Definition of AIDS and HIV Infection

AIDS stands for Acquired Immune Deficiency Syndrome. AIDS is a serious condition that weakens the body's immune system, leaving it unable to fight off illness.

AIDS is the last stage in a progression of diseases resulting from a viral infection known as the Human Immunodeficiency Virus (HIV or AIDS virus). The diseases include a number of unusual and severe infections, cancers and debilitating illnesses, resulting in severe weight loss or wasting away, and diseases affecting the brain and central nervous system.

There is no cure for HIV infection or AIDS nor is there a vaccine to prevent HIV infection. However, new medications not only can slow the progression of the infection, but can also markedly suppress the virus, thereby restoring the body’s immune function and permitting many HIV-infected individuals to lead a normal, disease-free life.

Description of AIDS and HIV Infection

The immune system is a network of cells, organs and proteins that work together to defend and protect the body from potentially harmful, infectious microorganisms (microscopic life-forms), such as bacteria, viruses, parasites and fungi. The immune system also plays a critical role in preventing the development and spread of many types of cancer.

When the immune system is missing one or more of its components, the result is an immunodeficiency disorder. AIDS is an immunodeficiency disorder.

Lymphocytes (white blood cells) are one of the main types of immune cells that make up the immune system. There are two types of lymphocytes: B cells and T cells. (T cells are also called CD4 cells, CD4 T cells, or CD4 cell lymphocytes). B cells secrete antibodies (proteins) into the body's fluids to ambush and attack antigens (foreign proteins such as bacteria, viruses or fungi). T cells directly attack and destroy infected or malignant cells in the body.

There are two types of T cells: helper T cells and killer T cells. Helper T cells recognize the antigen and activate the killer T cells. Killer T cells then destroy the antigen.

When HIV is introduced into the body, this virus is too strong for the helper T cells and killer T cells. The virus then invades these cells and starts to reproduce itself, thereby not only killing the CD4 T cells, but also spreading to infect otherwise healthy cells.

The HIV virus cannot be destroyed and lives in the body undetected for months or years before any sign of illness appears. Gradually, over many years or even decades, as the T cells become progressively destroyed or inactivated, other viruses, parasites or cancer cells (called "opportunistic diseases") which would not have been able to get past a healthy body's defense, can multiply within the body without fear of destruction. Commonly seen opportunistic diseases in persons with HIV infection include: pneumocystis carinii pneumonia, tuberculosis, candida (yeast) infection of the mouth, throat or vagina, shingles, cytomegalovirus retinitis and Kaposi's sarcoma.

Causes and Risk Factors of AIDS and HIV Infection

AIDS is transmitted via three main routes:

• The most common mode of transmission is the transfer of body secretions through sexual contact. This is accomplished through exposure of mucous membranes of the rectum, vagina or mouth to blood, semen or vaginal secretions containing the HIV virus.

• Blood or blood products can transmit the virus, most often through the sharing of contaminated syringes and needles.

• HIV can be spread during pregnancy from mother to fetus.

You cannot get AIDS/HIV from touching someone or sharing items, such as cups or pencils, or through coughing and sneezing. Additionally, HIV is not spread through routine contact in restaurants, the workplace or school. However, sharing a razor does pose a small risk in that blood from a minor nick can be transmitted from one person to another.

Symptoms of AIDS and HIV Infection

Immediately following infection with HIV, most individuals develop a brief, nonspecific “viral illness” consisting of low grade fever, rash, muscle aches, headache and/or fatigue. Like any other viral illness, these symptoms resolve over a period of five to 10 days. Then for a period of several years (sometimes as long as several decades), people infected with HIV are asymptomatic (no symptoms). However, their immune system is gradually being destroyed by the virus. When this destruction has progressed to a critical point, symptoms of AIDS appear. These symptoms are as follows:

• extreme fatigue

• rapid weight loss from an unknown cause (more than 10 lbs. in two months for no reason)

• appearance of swollen or tender glands in the neck, armpits or groin, for no apparent reason, lasting for more than four weeks

• unexplained shortness of breath, frequently accompanied by a dry cough, not due to allergies or smoking

• persistent diarrhea

• intermittent high fever or soaking night sweats of unknown origin

• a marked change in an illness pattern, either in frequency, severity, or length of sickness

• appearance of one or more purple spots on the surface of the skin, inside the mouth, anus or nasal passages

• whitish coating on the tongue, throat or vagina

• forgetfulness, confusion and other signs of mental deterioration

It can take as short as a year to as long as 10 to 15 years to go from being infected with HIV to "full-blown" AIDS.

