Published on Mar 27, 2019 and last reviewed on Aug 07, 2023 - 8 min read
Abstract
Human Immunodeficiency Virus (HIV) is the virus that causes HIV infection and AIDS (Acquired Immunodeficiency Syndrome). There are two types of HIV viruses, HIV-1 and HIV-2, which belong to the retrovirus group. AIDS is the most advanced form of HIV infection.
Human Immunodeficiency Virus (HIV) is the virus that causes HIV infection and AIDS (Acquired Immunodeficiency Syndrome). There are two types of HIV viruses, HIV-1 and HIV-2, which belong to the retrovirus group. This virus also has numerous subtypes. These viruses can only reproduce within a host cell by copying their genetic blueprint onto the genes of a person’s cells.
AIDS is the most advanced form of HIV infection. Both HIV-1 and HIV-2 can cause AIDS, but HIV-2 is less easily transmitted and takes longer for the illness to appear.
In 1959, the blood collected from a man in Kinshasa, the Democratic Republic of the Congo, showed HIV-1. In the 1980s, scientists began to use the term acquired immunodeficiency syndrome (AIDS) to describe opportunistic infections in previously healthy individuals. In 1983, scientists discovered the virus causing these infections and named it HTLV-III/LAV (human T-cell lymphotropic virus-type III/lymphadenopathy-associated virus).
In 1999, scientists found HIV-1 to have originated from chimpanzees infected with simian immunodeficiency virus (SIV). These chimpanzees are believed to be infected from two other primates. They believe that humans got infected when they got exposed to infected chimpanzee blood during hunting.
Early symptoms seen after HIV infection is not very specific and reliable. Testing is the only way to know for sure if a person is HIV positive or not. Not all people experience the same symptoms, but some of the most common symptoms seen are:
As the infection progresses, the virus attacks the immune system, making the body susceptible to various viral, bacterial, and fungal infections.
Men and women generally have the same warning signs, 2 to 4 weeks after getting infected with HIV. Some of the symptoms that are specific to women are:
HIV can pass from the mother to the baby through the placenta during pregnancy. During delivery, when the amniotic sac breaks, there is a chance for the baby to get infected. HIV can also be transmitted through breastfeeding.
The ways to reduce the risk of transmission during pregnancy are:
HIV spreads through bodily fluids like blood, semen, vaginal secretions, rectal fluids, and breast milk. The ways in which HIV can be transmitted are as follows:
The ways by which HIV does not spread are:
The seven stages of the HIV life cycle are:
Binding - When HIV attacks the CD4 cell, the virus attaches to the cell’s surface molecules.
Fusion - Here, HIV gets enveloped and fused with the CD4 cell membrane. After the virus is inside the CD4 cell, it releases HIV RNA and HIV enzymes.
Reverse Transcription - The virus releases and uses reverse transcriptase, which is an HIV enzyme, and converts HIV RNA into HIV DNA. This conversion allows HIV to enter the CD4 cell nucleus and combine with the cell DNA.
Integration - The virus also releases an enzyme integrase, that it uses to integrate its DNA with the host DNA.
Replication - After integrating with the host DNA, the virus begins to create long chains of HIV protein, which are building blocks for more HIV.
Assembly - In this stage, new HIV RNA and HIV proteins made by the virus move to the surface of the CD4 cells and assemble to form immature HIV.
Budding - The immature (noninfectious) HIV gets out of the CD4 cell and starts releasing an enzyme protease. This enzyme breaks the long protein chains of the noninfectious virus and forms mature and infectious HIV.
As the symptoms of HIV infection is not specific and conclusive, the only way to know for sure if you have HIV infection is by getting yourself tested. Always get tested if you feel you are at risk. There are three types of HIV test, which are:
When someone gets infected with HIV, the body starts producing antibodies to the virus antigens. The window period is the time between HIV exposure and when traceable amounts of HIV antibodies are present in the blood. The window period is usually 23 to 90 days.
HIV tests taken at this period will show a negative result even if you have been infected. But the rate of transmission is very high in this period, as the virus multiplies at a fast pace in the body. If you have had a potential exposure and tested negative in the window period, it is best to repeat the test after a month. Until then, prevent the spread of the virus by practicing safe sex.
Pre-exposure prophylaxis (PrEP) is a method used by people who are at high risk of getting infected. Here, an antiviral drug is taken every day to prevent HIV infection. The pill used is called Truvada, which is a combination of Tenofovir and Emtricitabine.
In people who have already been infected with the virus, this drug taken within 72 hrs might prevent the virus from causing a permanent infection. It has shown to reduce the risk of HIV infection by up to 92 %.
Post-exposure prophylaxis (PEP) is the use of antiretroviral medicines (ART) after potential exposure to HIV to prevent infection. It should be used within 72 hours after exposure and only in emergencies. It has to be taken ones or twice a day for 28 days.
PEP does not prevent HIV infection 100 %, so it is always better to engage in safe sex. The antiviral drugs used are Tenofovir, Emtricitabine, Raltegravir, and Dolutegravir. The problem with this treatment is if the antiviral medicines do not work and you get infected, the virus might be resistant to some HIV drugs.
