When HIV Becomes AIDS

http://www.youtube.com/watch?v=68I7JlVhuhY

REFERENCE

Reference for Info's

www.ansswers.com/HIV
http://www.chm.bris.ac.uk/

AIDS

Basic definition:

Acquired immune deficiency syndrome (AIDS), an infectious disease caused by the human immunodeficiency virus (HIV). It was first recognized in the United States in 1981. AIDS is the advanced form of infection with the HIV virus, which may not cause recognizable disease for a long period after the initial exposure (latency). No vaccine is currently available to prevent HIV infection. At present, all forms of AIDS therapy are focused on improving the quality and length of life for AIDS patients by slowing or halting the replication of the virus and treating or preventing infections and cancers that take advantage of a person's weakened immune system.

image from http://www.intmath.com/Differential-equations/HTML/AIDS__1.jpg

definition from http://www.answers.com/AIDS

DID YOU KNOW?

- 1981 - First cases of acquired immune deficiency syndrome (AIDS) reported.

- 1983 - Agent now known to be responsible for AIDS called human immunodeficiency virus (HIV), was isolated and identified.

- There are at least two types of HIV, HIV-2 which is mainly found in West Africa, and HIV-1 which is more virulent and causes the most AIDS worldwide.

- HIV generally leads to a depletion of CD4 T cells (a type of white blood cell).

- As of January 1999, there were an estimated 30 to 40 million cases of HIV worldwide

- The number of infected people worldwide continues to grow at an alarming rate:

Life Cycle of Virus

Life Cycle Of Virus

(click to zoom in) http://www.nwabr.org/education/pdfs/hiv_lifecycle.jpg

the video above is basically about the life cycle of HIV but in better explanation

http://www.youtube.com/watch?v=9leO28ydyfU

Transmission and progression of disease

Transmission

HIV can only survive in body fluids and is transmitted via:
- blood
- semen
- vaginal fluid
- milk

The disease can be contracted in the following ways:
- Intimate sexual contact (the disease was first associated with homosexual communities, notably in American cities such as San Francisco)
- Infected blood entering the blood stream
- receiving blood or blood products already infected with HIV
- contaminated needles used for intravenous drug delivery
- infected pregnant woman can pass on the virus to her baby through the placenta, at birth or through breast milk. (chances of about 25-50%)The chances of the infection being transmitted from the mother to her baby are estimated to be 25-50%. This can largely be prevented by treating infected pregnant women with the drug zidovudine (AZT).

Ways of prevention:
- Intensive blood screening of blood from blood donors.
- Treating infected women with drug zidovudine (AZT)

Progression of the disease

Most, but not necessarilly all, individuals infected with HIV progress over time to AIDS and following stages of the disease can be seen:

1. Initial infection with HIV may produce a short flu-like illness, but NO symptoms YET.
2. Onset of clinical signs (HIV-positive phase). Generally lasts between 2 -15 years. NO symptoms still but it is NOT static, (positive persistent replication of the virus)
3. Onset of opportunistic infections BUT not major. Common bacterial, viral and fungal infections occur. Oral and genital herpes or athlete's foot are common examples. Loss of weight may also be seen. There is a significant drop in the number of CD4 T cells.
4. Onset of AIDS-Opportunistic infections (protozoal, viral, bacterial or fungal), disease of body organs and development of secondary cancers are COMMON and LIFE THREATENING. Some individuals may lose a great deal of weight.

Introduction for HIV

HIV

HIV is an enveloped retrovirus whereby each virus particle contains two copies of an RNA genome. It also contains a number of enzymes: reverse trancriptase, integrase and viral protease. These molecules play an important role in making new copies of HIV and can be the targets of antiretroviral drugs. The HIV viral particle, or virion, has a capsid which is cone-shaped and is enclosed in a lipid bilayer, or envelope. This envelope contains viral glycoproteins which bind specifically to CD4 T cell receptors, enabling the virus to enter its host.

http://commons.wikimedia.org/wiki/File:HIV-budding-Color.jpg

The name retrovirus comes from the fact that the RNA genome is transcribed/copied back into DNA in the host cell (by reverse transcriptase).

biology.kenyon.edu/.../Lentiviral/hiv_image.jpg

The DNA is then incorporated into the host cell chromosome.HIV belongs to a group of retroviruses called lentiviruses, from the Latin lentus, meaning slow, because of the gradual course of the disease they cause.

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