health

1. Definition .
   
2. Description .
   
3. Demographics .
   
4. Causes and Symptoms .
   
5. Diagnosis .
   
6. Treatment .
   
7. Prevention .
   
8. The Future .

Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold Common Cold

The common cold is a contagious viral infection of the upper respiratory
tract (nose and throat). It is self-limiting, meaning that it clears up by
itself without the need for special medical treatment.
The disease got its name in the sixteenth century, when English doctors
noticed that colds are more frequent in northern countries during
the winter months and thought that exposure to low temperatures caused
colds. It was not until the eighteenth century that Benjamin Franklin
suggested that cold weather by itself does not cause colds but helps them
to spread by driving people indoors where they are crowded more closely
together. Although viruses had not been discovered by Franklin’s day, he
was correct in thinking that colds are transmitted from one person to
another through the air or by direct contact.

The common cold is one of the most widespread infectious diseases in
the world. It is caused by about 200 different viruses belonging to at least
eight different families of viruses. For most people, the classic symptoms
of a cold are an irritated nose or scratchy throat within eight hours to two
days after infection, followed quickly by a runny nose and sneezing.
Although many people experience headaches, general tiredness, and loss
of appetite as well, the main symptoms of a cold are in the nose.

A person can get a cold by inhaling the virus directly if they are sitting
close to an infected person who is sneezing or coughing. They can also get
a cold by touching their eyes, nose, or mouth after touching an object or
surface contaminated by the virus. Research indicates that cold viruses
can live on skin for as longas two hours and on drinking glasses or other
hard surfaces for as long as four days. People with colds are most likely
to spreadthe virus to others during the first two to three days of infection.
After that they are much less contagious.

No exact statistics are kept on the number of colds each year
in the United States or in any other country because the illness
is so common and many people take care of their symptoms
at home. The Centers for Disease Control and Prevention (CDC) estimates
that people in the United States suffer about 1 billion colds every year;
children lose between 22 and 189 million school days in an average year,
and theirparents lose 126 million work days to stay home and take care of
them.Other employees miss an average of 150 million work days every year
because of colds. The total impact of colds on the American economy
comes to an estimated $20 billion per year.
Colds are equally common in people of all races and ethnic groups.
Some studies indicate that boys younger than three are more likely than
girls to get colds in day care settings; however, in older children and
adults, males and females are equally likely to get colds. In terms of age,
children get colds more frequently than adults. Children average three to
eight colds every year, and parents frequently get colds from their children.
Colds become less frequent in later life, however; on average,
people over sixty have less than one cold a year.
Colds are more common in North America during the fall and
winter months, when children are in school and adults are spending
more time indoors. In tropical climates, colds are most common during
the rainy season, as humid conditions increase the viruses’ survival time
outside the human body.

The common cold is caused by at least 200 viruses that had been identified
as of 2008. A cold virus typically enters the body through the nasal
passages or mouth, but can also enter through the mucous membranes
covering the eyes. The virus spreads to the tissues lining the area between
the nose and the back of the throat, where it rapidly multiplies. Within
hours or a day or two after the virus enters the body, the infected person
feels a scratchy sensation at the back of the throat, followed by sneezing
and a constant flow of runny mucus from the nose. Researchers think
that these symptoms are caused by the body’s immune response to the
virus rather than by tissue damage caused by the virus.

In addition to the runny nose, sneezing, and coughing associated
with the common cold, people may also have:

• Low-grade fever (101°F [38.8°C] or lower)
  
• Muscle aches
  
• Headache
  
• Loss of the senses of taste and smell
• Loss of appetite
  
• Sore throat

Children are often sicker than adults when they get a cold because
their immune systems are less developed. Children may run a fever as
high as 102°F (38.9°C) with a cold; they may also develop an ear or sinus
infection following a cold. Children with asthma may have an attack triggered
by a cold.

For most people, the diagnosis of a cold is obvious from its symptoms,
particularly if they know they have recently been exposed to someone else
with a cold. Most people do not need to see a doctor to be diagnosed with
a cold. They should, however, see their doctor if they have any of the following
symptoms, which may indicate an allergy or a more serious illness:

• The symptoms last longer than two weeks.
  
• The patient has a fever of 102°F (38.9°C) or higher.
  
• They are coughing up thick mucus.
  
• They have severely swollen glands.
  
• They have severe pain in the sinuses.
  
• They are having chills or night sweats, or are extremely fatigued.
  

There is no cure for the common cold. Treatment is aimed at relieving
the sneezing and other symptoms until the body’s immune system clears
the virus. The sidebar lists some common home and over-the-counter
remedies that ease the symptoms of a cold.
Although many people ask their doctors for antibiotics to treat a
cold, it is important to know that antibiotics are not effective against
viruses. In fact, overprescribing of antibiotics is a major factor in the
emergence and spread of antibiotic-resistant bacteria. The doctor will,
however, prescribe antibiotics if the patient has developed a sinus infection
caused by bacteria.

There is no vaccine effective against colds. The following precautions,
however, can lower a person’s risk of getting frequent colds:

• Stay away from people with colds whenever possible.
  
• Wash the hands frequently.
  
• Avoid touching the mouth and face after being exposed to
  someone with a cold.
  
• Use alcohol-based hand sanitizers.
  
• Keep kitchen and bathroom countertops and other surfaces clean.
  
• Wash children’s toys after play.
  
• Do not share drinking glasses, cups, or food utensils. Use disposable
  paper cups when sick to protect other family members.
  

Several drug companies are working on antiviral drugs that might help
people recover from colds more rapidly. One such drug is being tested
in an oral form while a second drug is being developed that would be
applied as a nasal spray. One limitation of these drugs, however, is that
they would work only against cold viruses belonging to one of the eight
groups known to cause the common cold.
The development of an effective vaccine against colds is considered
unlikely. One reason is the sheer number of viruses known to cause
colds. Another reason is that these viruses mutate (change their DNA)
very rapidly; thus any vaccine that might be developed would be outdated
by the time it entered clinical trials, let alone be approved for use.