AIDS

AIDS: Since early in the 1980s, when a previously unknown disease began to cause people to die in large numbers in Africa, the Caribbean region, and the United States, this syndrome, known to all as AIDS, has become perhaps the most feared disease in the world. Despite these fears, AIDS is unusual in that there are well-known ways for an individual to avoid infection. These methods are simple and nearly completely effective.

Cause AIDS is caused by HIV (human immunodeficiency virus). HIV infects and reproduces in white blood cells in the human body. When body fluids primarily blood and sexual fluids, but also breast milk that contains infected white blood cells get into the bloodstream of an uninfected person, a new infection can occur.

Incidence As of the end of 1997, 641,068 cases of AIDS had been diagnosed in the United States. Worldwide, about 12 million people have died. Another 30 million worldwide are thought to be infected with the HIV virus but to have not progressed to AIDS. In 1997 the UN estimated that about 16,000 additional people were infected each day. Worldwide cases of HIV infection are expected to reach 40 million by the year 2000.
By the end of 1997, over the 16-year history of the disease, 3,130 individuals 13 to 19 years old had been diagnosed with AIDS in the United States. Today teens are one of the groups at greatest risk for HIV infection and AIDS.

Symptoms you are likely to notice On average, a person with HIV infection remains without symptoms for 10 to 12 years after infection. During this time the infected person can live a normal life - getting an education, working at a job, and enjoying hobbies, families, and friends. The first symptoms are usually general and include night sweats, unexplained weight loss, nausea, great fatigue, and white patches in the mouth. Not everyone with these symptoms has HIV infection; only a physician can make this determination.

Symptoms your physician may observe If a physician suspects HIV infection because of patient history or because of unusual infections, he or she will recommend that the individual take an HIV antibody test. This test will tell whether the person's immune system is making antibodies to fight HIV. If HIV antibodies are present, the person is HIV-infected (HIV positive).
The physician then will take blood to find out the person's T4 cell count. T4 cells are white blood cells in which the virus reproduces. As HIV infection progresses, the number of T4 cells declines. The number of T4 cells gives the physician an indication of where the person is in the progression of the HIV infection.
The physician may also test blood to determine viral load, that is, the amount of virus in the blood. Knowledge of viral load also helps the physician to identify the stage of infection and thus the selection of the best care.

Treatment options New treatments were introduced in the 1990s that have greatly improved the outlook for people with HIV infection. Two types of medications, called antiretrovirals and protease inhibitors, are used to slow the progression of HIV in the body. Infected individuals who take these medications generally stay healthy longer than individuals who do not take them. There is some evidence that early use of these medicines can eliminate HIV infection, but more study is needed before this can be confirmed. However, these medicines have serious side effects in some people, including anemias, pancreatitis and serious disturbances of fat metabolism.
Another option, still experimental, is to use vaccines to treat or prevent HIV infection. Continuing tests on both animals and humans, however, have not established that any vaccine so far developed is effective. Improvements in understanding the virus may lead to effective vaccines in the future.
If AIDS develops as a result of HIV infection, the impaired immune system makes the patient vulnerable to many infections. In that case, a physician may also prescribe medicine to prevent the more serious illnesses associated with HIV infection, such as Pneumocystis carinii pneumonia (PCP).

Stages and progress HIV gradually destroys the body's immune system as it commandeers white blood cells to reproduce itself. After it reproduces, HIV destroys the T4 cells, releasing HIV particles to infect new cells and repeat the cycle. This destruction occurs slowly, and it can take more than a decade before the immune system is weak enough for symptoms of illness to occur. When the first, general symptoms appear, the infected person is said to be HIV-positive symptomatic (HIV-infected with symptoms).
As the immune system is destroyed even further, the body becomes unable to fight off infections and diseases that a healthy person can control. When an HIV-infected person gets these secondary diseases, such as PCP and Kaposi's sarcoma, a type of cancer, we say that the person has AIDS. Other secondary diseases include cytomegalovirus retinitis, which destroys vision, cryptosporidiosis, an intestinal infection that reduces the ability to absorb nutrients, and tuberculosis of the lungs, bones, or other body organs.
One condition AIDS dementia - is caused by the HIV infection itself. HIV, if not checked by medication, sometimes gets into the brain and destroys brain cells. People with AIDS dementia lose some motor control and may have a shuffling gait. They also may become easily confused and experience feelings of paranoia.
Most people with AIDS have many secondary infections. It is these secondary diseases that eventually cause death in HIV-infected people.

