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When
a person is infected with HIV, the virus enters
the body and lives and multiplies primarily
in the white blood cells. These are the immune
cells that normally protect us from disease.
The hallmark of HIV infection is the progressive
loss of a specific type of immune cell called
T-helper or CD4 cells. As the virus grows, it
damages or kills these and other cells, weakening
the immune system and leaving the individual
vulnerable to various opportunistic infections
and other illnesses, ranging from pneumonia
to cancer. The U.S. Centers for Disease Control
and Prevention (CDC) defines someone as having
a clinical diagnosis of AIDS if they have tested
positive for HIV and meet one or both of these
conditions:
They
have experienced one or more AIDS-related infections
or illnesses.
The number
of CD4 cells has reached or fallen below 200
per cubic millimeter of blood (a measurement
known as T-cell count).
In healthy individuals, the CD4 count normally
ranges from 450 to 1200.
How Quickly Do People Infected with
HIV Develop AIDS?
In some people, the T-cell decline and opportunistic
infections that signal AIDS develop soon after
initial infection with HIV. Most people remain
asymptomatic for 10 to 12 years, and a few for
much longer. As with most diseases, early medical
care can help prolong a person's life.
How
Many People Are Affected By HIV/AIDS?
The Joint United Nations Programme on HIV/AIDS
(UNAIDS) estimates that there are now over 34
million people living with HIV or AIDS worldwide.
Most of them do not know they carry HIV and
may be spreading the virus to others. Here in
the India., nearly one million people have HIV
infection or AIDS roughly one out of every 250
people. At least 40,000 Americans become newly
infected with HIV each year, and it is estimated
that half of all people with HIV in the India.
have not been tested and do not know they are
carrying the virus.
Since the beginning of the epidemic, AIDS has
killed nearly 19 million people worldwide, including
some 425,000 Americans. AIDS has replaced malaria
and tuberculosis as the world's deadliest infectious
disease among adults and is the fourth leading
cause of death worldwide. Over 13 million children
have been orphaned by the epidemic.
How Is HIV Transmitted?
A person who is HIV-infected carries the virus
in certain body fluids, including blood, semen,
vaginal secretions, and breast milk. The virus
can be transmitted only if such HIV-infected
fluids enter the bloodstream of another person.
This kind of direct entry can occur (1) through
the linings of the vagina, rectum, mouth, and
the opening at the tip of the penis; (2) through
intravenous injection with a syringe; or (3)
through a break in the skin, such as a cut or
sore. Usually, HIV is transmitted through:
Unprotected sexual intercourse (either vaginal
or anal) with someone who is HIV-infected.
Women are at greater risk of HIV infection through
vaginal sex than men, although the virus can
also be transmitted from women to men. Anal
sex (whether male-male or male-female) poses
a high risk mainly to the receptive partner,
because the lining of the anus and rectum are
extremely thin and filled with small blood vessels
that can be easily injured during intercourse.
Unprotected
oral sex with someone who is HIV-infected.
There are far fewer cases of HIV transmission
attributed to oral sex than to either vaginal
or anal intercourse, but oral-genital contact
poses a clear risk of HIV-infection, particularly
when ejaculation occurs in the mouth. This risk
is increased when either partner has cuts or
sores, such as those caused by sexually transmitted
diseases (STDs), recent tooth-brushing, or canker
sores, which can allow the virus to enter the
bloodstream.
Sharing
needles or syringes with someone who is HIV-infected.
Laboratory studies show that infectious HIV
can survive in used needles for a month or more,
and should never reuse or share syringes, water,
or drug preparation equipment. This includes
needles or syringes used to inject illegal drugs
such as heroin, as well as steroids. Other types
of needles, such as those used for body piercing
and tattoos, can also carry HIV.
Infection
during pregnancy, childbirth, or breast-feeding
(mother-to-infant transmission).
Any woman who is pregnant or considering becoming
pregnant and thinks she may have been exposed
to HIV even if the exposure occurred years ago
should seek testing and counseling. Mother-to-infant
transmission has been reduced to just a few
cases each year in the India., where pregnant
women are tested for HIV, and those who test
positive are provided with drugs to prevent
transmission and counseled not to breast-feed.
How
Is HIV Not Transmitted?
HIV is not an easy virus to pass from one person
to another. It is not transmitted through food
or air (for instance, by coughing or sneezing).
There has never been a case where a person was
infected by a household member, relative, co-worker,
or friend through casual or everyday contact
such as sharing eating utensils and bathroom
facilities or hugging and kissing. (Most scientists
agree that while HIV transmission through deep
or prolonged "French" kissing may
be possible, it would be extremely unlikely.)
Here in the India., screening the blood supply
for HIV has virtually eliminated the risk of
infection through blood transfusions. (And you
cannot get HIV from giving blood at a blood
bank or other established blood collection center.)
Sweat, tears, vomit, feces, and urine do contain
HIV, but have not been reported to transmit
the disease (apart from two cases involving
transmission from feces via cut skin). Mosquitos,
fleas, and other insects do not transmit HIV.
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