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World AIDS Day: Explaining HIV/AIDS

In the fight against AIDS, education is undoubtedly one of the most powerful tools we have. Yet even in the developed world, very few of us really understand what AIDS is, how it is transmitted or how it is treated. This article aims to demystify the seemingly complex science behind HIV/AIDS.

So what is HIV/AIDS?

We’ve heard it referred to as HIV, AIDS, HIV/AIDS… What’s the difference? Why two acronyms and what do they both mean?

HIV stands for “human immunodeficiency virus”. HIV is a viral species which, in itself, has relatively few direct effects on the human body. However, the few that it does have are devastating. The most prominent impact of HIV is its implications for immune system functioning. As the name suggests, HIV produces a condition which is characterised by progressive failure of the immune system.

The name of this condition? “Acquired immunodeficiency syndrome”, or AIDS. So HIV is the virus responsible for AIDS, and AIDS is the condition produced as a result of contracting HIV.

But hang on, why doesn’t the immune system just get rid of HIV before it can do its damage?

For those who are a little rusty on their 10th grade science, the immune system is basically the body’s defence against all the nasties that make us sick. Some bugs are relatively easy for our body to fight on its own; less severe infections like colds, for example, will usually go away of their own accord after a couple of weeks. Even where medication is used to combat illness, they often employ mechanisms similar to those naturally used by the immune system, and in this way they help us get well quicker.

HIV, like most viruses, is a tricky little bugger for the immune system to get a handle on. The reason that it’s so difficult to medicate viral infections is basically because they’re particularly good at hiding. Viruses sneak into the cells in your body before they begin to wreak havoc. They take control of the processes in your cell, using the cell’s own machinery to produce toxins, misfolded proteins or viral offspring. And because the virus is hidden away inside the cell, it’s difficult for the immune system to get rid of it without killing the whole cell. This As if that wasn’t bad enough, the structure of the virus itself is constantly changing, so that the markers the immune system has learnt to identify it by disappear before a defence can be mounted. This is the same reason there’s no cure for the common cold.

How do you “catch” HIV?

HIV can be transmitted in three ways. The first is through unprotected sex with an infected individual. It can also be transmitted from infected mother to foetus or breastfeeding infant. Exposure to contaminated blood, through an intravenous injection or blood transfusion, is the third mode of transmission for HIV.

What makes AIDS so bad?

When the immune system is suppressed, as in the case of AIDS, the body struggles to fight off even the weak infections and mutations it would usually have no trouble nipping in the bud. As a result, AIDS sufferers often fall victim to opportunistic infections including pneumonia, tuberculosis and thrush. They also develop various kinds of malignant tumours, including those symptomatic of cervical cancer, Kaposi’s sarcoma and non-Hodgkin’s lymphoma. As diseases go, AIDS is an all-access pass to just about every other sickness, and it’s these sicknesses which technically cause death in HIV/AIDS victims.

So you’re saying that contracting HIV is a death sentence…

Once upon a time maybe, but that’s not exactly true anymore. Thanks to the wonders of modern medicine, therapeutic medications are available for HIV/AIDS sufferers which can extend life expectancy by up to 35 years.

What are these miracle drugs and how do they work?

Treatment for HIV/AIDS is limited to what’s known as Highly Active Antiretroviral Therapy (or HAART for short). It is so-named because of the genus “retroviridae” of which HIV is a member, and involves a combination of drugs aimed at targeting different aspects of the disease and the viral infection which causes it.

HAART is a multiple drug regimen which includes the following:

  • Anti-infectives: these are medications which prevent opportunistic infections by killing the bacteria, fungus, virus or other microbe responsible
  • Anti-neoplastics: these medications prevent the uncontrolled cell growth which leads to the development of tumours
  • Nucleoside analogues: in very simple terms, these stop the virus using the cell’s machinery for its own means
  • Protease inhibitor: this prevents the assembly of any little baby viruses

There are also drugs under investigation which interfere with the ability of the virus to enter the cell in the first place.

Then why are so many people still dying?

Routine HAART, like a lot of other essential medicines, is unavailable in many third world countries. This is largely due to an inability to afford the medication and/or a lack of appropriate healthcare infrastructure to allow its distribution. Funding from a variety of sources, from governments to not-for-profit charities, will allow the better treatment of HIV/AIDS in the developing world.

 

Hannah Meiklejohn is an undergradute Biomedical Science Student at Bond University. Hannah has a great interest in biology and the science of diseases.

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