AIDS

Definition

AIDS is the end stage of an infectious disease caused by the human

immunodeficiency virus, or HIV. The virus damages the person

immune system, leaving them vulnerable to certain cancerous tumors

and increasingly severe opportunistic infections. HIV can be transmitted

whenever a body fluid containing the virus (especially blood or sexual

fluids) comes into contact with a mucous membrane (soft tissues lining

various body cavities, like the mouth or vagina) or the bloodstream itself.

A person can get AIDS through sexual intercourse, anal or oral sex, childbirth,

breastfeeding, blood transfusion, or sharing hypodermic needles.

’s

Description

AIDS is now considered a pandemic because it has spread to every country in

the world. According to the World Health Organization (WHO), 33.2

million people around the world were living with HIV infection in 2007;

2.1 million people died in that year from the disease, 330,000 of them children.

Scientists think that the virus that causes AIDS originated somewhere

in the African rainforest as an infection of chimpanzees and Old World

monkeys. At some point in the twentieth century it jumped the species barrier

from monkeys into humans. AIDS was first defined as an epidemic

human disease in June 1981 by the Centers for Disease Control and

Prevention (CDC). The virus that causes AIDS was identified by two

teams of French and American scientists in 1983

HIV infection progresses in stages as the virus gradually weakens the

body

to progress to AIDS. AIDS is diagnosed when the count of certain white

blood cells in the patient

develops life-threatening tumors or opportunistic infections.

In the early stage of HIV infection, the patient may have no symptoms

at all or a mild flu-like illness with fever and headache within a few days or

weeks of getting infected. These symptoms usually go away without treatment

and the person feels normal, even though he or she can transmit the

infection to others. The infected person may continue to feel well for a

period ranging from a few months to several years.

Demographics

Worldwide, about 0.6 percent of the population is infected with HIV, or

about 35 million people. Ninety-five percent of these cases are in Africa

or southeastern Asia. About 25 million people have died of AIDS since

1981, making the disease one of the deadliest pandemics in history. In

the United States, the CDC

about 945,000 people have been diagnosed with AIDS since 1981, and

about 1.2 million are currently living with HIV infection. About a

quarter of these people are unaware that they are infected. The CDC estimates

that there are about 56,300 new cases of HIV infection in the

United States each year.

In terms of specific groups within the United States:

’s recently revised estimates indicate that

•

Worldwide, the figure is 50 percent.

•

are African American, 34 percent are Caucasian, 17 percent are

Hispanic, and 2 percent are Native American or Asian American.

In terms of race or ethnicity, 47 percent of persons with HIV infection

•

are men who had sex with men; 33 percent had high-risk heterosexual

sex; 13 percent are injection drug users; and the remainder

are people who engaged in more than one high-risk behavior.

In terms of method of transmission, 50 percent of infected persons

•

years of age; 15 percent are between the ages of thirteen and

twenty-four; 26 percent are between the ages of twenty-five and

thirty-four; 32 percent are between the ages of thirty-five and fortyfour;

20 percent are between the ages of forty-five and fifty-four;

8 percent are fifty-five or older.

Causes and Symptoms

The cause of AIDS is infection with human immunodeficiency virus or

HIV. HIV is a virus that reproduces by inserting its own genetic material

into a type of white blood cell called a CD4 lymphocyte. When the virus

copies break out of the infected white blood cell, they attack other CD4

cells and the cycle repeats. Eventually so many of the white blood cells

have been destroyed that the body

person can no longer fight off opportunistic infections. The person may

also develop certain cancers associated with a weakened immune system.

In the early stage of HIV infection, the patient may have no symptoms

or else a mild flu-like illness with headache, fever, and swollen

lymph nodes. Some patients have a second set of symptoms, often years

after the initial infection, characterized by diarrhea, weight loss, shortness

of breath, and coughing. To meet the official definition of AIDS, however,

the patient must develop an opportunistic infection and have a

CD4 cell count below 200. Opportunistic infections include diseases like

toxoplasmosis, yeast infections of the esophagus, pneumonia caused by

an organism known as

tract caused by parasites. Cancers associated with AIDS include Kaposi

sarcoma, a skin cancer; and non-Hodgkin lymphoma.

