What is AIDS?
AIDS stands for Acquired Immunodeficiency Syndrome. It is a kind of disease caused by
the virus HIV. When a person gets AIDS, his immune system is attacked and its T4 lymphocyte
cell count drops to less than 200. For a normal person, his T4 cell count is around 800-1200 per
1ul of blood. Therefore, the person’s immune system is weakened and loses its natural ability to
fight diseases. As a result, the infected person will have a variety of diseases and finally die.
A person will not have AIDS once the HIV infects him. He can still be very healthy and
have no symptoms of being infected. However, he can spread the infection to other people
silently and is called ‘carrier’.
Not all the people who are infected will develop AIDS in the same pace. It is estimated that
about 30% or so will develop AIDS within 5 years of infection. About 50% of infected people
will go on to develop AIDS within 8 to 10 years.
The starting of AIDS was thought from the Central Africa. Nowadays, the number of people
getting the HIV infection around the world is increasing.
Something about HIV
HIV (Human Immunodeficiency Virus) is a kind of viruses. It is an RNA virus and known
as retroviruses. It is a very weak virus, which will die soon outside the human body and can only
survive in body fluids. It is transmitted by blood or semen and causes AIDS. It replicates inside
the T4 lymphocytes.
HIV has a cone-shaped capsid, which is made of a helical spiral of capsomeres. The capsid
is enclosed in a protein shell, which is anchored in a lipid bilayer, or envelope, obtained from the
cell surface membrane of the previous host cell. This envelope contains viral glycoproteins,
which bind specifically to helper T-cell receptors, enabling the virus to enter its host. In the virus,
there is an enzyme called reverse transcriptase, which converts single stranded RNA into
double-stranded DNA copies.
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How HIV attacks our body?
The virus mainly attacks the T4 lymphocytes. It firstly binds to receptors on the surface of
the T4 lymphocytes. It then enters the lymphocytes by endocytosis and injects its viral RNA into
the cell. The reverse transcritase in the virus copies the viral RNA into DNA. The viral DNA
enters the lymphocyte nucleus and becomes a permanent part of the lymphocyte’s DNA as an
infected individual.
The viral DNA spreads its viral genes when the T4 lymphocyte divides, which is a rapid
process.
The viral DNA may remain dormant for at least six years. This period is called the latency
period. The T4 lymphocyte will then suddenly begin to make copies of the viral genes in the
form of messenger RNA. The messenger RNA leaves from the nucleus to the cytoplasm and
causes the synthesis of viral proteins and RNA as other normal messenger RNA. Therefore, new
HIV viruses are produced. They leave the T4 lymphocyte by budding out from underneath the
cell surface membrane. The viruses then attack other lymphocytes and brain cells.
During the virus’s replication inside the T4 lymphocytes, the lymphocytes are destroyed and
no longer can fight with other pathogen. Its immune function is lost and so the infected person
becomes weak.
How the HIV virus is transmitted?
HIV dies soon outside the human body. Basically, it is transmitted by body fluid and mainly
by three ways:
1. Blood contact
In blood, there is a high concentration of HIV. If a person gets blood from infected
person and the blood enters his body, he will be infected also.
Blood contact will happen when syringes are shared. Some abusers take drugs and share
one syringe. If one of the abusers has the HIV infection, the virus will be spread among them
through the syringe.
If a person receives blood which is donated from an infected person, he well get the HIV
virus.
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Also, close contact between infected and non-infected people through cuts and open wounds
can pass the virus.
2. Sexual contact
In semen and vaginal secretions, there are HIV viruses. Therefore, HIV can be spread
through intercourse, both vaginal and anal intercourse in homosexuals and heterosexual.
Therefore, if people have sex without using condoms, there will be contact of their body
fluids and the HIV virus can pass form one body to another.
3. From mother to child
If the mother is infected, her baby will get the virus through the placenta during
pregnancy and infected.
