Bacteriology at UW-Madison
The common cold is probably the most prevalent infectious disease that occurs in humans. It is estimated that there are up to a billion colds per year in the United States. Children have about 6 to 10 colds a year. This is due to lack of acquired immunity and because children are often in close contact with each other in daycare centers and schools. Adults average about 2 to 4 colds a year, although the range varies widely. Women, especially those 20 to 30 years of age, have more colds than men, possibly because of their closer contact with children. On average, people older than 60 have fewer than one cold a year.
Everyone is familiar with the symptoms of the common old, which are sore throat, cough, conjunctivitis and increased flow of mucus. Sneezing and coughing are common; fever is rare, except in young children. Usually, the infection is mild, lasting only a few days. However, it is a leading cause of doctor visits and missed days from school and work. According to the CDC, 22 million school days are lost annually in the United States due to the common cold.
Symptoms of the common cold http://www.cardiff.ac.uk/biosi/associates/cold/info.html Colds are diagnosed based on their symptoms. However, when the symptoms present, several diagnostic problems are met because the symptoms are difficult to distinguish from noninfectious rhinitis (i.e., allergy), or they may be prodromal symptoms of other more serious respiratory group diseases such as diphtheria, whooping cough, measles, or influenza.
Viruses that Cause Colds
The common cold (rhinitis or coryza) is caused by several groups of viruses, although rhinoviruses have gotten the most attention. Other cold-causing viruses include adenoviruses, coronaviruses, respiratory syncytial virus (RSV), parainfluenza and influenza viruses. Rhinoviruses seldom produce serious illness, but others such as parainfluenza and RSV can produce severe respiratory illness in infants and young children.
Rhinoviruses (from the Greek rhin, meaning "nose") cause an estimated 30 to 35 percent of all adult colds, and are most active in early fall, spring, and summer. More than 100 distinct serotypes (antigenic types) have been identified. Rhinoviruses grow best at temperatures of about 91 degrees Fahrenheit, the temperature inside the human nose.
Rhinovirus 14 as solved by x-ray crystallography. Rhinoviruses are picornaviruses - small, icosahedral, nonenveloped, sinlge stranded (+)RNA viruses.
Coronaviruses are apparently the second leading cause of adult colds. They bring on colds primarily in the winter and early spring. Of the more than 30 kinds, three or four infect humans. The 2003 SARS virus is a coronaviruses. Unlike rhinoviruses, coronaviruses are difficult to grow in the laboratory, so they have not been studied to the same extent as the rhinoviruses.
Approximately 10 to 15 percent of adult colds are caused by viruses
which are also responsible for other, more severe illnesses. These
include adenoviruses, coxsackieviruses, influenza viruses,
parainfluenza viruses, respiratory syncytial virus and
Actually, the causes of 30 to 50 percent of adult colds, are
unidentified and presumed to be viral.
such acetominophen (tylenol) aspirin, ibuprophen (Advil), and naproxyn
sodium (Naprosyn) are useful for reducing the pain and fever associated
with the common cold.
Decongestants such as pseudoephedrine hydrochloride (Sudafed) decrease nasal secretions and congestion.
Expectorants such as guaifenesin (Robitussin) thin respiratory secretions and decrease overall coughing.
Antitussives are opiate
derivatives, such as codeine and
dextromethorphan hydrobromide (Robitussin DM) that are useful in
suppressing coughing by depressing the nervous system.
Antihistimines such as chlorpheniramine maleate (Chlor-Trimeton), brompheniramine maleate (Dimetapp), Dipheniramine hydrochloride (Benadryl), and triprolidine hydrochloride (Actifed) have been used to treat symptoms, since they theoretically block release of the inflammatory agent, histamine.
Antivirals to human rhinoviruses have been recently developed
for the treatment of the
common cold. The mechanisms of these drugs usually involve prevention
of viral attachment to a cognate cell receptor.
While traditional medicines have
shown to relieve the symptoms of the common cold, there is mounting
evidence that several alternative treatments can prevent the
onset or shorten the duration of common cold symptoms. Most alternative
medicines appear to have no serious side effects, especially if
marketed products are used. Some treatments that have been found
to be effective include:
Zinc lozenges have been
shown to reduce the duration of the common cold. Zinc deficiency has
linked to a variety of immune system abnormalities.
9. Make sure your environment is not too dry. Keep the air moist enough so that your nasal passages do not dry out. Consider using a humidifier.
8. Be careful with items such as money, pens, and keypads in public places. They are all potential sources of infection.
7. Take precaution when flying on commercial airlines. The recirculation systems aboard planes has been implicated in the spread of airborne infectious diseases
6. Garlic nose drops have been known to kill the viruses that cause colds (if you don't mind the smell of garlic!). In his book The Healing Power of Garlic Paul Bergner suggests crushing some garlic to obtain juice, adding ten parts water and mixing well.
5. If someone in your household is sick, let them use separate items, such as hand towels, from those who are healthy.
4. Keep your feet warm. Cold feet cannot cause a viral infection, but they can undermine your defenses thereby opening the door to them.
3. Keep your nasal passages clear and breathe through your nose. Your nose is able to filter out airborne dust and germs.
2. Alternative medications. Recent studies have shown that alternative medications such as zinc and Echinacea may help prevent the onset of colds.
1. Never put your hands in your
eyes or to your nose without washing them
Vaccines for the Common Cold
Vaccines are not forthcoming because colds are caused by over 200
colds are not life-threatening, and there is too much money to be made
off of the relief of symptoms.