Representational image | ShutterstockAcquired immunodeficiency Syndrome or AIDS is a group of diseases that is caused by the Human Immunodeficiency Virus (HIV). This virus typically attacks the patient’s immune system and lowers the body’s resistance against infection.
The main methods of transmission of HIV from an infected person are:
- Sexual transmission either through vaginal or anal sex
- Sharing of contaminated, unsterilised needles for injections, drug abuse, tattoos etc.
- Transfusion of infected blood, nowadays a very rare occurrence.
- From a pregnant mother to child during pregnancy, at childbirth or during breastfeeding.
The primary reason for HIV to transform into AIDS is a lack of medication. Patients receiving Anti-Retroviral Therapy (ART) during the early stages of HIV infection normally do not reach the most severe stage, AIDS. Usually, patients develop AIDS because they might have been unaware of their HIV positivity, or because they neglected the ART regimen. The medication might not have been effective too, in some cases.
When a person is infected with HIV and is not provided medication, the infection progresses through three stages:
Acute stage: Typically lasts for four weeks after the infection occurs. It is very contagious due to a high viral load in the blood. Symptoms resembling a flu attack may develop. Antigen and antibody tests along with nucleic acid tests help in diagnosis.
Chronic stage: It may last more than a decade or longer. It is asymptomatic initially, with lower viral load, but still capable of transmitting infection. Without medication, it can progress to become symptomatic. The patient starts to develop a higher viral load, causing a drastic fall in the blood CD4 cell (a type of white blood cell) count.
AIDS: This is the terminal stage of HIV infection. It may extend for up to three years. The patient develops a very high viral load and is very infectious. If the CD4 level drops below 200/mm, or if certain Opportunistic Infections (OI) develop, a diagnosis of AIDS is confirmed.
Full-blown AIDS damages the body’s immune system and its resistance to even minor infections.
Common OIs, signs and symptoms
- Candidiasis: It is a common fungal infection but is classified as an OI when it is severe and persistently infects the mouth and vagina. It can also invade the food pipe (oesophagus), windpipe (trachea) and reach the lungs.
The following viral diseases can add to complications if contracted alongside AIDS:
- Cytomegalovirus: This can cause infection of the stomach and brain. The retina can become severely damaged and this may lead to blindness.
- Herpes Simplex Virus: This is a common infection which is self-limiting in most people with a normal immune system. But in an AIDS patient with compromised immunity, it presents as recurrent, painful ulcers around the mouth, in the genital region and the anus. It can spread to invade the trachea, oesophagus and the bronchus.
- Human Herpes Virus 8: This causes the characteristic sign of AIDS, called Kaposi’s Sarcoma. It is a tumour of the cells lining smaller lymphatic and blood vessels. It appears as red or purple patches on the skin and often on the roof of the mouth. It can be life threatening when it invades the lungs, liver or the digestive tract.
Other common OIs are lymphomas, tuberculosis and pneumonia.
Wasting syndrome is typically seen in AIDS patients, where there is a loss of 10 percent of the body weight within 30 days of fever and diarrhoea.
Diagnosis
Once a person is exposed to HIV, a positive result can be obtained usually after a window period of 3-4 weeks. There are many kinds of tests to detect HIV infection.
- Nucleic Acid Tests can confirm HIV from 2-4 weeks after the infection. They are usually expensive.
- Antigen/antibody tests performed by labs on blood drawn from a vein can give a diagnosis from 3 weeks to 10 weeks after exposure. Blood collected from a finger prick usually takes a longer time for a confirmatory diagnosis.
- Rapid test and home testing kits which detect antibodies are also available and require a longer wait for confirming a positive result.
- The onset of AIDS from a chronic stage of HIV is confirmed by the appearance of the typical Kaposi’s Sarcoma. Although it can be diagnosed visually by its typical appearance, a biopsy is used to confirm the presence of this sarcoma.
Treatment
An ART regimen covers an umbrella of seven classes of drugs that are given for HIV infection:
- CCR5 Antagonists, and fusion inhibitors – these drugs prevent the virus from entering the immunity causing CD4 T lymphocyte cells.
- Integrase Inhibitors prevent HIV replication by blocking the HIV enzyme integrase.
- Non-nucleoside and Nucleoside Reverse Transcriptase inhibitors act by blocking the enzyme reverse transcriptase and prevent HIV replication.
- Post-attachment inhibitors block the virus from binding to the CD4 cells.
- Protease inhibitors block the HIV enzyme protease and prevent the development of an immature HIV to a mature one.
Although HIV infection cannot be cured, its progression to the terminal stage AIDS can be slowed down considerably and, in many cases, prevented.
The best alternative is prevention by means of practising safe sex.
Sources:
1.https://www.cdc.gov/hiv/basics/whatishiv.html
2.https://www.who.int/news-room/fact-sheets/detail/hiv-aids
3.https://www.hiv.gov/hiv-basics/overview/about-hiv-and-aids/what-are-hiv-and-aids
