HIV VIRUS: Detailed explanation
The human immunodeficiency virus (HIV) is a lentivirus (a subgroup
of retrovirus) that causes HIV infection and over time acquired
immunodeficiency syndrome (AIDS). AIDS is a condition in humans in which
progressive failure of the immune system allows life-threatening opportunistic
infections and cancers to thrive. Without treatment, average survival time
after infection with HIV is estimated to be 9 to 11 years, depending on the HIV
subtype. Infection with HIV occurs by the transfer of blood, semen, vaginal
fluid, pre-ejaculate, or breast milk. Within these bodily fluids, HIV is present
as both free virus particles and virus within infected immune cells.
HIV is different in structure from other retroviruses. It is roughly
spherical with a diameter of about 120 nm, around 60 times smaller than
a red blood cell. It is composed of two copies of positive single-
stranded RNA that codes for the virus's nine genes enclosed by a
conical capsid composed of 2,000 copies of the viral protein p24. The single-
stranded RNA is tightly bound to nucleocapsid proteins, p7, and enzymes
needed for the development of the virion such as reverse
transcriptase, proteases ,ribonuclease and integrase. A matrix composed of
the viral protein p17 surrounds the capsid ensuring the integrity of the
Retroviruses are a unique class of single-stranded ribonucleic acid (RNA)
containing viruses, which replicate their genome through a double-stranded viral
deoxyribonucleic acid (DNA) intermediate in the nucleus of the host cell. This is in
contrast to all other RNA-containing viruses that replicate their genomes through
double-stranded RNA intermediates almost always in the cytoplasm of host cells. Most
retroviruses contain an RNA genome of 9 to 10 kilobases in length, which encodes a
minimum of three genes required for replication. These are referred to
as gag (structural proteins of the virus), pol (enzymes involved in replication),
and env (envelope glycoproteins required for the virus to attach to a receptor of a new
host cell). Human immunodeficiency virus (HIV), which
causes acquired immunodeficiency syndrome (AIDS),
belongs to a subclass of retroviruses, the lentiviruses, which encode additional viral
genes that permit the virus
to grow in nondividing cells, such as white blood cells.
The remarkable replication pathway of retroviruses requires that once the virus enters the host
cell, a viral pol gene–encoded enzymecalled reverse transcriptase (RT), which is packaged in
virus particles, reverse transcribes the single-stranded RNA genome into a double-stranded DNA.
This DNA intermediate migrates to the nucleus of the cell where it is integrated into the host
cell genome. This process is catalyzed by another viral enzyme.
called integrase (IN). Since there is no matching sequence between the
viral DNA and the host genomic DNA,
sites of insertion are mostly randomly distributed.
Because the viral DNA is now part of the cellular chromosome ,
it is duplicated whenever the cell's own DNA is replicated.
Prevention: Methods and measures
There's no vaccine to prevent HIV infection and no cure for AIDS. But it's
possible to protect yourself and others from infection. That means educating
yourself about HIV and avoiding any behavior that allows HIV-infected fluids —
blood, semen, vaginal secretions and breast milk — into your body.
Pre-exposure prophylaxis (PrEP) is an HIV prevention option for people who
don’t have HIV but who are at high risk of becoming infected with HIV. PrEP
involves taking a specific HIV medicine every day. PrEP should always be
combined with other prevention options, such as condoms
In the United States, HIV is spread mainly by having sex or sharing injection
drug equipment, such as needles, with someone who has HIV.
To reduce your risk of HIV infection, use condoms correctly every time you
have vaginal, oral, or anal sex. Don’t inject drugs. If you do, use only sterile
injection equipment and water and never share your equipment with others
Use a new condom every time you have sex. If you don't know the HIV
status of your partner, use a new condom every time you have anal or vaginal
sex. Women can use a female condom.
Use only water-based lubricants. Oil-based lubricants can weaken condoms
and cause them to break. During oral sex use a nonlubricated, cut-open
condom or a dental dam — a piece of medical-grade latex.
Consider the drug Truvada. Use of the combination drug emtricitabine-
tenofovir (Truvada) can reduce the risk of sexually transmitted HIV infection
in those who are at high risk. Truvada is also used as an HIV treatment along
with other medications.
