HIV and its progression to AIDS

HIV

The human immunodeficiency virus (HIV) is one of the most unique and dangerous virus. I say unique because of the fact that once the virus colonizes the host, the host cannot get rid of the virus till it is alive. That means that once a person is having HIV, he/she has to live it with for the rest of his/her life. It basically compromises the human immune system, giving an easy access to various pathogens to the body, that is otherwise not possible in a normal condition.

The Simian Immunodeficiency virus (SIV), which is the chimpanzee version of the immunodeficiency virus is thought to be the ancestor to HIV. The SIV most probably would have transmitted to the human when the chimpanzees were hunted for meat and came into contact with their infected blood and would have mutated to form the HIV.

Talking about the structure of HIV, each of the them consists of a viral envelope and associated matrix enclosing a capsid that possesses two copies of viral ribonucleic acid (RNA) along with few enzymes.

Connected Read: Electron Microscopic images of HIV

HIV Progression:

HIV is a virus spread through body fluids that affect the CD4 cells, or T-cells (cells of the immune system). Over time, HIV can destroy so many of these cells that the body can’t fight off infections and disease. When this happens (CD4 cell count falls below 200 cells per cubic millimeter of blood, i.e, 200 cells/mm³), HIV infection leads to AIDS.  (The CD4 count of a healthy adult ranges from 500 cells/mm³ to 1,600 cells/mm³).

HIV infection progresses in three stages:

1. Acute infection:
   This is the earliest stage of the HIV infection when the HIV increases in number rapidly and spreads throughout the body. The symptoms include flu-like symptoms like fever, headache, and rash. This stage develops 2-4 weeks after the initial HIV exposure and has the highest potential for the transmission of the virus, although the virus can be transmitted during any stage of infection. the CD4 cells of the immune system that are generally involved in the prevention of infections, are targeted and are destroyed.
2. Chronic infection:
   This is the next stage in the HIV infection cycle where the HIV continues to multiply in the host body but the rate of multiplication is lesser than the earlier stage. This infection stage of HIV generally progresses to AIDS in around 10 years, unless otherwise treated with medicines.
3. AIDS:
   This is the next and the last stage of HIV infection cycle. By now the immune system is heavily damaged by the HIV and is incapable of fighting infections. Generally, the life span of people diagnosed with AIDS, without any treatment is 3 years.

 How does the HIV spread:

Compared to many other viruses the spread of HIV is not very common. It transfers from the infected person to a healthy individual via some specific activities like sexual contacts and needle or syringe use.

Now how does the virus actually travel from the infected to a healthy individual? HIV can use the following medium to travel: Blood, Semen, Pre-seminal fluid, Rectal fluids, Vaginal fluids and Breast milk. When any of this body fluid come in contact with a mucous membrane (present inside the rectum, vagina, penis, and mouth) or damaged tissue or blood stream directly, the HIV can transfer to the healthy individual.

 The journey  of HIV inside the host cell:

The human immunodeficiency virus (HIV) replication cycle involving a host cell within the human body, beginning with a HIV virion attaching to the host cell wall, dumping its contents into the matrix of the host cell, conversion of the viral RNA to viral DNA, which combines with the host cell DNA, leading to the creation of new viral RNA, which migrates to the host cell periphery, and forms a vacuole around the new viral RNA using the host cell wall, thereafter, budding off as a newly-created mature HIV virion. The figure below depicts the various stages of the HIV replication cycle in the human host cell.

Is HIV and AIDS same?

Most of the times the terms HIV and AIDS are used interchangeably. But is it the same? Is the presence of HIV, implies that the individual is suffering from AIDS. The answer to both of these question is no. The HIV is the virus and the AIDS is the result of HIV infection (late stage) when the infected individual’s immune system is incapable of fighting diseases.

Can we cure HIV?

Although there is no effective cure currently exist, but it can be controlled with proper medication. The antiretroviral therapy (ART) which is currently employed to treat HIV, if administered properly, can dramatically prolong the lives of the people infected with HIV, keep them healthy, and drastically reduce their chance of infecting others. The lifespan of a person with HIV today can be as long as with someone without it, provided the infected person is treated well before the disease has reached an advanced stage.

Read More:

https://www.aids.gov

https://www.cdc.gov/

http://www.who.int/mediacentre/factsheets/fs360/en/

http://www.healthline.com