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AIDS
Awareness
AIDS - acquired immune deficiency syndrome - was first reported
in the United States in 1981 and has since become a major
worldwide epidemic. AIDS is caused by the human immunodeficiency
virus (HIV). By killing or impairing cells of the immune system,
HIV progressively destroys the body's ability to fight infections
and certain cancers. Individuals diagnosed with AIDS are susceptible
to life-threatening diseases called opportunistic infections,
which are caused by microbes that usually do not cause illness
in healthy people.
More
than 600,000 cases of AIDS have been reported in the United
States since 1981, and as many as 900,000 Americans may be
infected with HIV. The epidemic is growing most rapidly among
minority populations and is a leading killer of African-American
males. According to the U.S. Centers for Disease Control and
Prevention (CDC), the prevalence of AIDS is six times higher
in African-Americans and three times higher among Hispanics
than among whites.
Transmission
HIV
is spread most commonly by sexual contact with an infected
partner. The virus can enter the body through the lining of
the vagina, vulva, penis, rectum or mouth during sex.
HIV
also is spread through contact with infected blood. Prior
to the screening of blood for evidence of HIV infection and
before the introduction in 1985 of heat-treating techniques
to destroy HIV in blood products, HIV was transmitted through
transfusions of contaminated blood or blood components. Today,
because of blood screening and heat treatment, the risk of
acquiring HIV from such transfusions is extremely small.
HIV
frequently is spread among injection drug users by the sharing
of needles or syringes contaminated with minute quantities
of blood of someone infected with the virus. However, transmission
from patient to health-care worker or vice-versa via accidental
sticks with contaminated needles or other medical instruments
is rare.
Women
can transmit HIV to their fetuses during pregnancy or birth.
Approximately one-quarter to one-third of all untreated pregnant
women infected with HIV will pass the infection to their babies.
HIV also can be spread to babies through the breast milk of
mothers infected with the virus. If the drug AZT is taken
during pregnancy, the chance of transmitting HIV to the baby
is reduced significantly. If AZT treatment of mothers is combined
with cesarean sectioning to deliver infants, infection rates
can be reduced to 1 percent. In Maryland, all pregnant women
who seek prenatal care must routinely receive counseling about
HIV, and be offered voluntary HIV antibody testing. If a woman
is considering pregnancy, she may want to be tested for HIV.
Although
researchers have detected HIV in the saliva of infected individuals,
no evidence exists that the virus is spread by contact with
saliva. Laboratory studies reveal that saliva has natural
compounds that inhibit the infectiousness of HIV. Studies
of people infected with HIV have found no evidence that the
virus is spread to others through saliva such as by kissing.
No one knows, however, the risk of infection from so-called
"deep" kissing, involving the exchange of large
amounts of saliva, or by oral intercourse. Scientists also
have found no evidence that HIV is spread through sweat, tears,
urine or feces.
Studies
of families of HIV-infected people have shown clearly that
HIV is not spread through casual contact such as the sharing
of food utensils, towels and bedding, swimming pools, telephones
or toilet seats. HIV is not spread by biting insects such
as mosquitoes or bedbugs.
HIV
can infect anyone who practices risky behaviors such as:
- sharing
drug needles or syringes;
- having
sexual contact without using a latex male condom with an
infected person or with someone whose HIV status is unknown.
Having
another sexually transmitted disease such as syphilis, herpes,
chlamydial infection, gonorrhea or bacterial vaginosis appears
to make someone more susceptible to acquiring HIV infection
during sex with an infected partner.
Early
Symptoms
Many
people do not develop any symptoms when they first become
infected with HIV. Some people, however, have a flu-like illness
within a month or two after exposure to the virus. They may
have fever, headache, malaise and enlarged lymph nodes (organs
of the immune system easily felt in the neck and groin). These
symptoms usually disappear within a week to a month and are
often mistaken for those of another viral infection. People
are very infectious during this period, and HIV is present
in large quantities in genital secretions.
More
persistent or severe symptoms may not surface for a decade
or more after HIV first enters the body in adults, or within
two years in children born with HIV infection. This period
of "asymptomatic" infection is highly variable.
Some people may begin to have symptoms in as soon as a few
months, whereas others may be symptom-free for more than 10
years. During the asymptomatic period, however, HIV is actively
multiplying, infecting and killing cells of the immune system.
HIV's effect is seen most obviously in a decline in the blood
levels of CD4+ T cells (also called T4 cells) - the immune
system's key infection fighters. The virus initially disables
or destroys these cells without causing symptoms.
As
the immune system deteriorates, a variety of complications
begins to surface. One of the first such symptoms experienced
by many people infected with HIV is large lymph nodes or "swollen
glands" that may be enlarged for more than three months.
Other symptoms often experienced months to years before the
onset of AIDS include a lack of energy, weight loss, frequent
fevers and sweats, persistent or frequent yeast infections
(oral or vaginal), persistent skin rashes or flaky skin, pelvic
inflammatory disease that does not respond to treatment, or
short-term memory loss.
Some
people develop frequent and severe herpes infections that
cause mouth, genital or anal sores, or a painful nerve disease
known as shingles. Children may have delayed development or
failure to thrive.
Diagnosis
Because
early HIV infection often causes no symptoms, it is primarily
detected by testing a person's blood for the presence of antibodies
(disease-fighting proteins) to HIV. HIV antibodies generally
do not reach detectable levels until one to three months following
infection and may take as long as six months to be generated
in quantities large enough to show up in standard blood tests.
HIV testing may also be performed on saliva and urine samples,
in addition to blood samples.
