All About HIV -- Questions & Answers
What kind of virus is HIV?
HIV is a retrovirus. That means it digs things like the 70s. Just seeing if you're paying attention. What this means is that a retrovirus does things in the reverse of the way all other life does. HIV also belongs to a subgroup of viruses called lentiviruses. The word lenti means slow in Latin. HIV is a virus that infects the immune system, the very system that fights infections.
The outside of the HIV virus is called the envelope and consists of lipids, fats, and glycoproteins. It is the glycoproteins play a critical role in how HIV attaches itself to the immune system.
Inside the envelope surrounding the HIV virus is it's genetic core. This is called RNA. Within the RNA are three enzymes; reverse transcriptase, protease, and integrase. These enzymes are what enables the HIV virus to reproduce itself.
How does HIV infect the blood?
HIV targets the specific type of white blood cell called T-helper cells. T-helper cells are like the generals of an army. T-helper cells command other immune cells to destroy infections and diseases. HIV kills the T-helper cells, and once these are killed off the rest of the immune system has no idea what to do.
Each cell in the body has areas called receptors. Think of it as a round hole. Unless the virus or other infectious agent has a round peg, they won't fit and the infections can't hurt that particular cell. HIV would therefore have a round peg that neatly fits into the T-helper cells round hole or receptor. These receptor sites are called CD4 receptor sites.
The body produces antibodies to fight the HIV virus. But this is ineffective because the HIV is hiding inside of the T-helper cell. Thus if the antibody does kill the HIV Virus, it also kills the T-helper cell. Remember these are like the generals commanding the body's immune system. So then you have either an a bunch of antibodies not knowing what to do because their are no T-helper cells telling them what to do or you have the antibodies attacking the HIV virus and killing not only the virus but the "general" as well. Remember the HIV virus lives inside of the T-helper cell.
So if the HIV virus wouldn't fit into the CD4 receptors HIV couldn't hurt you?
Correct, in fact there are a few people who have CD4 cells that are just differnt enough to keep the HIV from attaching itself. These people carry the HIV virus and can spread it but do not get infected.
Is there more than one type of HIV virus?
Yes there are two known types the first kind is called HIV type-1. It is commonly known as HIV-1. This accounts for the majority of AIDS cases in the world and virtually all the AIDS cases in the United States.
A second HIV virus is appropriately named HIV-2. It is most common in East Africa.
The SIV virus, which affects apes, is actually a form of HIV. But it was called SIV for political reasons. Researches generally agree and there is far less difference between HIV-2 and some kinds of SIV then between HIV-1 and HIV-2. And the same applies for types of SIV and HIV-1. So it is actually the same virus.
The two HIV viruses are somewhat different. For starters HIV-2 is not as widespread and when it infects someone it takes much longer to kill off T-helper cells. Because HIV-2 is located mostly in Africa it is not nearly as well studied as HIV-1.
For this part of my website when I say HIV it means HIV-1 unless I specifically address it as HIV-2
What do they mean by HIV cycle?
A virus is a bridge between things living and not living. By itself it cannot live, it must "hijack" a cell and use the cell's ability to reproduce to make copies of itself. One of the most perplexing thins is HIV the cycle of reproduction is reversed from almost all other kinds of life.
The first step is the HIV virus attaches itself to a CD4 receptor site of the host cell it is trying to take over or "hijack". HIV unlike most other viruses uses RNA not DNA for it's main genetic material.
So the HIV virus injects it's inner core of RNA and another enzyme called reverse transcriptase and this transforms the HIV RNA into HIV DNA.
This transformed HIV viral DNA then enters the host cell's nucleus where the host cell's DNA exists. So now in the nucleus of the cell you have HIV viral DNA and the cell's own DNA. The HIV viral DNA then weaves itself into the cell's own DNA and this forms what is called a pro-virus.
The host cell now has new DNA, which is actually part of its own DNA and part of HIV's DNA. This new cell now directs the cell to release more HIV into the body. An enzyme called protease plays a very important part in assembling new HIV particles.
This new HIV then goes on to other cells and repeats the cycle.
Drugs that treat HIV try to interfere with the protease or the reverse transcriptase. As you can see without these important enzymes HIV cannot reproduce.
Why has HIV become such a devastating disease?
Partly because it takes so long for symptoms to show up, it's hard to say just who has the disease. Because it is always fatal, it is hard to do proper testing on it. Political aspirations both for and against homosexuals have interfered with proper procedure. HIV in Africa is so hard hitting because the extreme poverty only makes the disease worse; because good nutrition and exercise are important to staying healthy and that is hard to come by in Africa. Lastly HIV spreads through sexual contact and IV drug use, behaviours that are hard to change, and are taboo, so people simply deny it.
Why is HIV so hard to fight compared to others viruses?
It is hard because HIV is attacking the very cells that are used to fight disease. Chicken Pox, Measles, Ebola, Lassa Fever, even a simple cold sore, do not target the immune system, so the immune system can fight those diseases off. Not always, but even with Ebola people can recover. But with HIV because it hides in the immune systems own cells if you kill the virus you kill the very cell that commands the immune system, leaving the body unable to fight another disease.
For example to put make an oversimplified example:
Let's say you get measles.
The immune system calls out the troops and after a battle, this is called "being sick" the immune system usually wins and you get better. Your body produces antibodies, fevers and such to do battle and beat the measles virus.
But let's say you have HIV. If you have HIV and you destroy the cell were HIV is living you will destroy the immune system. Now measles virus invades, can your body fight it off? No, because when you killed the HIV you killed the immune system, so you die of measles.
Now the above example is an vast oversimplification but this shows why people rarely die of HIV itself but rather of other illness that the immune system cannot fight off anymore.