Other symptoms of full-blown AIDS include:

’s immune system is weakened and thePneumocystis, and various disorders of the digestive

•

Soaking night sweats

•

Fever over 100°F (37.7°C) that lasts for several weeks

•

Headaches

•

Blurred vision or other vision problems

•

Chronic diarrhea

•

Swelling in the lymph nodes that lasts for three months or longer

Diagnosis

The diagnosis of HIV infection and AIDS is complicated by the fact that

many people are afraid to be tested for the disease. They may fear that a

positive test will lead to the loss of housing, jobs, relationships, or the

chance to complete their education. Because many infected persons put

off getting tested and telling their partners, the disease continues to

spread. In 2006, the CDC recommended routine HIV screening for all

adults, adolescents, and pregnant women within health care settings, not

just those considered to be high-risk.

Testing for HIV is a two-step process. The first test is a screening

test, which usually involves taking a sample of the patient

are newer screening tests that can use a sample of the person

saliva. These rapid screening tests look for antibodies to the HIV virus

and give results in about twenty minutes. If the person tests positive

for HIV infection, a more specific second test, called a Western blot

test, is performed. This test uses a blood sample to identify antibodies

against HIV.

In 1996 the Food and Drug Administration approved a test kit that

people can use at home called the Home Access HIV-1 Test. The person

pricks their finger on a special blotting card and mails it back to the

company. The sample is identified only by a code number, which allows

the person to remain completely anonymous. The test costs about

$45.00 and results are available in seven days.

An important point to keep in mind is that it may take the body several

weeks to three months after a person is infected to produce enough

antibodies to HIV to be detected by a blood test. This period of time is

called the window period. A person who tests negative for HIV infection

after high-risk behaviors should wait three months and have another

blood test to make sure they are not infected.

’s blood. There’s urine or

Treatment

There currently is no cure for HIV infection or AIDS. When a person

tests positive for HIV infection, the doctor will measure the amount of

virus in the patient

load helps the doctor to decide when to start drug treatment for HIV.

The current method of treatment is called highly active antiretroviral

therapy or HAART. Introduced in 1996, HAART consists of combinations

of three or more different drugs from two or more of the classes

of antiretroviral drugs presently available. HAART is not a cure for AIDS,

but it reduces the viral load, improves the patient

and extends life expectancy.

HAART has several drawbacks. First, it can be very expensive form

of treatment. In addition, the drugs used in HAART have troublesome

side effects; as a result, some AIDS patients simply stop taking their medications.

Last, some patients develop resistance to the antiretroviral drugs

and no longer respond to treatment especially if the patient does not

follow the treatment course and misses dosages. The doctor can sometimes

switch one of the drugs in the patient

within the same class or another class.

’s combination to another drug

Prognosis

AIDS cannot be cured. Without treatment, HIV infection progresses to

AIDS in an average of eleven years. After diagnosis with AIDS, the patient

has a life expectancy of just over nine months without treatment.

A person diagnosed with HIV infection who begins treatment with

HAART can expect to live about twenty years or more after the diagnosis.

Unfortunately, about half of patients who begin treatment with HAART

fail to benefit from it as much as they had hoped and discontinue it.

Prevention

There is no vaccine against HIV infection; moreover, it is unlikely that an

effective vaccine will be developed in the foreseeable future because the

virus that causes AIDS mutates so rapidly. Although various vaccines

against HIV have been tested by the National Institutes of Health since

1996, none have so far been approved for use outside clinical trials.

People can lower their risk of HIV infection by taking the following

precautions recommended by the CDC:

•

and is faithful.

Limit sexual activity to a single partner who is known to be uninfected

•

unknown.

Use a condom when having sex with anyone whose HIV status is

•

Do not share needles or inject illegal drugs.

•

Do not exchange sex for drugs.

•

needle sticks and other accidental exposures to body fluids that

may be contaminated with HIV.

Health care workers should follow guidelines for protecting against

•

if the test results are positive, inform all current sexual

partners.

Get tested for HIV infection after engaging in high-risk activities;

The Future

The demographics of HIV infection within the United States are

changing somewhat, with women accounting for more new cases than

in 1998. A worrisome new trend is the return and increase of high-risk

behaviors among men who have sex with men. This trend appears to

have been triggered by the spread of methamphetamine addiction

from the West Coast to the Eastern Seaboard over the past several

years.

Researchers at the National Institutes of Health are continuing to

test various vaccines against HIV. They are also working on developing

new antiretroviral drugs for patients who have developed resistance to

those presently in use.

SEE ALSO

Syphilis; ToxoplasmosisDepression; Gonorrhea; Hemophilia; Lymphoma; Pneumonia;’s blood. This level is called the viral load. The viral’s overall quality of life,In terms of age group, 1 percent of infected persons are under thirteenMales account for 74 percent of persons with HIV infection.–1984.’s immune system. It takes an average of eleven years for HIV infection’s blood drops to a critical level or the patient

AIDS