HIV; General Study

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HIV or Human Immunodeficiency Virus is belong to retrovirus group and infect humans. HIV has two types, HIV-1, HIV-2. These two types of viruses cause AIDS (Acquired Immuno Deficiency Syndrome). AIDS is a viral infection making human immune system weaker day by day. The AIDS is often transmitted through sexual intercourse or sexual discharge (semen, vaginal fluid, sperms). This syndrome has a depressing effect on human immune system, making it less responsive against foreign antigens (pathogens). AIDS has two phases/types:
 1. When HIV positive has been detected
 2. When HIV positive develops AIDS
      There is a huge time lapse between the detection of HIV and AIDS development. In some cases, HIV positive people do not develop the syndrome and they don't show any signs and symptoms of AIDS. It means that they are not safe, however they can transmit this syndrome to any person they contact physically. Their children may possibly develop AIDS or HIV positive. A person with HIV should be quarantined physically not socially. Try to avoid any physical relationship with HIV infected individual.
     
Microscopic view of HIV Virus structure 


Classification 

      HIV belongs to Lentivirus genus of Retroviridae family. The HIV has a longest incubation period means an infected person with HIV shows symptoms 9 years later of its infection on average. Lentiviruses are positive sense, single stranded and enveloped RNA viruses. Whenever the viral genome enters human cell/body this RNA stranded is transcribed and converted into DNA strand through reverse transcriptase enzyme of human cell. This newly manufactured DNA moves to cell nucleus and integrated with human DNA by integrate enzyme. This is the turning point in human body because our immune system can not distinguish between Viral DNA and human DNA. So, the HIV gets some sort of shield against first line of defense. 
       HIV may remain dormant for many years inside the human body. Secondly these viruses have longer incubation periods, making it less detectable. On an average HIV can remain dormant in human body for 10 years, and do not show any type of symptoms. But, during this period HIV virus can make its viral genome copies and transmit through physical contact. 
      Two types of HIV viruses have been detected: 
  1. HIV-1; This viral strain is older than other strain. HIV-1 viral strain is more virulent and is more infective and rapidly transmitted. 
  2. HIV-2; This type of viral strain is less virulent and recently discovered. HIV-2 has a lower infection rate and longer incubation periods. This is sometimes called dormant HIV. 
        
Entry and spread of HIV virus into human cell

History

The initial detection of this virus happened in US. The first cases were reported in gay individuals with a persistent habit of drug abuse (injectable drugs). Centre for Disease Control US analyzed cases and started research against this new infection. The first suspected case is indicated to be found in Norway in 1966. The term AIDS was coined in 1982 during a CDC conference. In 1983, researchers came to conclusion that AIDS was caused by viruses from the Retroviridae family. These retroviruses resembled with HTLV (Human T-Lymphotrophic Viruses). 

AIDS signs and symptoms 

Origin 

The origin of these retroviruses is not perfectly known but it's believed that these retroviruses may have originated from non-human primates in West Africa. They are believed to be transmitted to humans through zoonosis during 20th century. 
  
   We will discuss the medicines against AIDS in our next blog, stay tuned and subscribe to our email notifications. 

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