According to the Center for Disease Control and Prevention, a person is considered to have AIDS when they have a T cell count (also called CD4 cell count) of 200 or less (healthy T cell levels range from 500 to 1500) or they have an AIDS-defining condition. The AIDS-defining conditions are:

• Candidiasis

• Cervical cancer (invasive)

• Coccidioidomycosis, Cryptococcosis, Cryptosporidiosis

• Cytomegalovirus disease

• Encephalopathy (HIV-related)

• Herpes simplex (severe infection)

• Histoplasmosis

• Isosporiasis

• Kaposi's sarcoma

Lymphoma (certain types)

• Mycobacterium avium complex

• Pneumocystis carinii pneumonia

• Pneumonia (recurrent)

• Progressive multifocal leukoencephalopathy

• Salmonella septicemia (recurrent)

• Toxoplasmosis of the brain

• Tuberculosis

• Wasting syndrome

People who are not infected with HIV may also develop these diseases; the presence of any one of these conditions does not mean the person has AIDS. To be diagnosed with AIDS, a person must be infected with HIV.

Some people infected with HIV may develop a disease that is less serious than AIDS, referred to as AIDS Related Complex (ARC). ARC is a condition caused by the AIDS virus in which the patient tests positive for AIDS infection and has a specific set of clinical symptoms. However, ARC patients' symptoms are often less severe than those with classic AIDS because the degree of destruction of the immune system has not progressed as far as it has in patients with classic AIDS.

Symptoms of ARC may include loss of appetite, weight loss, fever, night sweats, skin rashes, diarrhea, tiredness, lack of resistance to infection or swollen lymph nodes.

Note: Not everyone who has been infected with HIV develops AIDS. Very rarely, some individuals can be infected with HIV yet maintain normal immune function and general good health even after 20 years of infection.

Diagnosis of AIDS and HIV Infection

Screening for HIV infection is most commonly done by testing blood for HIV antibodies. A newer test, the Orasure test, involves collecting secretions between the cheek and gum and evaluating them for HIV antibodies. Orasure is essentially as accurate as a blood test, and, because it doesn't involve a needle stick, it is favored by many individuals. Orasure is available through physicians’ offices and many public health clinics. Finally, a new urine test available for screening, although if the test is positive, blood tests need to be performed for confirmation of the presence of HIV.

In 1996, a home HIV blood test (called Home Access) became available to the public. These home kits are available in pharmacies and by mail. The kit contains a few sharp tools called lancets, a piece of blotting paper marked with a unique identification number and a prepaid return envelope with a protective pouch. After pricking the finger with the lancet, a few drops of blood are blotted onto the paper, sealed into the envelope and sent to the address on the envelope. In about a week, the person calls a toll-free number to get the results of the test.

Prevention of AIDS and HIV Infection

The only way to protect from contracting AIDS sexually is to abstain from sex outside of a mutually faithful relationship with a partner whom the person knows is not infected with the AIDS virus. Otherwise, risks can be minimized if they:

• Don't have sexual contact with anyone who has symptoms of AIDS or who is a member of a high risk group for AIDS.

• Avoid sexual contact with anyone who has had sex with people at risk of getting AIDS.

• Don't have sex with prostitutes.

• Avoid having sex with anyone who has multiple and/or anonymous sexual partners.

• Avoid oral, genital and anal contact with partner's blood, semen, vaginal secretions, feces or urine. Unless they know with absolute certainty that their partner is not infected, a latex condom should be used during each sexual act, from start to finish. The use of a spermicidal agent may provide additional protection.

• Avoid anal intercourse altogether.

• Don't share toothbrushes, razors or other implements that could become contaminated with the blood of anyone who is or might be infected with the AIDS virus.

