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A person with untreated HIV infection will experience several
stages in infection.
These include:
- Viral transmission,
- Primary HIV infection,
- Seroconversion,
- Asymptomatic HIV infection,
- Symptomatic HIV infection, and
- AIDS.
These stages as sometimes called the "natural history" of
disease progression and are described below. The natural history
of HIV infection has been altered dramatically in developed
countries because of new medications. In countries where there
is no access to these expensive medications, or in cases where
people do not become aware of their HIV infection until very
late, the disease progresses as described below.
Currently, if the infection is untreated, the average time
from HIV infection to death is 10-12 years. Early detection
and medical treatment may mean that the person will live longer.
Viral transmission is the initial infection with HIV.
When a person is infected with HIV, they will probably have
virus circulating in their bloodstream, and may become infectious
to others within five days. The person may be infectious
before the onset of any symptoms. They will remain infectious
for the rest of their lives.
During primary HIV infection, the first few weeks
of HIV infection, an infected person has a very high amount
of virus in their bloodstream. The high viral load
means the individual may more easily pass the virus to others.
Unfortunately, during primary infection, many people are unaware
that they are infected.
The most common symptoms noticed by persons newly infected
with HIV are fever, swollen glands in the neck, armpits and/or
groin, rash, fatigue and a sore throat. These are symptoms
are common to many other infections. These initial symptoms
go away in a few weeks, but the individual continues to be
infectious to others. It resembles mononucleosis infection,
with similar symptoms and length of illness.
It is extremely important that healthcare providers consider
special testing for HIV itself (not antibodies) if an individual
has behaviors which put him or her at risk for HIV and is
presenting with the above symptoms. If individuals experience
these symptoms after having unprotected sex or sharing needles,
they should seek medical care and tell their provider why
they are concerned about HIV infection.
Some healthcare providers believe that a newly HIV-infected
person should begin to take drug therapies immediately. Others
believe that people should wait. However, people should also
assume that they could be taking HIV-related medications the
remainder of their lives.
The window period (or seroconversion period)
is the period of time after the virus enters the body and
attacks the CD4 cells until the body produces antibodies to
the virus. It may take between two weeks to six months for
antibodies to develop. This may vary from person to person.
HIV antibodies are detectable sometime generally within the
first three months of infection. During this time, the person
is infectious; s/he can pass the virus to someone else, and
will remain infectious throughout life. However, the person
may not have produced sufficient antibodies to be detectable
on an HIV antibody test. A newly infected person can infect
a partner before antibodies develop, when high amounts of
virus in the blood are present.
Asymptomatic HIV infection is the time period an HIV-infected
person has no noticeable signs or symptoms. The person may
look and feel healthy, but can still pass the virus to others.
It is not unusual for an HIV-infected person to live 10 years
or longer without any outward physical signs of progression
to AIDS. Meanwhile, the person's blood and other systems are
affected by HIV. This would be reflected in laboratory tests.
Unless a person in this stage has been tested for HIV, they
will probably not be aware they are infected.
During the symptomatic stage of HIV infection, a person
begins to have noticeable physical symptoms that are related
to HIV infection. Although there are no symptoms that are
specific ONLY to HIV infection, some common symptoms are:
- a persistent low grade fever
- pronounced weight loss that is not due to dieting
- persistent headaches
- diarrhea that lasts more than one month
- difficulty recovering from colds and the flu o a person
may become sicker than they normally would
- women may have recurrent vaginal yeast infections o thrush
(a yeast infection) coating the mouth or tongue
The specific definition of AIDS has changed over the
years. In 1987, the CDC defined AIDS using a positive HIV
antibody test plus a list of conditions that indicated a deficient
immune system. The original case definition of HIV infection
was based on the clinical symptoms seen in men.In 1993, the
CDC revised the classification system for HIV infection and
expanded the case definition for AIDS to include more conditions
and a variety of CD4-cell counts; it included invasive cervical
cancer, obviously a condition found only in women. The revised
definition meant that more people were considered to have
AIDS. That year there was a "jump" in the number of people
with AIDS which reflected the change in classification system.
The 1993 the Revised AIDS Surveillance Case Definition for
Adolescents and Adults, was comprised of a 3 x 3 staging system.
In this definition, any person who was HIV-infected and had
either an AIDS indicator condition or a CD4+, the T-cell count,
less than 200 cells/mm3, or less than 14%, was considered
to have AIDS.
In 2008, for adults and adolescents (aged >13 years), the
case definitions for HIV infection and AIDS was revised into
a single case definition for HIV infection that includes AIDS
and incorporates the HIV infection classification system.
Laboratory-confirmed evidence of HIV infection is now required
to meet the surveillance case definition for HIV infection,
including stage 3 HIV infection (AIDS). Diagnostic confirmation
of an AIDS-defining condition alone (see below), without laboratory-confirmed
evidence of HIV infection, is no longer sufficient to classify
an adult or adolescent as HIV infected for surveillance purposes.
The 2007 World Health Organization (WHO) revised surveillance
case definition for HIV infection also requires laboratory
confirmation of HIV infection (CDC, 2008c).
AIDS Indicator/Defining Conditions (Adults)
-
Candidiasis, of esophagus, trachea, bronchi
or lungs
-
Cervical cancer, invasive
-
Coccidioidomycosis, extrapulmonary
-
Cryptococcosis, extrapulmonary
-
Cryptosporidiosis with diarrhea greater
than one month
-
Cytomegalovirus of any organ other than
liver, spleen, or lymph nodes
-
Herpes simplex with mucocutaneous ulcer
lasting longer than one month or bronchitis, pneumonitis,
esophagitis
-
Histoplasmosis, extrapulmonary
-
HIV-associated dementia: disabling cognitive
and/or motor dysfunction interfering with activities of
daily living
-
HIV-associated wasting: involuntary weight
loss >10% of baseline plus chronic diarrhea (2 loose stools/day
for 30 days) or chronic weakness and documented enigmatic
fever 30 days
-
Isosporiasis, chronic intestinal (greater
than 1 month's duration)
-
Kaposi's sarcoma
-
Lymphoma of brain
-
Lymphoma, non-Hodgkins of B-cell or unknown
immunologic phenotype and histology showing small, noncleaved
lymphoma or immunoblastic sarcoma
-
Mycobacterium avium complex or M. kansasii,
disseminated
-
Tuberculosis
-
Pneumocystis jiroveci (carinii) pneumonia
-
Pneumonia, recurrent-bacterial (2 episodes
in 12 months)
-
Progressive multifocal leukoencephalopathy
-
Salmonella septicemia (non-typhoid), recurrent
-
Toxoplasmosis of internal organs
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