Monday, 8 October 2018

Class 9 - 12 - Biology - Know About Disease - Brief Notes About AIDS (#cbsenotes)(#eduvictors)

AIDS(A Brief Introduction)

Class 9 - 12 - Biology - Know About Disease - Brief Notes About AIDS (#cbsenotes)(#eduvictors)


Meaning of AIDS

The word AIDS stands for Acquired Immuno Deficiency Syndrome. This means a deficiency of the immune system, acquired during the lifetime of an individual indicating that it is not a congenital disease [disease or abnormality present from birth]. ‘Syndrome’ means a group of symptoms.


AIDS was first reported in 1981 and in the last twenty-five years or so, it has spread all over the world.

Luc Montagnier, Françoise Barré-Sinoussi, and their colleagues at the Pasteur Institute in Paris were the first to report the discovery of the virus now called the human immunodeficiency virus (HIV) associated with AIDS.


Causes of AIDS



AIDS is caused by the Human Immuno Deficiency Virus (HIV), a member of a group of viruses called Retrovirus, which have an envelope enclosing the RNA genome. A retrovirus is a type of virus that contains two copies of a single-stranded RNA.

Transmission of HIV-infection generally occurs by
a) sexual contact with infected person,
b) by transfusion of contaminated blood and blood products,
c) by sharing infected needles as in the case of intravenous drug abusers and
d) from infected mother to her child through the placenta.

So, people who are at high risk of getting this infection include
a) individuals who have multiple sexual partners,
b) drug addicts who take drugs intravenously,
c) individuals who require repeated blood transfusions and
d) children born to an HIV infected mother.

It is important to note that HIV/AIDS is not spread by mere touch or physical contact; it spreads only through body fluids. It is, hence, imperative, for the physical and psychological well-being, that the HIV/AIDS infected persons are not isolated from family and society.

There is always a time-lag between the infection and appearance of AIDS symptoms. This period may vary from a few months to many years (usually 5-10 years).


Mechanism of HIV Proliferation in Human Body
Class 9 - 12 - Biology - Know About Disease - Brief Notes About AIDS (#cbsenotes)(#eduvictors)
HIV Cycle
Credits: Raul654, Wikimedia

After getting Into the body of the person, the virus enters into macrophages where RNA genome of the virus replicates to form viral DNA with the help of the enzyme Reverse Transcriptase.

This viral DNA gets incorporated into the host cell’s DNA and directs the infected cells to produce virus particles. The macrophages continue to produce virus and in this way acts like an HIV factory.

Simultaneously, HIV enters into helper T-lymphocytes (Th), replicates and produce progeny viruses. The progeny viruses released in the blood attack other helper T-lymphocytes. This is repeated leading to a progressive decrease in the number of helper T-lymphocytes in the body of the infected person. During this period, the person suffers from bouts of fever, diarrhoea and weight loss.

Due to the decrease in the number of helper T lymphocytes, the person starts suffering from infections that could have been otherwise overcome such as those due to bacteria especially Mycobacterium, viruses, fungi and even parasites like Toxoplasma. The patient becomes so immuno-deficient that he/she is unable to protect himself/herself against these infections.


Prevention of AIDS


A widely used diagnostic test for AIDS is Enzyme Linked Immuno-Sorbent Assay (ELISA).


Treatment of AIDS with anti-retroviral drugs is only partially effective. They can only prolong the life of the patient but cannot prevent death, which is inevitable.


As AIDS has no cure, prevention is the best option. Moreover, HIV infection, more often, spreads due to conscious behaviour patterns and is not something that happens inadvertently, like pneumonia or typhoid.

Of course, infection in blood transfusion patients, new-borns (from mother) etc., may take place due to poor monitoring. The only excuse may be ignorance and it has been rightly said - “don’t die of ignorance”.

In India, the National AIDS Control Organization (NACO) and other non-governmental organizations (NGOs) are doing a lot to educate people about AIDS.

WHO has started a number of programmes to prevent the spreading of HIV infection.

Making blood (from blood banks) safe from HIV, ensuring the use of only disposable needles and syringes in public and private hospitals and clinics, free distribution of condoms, controlling drug abuse, advocating safe sex and promoting regular check-ups for HIV in susceptible populations, are some such steps taken up.

Infection with HIV or having AIDS is something that should not be hidden - since then, the infection may spread to many more people.

HIV/AIDS-infected people need help and sympathy instead of being shunned by society.

Unless society recognizes it as a problem to be dealt with in a collective manner - the chances of wider spread of the disease increase manifold.

It is a serious matter that can only be tackled, by the society and medical fraternity acting together, to prevent the spread of the disease.