AIDS

DEFINITION

AIDS is the abbreviation for acquired immune deficiency syndrome. The disease is caused by a virus known as the human immunodeficiency virus, or HIV. The disease was first recognized in the United States in 1981.

A person can be infected with HIV without developing AIDS. The virus can remain in a person's body for many years without causing serious health problems. During this period, the virus is said to be latent, or inactive. Eventually, however, most people who are infected with HIV do develop AIDS. Treatment of HIV patients involves trying to slow or stop the virus from spreading in the body's cells and treating or preventing diseases that develop when a person's immune system has been damaged by the virus.

DESCRIPTION

AIDS is considered one of the most serious public health problems in modern history. In 1998 the U.S. Centers for Disease Control and Prevention (CDC) estimated that between 650,000 and 900,000 Americans were HIV-positive. HIV-positive means that a person has been infected with the virus. The CDC estimates that as of 1998 some 300,000 Americans were living with AIDS.

Nearly half of all AIDS patients are gay or bisexual men. About one quarter are intravenous drug users. An intravenous drug user is someone who takes drugs illegally by means of injection with a hypodermic needle. About 18 percent of AIDS patients are women. In addition, between one thousand and two thousand children are born infected with HIV each year.

AIDS is a far worse problem in some parts of the world than it is in others. The World Health Organization (WHO) estimates that 32.2 million adults and 1.2 million children worldwide were infected with HIV or AIDS as of 1998. Most of these cases occur in the developing countries of Asia and Africa.

At one time, people were concerned that HIV could be transmitted by casual contact, such as shaking hands or eating in the same room with an infected person. Scientists now know that the virus is never passed during casual contact of this kind. HIV can be transmitted in several ways:

SEXUAL CONTACT. HIV can be transmitted any time two people exchange bodily fluids, such as semen or blood. Most forms of sexual contact involve some exchange of bodily fluids. The risk of contracting the virus increases if an individual has a high number of different sexual partners or practices unsafe sex. Unsafe sex refers to having sexual contact without using any method to prevent the exchange of bodily fluids. In the United States and Europe, most cases of sexually transmitted HIV infection occur during homosexual contact, that is, between two people of the same gender. In Africa, Asia, and other parts of the world, HIV is transmitted primarily through heterosexual contact, that is, between two people of opposite genders.

EXPOSURE TO CONTAMINATED BLOOD OR BLOOD PRODUCTS. Early in the HIV epidemic, the virus was sometimes transmitted during blood transfusions. Blood taken from one person with the HIV infection was given to a second person for medical treatment, he or she also received the virus. Hemophiliacs (pronounced hee-muh-FIH-lee-ak; see hemophilia entry), people who require blood transfusions quite often, were especially at high risk for HIV infection.

In the 1980s, new rules were adopted for the screening of donated blood. Since that time, the rate of HIV infections from contaminated blood and blood products has been greatly reduced. However, HIV infection is still spread by this method among illegal drug users. These men and women often share the same needle with each other. When they do so, the blood from one person is easily transferred to a second person. If the first person is infected with HIV, the virus may be passed on.

NEEDLE STICKS. Health professionals sometimes poke themselves accidentally with a needle when drawing blood from a patient. If the patient is infected with HIV, the health professional may receive the virus from the needle stick. The risk of transmitting the virus this way is very small (virtually zero) when health professionals use standard procedures for drawing blood and handling needles.

PREGNANCY AND BIRTH. A woman infected with HIV can transmit the virus to her unborn child. The virus passes through the amniotic fluid (the fluid surrounding the unborn baby) and into the child's bloodstream. A young baby can also get the virus from an infected woman during breast feeding.

CAUSES

AIDS develops when HIV attacks and destroys certain types of cells that are part of the immune system. The immune system consists of all those cells, tissues, and substances that protect the body from infection by foreign bodies, such as bacteria. An important element of the immune system is a group of white blood cells that include helper T cells, macrophages (pronounced MAK-ruh-fages), and monocytes (pronounced MON-uh-sites). These cells attack foreign bodies and prevent them from causing disease and infection.