• Exercise caution regarding procedures, such as acupuncture, tattooing, ear piercing, etc., in which needles or other nonsterile instruments may be used repeatedly to pierce the skin and/or mucous membranes.

Such procedures are safe if proper sterilization methods are employed or disposable needles are used. Ask what precautions are taken before undergoing such procedures.

• If an individual is scheduling surgery in the near future, and is able, they could consider donating blood for their own use. This will eliminate completely the already very small risk of contracting AIDS through a blood transfusion. It will also eliminate the risk of contracting other bloodborne diseases (such as hepatitis) from a transfusion.

If a person is an IV drug user, adhere to the prevention tips mentioned earlier, as well as:

• Get professional help for terminating the drug habit.

• Do not share needles or syringes. Be aware that some street sellers are resealing previously used needles and selling them as new.

• Clean the needle before using.

Some people apparently remain well after infection of the AIDS virus. They may have no physically apparent symptoms of illness. However, if proper precautions are not used with sexual contacts and/or intravenous drug use, these infected individuals can spread the virus to others.

Anyone who thinks he or she is infected, or who is involved in high-risk behaviors, should not donate his/her blood, organs, tissues, or sperm as they may now contain the AIDS virus.

In general, taking only one or two drugs is not recommended because any decrease in viral load is almost always temporary without three or more drugs. The exception is the recommendation for pregnant women, who may take Combivir plus nevirapine to reduce the risk of passing HIV to their infants. If you are pregnant or considering becoming pregnant, there are additional treatment considerations. Recently, a number of drugs have been developed that combine two or even three separate medications in a single pill. Some of these, such as Truvada (emtricitabine + tenofovir) and Epzicom (abacavir + lamivudine) need be taken only once daily. Atripla (emtricitabine + tenofovir + efavirenz) combines three drugs in one pill and needs to be taken only once daily, thereby providing a complete HAART regimen with one pill once daily.

The treatment of HIV infection and AIDS is in a highly dynamic state. Individuals with this condition are advised to seek out experts in their local community who are current with the latest modes of therapy and ongoing clinical trials for evaluating newer therapies.

When HIV infects a CD4 cell in a person's body, it copies its own genetic code into the cell's DNA. The CD4 cell is then "programmed" to make new HIV genetic material and HIV proteins. The proteins must be cut up by the HIV protease—a protein-cutting enzyme—to make functional new HIV particles. PIs block the protease enzyme and prevent the cell from producing new viruses. It is recommended that they be used in combination with at least two other HIV drugs to treat HIV infection.

In order for viruses to reproduce, they must infect a cell. Viruses are not technically alive: they are sort of like a brain with no body. In order to make new viruses, they must hi-jack a cell, and use it to make new viruses. Just as your body is constantly making new skin cells, or new blood cells, each cell often makes new proteins in order to stay alive and to reproduce itself. Viruses hide their own DNA in the DNA of the cell, and then, when the cell tries to make new proteins, it accidentally makes new viruses as well. HIV mostly infects cells in the immune system.

Infection: Several different kinds of cells have proteins on their surface that are called CD4 receptors. HIV searches for cells that have CD4 surface receptors, because this particular protein enables the virus to bind to the cell. Although HIV infects a variety of cells, its main target is the T4-lymphocyte (also called the "T-helper cell"), a kind of white blood cell that has lots of CD4 receptors. The T4-cell is responsible for warning your immune system that there are invaders in the system.

Replication: Once HIV binds to a cell, it hides HIV DNA inside the cell's DNA: this turns the cell into a sort of HIV factory.

Definitions

There are a few things you need to know in order to understand HIV infection.

DNA: DNA is like the "blueprint" for building living cells.

Enzymes: Enzymes are like the workers of a cell. They build new proteins, transport materials around the cell, and carry out other important cellular functions.

RNA: RNA is like the construction boss. Cells use RNA to tell enzymes how to build a specific part of a cell. To make a new protein, enzymes will copy a specific part of the DNA into a piece of RNA. This RNA is then used by other enzymes to build a new protein or enzyme.

Proteins: The building blocks that are used to make living things.

Nucleus: A small package inside the cell where the genetic material is kept.

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