It sounds like your immune system is constantly at war?
It not only sounds like it is, but in fact it is at war constantly. People rarely realize how beautiful the immune system is and how effective it is at keeping our bodies alive. It doesn't help that commercials make it sound like your immune system is weak and if you don't take a megaload of vitamins or any other product they are trying to sell you'll die. The immune system in America are not in any danger.
Is that the only reason why HIV is hard to fight?
No, HIV mutates very rapidly. Normally when a cell, any cell in your body divides and produces a new cell, the DNA in that cell has a very strict correction system. If the DNA isn't matching the cell's DNA, the cell will destroy it and start over.
But HIV is sloppy in its reproduction. It doesn't care if it produces a sloppy copy of itself. Eventually these bad copies look different enough from the original HIV virus that your body's antibodies don't recognize it as HIV.
Antibodies can actually "see" what virus they fight?
In away yes, but the system isn't fool proof. For instance the first time you are exposed to measles, you may get sick; if you do get the illness your body defeats the measles and you become well. From that point on the immune system knows what a measles virus "looks like" and as soon as one measles virus comes into your body it's killed right away thus never getting the chance to make you ill. This is why you don't get the measles twice. OK there are rare examples, where you do but those are not at all common.
So if the virus changes even a little bit the immune system can't recognize it.
No, it has to change significantly. For instance many viruses are close enough to fool the immune system.
Let's take cowpox for example. cowpox is a mild illness almost no one ever dies from. Smallpox is a horrible disease, which a lot of people have died from. From ancient times people saw that anyone who got cowpox almost never got smallpox or if they did get smallpox it was very mild. They didn't know why, all they knew is the diseases didn't co-exist. The reason is cowpox is similar enough to smallpox that if you have had cowpox, the body has produced antibodies to it. As soon as any smallpox shows up in your body, the immune system destroys it quickly. This is because the immune system thinks cowpox is smallpox. They are close enough so you don't get sick from smallpox.
So it doesn't have to be exact but close enough. This is why you don't get the flu from the flu shot. The body sees dead flu viruses and makes antibodies to that kind of flu. It can't recognize the difference between a live or dead virus. This again is a bit of an oversimplification but that is the general idea.
So HIV changes a lot?
Yes, it doesn't care how good a copy of its own DNA is. Here's an example, ever have sunburn? Ultraviolet light is DNA biggest enemy. It quickly destroys DNA. What happens is the skin's DNA is so damaged; the body quickly gives up and sheds all your skin so all that sloppy DNA won't reproduce. This is why you peel in sunburn.
This is why after lying in the sun you will get moles. These moles represent DNA in your skin that was not correctly coded by the DNA in your skin.
Is that were skin cancer comes in?
Yes, cancer is not a disease per say it is simply your body reproducing cells uncontrollably. These uncontrolled cells kill by overcrowding the normal cells out. Normally your body keeps cell reproduction in check.
So HIV mutates because it's sloppy?
Correct it doesn't care. Because HIV is a retrovirus, which means it uses RNA as it's genetic material and not DNA like almost every other life form, it's sloppy. This can be good as it may make the virus less dangerous, or it could just as easily make it worse. For instance if you're using a drug that fights HIV and the virus mutates, the drug might not kill this new mutation anymore. So this new mutation is free to reproduce.
Enough mutations will make it a different strain of HIV. The basic types are HIV-1 and HIV-2. Each main type of HIV is subdivided into further into groups.
What is HTLV-III?
In the 1970s when retroviruses were first discovered it was thought they caused cancers. In fact it was hoped that various types of HTLV viruses caused all cancers. This of course, turned out to be wrong. The viruses were interesting because they were retroviruses meaning they use RNA not DNA as their genetic material.
HTLV-1 virus causes Leukemia, which is a cancer of the white blood cells.
HTLV-2 seems to be related to Leukemia but its roles isn't definitely understood.
When scientists in the United States first found the virus that causes AIDS, they found it was a retrovirus, so they called it HTLV-III.
While this was happening scientists in France found the virus, in fact they found it first and called it LAV. After a lengthy court battle, to determine patent rights among other things, the scientific community realized HTLV-III and LAV were indeed the same virus. So they adopted the name HIV instead.
So HTLV-III and LAV are actually the same as HIV?
Yes HTLV-III and LAV are in fact HIV. While the HTLV viruses are related to HIV and both disable white blood cells the diseases are different. Leukemia is the uncontrolled growth of white blood cells, while HIV infections kills white blood cells.
HTLV viruses do not cause AIDS and HIV does not cause Leukemia.
Is HIV related to hepatitis?
No other than they are both viruses, they are not related. HIV affects gay men and IV drug users. Hepatitis also affects gay men and IV drug users. Therefore the two often go hand in hand but one has nothing to do from the other. For instance rimming is nearly 100% safe for risk of HIV but is an excellent way to get hepatitis-B. Because hepatitis-B is considered an STD the two often occur in the same patient.
Is HIV related to herpes?
No, but some herpes viruses are sexually transmitted so it's not uncommon to see people with HIV with herpes.
Additionally herpes depends on the immune system to keep it under control. For instance if you ever had a fever blister (also called a cold sore) you have had herpes. It's a virus called herpes-1. The immune system battles it off and you may never get another fever blister, but the virus still lives on. But because your immune system keeps the virus in check the fever blister heals but the virus hides and keeps on living. As you can see if you have a compromised immune system the herpes can easily take advantage and come back.
Is HIV related to cancer?
No, but because the first retroviruses were though to play a major role in cancer HIV began to first be studied by cancer researchers.
Does it matter what type of blood you are?
No all blood types A+, A-, B+, B-, AB+, AB-, O+ and O- contain immune cells with CD4 receptors, so it makes no difference.