When used to help prevent HIV infection, Truvada is only appropriate if your
doctor is certain you don't already have an HIV infection. Your doctor should
also test for hepatitis B infection. If you have hepatitis B, your doctor should
test your kidney function before prescribing Truvada.
Truvada must be taken daily, exactly as prescribed. Truvada should only be
used along with other prevention strategies, such as condom use every time
you have sex, as it doesn't protect against other sexually transmitted
infections, and it can't provide complete protection against HIV transmission.
If you're interested in Truvada, talk with your doctor about the potential risks
and benefits of the drug.
Tell your sexual partners if you have HIV. It's important to tell anyone with whom you've had
sex that you're HIV-positive. Your partners need to be tested and to receive medical care if they
have the virus. They also need to know their HIV status so that they don't infect others.
Use a clean needle. If you use a needle to inject drugs, make sure it's sterile and don't share it.
Take advantage of needle-exchange programs in your community and consider seeking help for
your drug use.
If you're pregnant, get medical care right away. If you're HIV-positive, you may pass the
infection to your baby. But if you receive treatment during pregnancy, you can cut your baby's
Consider male circumcision. There's evidence that male circumcision can help reduce a man's
risk of acquiring HIV.
Possible cure for HIV/minimizing its
There are many treatments now that can help people with HIV. As a result,
many people with HIV are living much longer and healthier lives than before.
Currently, medicines can slow the growth of the virus or stop it from making
copies of itself. Although these drugs don't eliminate the virus from the body,
they keep the amount of virus in the blood low. The amount of virus in the
blood is called the viral load, and it can be measured by a test.
There are several types of anti-HIV drugs. Each type attacks the virus in its
own way. It's similar to the way the military plans an attack using the
different strengths of the Army, Navy, Air Force, and Marines.
. How are the drugs taken?
Most people who are getting treated for HIV take 3 or more drugs. This is called combination
therapy or "the cocktail." (It also has a longer name: Anti-Retroviral Therapy (ART) or Highly
Active Anti-Retroviral Therapy (HAART.) Combination therapy is the most effective treatment for
People who are HIV positive need to work closely with their doctors to decide when to start
treatment and which drugs to take.
Is it hard to take these drugs?
HIV medicines have become much easier to take in recent years. Some newer drug combinations
package 3 separate medicines into only 1 pill, taken once a day, with minimal side effects. For
the great majority of people, HIV medicines are tolerable and effective, and let people infected
with HIV live longer and healthier lives. Still, for some people taking medicine for HIV can be
complicated. Some of the drugs are difficult to take, can cause serious side effects, and don't
work for everyone. Even when a drug does help a particular person, it may become less
effective over time or stop working altogether.
Once on medications, patients must work with their health care providers to monitor how well
the drugs are working, deal with side effects, and decide what to do if the drugs stop working.
The good news is that experts are learning more about the virus and creating new treatments
for HIV, making it easier to take these medicines.
Do you have to be treated for the rest of your life?
Right now, there is no cure for HIV infection or AIDS. So, once you start treatment, you
have to continue to be sure the virus doesn't multiply out of control.
Are there long-term effects?
Over time, HIV-positive people may experience symptoms from the infection and side
effects from their anti-HIV drugs. Sometimes it is not clear whether the virus or the
medications are causing the problems.
One long-term effect that some people experience is a change in the way their bodies
handle fats and sugars. In some cases, these changes can raise the person's risk for
heart disease and diabetes. Some people have experienced visible changes in body
shape and appearance, including increased fat in the belly, neck, shoulders, breasts, or
face--or loss of fat in the face, legs, or arms.
Experts aren't sure whether these changes in body fat are due to HIV itself, or to the
anti-HIV drugs. There are no proven cures at this time, but there are steps people can
take to reduce the effects. These include changes in diet, exercise, medication, even
plastic surgery. For more information, go to Body Shape Changes in the Just Diagnosed
Over time, HIV infects and kills off immune cells. This leaves the body unable to fight
certain kinds of serious, sometimes deadly, infections. These are called opportunistic
infections because they take the opportunity to attack when a person's immune system
is weak. Having HIV can also increase the risk of getting certain cancers. They may
reach the advanced stage of infection called AIDS. For more information, go to
Infections and Cancers in the Just Diagnosed section.
.Is HIV always fatal?