Infections that occur or are more severe in individuals with HIV infection as compared to people with a healthy immune system are called opportunistic infections. HIV weakens the immune system, thus making it hard for the body to fight off infections. The common opportunistic infections seen with HIV are:
HIV infection can be prevented in the following ways:
Currently, there is no permanent cure for HIV infection. Antiretroviral medicines keep the virus from spreading or being detected in the blood. They protect the CD4 cells and help the immune system from fighting off the infection. Antiretroviral drugs prevent HIV infection from progressing to AIDS.
Once the person stops taking medicines, the viral load will increase and the virus will start attacking the CD4 cells. The following medications are given in different combination for treatment:
As of now, there is no vaccine that can prevent HIV. However, active researches are going on over the topic and sooner HIV vaccines will be released into the markets. Researchers are currently working on two distinct types of HIV vaccines: therapeutic HIV vaccine and preventive HIV vaccine. Therapeutic HIV vaccines is aimed for active HIV patients while the other one is for preventive purpose.
With proper treatment and care, people with HIV infection can have a near normal lifespan. With the advancement in antiretroviral drugs, the lifespan of people with HIV has improved a lot. The lifespan also depends on the CD4 cell count, viral load, the presence of opportunistic infections, drug use, smoking, age, and other health conditions. Without treatment and when HIV infection advances to AIDS, life expectancy is about 3 years.
- HIV is not the same as AIDS. The virus that causes AIDS is HIV. If one's CD4 count falls below 200 or they have certain infections or cancers, they have AIDS. One can live with HIV for years without developing AIDS. Therefore, being infected with HIV does not imply that they have AIDS.
- Lesbians can contract HIV. It is uncommon for women who have only ever had sex with other women to contract or pass HIV. However, HIV can be transmitted through vaginal fluids and menstrual blood.
- HIV can be contracted through tattoos or body piercings. Sharing needles is the second most frequent way HIV is transmitted. Anyone who shares needles with an HIV-positive person or whose HIV status is unknown is at risk of contracting the virus.
HIV can be transmitted through bodily fluids such as blood, rectal fluids, vaginal secretions, semen, and breast milk. Most people contract HIV through anal or vaginal sex or sharing syringes, needles, or other drug injection equipment (for example, cookers). However, there are effective tools available to help prevent HIV transmission.
If a pregnant woman is HIV positive, her pregnancy is considered "high risk." A mother's HIV can be passed on to her baby during pregnancy, delivery, or breastfeeding. Therefore, it is critical for the mother's and her baby's health to see the doctor regularly for blood tests and prenatal visits. All HIV-positive pregnant women should take HIV medications throughout their pregnancy for their health and prevent perinatal HIV transmission. (Antiretrovirals are HIV medications.)
HIV can be transmitted to a baby by an HIV-positive mother at any time during pregnancy, childbirth, or breastfeeding. However, this does not preclude one from having children. Treatment with a combination of HIV medications (known as antiretroviral therapy or ART) can prevent HIV transmission to the baby while also protecting their health.
Pre-exposure prophylaxis (PrEP) is a method of preventing HIV infection by taking an antiviral drug every day. PrEP is considerably more effective than condoms at preventing HIV transmission during sexual contact. However, it does not protect against other types of STDs, so even if one is on PrEP, one should still use a condom.
PrEP is not recommended for people exposed to HIV within the last 72 hours. If a person was exposed to HIV in the last 72 hours, speak with the doctor or an urgent care provider regarding PEP (post-exposure prophylaxis). It should only be used in an emergency and within 72 hours of exposure. It must be taken once or twice a day for 28 days.
Taking two PrEP pills at the same time or on the same day is not dangerous. In fact, in some cases, taking two pills simultaneously is the recommended way to begin using PrEP. Therefore, there is no need to be concerned if one has accidentally taken two PrEP pills in one day. Simply continue taking the PrEP as directed the next day.
Once a person starts PrEP, they must take it every day. When PrEP is not taken daily, it is far less effective. An occasional missed dose of PrEP pills will not significantly impact overall effectiveness, but taking the medication as directed is critical.
The process begins when HIV comes into contact with a CD4 cell. HIV replicates by using CD4 immune cells. And each infected CD4 cell generates hundreds of new HIV particles. The process is referred to as the HIV life cycle. Each replication cycle lasts only one to two days.
There is no vaccine available to either prevent or treat HIV infection. However, more than 40 vaccines are in the early stages of development. These are intended to produce antibodies that fight the virus or increase the body's T cells, which aid in killing HIV-infected cells. All of this research suggests that an HIV vaccine could be available within the next decade.
Although the virus is unlikely to be fatal, it can significantly impact one's life and health. According to one study, people with HIV live 16 lesser years in good health than those who do not have the virus. However, according to a life expectancy study, HIV-positive people who begin antiretroviral therapy (ART) promptly and have access to medical care outlive their HIV-negative peers.
Last reviewed at:
07 Aug 2023 - 8 min read
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