Prevention There is no cure for HIV infection or for AIDS, and there is no vaccine to prevent infection. The only option at present is to prevent HIV infection in the first place.
HIV infection is the result of engaging in specific behaviors with an HIV-infected individual. HIV is passed from person to person when they have sex without using a condom or when they share needles to inject drugs, steroids, or other substances. Almost all of the cases of AIDS in the world have resulted from one or both of these behaviors. Fewer cases - about 3% in the United States - have occurred when a person received infected blood during a transfusion or infected blood products to treat hemophilia. Today all blood and blood products are tested to prevent transmission in this way. About 1.5% of all cases in the United States occur when a baby is born to an infected woman. About 25% of babies born to HIV-infected women are born with the virus. New treatments during pregnancy, however, can reduce transmission to 8%.
The best prevention is to not use drugs and to have sex only when certain that one's partner is not infected with HIV. The next best prevention is to use a condom correctly with every partner, every time, for vaginal, oral, or anal sex. For people who use needle drugs, the best prevention is to not share needles, syringes, or other drug paraphernalia.

History and risk factors In the United States AIDS was identified as a new, unique disease in 1981. The first cases were in young men who were homosexual. Soon cases were identified in drug users, their sexual partners, and among the babies of HIV-infected women. In 1984 HIV was recognized as the virus that causes AIDS, and in 1985 a blood test was developed to identify blood and body fluids containing the virus.
It is clear that risky behaviors, not risk groups, are the focus for prevention. Many men who have sex with men do not identify themselves as being homosexual, and many people who occasionally use injected drugs do not think of themselves as being drug users. But these individuals are at risk for HIV infection. On the other hand, many homosexual men are in monogamous relationships and many drug users do not share needles, and so are not at risk for HIV infection.

Effects on world population and health AIDS is a major killer worldwide of people 20 to 40 years of age. In some regions of Africa there are villages where all adults and babies have died of AIDS. Whole nations are at risk; one person in five in Zimbabwe is thought to be HIV infected, for example. It is estimated than more than 500,000 children have been born with AIDS in Africa alone.
The pattern of AIDS infection differs in different parts of the world. In the Americas and Western Europe four out of five cases are in men. In Africa south of the Sahara approximately equal numbers of men and women have AIDS, chiefly, it is thought, as a result of heterosexual transmission. But this is changing. In the United States increasing numbers of heterosexually transmitted cases in women are being seen each year.

HIV testing A person who is infected with HIV can live for many years without knowing that he or she is infected. The only way to know for certain is to take a blood test. An HIV blood test looks for antibodies that fight HIV. People who are not infected do not have HIV antibodies; people who are infected do. The body starts making antibodies soon after infection occurs. These antibodies float in the blood and circulate through the body. At first there are only small amounts of HIV antibodies in the blood of an infected person, but after about 30 days there are enough antibodies for the HIV test to "see" them.
The HIV test is actually two tests. The first test is very sensitive; it finds anything that looks at all like HIV antibodies. This is the test that is used to screen blood and blood products. If the first test is positive, that is, antibodies to HIV appear to be present, another test is done. The second test is specific and is called a confirmatory test. It separates the false positives from the true positives of the first test. A person is HIV-positive only if the second test is positive for HIV antibodies.
Health departments in many states offer free or inexpensive testing. A sexual and drug history may be taken. Information about state laws regarding confidentiality of test results is given. Prevention education may be given and resources for HIV-infected individuals discussed. The person wanting the test may be asked how he or she might react if the test were positive. Home test kits are also available.
In most states a person has to return to the testing site to get results. This enables the individual to get a clear explanation of what the test means - and what it does not mean. A negative test result means that the person is not infected only if the last risky behavior occurred more than 30 days before the test. If there has been recent risky behavior, the person will be asked to be retested 30 days after that behavior.
A positive test result means that the person is infected but does not mean that he or she will be ill soon. The infected person must see a physician to get this information and appropriate care.