough viruses to continue replicate in the body. During the following years, over 100 billion new viruses may be produced daily, and the body may remove them all.

    With time, the number of CD4 cells goes down. After a few years, the number of viruses in the body rises without the body being able to control it, while the number of CD4 cells goes further down. This condition is now called AIDS (while up until now it was called an HIV infection).

    Since CD4 cells are important in fighting many forms of infections, when their numbers go down, infections start appearing and without treatment usually lead to death.

    How does it feel?

    Infections with HIV have two phases along the way:

    1. Acute retroviral syndrome – Over 50% of people who get infected by HIV experience this. It happens 2-6 weeks after the infection, and may feel just like the flu, including fever, sore throat, rash, joint pain and headache. It lasts for several days to 3 weeks. A rash can also appear.

    Unfortunately, since all of this resembles the common cold or flu, usually infection by HIV isn’t suspected.

    2. AIDS – Once the number of CD4 cells goes down (usually after a few years), the infected person starts getting infected with opportunistic infections. These are infections that may reside in our body but that don’t do anything when our immune system is normal. When it’s damaged, like in this case, they start acting up.

    There are many infections that can occur here into which we won’t go into detail.

    There are, though, a few symptoms which are common in this stage:

    - Diarrhea

    - Weight loss

    - Fever

    - Cough and shortness of breath

    - Swollen lymph nodes

    This video should sum up what you’ve read above:

    How is it discovered?

    An infection with HIV is detected by a blood or saliva test called ELISA, in which the test tries to discover antibodies our body produces to fight against the virus. Antibodies are molecules created to fight infections.

    These tests aren’t very useful during the first 1-2 weeks of infection. At this time, a special test can detect the virus’ DNA. This time is called the "window period".

    How is it treated?

    Today there are drugs which can fight the virus. They don’t eliminate it from the body, which means it will still lie within our cells and continue replicating. But they can prevent opportunistic infections from occurring for many years, even indefinitely.

    During the lifetime of the disease, blood tests are taken to test the level of CD4 cells and the number of viruses in the blood. Usually, treatment doesn’t start until the disease progresses enough to justify it.

    What happens after treatment?

    When not treated, the life expectancy of someone suffering from AIDS ranges between 2-3 years. When treated, though, people can live for many years with the disease.


    The bottom line – How do I avoid it?

    1. Know the HIV state of your sexual partner – And don’t engage in unprotected sex unless you’re certain they are not infected.
    2. Use a latex or polyurethane condom every time you have sex – If you don’t know the HIV status of your partner. Avoid lambskin condoms, as they don’t protect from HIV. When using lubricants, only use water-based lubricants, as others (such as petroleum jelly) may cause the condom to break.
    3. Consider male circumcision – A large study in 2006 by the National Institutes of Health (NIH) showed that it significantly reduces your risk when having heterosexual intercourse.


    What next?

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    Posted by Roy @ 11:48 am

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