After it enters the body, HIV attaches itself to a certain part of these cells called the CD4 protein. The virus then takes command of the chemical changes that take place within the cell. It orders the cell to start making copies of the HIV virus. It eventually causes the cell's death. As the cell dies, it breaks apart and releases many new copies of the HIV. The new HIV cells then travel through the bloodstream and attack other white blood cells.

As white blood cells die, the immune system becomes weaker. The body is no longer able to fight back against infection. Infections that would normally be relatively harmless, such as the common cold (see common cold entry), can become life-threatening to someone who is HIV positive.

SYMPTOMS

A person who has been infected with HIV is likely to pass through three stages of the disease. Not all individuals experience all of the stages.

Acute Retroviral Syndrome

Acute retroviral syndrome is a term used to describe a group of symptoms that can resemble mononucleosis (pronounced MON-o-NOO-klee-O-siss; see infectious mononucleosis entry). Mononucleosis is a flu-like infection. Its symptoms include fever, fatigue, muscle aches, loss of appetite, upset stomach, weight loss, skin rash, headache, and swollen lymph nodes. These symptoms occur in 50 to 70 percent of all men who are HIV positive and in 45 to 90 percent of all women with the infection. The symptoms develop between one and six weeks after infection and last for two to three weeks.

Latency Period

After entering a person's lymph nodes, the virus becomes latent. Latency means that the virus is still present in the body, but that there are no signs of infection. Therefore, a person may appear to be perfectly healthy even though blood tests show that the virus is present.

HIV infection has an unusually long latency period. It may last for ten years or more. During this period, the virus continues to reproduce itself in the lymph nodes. As a result, certain abnormal conditions and symptoms may develop. These include the following:

• Persistent Generalized Lymphadenopathy (PGL). As HIV continues to reproduce, it can cause swelling of the lymph nodes known as persistent generalized lymphadenopathy (pronounced lim-fad-uhn-AP-uh-thee). The nodes become larger, but are usually not sore or painful. The lymph nodes most commonly affected are those in the neck, jaw, groin, and armpits. PGL affects between 50 to 70 percent of all patients during latency.
• Constitutional Symptoms. Many patients will develop low-grade fevers, fatigue, and general weakness. The virus may also cause a loss of appetite, a decrease in the body's ability to absorb food, and an increased rate of metabolism, the process by which the body converts food to energy. These changes result in a condition called wasting in which a person continually loses weight and energy.
• Other Symptoms. At any time during the course of HIV infection, the virus may cause problems with organs and tissues throughout the body. A common problem is a yeast infection in the mouth known as thrush. Ulcers and open sores can also develop in the mouth. The virus can also damage the digestive system. Patients may develop diarrhea or malnutrition as a result. The virus can also destroy cells in the lungs, kidneys, and nervous system. Damage to the nervous system leads to a general loss of strength, loss of reflexes, and feelings of numbness or burning sensations in the feet or lower legs.

Late-stage AIDS

Late-stage AIDS is the period of HIV infection when the virus has become very active and has started to cause massive damage to the immune system. One sign of late-stage AIDS is a sharp decrease in the number of white blood cells known as CD4 lymphocytes. The patient also begins to have more frequent and more serious medical problems, such as infectious diseases and cancers (see cancer entry). The infections that occur are called opportunistic infections. That term means that foreign bodies, such as bacteria, have taken advantage of the bodies weakened immune systems.

CD4 cell counts are an important indication of the course of the HIV infection. Doctors use these counts to determine how far the disease has developed and what treatments to use. About 10 percent of those individuals infected with HIV never reach this final stage of disease. Researchers do not know why these individuals are more resistant to the virus than others who do develop late-stage AIDS.

AIDS dementia (pronounced dih-MEN-sha) complex usually occurs late in the progress of AIDS. It is marked by loss of reasoning ability, loss of memory, inability to concentrate, listlessness, and unsteadiness in walking. Scientists do not understand how HIV causes AIDS dementia. There are no treatments for the condition.

Patients in late-stage AIDS may develop inflammation of the muscles, especially in the hip area. They may experience pain in their joints similar to those that occur with arthritis (see arthritis entry). Thrush and ulcers (open sores) in the mouth continue to occur during the late stages of AIDS. Another common condition of this stage is hairy leukoplakia (pronounced looko-PLA-kee-uh) of the tongue. Hairy leukoplakia is characterized by a white area on the tongue that may be flat or slightly raised.

