HIV

How is HIV transmitted?

• 1)     Contact with blood of HIV infected person through cuts in the skin (also through shared injection needles
• 2)      Breast milk
• 3)      Semen and vaginal fluids

History of the disease:

A person gets infected with the HIV virus. 1-2 months after infection, the person gets an infection with fever, headache or rushes. Afterwards, the HIV can stay dormant inside host cells for many years. After around ten years, the immune system is so weak that small infection can already be life-threatening. This stage is called AIDS, when the HIV viruses have killed so many CD4 host cells that there are less than 200 CD4 cells per mm^3.

Basic structure:

Life cycle:

At first, a person is infected either via another person that is infected with HIV.  The HIV virus searches for a host cell in the human blood. This is the CD4 cell, a white blood cell. The HIV virus goes into the the host cell by docking on to a receptor and using endocytosis to enter the cell. There, by reverse transcriptase, it converts its RNA into DNA, which can then enter the nucleus. In the nucleus, the DNA of the virus inserts itself into the cells DNA and thus is transcribed and translated. Thus, proteins are produced for new HIV in the cell. The newly created cells, together with HIV RNA exit the cell by budding of and form new HIV cells.

The effects of HIV on the immune system:

The HIV virus kills the white blood cells, called CD4 cells, which help to protect the body from diseases. Through the progressing destruction of these CD4 cells, the immune system becomes weaker and weaker. When infected, the person will develop a small infection after 1-2 months. In the following years, the HIV can be passive and be dormant in the host cell. After 10 years, the immune system is so weak that a small infection can kill the person.

Why can the body not get rid of HIV?

Because the HIV takes a host cell to replicate, because it does not have an own metabolism. It takes the CD4 cell to replicate inside its DNA. This means, that antiviral drugs would have to aim to kill these CD4 cells, to kill HIV, but through this they would destroy the majorly important CD4 cells, which are part of the immunity of the body.

Why does nobody die directly after an infection with HIV?

Because at the beginning, the HIV has to replicate, because there are too little viral cells to be able o cause much damage to the immune system. Thus, as soon as the HIV viruses enter the body, they will hide in the host cell. Throughout the course of the 10 years of infection, the viruses will slowly destroy their host cells, which can then not anymore defend the body from the HIV virus. Thus, after 10yars the body is finally to weak to fight against HIV.

Opportunistic infections which can lead to death in weakened immune systems:

Salmonella, Pneumonia, bronchitis

Cancers:

Invasive cervical cancer, non-hodkin lymphoma, anal-, liver and lung cancer

Other symptoms:

Fever, chills, rush, mouth ulcers, night sweats, swollen lymph nodes, muscle ache, sore throat

Tests:

A laboratory test, whichtests for HIV antibodies and antigens in the blood is conducted. There is a window period in the first 4 weeks, where you cannot detect HIV infection in your blood, but after 6-8 weeks the reliability of the test increases.

Treatments:

In different stages, different antiretroviral therapy(ART) is done. A combination of 2 are taken in each stage (called antiviral regimen). The drugs are also called antiretrovirals (ARV):

For stage 1: Entry inhibitors (before virus enters host)

Stage 2: Fusion inhibitors (stop virus from being docking on to receptor)

Stage 3: non-nucleoside reverse transcriptase inhibitors, nucleoside reverse transcriptase inhibitors (stopping virus from converting into DNA)

Stage 4: Integrase inhibitors (Stopping virus from joining cell DNA)

Stage 5: protease inhibitors (stopping viral proteins from being produced)

Vaccination:

There is no vaccination on the market yet but scientists are working on it.

Prevention:

Getting tested

Know the sex partner’s HIV status

Use condoms

Don’t inject drugs

Take pre-exposure prophylaxis

Social implications of for infected (voluntary or mandatory):

Stigmatization and discrimination of HIV: Many people refer to it in a prejudiced way and have negative attitudes towards people who have HIV. People can be afraid because of fear of contagion. The infected have a low reputation because many people don’t approve of their sex life or habits (drug use).