Moreover, through breast milk, the baby can get the HIV from the mother.
What happens to the infected person?
A person will not have AIDS when he is infected by HIV immediately. The person will not
have AIDS after a period of time, which is different from person to person.
The HIV infection can be divided into four stages.
1.
During the first stage, the body will produce the anti-HIV antibodies. The person will
get a flu-like illness within three to six weeks after getting the virus. The illness is called
Acute HIV syndrome. It includes fever, headache, tiredness, nausea, diarrhea and swollen
lymph nodes. However, the symptoms will disappear within a week to a month.
2.
The second stage is the asymptomatic period. During this stage, the number of virus is
increasing rapidly while the number of T4 lymphocytes is decreasing. T4 lymphocytes are
produced every day in large amount to flight with the HIV and destroyed. However, the
infected person has no symptoms.
3.
The third stage is the AIDS-related complex (ARC) period. The infected person will be
infected by Opportunistic Infections since the immune system of the person is very weak now.
At this stage, the number of T4 lymphocytes per milliliter of blood falls below 200. The
Opportunistic Infections are caused by bacteria, virus, fungus and parasites. These infections
include Mycobacterium avium complex (MAC), Tuberculosis (TB), Salmonellosis, Bacillary
Angiomatosis (all caused by bacteria); Cytomegalovirus (CMV), Viral hepatitis, Herpes,
Human papillomavirus (HPV), Progressive multifocal leukoencephalopathy (PML) (caused
by virus); Candidiasis, Cryptococcal meningitis (caused by fungus) and Pneumocystis Carinii
pneumonia (PCP). Toxoplasmosis. Cryptosporidiosis (caused by parasites).
The infected person will also get cancers like Kaposi's sarcoma and lymphoma. These
infections are called AIDS-indicator illness.
4.
At the later stage of HIV infection, the infected person starts developing AIDS.
Some common symptoms of AIDS
-Lack of energy
-Weight loss
-Frequent fevers and sweats
-Severe vaginal yeast infections
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-A thick, whitish coating of the tongue or mouth (thrush) that is caused by a yeast infection
and sometimes accompanied by a sore throat
-Become fatigue and have headaches, lightheadedness and dizziness
-Bruise easily
-Deep and dry coughing
-Difficult in breathing
-Bleeding without reasons
-Loss of muscle control and reflex, paralysis
-Children grow slowly or become sick frequently
When a person has most of the symptoms above, he has AIDS.
How to test if you have been infected by HIV?
In the early stage of infection, the infection can be diagnosed by testing a person’s blood.
This includes looking for the presence of anti-HIV antibodies produced by the body and looking
for the virus.
1. Looking for the presence of anti-HIV antibodies
This can be don by the ELISA test (Enzyme Linked Immunosorbent Assay). When the
test is positive, it still has to be proved by another test called Western Blot or
Immunoflouroscent Assay (IFA). The test is repeated to confirm a person’s HIV status. A
person infected with HIV is termed HIV-positive or seropositive.
Sometimes the ELISA test still gives negative result when the person is infected by HIV.
This is because there is a Window period. During the Window Period, the anti-HIV
antibodies do not reach a detectable lever, which is within the first three month after infected.
That’s why the test will give a negative result.
Moreover, the ELISA test is very slow since blood samples have to be sent to a
laboratory, which lasts for about several days or weeks. Therefore, the Rapid Tests are
preferred. They can give results in 5 to 30minutes but are more expensive. These tests have
the same accuracy as the ELISA test.
Sometimes the Western Blot test results are uncertain. The Radio Immuno Precipitation
Assay (RIPA) test can be done to confirm the HIV infection.
2. Looks for the HIV
This is done by the Polymerase Chain Reaction (PCR) test. The test can recognize the
presence of the virus’ genetic material in the blood. Even the person is infected only for few
days, the virus can be detected by the PCR test.
Other tests, such as Rapid Latex Agglutination Assay, p24 Antigen Capture Assay, etc, can
also be done for testing the HIV infection.