Patients with late-stage AIDS may develop a form of cancer known as Kaposi's (pronounced kuh-PO-seez) sarcoma (KS). KS is a form of skin cancer characterized by reddish-purple blotches or patches. The disease may also occur in the digestive tract or lungs. KS is one of the most common causes of death in AIDS patients.

DIAGNOSIS

HIV infection can be difficult to diagnosis. Its symptoms are often similar to those of other diseases. To aid doctors in diagnosing the disease, the CDC has drawn up a list of thirty-four conditions to look for. These conditions can be used to decide which of three categories a patient falls into. Those categories include the following:

• Definite diagnosis with or without laboratory evidence of HIV infection.
• Definite diagnosis with laboratory evidence of HIV infection.
• Probable diagnosis with laboratory evidence of HIV infection.

Many symptoms discovered during a physical examination suggest the possibility of HIV infection. Some of these are more reliable predictors than others. Hairy leukoplakia of the tongue and KS are examples of strong predictors of HIV infection.

The presence of HIV infection is always confirmed with one or more blood tests. The first of these tests is called an enzyme-linked immunosorbent assay (ELISA). A person who tests positive on an ELISA test is then given a second blood test. That test is called a Western blot or immunofluorescence (pronounced im-yuh-no-flur-ES-uhnts) assay (IFA). A combination of the ELISA and Western blot test is 99.9 percent accurate in diagnosing HIV infection. In rare cases where doubt still exists, a third test is available, the polymerase (pronounced POL-uh-muh-raze) chain reaction (PCR) test.

A variety of tests are available to track the course of HIV infection. Among these are blood counts that measure the number and kind of white blood cells present. Tests also track the development of opportunistic infections, such as damage to the nervous system, and cancers.

TREATMENT

Treatment for AIDS involves the following:

• Prophylactic Treatment for Opportunistic Infections. Prophylactic (pronounced pro-fuh-LAK-tik) treatment is treatment given to prevent disease. Certain symptoms, such as persistent weight loss, low white blood cell counts, and the presence of thrush, are used to determine when prophylactic treatments should be given. Three drugs used in treatment are trimethoprim-sulfamethoxazole (pronounced tri-METH-o-prim SULL-fuhmeth-OCK-suh-zole), dapsone, and pentamidine (pronounced pen-TAM-uh-deen).

AZT shown at 25-times enlargement. (Reproduced by permission of

AP/Wide World Photos

)

• Treatment of Opportunistic Infections and Cancers. These treatments are often made more difficult because the organisms that cause the diseases may become resistant to the usual drugs used to kill them. In such cases, doctors have to look for other drugs with which to treat the infections. Both radiation therapy and chemotherapy (pronounced kee-mo-THAIR-uh-pee) can be used to treat some types of infections and forms of cancer.
• Anti-retroviral Treatment. Anti-retroviral treatments make use of drugs that attack and destroy the virus itself rather than treating the infections and diseases it causes. The first successful drugs of this kind were nucleoside analogues. A nucleoside analogue is a chemical that interferes when the virus tries to make copies of itself inside cells. If the virus cannot reproduce in cells, it cannot continue to damage white blood cells. The best known of these drugs is zidovudine (pronounced zie-DOE-vyoo-deen), sometimes called azidothymidine (pronounced AZE-ih-do-thi-mih-deen) or AZT.

One of the most serious problems in developing treatments for AIDS is that HIV mutates (changes) rapidly. In a short period of time, it can become resistant to drugs that could once kill it. As those drugs become ineffective against the disease, new ones must be found to replace them.

In 1997, the first of a new class of drugs was approved for use with AIDS patients. This class of drugs is the protease inhibitors and includes saquinavir (pronounced suh-KWIN-uh-ver). The protease inhibitors are now used by themselves or in combination with nucleoside analogues to kill the virus.

