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The Natural History of HIV Infection
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.
A cofactor is a separate condition that can change
or "speed up" the course of disease. There are several cofactors
that can increase the rate of progression to AIDS. They include
a person's age, certain genetic factors and possibly drug
use, smoking, nutrition and hepatitis C (HCV).
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 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. This is sometimes called "seroconversion syndrome"
or "seroconversion sickness." 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 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. 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.
Seroconversion is the time period that it takes from
infection to the production of antibodies, which would show
positive on an HIV test. This may vary from person to person.
HIV antibodies are detectable sometime within the first three
to six months of infection, and in most cases will be detectable
for life
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.
The incubation period is the interval between HIV
infection and the appearance of the first symptoms. It may
be several months to many years before persistent symptoms
occur.
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.
- A person may become sicker than they normally would.
- Women may have recurrent vaginal yeast infections.
- Thrush (a yeast infection) coating the mouth or tongue.
The latency period is the time frame from HIV infection
until the start of persistent symptoms of AIDS. Even without
antiretroviral therapy, there is an average of ten years in
the latency period. During this time, an HIV-infected person
looks and feels fine, but the virus is replicating and slowly
destroying CD4 cells and the immune system.
Over time, people with AIDS frequently have a reduced white
blood cell count and develop poorer health. They may also
have a significant amount of virus present in their blood,
which is measured as viral load. When a person's immune system
is suppressed, they have weaker defenses against the wide
variety of bacteria, viruses, fungi and other pathogens that
are present almost everywhere. A clinical manifestation
is the physical result of some type of illness or infection.
The opportunistic diseases and infections associated
with HIV infection are any of the infections that are part
of an AIDS-defining classification (covered above). For example:
the opportunistic infection cytomegalovirus often causes the
clinical manifestation of blindness in people with AIDS.
HIV affects:
- The kind and number of blood cells.
- The amount of fat and muscle distribution in the body.
- The structure and functioning of the brain.
- The normal functioning of the immune system.
- The body's basic metabolism.
HIV infection can cause many painful or uncomfortable conditions,
including:
- Confusion or dementia.
- Diarrhea.
- Fatigue.
- Fever.
- Nausea or vomiting.
- Painful joints, muscles, or nerve pain.
- Difficulty with breathing.
- Urinary or fecal incontinence.
- Vision or hearing loss.
- Thrush (yeast infections in the mouth).
- Chronic pneumonias, sinusititis, or bronchitis.
- Loss of muscle tissue and body weight.
Continue on to Prevalence
of HIV and AIDS
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