(N/A) $AIDS$ stands for Acquired Immuno Deficiency Syndrome.
$AIDS$ is not a congenital disease; it is acquired during the lifetime of an individual,indicating a deficiency of the immune system. Syndrome means a group of symptoms.
It was first reported in $1981$ in the $USA$. In the last few decades,it has spread all over the world,killing millions of people. It was first reported in India in $1986$ in Tamil Nadu.
It is caused by the Human Immuno Deficiency Virus $(HIV)$,a member of a group of viruses called retroviruses. They have an envelope enclosing $RNA$ as their genetic material.
After entering the human body,the virus enters macrophages. With the help of the reverse transcriptase enzyme,viral $RNA$ is converted into viral $DNA$,which then incorporates into the host genome. The macrophage acts as an $HIV$ factory.
Subsequently,$HIV$ enters helper $T$-lymphocytes,replicates,and produces progeny viruses. These new viruses attack other $T$-cells,leading to a progressive decrease in the number of helper $T$-cells in the body.
$AIDS$ spreads through:
$1$. Sexual contact with an infected person.
$2$. Transfusion of $HIV$-contaminated blood.
$3$. Sharing infected needles or syringes.
$4$. From an infected mother to her child through the placenta or breastfeeding.
It does not spread by mere physical contact or sharing utensils.
There is a time lag between infection and the appearance of symptoms,which may vary from a few months to many years (usually $5$ to $10$ years). During this period,the person may appear healthy but can act as a carrier.
Symptoms include persistent fever,weight loss,diarrhea,fatigue,and body aches. In the final stages,patients may suffer from severe weight loss,prolonged fever,chronic diarrhea,pneumonia,and cancers like Kaposi's sarcoma.
There is no complete cure for $AIDS$. Treatment with anti-retroviral drugs is only partially effective; it can prolong the life of the patient but cannot prevent death. There is no vaccine available,making it an incurable disease. Organizations like $NACO$ and $WHO$ run various programs to prevent the spread of $HIV$ infection.