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 The year is 1959. A man in Congo dies of an unidentified cancer. What puzzled doctors wasn't the cancer, it was the mans immune system, that seemed to have been completely broken down and powerless to fend of the disease.

 Its 1981, the CDC (The Centers for Disease Control and Prevention) notices a high rate of otherwise rare cancer claiming more lives. Thus begins the era of a new and undying  bubonic plague that shattered lives--countries--an entire civilization. As the 78th anniversary of AIDS approaches scientist around the world still struggle to find a cure.

 This comprehensive article is brought to you in recognition of World Aids Day that falls on the 1st of December.

.::The Aids Epidemic::.

• The flu pandemic of 1918 killed approximately 20 million people worldwide.
• World War II killed approximately 40 million people.

Clearly the AIDS pandemic has had, and will continue to have, a significant and global impact.

HIV, the virus that causes AIDS, is shown budding out of a human immune cell.

• Sexual contact
• Sharing contaminated intravenous needles
• Breastfeeding (mother to baby)
• Infected mother to fetus during pregnancy or birth
• Blood transfusions (Rare in countries where blood is screened for HIV antibodies.)

 

HIV And Mosquitoes One of the most prevalent myths about HIV transmission is that mosquitoes or other bloodsucking insects can infect you. There is no scientific evidence to support this claim. To see why mosquitoes don't aid in the transmission of HIV, we can look at the insect's biting behavior. When mosquitoes bite someone, they do not inject its own blood or the blood of an animal or person it has bitten into the next person it bites. The mosquito does inject saliva, which acts as a lubricant so that it can feed more effectively. Yellow fever and malaria can be transmitted through the saliva, but HIV does not reproduce in insects, and therefore doesn't survive in the mosquito long enough to be transmitted in the saliva. Additionally, mosquitoes don't normally travel from one person to another after ingesting blood. The insects need time to digest the blood meal before moving on.

There is also a slight chance of transmission through kissing and biting. However, there have been very few cases of HIV being transmitted through either method. In fact, the CDC has investigated only one case in which HIV infection was attributed to open-mouth kissing.

HIV does not transmit through the air or surface contact like cold and flu viruses do. HIV is a fragile virus and doesn't survive well outside the human body. This fragility makes the possibility of environmental transmission very remote. Outside of a host cell, HIV doesn't survive for very long. In laboratory studies, the CDC has shown that once the fluid (blood, sweat, tears, etc..) containing the HIV virus dries, the risk of environmental transmission is nearly zero.

There is a lot of misinformation about how HIV can be transmitted. So, here is a list of ways in which HIV is not transmitted:

• Saliva, tears and sweat - Saliva and tears contain only small amounts of HIV, and scientists haven't detected any HIV in the sweat of an infected person.
• Insects - Studies show no evidence of HIV transmission through bloodsucking insects. This is true even in areas where there are many cases of AIDS and large populations of mosquitoes.
• Using the same toilet seat
• Swimming in the same pool
• Touching, hugging or shaking hands
• Eating in the same restaurant
• Sitting next to someone

In the next section, you will learn what happens once the HIV virus enters the body, and how it attacks the immune system.

The Life-Cycle Of HIV
Like all viruses, HIV treads the fine line that separates living things from nonliving things. Viruses lack the chemical machinery that human cells utilize to support life. So, HIV requires a host cell to stay alive and replicate. To replicate, the virus creates new virus particles inside a host cell and those particles carry the virus to new cells. Fortunately the virus particles are fragile.

The model of the HIV virus

Viruses, like HIV, don't have cell walls or a nucleus. Basically, viruses are made up of genetic instructions wrapped inside a protective shell. An HIV virus particle, called a virion, is spherical in shape and has a diameter of about one 10,000th of a millimeter.

HIV infects one particular type of immune system cell. This cell is called the CD4+T cell, also know as a T-helper cell. Once infected, the T-helper cell turns into a HIV-replicating cell. T-helper cells play a vital role in the body's immune response. There are typically 1 million T-cells per one milliliter of blood. HIV will slowly reduce the number of T-cells until the person develops AIDS.

To understand how HIV infects the body, let's first look at the virus's basic structure. Here are the basic parts of the HIV virus:

• Viral envelope - This is the outer coat of the virus. It is composed of two layers of fatty molecules, called lipids. Embedded in the viral envelope are proteins from the host cell. There are also about 72 copies of Env protein, which protrudes from the envelope surface. Env consists of a cap made of three or four molecules called glycoprotein (gp) 120, and a stem consisting of three to four gp41 molecules.
• p17 protein - The HIV matrix protein that lies between the envelope and core
• Viral core - Inside the envelope is the core, which contains 2,000 copies of the viral protein, p24. These proteins surround two single strands of HIV RNA, each containing a copy of the virus's nine genes. Three of these genes -- gag, pol and env -- contain information needed to make structural proteins for new virions.

HIV is a retrovirus, which means it has genes composed of ribonucleic acid (RNA) molecules. Like all viruses, HIV replicates inside host cells. It's considered a retrovirus because it uses an enzyme, reverse transcriptase, to convert RNA into DNA.

Once the HIV virus enters the body, it heads for the lymphoid tissues, where it finds T-helper cells. Let's look at how the HIV virus infects immune system cells and replicates:

1. Binding - The HIV attaches to the immune cell when the gp120 protein of the HIV virus binds with the CD4 protein of the T-helper cell. The viral core enters the T-helper cell and the virion's protein membrane fuses with the cell wall.
   