Stimulation of Blood Cell Production

Many AIDS patients have very low levels of white and red blood cells. People with low red blood cell counts often suffer from anemia (see anemia entry), a condition that causes weakness, exhaustion, and generally poor health. People with low white blood cell counts are unable to fight off infections. To protect AIDS patients against these conditions, drugs may be given to stimulate the production of both red and white blood cells.

Alternative Treatment

For many years, doctors were able to offer AIDS patients little assistance in treating their disease. As a result, patients became very interested in alternative forms of treatment. Among those treatments were a variety of Chinese and Western herbal medicines and specialized diets designed to strengthen the immune system. Patients also tried nonphysical methods, such as visualization. In visualization, a person tries to imagine what a virus looks like and what kind of battle is going on in his or her body. By this method, the person believes that he or she may have some control over that battle.

Patients have tried a variety of pain control techniques as well. These have included hydrotherapy (the use of water baths and treatments), acupuncture (a Chinese therapy technique where fine needles puncture the body), meditation, and chiropractic (pronounced KIRE-uh-prak-tik; therapy that involves manipulation of the spine).

PROGNOSIS

At present there is no cure for AIDS. At one time, however, a diagnosis of HIV infection was thought to be a death sentence. Today, that situation has changed. The development of new drugs and new ways of using those drugs has made it possible to prolong the life of an AIDS patient. Since the introduction of drug cocktails (the combining of two or more drugs) in the treatment of HIV infection, the death rate from AIDS in the United States and other developed countries has dropped dramatically.

The situation is quite different in some countries because the drugs used to treat AIDS are very expensive. People who are HIV positive in developing nations are seldom able to afford the expense of taking such drugs. The AIDS epidemic is, therefore, still out of control in most parts of the world.

PREVENTION

The ultimate goal of many AIDS researchers is to find a vaccine against the virus. If such a vaccine were found, people could be protected against the disease as they are against measles, mumps, and other infectious diseases. As of 1999 more than a dozen different vaccines were being tested.

This seven-year-old Kenyan girl, looking much younger due to her illness, is suffering from pneumonia due to HIV complications. (Reproduced by permission of

AP/Wide World Photos

)

Until a vaccine is developed, the best protection against AIDS is to avoid contracting the HIV virus by doing the following:

• Limiting the number of sexual partners and practicing safer sex. The fewer partners one has and the better one knows those partners, the less the risk of HIV infection. The risk of transmitting the virus can also be reduced by some simple practices, such as using a condom.
• Avoiding the sharing of needles among intravenous drug users.
• Making plans to use one's own blood when major surgery is planned. By doing so, there is no risk of contracting HIV from the blood of an infected donor.
• Observing normal and standard procedures for handling needles and blood products by health care professionals. These procedures include the wearing of face masks and gloves when working with patients.
• Having an HIV test as soon as one suspects that he or she may have been infected with the virus. In general, the sooner one knows that infection has occurred, the more effective treatment can be.

FOR MORE INFORMATION

Books

Check, William A. AIDS: The Encyclopedia of Health. New York: Chelsea House Publishers, 1998.

Newton, David E. AIDS Issues: A Handbook. Hillside, NJ: Enslow Publishers, 1992.

Silverstein, Alvin, Virginia B. Silverstein, and Laura Silverstein Nunn. AIDS: An All-About Guide for Young Adults. Hillside, NJ: Enslow Publishers, 1999.

Organizations

AIDS Action. 1875 Connecticut Avenue NW, Washington, DC 20009. (202) 986–1300. http://www.aidsaction.org.

American Foundation for AIDS Research (AmFAR). 120 Wall Sreet, 13th floor, New York, NY 10005. (212) 806–1600. http://www.amfar.org.

Gay Men's Health Crisis, Inc. 129 West 20th Street, New York, NY 10011–0022. (212) 807–6655.

National AIDS Hot Line. (800) 342–AIDS (English); (800) 344–SIDA (Spanish); (800) AIDS–TTY (hearing impaired).

Web sites

AVERT-AIDS Education and Research Trust. [Online] http://www.avert.org (accessed on June 15, 1999).

HIV InSite: Gateway to AIDS Knowledge. [Online] http://HIVinsite.ucsf.edu (accessed on October 7, 1999).