Most people who do not receive treatment for HIV will eventually (over years) become ill
and die of complications of HIV infection. With treatment (called antiretroviral therapy),
though, most people with HIV infection can lead long and healthy lives; this is especially
true if they start HIV treatment when their immune system is still relatively strong.
What is HIV and hepatitis C coinfection?
Coinfection is a medical term meaning that you have two or more infections in your
body at the same time. If you have HIV and hepatitis C coinfection, then you have both
HIV and hepatitis C.
HIV is spread mainly through the blood and through sexual contact. It can wear down
your body's immune system, making it hard for your body to fight off dangerous
Hepatitis C is a disease that affects your liver. It is caused by a virus called the
hepatitis C virus and it is spread mainly by blood, but sometimes by sex. In many
cases, if you have hepatitis C, it never goes away. Over time, it can cause other health
problems, such as cirrhosis (or scarring of the liver) and liver cancer.
How does being coinfected affect your health?
HIV affects your whole immune system, including your body's ability to fight off
hepatitis C. As a result, you might develop a case of hepatitis C that is worse than
it would have been if you didn't have HIV.
If you have both diseases, your treatments can be affected, too. Some HIV
treatments can damage your liver, so your doctor may want you to try other
treatments. And if you have HIV, you might experience worse side effects or other
problems when you take certain medicines for hepatitis C.
These illnesses are very different, so it is important that you learn about both of
them. For more information, go to HIV and Hepatitis C Coinfection in the Just
Respect your body.
Eat healthy food, drink plenty of water, and get restful sleep. Try to exercise every day.
Do not drink alcohol.
Alcohol weakens your immune system and damages your liver even when you are
healthy. Drinking alcohol when you have HIV and hepatitis C makes the damage much
worse. Remember, there is no "safe" amount of alcohol you can drink when you have
HIV and hepatitis C. It doesn't help to switch from "hard" liquor to beer, cider, or wine.
If you need help to stop drinking alcohol, talk to your doctor.
Don't have unsafe sex.
Practicing safer sex is the best way to keep other people from getting HIV. Hepatitis C
isn't spread as easily as HIV by having sex. But you can still give hepatitis C to someone
you have sex with, if you're not careful. If you have sex, the best thing to do is
practice safer sex all the time. To do so, always use a condom, dental dam, or other
latex barrier and avoid "rough sex" or other activities that might cause bleeding.
. Do not use injection drugs.
Remember that drugs like heroin, cocaine, and speed (crystal, meth, crank, Tina) can make your
illness worse. The best thing to do, especially if you have hepatitis C or HIV, is not use drugs. If you
use drugs, make sure that your needle and works are clean (or brand new) every time and never share
them with anyone else. Sharing needles or works to inject drugs is one of the easiest ways to spread
hepatitis C and HIV. By sharing needles or works, you can even spread both of these viruses at the
same time. Talk to your doctor about getting help to stop.
Talk with your doctor if you can't stop drinking, taking drugs, or having unsafe sex. Ask your doctor
where you can get support in your area. If you already get services from an AIDS organization, ask
about support groups for people who have HIV and hepatitis C.
HIV and hepatitis C are two of the most important medical issues today. Try to educate yourself about
them. Ask your doctor if you need help making sense of anything you hear on the news or read in the
Excellent treatments are available for both HIV and hepatitis C, and more medications for hepatitis C
are expected soon. Treatment for HIV controls the HIV virus and protects the immune system but does
not cure the infection. Treatment for hepatitis C can cure the infection. Treatment for these two
infections is important for the health of the coinfected individual, and receiving treatment also
reduces the chance of transmitting infection to others.
Follow your doctor's advice.
Follow all instructions you get from your doctor. Try to keep all of your appointments.
Call your doctor immediately if you have any problems.
Get vaccinated against other hepatitis viruses.
Having hepatitis C does not mean that you can't get other kinds of hepatitis. Talk to
your doctor about getting vaccinations (or shots) to protect you from hepatitis A and B.
Avoid taking medicines, supplements or natural or herbal remedies that might
cause more damage to your liver.
Even ordinary pain relievers can cause liver problems in some people. Check with your
doctor before you take any natural or herbal remedy, supplement, prescription, or
non-prescription medicine. And, make sure your doctor knows all the medicines you
are taking for HIV and hepatitis C.