2. Reverse transcription - The viral enzyme, reverse transcriptase, copies the virus's RNA into DNA.
   
3. Integration - The newly created DNA is carried into the cell's nucleus by the enzyme, viral integrase, and it binds with cell's DNA. HIV DNA is called a provirus.
   
4. Transcription - The viral DNA in the nucleus separates and creates messenger RNA (mRNA), using the cell's own enzymes. The mRNA contains the instructions for making new viral proteins.
   
5. Translation - The mRNA is carried back out of the nucleus by the cell's enzymes. The virus then uses the cell's natural protein-making mechanisms to make long chains of viral proteins and enzymes.
   
6. Assembly - RNA and viral enzymes gather at the edge of the cell. An enzyme, called protease, cuts the polypeptides into viral proteins.
   
7. Budding - New HIV virus particles pinch out from the cell membrane and break away with a piece of the cell membrane surrounding them. This is how enveloped viruses leave the cell. In this way, the host cell is not destroyed.

The newly replicated virions will infect other T-helper cells and cause the person's T-helper cell count to slowly dwindle. The lack of T-helper cells compromises the immune system. When a person's T-helper cell count drops below 200,000 cells per one milliliter of blood, he or she is considered to have AIDS. The development of AIDS takes about two to 15 years, but about half of all people with HIV will develop AIDS within 10 years after becoming infected, according to the CDC.

No one dies from AIDS or HIV specifically. Instead, an AIDS-infected person dies from infections, because his or her immune system has been dissipated. An AIDS patient could die from the common cold as easily as he or she could from cancer. The person's body cannot fight off the infection, and he or she eventually dies.

.::World Impact::.

To understand the devastation of AIDS, you have to understand the high mortality rate of people who develop the disease. If you counted every person in the city of Chicago, which is about 3 million, you would get the idea of how many people died worldwide from AIDS in 2000. Basically, that means that each year AIDS kills the same number of people that populate the third largest city in the United States.

More than 40 million people are infected with the HIV virus worldwide, with 25.3 million of those cases in sub-Saharan Africa. Additionally, anther 5.3 million new HIV infections occurred in 2000, which represents about 16,000 new cases per day. The regions with the greatest number of people living HIV/AIDS, according to the World Health Organization, include:

• Sub-Saharan Africa - 25.3 million
• South and Southeast Asia - 5.8 million
• Latin America - 1.4 million
• North America - 920,000
• Eastern Europe/Central Asia - 700,000

In the United States, 753,907 cases had been reported to the CDC through June 2000. However, the CDC estimates that as many as 900,000 Americans are living with HIV or AIDS.

 

HIV/AIDS History (Timeline) 1926-46 - HIV possibly spreads from monkeys to humans. No one knows for sure. 1959 - A man dies in Congo in what many researchers say is the first proven AIDS death. 1981 - The Centers for Disease Control and Prevention (CDC) notices high rate of otherwise rare cancer 1982 - The term AIDS is used for the first time, and CDC defines it. 1983/84 - American and French scientists each claim discovery of the virus that will later be called HIV. 1985 - The FDA approves the first HIV antibody test for blood supplies. 1987 - AZT is the first anti-HIV drug approved by the FDA. 1991 - Basketball star Magic Johnson announces that he is HIV-positive. 1996 - FDA approves first protease inhibitors. 1999 - An estimated 650,000 to 900,000 Americans living with HIV/AIDS. 2001 - AIDS global death toll reaches nearly 22 million.

AIDS is clearly one of the worst health crises facing the world today. Without any truly effective treatment, most health experts are putting an emphasis on prevention to stop the spread of HIV.

HIV and AIDS is a global emergency claiming over 8,000 lives every day.

In fact 5 people die of AIDS every minute.

In 2002, 5 million people acquired HIV, which means there are now 42 million people living with HIV and AIDS

In the UK, fewer people are dying of AIDS but there are more people living with HIV than ever before.

HIV is the one of the world's and the UK's biggest social, economic and health challenges.

• The human immunodeficiency virus (HIV) is a type of virus called a retrovirus, which infects humans when it comes in contact with tissues such as those that line the vagina, anal area, mouth, or eyes, or a break in the skin.
  
  
• HIV infection is generally a slowly progressive disease in which the virus is present throughout the body at all stages of the disease.
  
  
• Three stages of HIV infection have been described.
  
  1.  The initial stage of infection (primary infection), which occurs within weeks of acquiring the virus, is often characterized by a "flu"- or "mono"-like illness that generally resolves within weeks.
  
  2.  The stage of chronic asymptomatic infection (meaning a long duration of infection without symptoms) lasts an average of 8 to10 years.
  
  3.  The stage of symptomatic infection, in which the body's immune (or defense) system has declined so that complications have developed, is called the acquired immunodeficiency syndrome (AIDS). The symptoms are caused by the complications of AIDS, which include one or more unusual infections or cancers, severe loss of weight, and intellectual deterioration (called dementia).
  
  
• When HIV grows (that is, by reproducing itself), it acquires the ability to change (mutate) its own structure. This mutation enables the virus to become resistant to previously effective drug therapy.
  
  
• The goals of drug therapy are to prevent damage to the immune system by the HIV virus and to halt or delay the progress of the infection to symptomatic disease.
  
  

• Therapy for HIV includes combinations of drugs that decrease the growth of the virus to such an extent that the treatment prevents or markedly delays the development of viral resistance to the drugs.

• The best combination of drugs for HIV has not yet been defined, but one of the most important factors is that the regimen be well tolerated so that it can be followed consistently without missing doses.

-Various Sources-

*In recognition of World Aids Day that falls on the 1st of December*