Human Immunodeficiency Virus (HIV) & Acquired ImmunoDeficiency Syndrome (AIDS)
18 January 2022
Origin of HIV
HIV belongs to the lentivirus family which attacks the immune system. Initially, there was a virus known as Simian Immunodeficiency virus (SIV) that attacked the immune system in apes and monkeys. This was first found in the chimpanzees where it was hypothesized that it had eaten two smaller monkeys and hence the virus entered into the body. Earlier, humans hunted on chimpanzees and during consumption or hunting, the blood seeping into the skin thus SIV invading humans. However, humans had strong immune system and SIV was fought off. The SIV then adapted into the form of HIV-1 and hence started infecting humans thereon. Studies show that this must have occurred in the 1920s in Democratic republic of Congo and the spread might have occurred due to higher levels of migrations and presence of sex trade. Every time SIV entered human body, it adapted into different forms hence showing evidence to the four different types of HIV-1 (M, N, O, P) that are prevalent today. The most infective strain is the HIV-1 M type. There is also an HIV-2 type which arises from monkeys and not chimpanzees. However, it is rarer and less infectious type HIV. It is usually found in Angola, West Africa and Mozambique. In 1983, HIV-1 was first isolated and studied at the Pasteur Institute in France. In the 1980s, many cases emerged in USA leading it to an epidemic.
How does HIV infect?
This virus invades the human body and attacks the T helper cells of the body, also known as CD4 cells and then uses these to replicate and form multiple copies of itself. This leads to weakening of the immune system and the individual becomes more susceptible to other infections which could be life-threatening. It is however not very immediate. The infection takes place in 3 stages:
- Stage 1: Acute primary infection
After the virus invades the immune system, around 1-4 weeks later, flu-like symptoms arise resolving in a couple of days. Not all experience these symptoms. It is a highly infectious stage, but very rarely it can be diagnosed.
- Stage 2: Asymptomatic stage
HIV is very active, making multiple copies of itself. However, the individual will not manifest any clinical signs and symptoms. This stage usually lasts up to 10- 15 years. HIV antibodies can be detected at this stage. The immune system is severely damaged after this stage.
- Stage 3: Symptomatic infection
At this stage AIDS develops. The body is too weak to fight off infections and hence several symptoms and illnesses arise. If left untreated, any infection can cause severe circumstances and can ultimately lead to death. Symptoms usually observed are weight loss, chronic diarrhoea, night sweats, fever, persistent cough, regular infections, serious illnesses and diseases, etc.
How is it spread?
HIV is found in bodily fluids such as semen, blood, vaginal and anal fluids, and breastmilk. Major routes of transmission include through unprotected sex (without a condom), sharing needles or syringes, during pregnancy, birth or breastfeeding and rarely through blood transfusions.
NOTE : It is not spread via SALIVA, shaking hands, sharing cutlery, touching, kissing.
How to detect?
There are various blood detection tests, ELISA, HIV antigen test, western blot, HIV viral load test, Absolute CD4 lymphocyte test; Urine tests; Oral tests where blood- derived fluids from the gums is withdrawn.
Are there any treatment options?
It is a preventable and a manageable disease but not curable.
Prevention and early treatment of infections, positive living and ART (Antiretroviral therapy) are some of the options.
ART can reduce HIV transmission to a great extent, protects the immune system and prevents progression to AIDS if diagnosed early. It helps individual live a longer, healthier life. The viral load is reduced so much that no transmission to HIV- negative person occurs even through sexual activity. ART includes a cocktail of drugs which affects the viral life cycle. Some of them are nucleoside/ nucleotide reverse transcriptase inhibitors, nonnucleoside reverse transcriptase inhibitors, protease inhibitors, fusion and entry inhibitors, integrase inhibitors.
How to prevent acquiring HIV?
- Interventions to Prevent Sexual Transmission- Abstinence from sexual activity, monogamous relationship, protected sexual activity through use of condoms, STI screening and treatment.
- Prevention of Mother-to-Child Transmission- Avoidance of unwanted pregnancies among infected mothers, use of antiretroviral therapy, feeding substitution.
- Prevention of Bloodborne Transmission- use sterile needles, no sharing of blades and implementation of blood safety practices.
- Information, education, and communication about HIV and AIDS- Through School based sex education, peer-based programs, voluntary counselling and testing.
Until now, an estimated 75.7 million people has become infected with HIV and 32.7 million people have died of AIDS-related illnesses. India is the third largest HIV epidemic in the world. However currently, overall prevalence of HIV is decreasing. But to completely eradicate it, early detection, HIV treatment and preventive measures are the keys to end AIDS as a global public health threat.