I am pretty sure that everyone has heard about HIV and AIDS, either at school or in some piece of news, and I am pretty sure too that most people might still have questions about HIV and why it is so dangerous. What makes HIV so different from the viruses that give us a cold every winter? How is HIV transmitted? Can we cure HIV? What is the difference between HIV and AIDS? … Just give me a moment, and I can answer these questions, let me begin with the basics, and then we will get into more detail.
First things first, what is a virus?
As we all know, HIV is the acronym for human immunodeficiency virus. But…, what is a virus? A virus is a small parasite made of DNA or RNA that cannot reproduce by itself. Unlike human cells, plant cells or even some bacterial cells, viruses always need to infect another organism to reproduce themselves.
These small parasites get inside the cells and use the energy reservoirs to make multiple copies of themselves, however, not all of them act the exact same way. We can roughly divide the viruses in two very broad categories: those with a lytic cycle and those with a lysogenic cycle.
What’s the difference between the different viral cycles?
Some viruses have a very short life cycle, where they enter the cells, make multiple copies of themselves using the cellular machinery and eventually kill the cell, releasing new viruses which can, in turn, infect new cells. These viruses have a lytic cycle.
Other viruses have a slightly different life-cycle. They first enter the cells, but instead of immediately start making copies of themselves, they integrate their DNA or RNA into the cells’ nucleus and stay dormant. The cell keeps on growing and reproducing, and the DNA from the virus is transmitted to all daughter cells. This is called a lysogenic cycle.
When the conditions change, the viral DNA from the lysogenic cycle is detached from the nucleus and starts to reproduce itself until it kills the cell letting out multiple viral copies, following a lytic cycle.
What makes HIV so dangerous?
The HIV is one of the best examples of a lysogenic virus. It can be dormant within the cells for years, before it actually manifests itself, causing the symptoms known as acquired immune deficiency syndrome (AIDS).
Viruses attack very specific cells, just like koalas feed on eucalyptus and pandas love eating bamboo, each virus has a favourite cell to infect. HIV infects T lymphocytes, which unfortunately for us, are the main component of the immune system.
While the HIV is integrated within the nucleus of our T lymphocytes, there are no symptoms. However, once the virus starts to replicate, it ends up killing the T cells, damaging the immune system and causing AIDS.
How is HIV transmitted?
Before you get anxious about getting infected with HIV, remember that HIV is not a common cold. So don’t worry too much! Luckily for everyone, you cannot get infected by touching someone who’s sick, or by getting bitten by an insect.
You can only get HIV if you have unprotected sex, if you get a blood transfusion from someone who has HIV, if you share injecting equipment or if your mother had HIV. So, just be careful and try to avoid these situations, and you will have nothing to worry about.
Is there a cure for HIV?
As much as I would love to say yes, I am afraid there’s currently no cure for HIV. The virus is normally hidden within our own T-cells and we cannot kill them. There are however medications (antiretrovirals) that help relieve the symptoms, protecting the people infected with HIV from developing AIDS, but not curing them.
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