Microbial

MICROBES CAN CAUSE DIFFERENT KINDS OF INFECTION.
 
Some disease-causing microbes can make you
very sick quickly and then not bother you again.
Some can last for a long time and continue to
damage tissues. Others can last forever, but you
won’t feel sick anymore, or you will feel sick only
once in a while. Most infections caused by
microbes fall into three major groups:

* Acute infections
* Chronic infections
* Latent infections

ACUTE INFECTIONS

Acute infections are usually severe and last a
short time. They can make you feel very
uncomfortable, with signs and symptoms such as
tiredness, achiness, coughing, and sneezing. The
common cold is such an infection. The signs and
symptoms of a cold can last for 2 to 24 days
(but usually a week), though it may seem like a
lot longer. Once your body’s immune system has
successfully fought off one of the many different
types of rhinoviruses or other viruses that may
have caused your cold, the cold doesn’t come
back. If you get another cold, it’s probably
because you have been infected with other cold-
causing viruses.

CHRONIC INFECTIONS

Chronic infections usually develop from acute
infections and can last for days to months to a
lifetime. Sometimes people are unaware they are
infected but still may be able to transmit the
germ to others. For example, hepatitis C, which
affects the liver, is a chronic viral infection. In
fact, most people who have been infected with
the hepatitis C virus don’t know it until they have
a blood test that shows antibodies to the virus.
Recovery from this infection is rare—about 85
percent of infected people become chronic
carriers of the virus. In addition, serious signs of
liver damage, like cirrhosis or cancer, may not
appear until as long as 20 years after the
infection began.

LATENT INFECTION

Latent infections are “hidden” or “silent” and may
or may not cause symptoms again after the first
acute episode. Some infectious microbes, usually
viruses, can “wake up”—become active again but
not always causing symptoms—off and on for
months or years. When these microbes are active
in your body, you can transmit them to other
people. Herpes simplex viruses, which cause
genital herpes and cold sores, can remain latent
in nerve cells for short or long periods of time, or
forever.

Chickenpox is another example of a latent
infection. Before the chickenpox vaccine became
available in the 1990s, most children in the United
States got chickenpox. After the first acute
episode, usually when children are very young, the
Varicella zoster virus goes into hiding in the body.
In many people, it emerges many years later when
they are older adults and causes a painful disease
of the nerves called herpes zoster, or shingles.
Researchers are studying what turns these
microbial antics off and on and are looking for
ways to finally stop the process