People
exposed to HIV should be tested for HIV infection as soon
as they are likely to develop antibodies to the virus. Such
early testing will enable them to receive appropriate treatment
at a time when they are most able to combat HIV and prevent
the emergence of certain opportunistic infections. Early testing
also alerts HIV-infected people to avoid high-risk behaviors
that could spread HIV to others.
If
a person thinks they have been exposed to the AIDS virus,
they may want to be tested for HIV. Confidential and anonymous
HIV antibody testing are both offered in Maryland. Pre-test
counseling and written informed consent are required prior
to HIV antibody testing.
Two
different types of antibody tests, ELISA and Western Blot,
are used to diagnose HIV infection. If a person is highly
likely to be infected with HIV and yet both tests are negative,
a doctor may test for the presence of HIV itself in the blood.
The person also may be told to repeat antibody testing at
a later date, when antibodies to HIV are more likely to have
developed.
In
addition, blood samples for anonymous HIV testing may now
be collected at home. Home-based test kits are available by
telephone order or over the counter at pharmacies.
Babies
born to mothers infected with HIV may or may not be infected
with the virus, but all carry their mothers' antibodies to
HIV for several months. If these babies lack symptoms, a definitive
diagnosis of HIV infection using standard antibody tests cannot
be made until after 15 months of age. By then, babies are
unlikely to still carry their mothers' antibodies and will
have produced their own, if they are infected. New technologies
to detect HIV itself are being used to more accurately determine
HIV infection in infants between ages 3 months and 15 months.
A number of blood tests are being evaluated to determine if
they can diagnose HIV infection in babies younger than 3 months.
Treatment
When
AIDS first surfaced in the United States, no drugs were available
to combat the underlying immune deficiency and few treatments
existed for the opportunistic diseases that resulted. Over
the past 10 years, however, therapies have been developed
to fight both HIV infection and its associated infections
and cancers.
The
Food and Drug Administration has approved a number of drugs
for the treatment of HIV infection. The first group of drugs
used to treat HIV infection, called nucleoside analog reverse
transcriptase inhibitors (NRTIs), interrupt an early stage
of virus replication. Included in this class of drugs are
zidovudine (also known as AZT), zalcitabine (ddC), didanosine
(ddI), stavudine (D4T), lamivudine (3TC) and abacavir succinate.
These drugs may slow the spread of HIV in the body and delay
the onset of opportunistic infections. Importantly, they do
not prevent transmission of HIV to other individuals. Non-nucleoside
reverse transcriptase inhibitors (NNRTIs) such as delavirdine,
nevirapine and efavirenz are also available for use in combination
with other antiretroviral drugs.
A
third class of anti-HIV drugs, called protease inhibitors,
interrupts virus replication at a later step in its life cycle.
They include ritonavir, saquinivir, indinavir and nelfinavir.
Because HIV can become resistant to each class of drugs, combination
treatment using both is necessary to effectively suppress
the virus.
Currently
available antiretroviral drugs do not cure people of HIV infection
or AIDS, however, and they all have side effects that can
be severe. AZT may cause a depletion of red or white blood
cells, especially when taken in the later stages of the disease.
If the loss of blood cells is severe, treatment with AZT must
be stopped. DdI can cause an inflammation of the pancreas
and painful nerve damage.
The
most common side effects associated with protease inhibitors
include nausea, diarrhea and other gastrointestinal symptoms.
In addition, protease inhibitors can interact with other drugs
resulting in serious side effects. Investigators also recently
have reported cases of abnormal redistribution of body fat
among some individuals receiving protease inhibitors.
A
number of drugs are available to help treat opportunistic
infections to which people with HIV are especially prone.
These drugs include foscarnet and ganciclovir, used to treat
cytomegalovirus eye infections, fluconazole to treat yeast
and other fungal infections, and TMP/SMX or pentamidine to
treat Pneumocystis carinii pneumonia (PCP).
In
addition to antiretroviral therapy, adults with HIV whose
CD4+ T-cell counts drop below 200 are given treatment to prevent
the occurrence of PCP, which is one of the most common and
deadly opportunistic infections associated with HIV. Children
are given PCP preventive therapy when their CD4+ T-cell counts
drop to levels considered below normal for their age group.
Regardless of their CD4+ T-cell counts, HIV-infected children
and adults who have survived an episode of PCP are given drugs
for the rest of their lives to prevent a recurrence of the
pneumonia.
HIV-infected
individuals who develop Kaposi's sarcoma or other cancers
are treated with radiation, chemotherapy or injections of
alpha interferon, a genetically engineered naturally occurring
protein.
Prevention
Since
no vaccine for HIV is available, the only way to prevent infection
by the virus is to avoid behaviors that put a person at risk
of infection, such as sharing needles and having unprotected
sex.
Because
many people infected with HIV have no symptoms, there is no
way of knowing with certainty whether a sexual partner is
infected unless he or she has been repeatedly tested for the
virus or has not engaged in any risky behavior. It is recommended
that people either abstain from sex or protect themselves
by using barriers such as latex condoms, dental dams and female
condoms whenever having oral, anal or vaginal sex. Water-based
rather than oil based lubricants should be used with latex
condoms.
Although
some laboratory evidence shows that spermicides can kill HIV
organisms, in clinical trials, researchers have not found
that these products can prevent HIV.
In
Maryland, all pregnant women who seek prenatal care must routinely
receive counseling about HIV, and be offered voluntary HIV
antibody testing. If a woman is considering pregnancy, she
may want to be tested for HIV. The risk of HIV transmission
from a pregnant woman to her fetus is significantly reduced
if she takes AZT during pregnancy, labor and delivery, and
her baby takes it for the first six weeks of life.
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