This article deals with the most dangerous disease AIDS caused due to a virus called HIV

Acquired immuno deficiency syndrome is a medical condition cause due to a virus called HIV. HIV is the virus,AIDS is a medical syndrome caused due to HIV. Aids usually arises in the later stages of infection of HIV ,many people can live a healthy life with this infection with proper treatments.

HIV is a retrovirus, which basically targets the body's immune system. It replicates itself,and attacks cells of the immune system of the body. Body tries to neutralise the effect by creating more cells of its own or trying to contain the virus, but eventually HIV wins out and then body becomes suceptible to any sort of infection which may even cause cancer and further leads to death

In this article, I will be discussing about the structure of HIV virus, how it invades the immune system and destroys it and then how it causes AIDS

STRUCTURE OF HIV VIRUS

HIV is in the shape of a sphere, with several spikes projecting out of it. HIV particle surround itself with a coat of fatty material called viral envelope, from where 72 spikes project out. Beneath that is a layer of proten called matrix. Below that lies the core, which contains 3 enzymes which is necessary for human replication. The core also contains HIV's genetic material, which contain two strands of RNA

HIV belongs to a class of viruses called the retrovirus. Retrovirus differs from other virus's in the fact that , their genetic material is made up of RNA and not DNA. Majority of the organisms and viruses have DNA as their genetic material.. This makes the HIV virus replication slightly more complicated. HIV just has 9 genes, compared to other viruses and bacteria

HIV REPLICATION CYCLE

1) HIV can only replicate within human body. Each cell has a protein layer called CD4 , when HIV comes into contact with this particular cell, spikes of the HIV virus fuses with cell membrane .Contents of HIV particles are then injected into the human cell

2) Once it is inside the cell, HIV virus converts RNA into DNA,so that it is compatible with the human genetic material. Then it traverses into the cell's nucleus and integrates with the human DNA. Finally it becomes HIV DNA and its called provirus

3) This virus can  be dormant in the cell for years, but once it becomes active, the cell treats HIV genetic material in the same way as it treats human genetic material..It is converted into RNA using suitable human enzymes , then transported around the body and further it produces more enzymes

4) The newly formed HIV particles are ready to infect others and in this way they replicate themselves in a rapid process and infect the entire body

HOW HIV ATTACKS THE IMMUNE SYSTEM

what makes HIV such a deadly virus is because of how rapidly this virus evolves and its ability to replicate so fast ,that it is very hard to stop especially in the advance stage. As mentioned above there is an enzyme which converts HIV's RNA TO DNA. This enzyme often makes quite a mistake,as a result a different DNA is produce and a different HIV virus is formed. Sometimes the HIV virus so formed can be harder to destroy because its immunity might be too high. Therefore HIV Is constantly changing and trying to destroy the human immunity system.

There are 3 main ways by which HIV destroys the immune system

1) The normal cells which are infected with the HIV virus, may get destroyed when a large amount of this virus is produced or when it nips out from the cell membrane causing the membrane to break , thereby destroying it. Also the HIV virus may use the cell's enzymes for its own survival , thus making it difficult for the cell to perform its functions, thereby killing it

2) When a large amount of HIV virus are formed and when it disrupts the cell's functioning , then a case arises when cell itself commits suicide. This is called programmed death. This is a common phenomenon which occurs in the blood stream and lymph nodes of HIV patients

3) HIV's envelope protein closely resembles human envelope proteins. Killer T cells are the cells which fights off infections by fighting the killer cells. Sometimes HIV may bind itself to another neightbouring cell,but the cell might be unaffected. The antibodies in the cell mistaking it to be a virus and kills the uninfected cells.. Also sometimes becuase they closely resemble our cells,antibodies might mistake them to be an infected cell and kills them off

HIV virus after infection can hide in the cytoplasm , thereby hiding from body's immune system. This makes it dormant for maybe even years until it becomes active. HIV can hide anywhere in the brain,liver,kidneys,intestines

PROGRESSION TO AIDS

In the first stage, HIV enters the cells ,replicates itself spreading throughout the body and deposting in various organs. It is possible for the virus to integrate and hide in bodies genetic material, therby hiding from the body's immune system. In this way it can lie dormant for years

After 2 to 3 weeks of exposure , body's immune system starts fighting off the virus,by generating killer T cells and anti bodies. This reduces the level of HIV virus dramatically and also leads to increase in the immune cells count and CD4+ T Cells may return to normal

But the HIV may still continue to replicate, but its not a threat to human body yet., so body does not develop any symptoms ,and this condition may last for years

HIV finally progresses to AIDS when it immune systems have deteriorated so rapidly that the body is unable to fight off any infections. This results in a large amount of the HIV virus and lesser amount of the antibodies and CD4+T Cells. The person is then identified with AIDS,when he is diagonsed with cancer or tuberculosis and when the count of CD4+T cells are lesser than 200

HOW IS HIV TRANSMITTED

1) Blood transfusions: Sharing and reusing syringes with contaminated blood may lead to HIV . Also people who gets tattoos and piercings are also highly prone to AIDS. But nowdays because of the strict ordeal in hospitals, this risk has been considerably reduced

2) Sexual transmission: This is the most common type by which HIV can be transmitted..It may include oral sex,anal sex or vaginal sex

3) Perinatal transmission: HIV infected mother can transmit this virus to her baby through pregnancy,breast feeding etc

HIV is not transmitted due to handshake,hugging,sneezing,sharing towels etc

TREATMENT

Unfortunately,there is no cure for HIV,atleast not yet. The only way is to slow down the infection. Anti retro viral is one such drug which slows down the infection and spread of virus in the body .It must be taken daily .Common side effects include fever,rash,nausea,fatigue etc