The treatment of AIDS
Nowadays, there is no cure and no vaccine for the HIV infection. However, there are three
kinds of medicines, which can slow down the growth of the virus.
The first kind of medicines is the nucleoside analog reverse transcriptase inhibitors. They
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get into the DNA of the virus and stop its building process. Since the DNA of the virus is not
complete, it cannot make new virus. These medicines include AZT, ddI, ddC, 3TC, etc.
The second kind of medicines is the non-nucleoside reverse transcriptase inhibitor. This
medicine gets into the reverse transcriptase enzyme of the virus and stops it from making DNA.
As a result, new virus cannot be made. Examples of the medicine are EFV, Delavirdine, etc.
The third kind of medicines is protease inhibitors. This medicine stops the making and
release of HIV from infected cells. These medicines include Indinavir, Saquinavir, etc.
Usually, the three kinds of medicines are used together for efficiency.
However, these medicines will have side effect such as vomiting, fatigue, anemia, nausea,
etc. Therefore, they must be used according to the doctor’s instruction.
How to prevent the spreading of HIV infection?
To prevent HIV infection, we should have safety sexual intercourse. Condoms should be
used and so infection through blood or semen can be prevented.
It is safer to have one sexual partner. Therefore, the chance of getting HIV infection from
the sexual partner is lower.
When a mother knows that she has the HIV infection, she is better to avoid having a baby.
Also, she should not carry out breast breeding. Therefore, the HIV will not be passed to the baby.
When someone knows that he has the HIV infection, he should avoid giving blood. In
Britain, all blood donated has been tested for the presence of antibodies to HIV. If anti-HIV
antibodies are present, the blood will not be used.
Sharing of syringes increases the chance of getting HIV infection. Drug abusers should get
his own syringe and don’t share it with other people. In some European countries, free sterilized
syringes are provided for the abusers.
However, the best way of prevent of AIDS is to educate people about AIDS. It is very
important for people to understand and have the awareness of AIDS. Every body should know
what they should do and so the spreading of HIV infected can be stopped.
AIDS in the world
AIDS is a very frightening disease in the world. The number of having HIV infection every
day is increasing. Recently, there has been a rapid increase of having HIV infection in China and
the government of China is focusing on the problem.
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It can be seen that the problem of HIV infection is very serious in Africa, especially in
Sub-Saharan Africa. There are 28,500,000 people getting infected in Sub-Saharan Africa. Every
day, there are 14,000 people who are newly infected in 2001.
AIDS is the main killer in Africa.
There are two main reasons why AIDS in Africa is so serious.
1. The living standard of Africa is very poor
In Africa, the hygiene is very poor. The medical waste is thrown everywhere.
Therefore, people have the chance of touching blood from other patients. As the
concentration of HIV in blood is very high, people may get the HIV infection through the
blood.
Africa is a very poor country. The resident even have problems on their daily lives.
Even they know the have AIDS, they cannot afford to buy the medicines. Therefore, the
deaths caused by AIDS in Africa are very high.
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Moreover, the governments in Africa do not have enough money to improve the
living standard of their resident. They do not have enough medical resources to help though
patients who get AIDS.
2.People in Africa are not educated
Most of the people in Africa are not educated. They know nothing about AIDS and
ways to prevent it. Therefore, they have no awareness of AIDS and may pass the HIV and
get HIV infection easily.
Since they do not know that they can get the HIV infection through blood, they will
not avoid touching blood of other people. If the person has the HIV infection, they will get
the virus also.
Also, they will not use condoms when they have sex and therefore the chance of
getting HIV infection through semen and vaginal fluid is very high.
To improve the problem in Africa, help from other developed countries is needed. The
developed countries can help to improve the living standard and the hygiene of Africa. They can
provide some ways for Africa to improve the health of the people living there.
Only every country helps each other, the problem of AIDS can be solved.
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