For a villain character in
, often known as the '''common cold''', is a mild
Viral Infectious Disease of the the upper
Respiratory System (
Nose and
Throat ). Symptoms include
Sneezing , sniffling,
Nasal Congestion ; scratchy, sore, or
Phlegmy throat;
Cough ing;
Headache ; and tiredness. Colds typically last three to five days, with residual coughing lasting up to three weeks. As its name suggests, it is the most common of all human
Disease s, infecting subjects at an average rate of slightly over one infection per year per person. Infection rates greater than three infections per year per person are not uncommon in some populations. Children and their caretakers are at a higher risk, probably due to the high population density of schools and the fact that transmission to family members is highly efficient.
The common cold belongs to the
Upper Respiratory Tract Infection s. It is different from
Influenza , a more severe viral infection of the respiratory tract that shows the additional symptoms of rapidly rising
Fever ,
Chills , and body and
Muscle Aches . While the common cold itself is rarely life threatening, its complications, such as
Pneumonia , can very well be.
The common cold is caused by numerous
Viruses (mainly
Rhinovirus es,
Coronavirus es, and also certain
Echovirus es,
Paramyxovirus es, and
Coxsackievirus es) infecting the upper respiratory system. Several hundred cold-causing viruses have been described, and a virus can mutate to survive, ensuring that any cure is still a long way off. The nasopharynx is the central area infected. The reasons that the virus concentrates in the nasopharynx rather than the throat may be the low temperature and high concentration of cells with
Receptors needed by the virus.
The viruses are transmitted from person to person by droplets from
Cough s or
Sneeze s. The droplets or droplet nuclei are either inhaled directly, or transmitted from hand to hand via
Handshake s or objects such as door knobs, and then introduced to the nasal passages when the hand touches the nose or eyes.
The virus takes advantage of sneezes and coughs to infect the next person before it is defeated by the body's
Immune System . Sneezes expel a significantly larger concentration of virus "cloud" than coughing. The "cloud" is partly invisible and falls at a rate slow enough to last for hours—with part of the water droplets evaporating and leaving much smaller and invisible "droplet nuclei" in the air. Droplets from turbulent sneezing or coughing or hand contact also can last for hours on surfaces, although less virus can be recovered from porous surfaces such as wood or paper towel than non-porous surfaces such as a metal bar. A sufferer is most infectious within the first three days of the illness. Symptoms, however, are not necessary for viral shedding or transmission, as a percentage of asymptomatic subjects exhibit viruses in nasal swabs, likely controlling the virus at concentrations too low for them to have symptoms.
The virus enters the
Cells of the lining of the
Nasopharynx (the area between the nose and throat), and rapidly multiplies. The major entry points are the nose and eyes, through the
Nasolacrymal Duct drainage into the
Nasopharynx . The mouth is not a major point of entry and transmission does not usually occur with kissing or swallowing.
The virus enters the cell by binding to
ICAM-1 receptors in these cells. The presence of ICAM-1 affects whether a cell will be infected. Its concentration also can be affected by various other factors, including
Allergic Rhinitis and some other irritants including rhinoviruses themselves. ICAM-1 has been a major focal point in drug research into cold treatments.
Ninety-five percent of people exposed to a cold virus become infected, although only 75% show symptoms. The symptoms start 1–2 days after infection. Generally a cold starts with a sore throat, without any respiratory blockage. From then onwards the symptoms are a result of the body's defense mechanisms: sneezes, runny nose, and coughs to expel the invader, and
Inflammation to attract and activate
Immune Cell s.
After a common cold, a sufferer develops immunity to the particular virus encountered. However, because of the large number of different cold viruses, this immunity offers limited protection. A person therefore can be easily infected by another cold virus, starting the process all over again.
Bacteria that are normally present in the respiratory tract can take advantage of the weakened
Immune System during a common cold and produce a coinfection.
Middle Ear Infection (in children) and bacterial
Sinusitis are common coinfections. A possible explanation for these coinfections is that strong blowing of the nose drives nasal fluids into those areas.
The best way to blow the nose is keeping both nasal openings open when blowing and wiping rather than fully covering them, permitting pressure to partially dissipate. Doing so will reduce the pressure that would otherwise drive fluid into the ears or sinuses.
The best way to avoid a cold is to avoid close contact with existing sufferers, to wash hands thoroughly and regularly, and to avoid touching the face. Anti-bacterial soaps have no effect on the cold virus - it is the mechanical action of hand washing that removes the virus particles. In 2002, the
Centers For Disease Control And Prevention recommended alcohol based hand gels as an effective method for reducing infectious viruses on the hands. However, as with standard handwashing, alcohol gels provide no residual protection from re-infection.
Tobacco Smoking has also been linked with the weakening of the immune system; non-smokers are known on average to take fewer days off sick than the smoking population. Smokers on average take 25% more sick days a year.
Because of the large variety of viruses causing the common cold,
Vaccination is impractical.
In 2005 levels in the upper respiratory tract, and by stimulating cells to produce large amounts of
Mucus , flushing out the virus.
There is no cure for the common cold, i.e. there is no treatment that directly fights the virus.
Only the body's
Immune System can effectively destroy the invader. A cold may be composed of several million viral particles, and typically within a few days the body begins mass producing a better tailored
Antibody that can prevent the virus from infecting cells, as well as
White Blood Cells which destroy the virus through
Phagocytosis and destroy infected cells to prevent further viral replication. Furthermore the duration of infection is on the order of a few days to one week so at most a "cure" could hope to reduce the duration by only a few days.
ViroPharma Incorporated and
Schering-Plough have been developing an anti-viral drug that targets
Picornaviruses , that cause the majority of common colds.
Pleconaril has been shown to be effective in an
Oral form, but there were safety problems with that formulation.
Schering-Plough is developing an
Intra-nasal formulation that may overcome some of those safety issues. However it may not be until 2008 or 2009 that the drug is on the market and it is unlikely that benefit will be more than one day.
Available treatments do not treat the viral infection, but focus on relieving the symptoms.
For some people, even without these
Remedies , colds are relatively minor inconveniences and they can go on with their daily activities with tolerable discomfort. This discomfort has to be weighed against the price and possible side effects of the remedies, and the possibility, not yet scientifically proven, that by suppressing responses evolved to fight the cold, the symptom suppressants may prolong the illness.
Common treatments include:
Analgesic s such as
Aspirin or
Acetaminophen /
Paracetamol , as well as localised versions targeting the throat (often delivered in
Lozenge form), nasal decongestants which reduce the inflammation in the nasal passages by constricting local blood vessels,
Cough Suppressants (which work to suppress the cough reflex of the brain or by diluting the mucus in the lungs), and first-generation
Anti-histamine s such as
Brompheniramine ,
Chlorpheniramine , and
Clemastine (which reduce mucus gland secretion and thus combat blocked/runny noses but also may make the user drowsy). Second generation anti-histamines do not have a useful effect on colds.
A warm and humid environment and drinking lots of fluids, especially hot liquids, alleviate symptoms somewhat. Common home remedies include
Chamomile ,
Lemon or
Ginger Root Tisane s and
Chicken Soup (which probably work by soothing the irritated respiratory passages with their steam), nebulized medicinal mixtures, hot compresses,
Mustard Plaster s,
Hot Toddies , licorice and
Echinacea .
Although there have been scientific studies done on
Echinacea , its effectiveness has not been demonstrated. A peer-reviewed
Clinical Study published in the
New England Journal Of Medicine concluded that ''...extracts of E. angustifolia root, either alone or in combination, do not have clinically significant effects on rhinovirus infection or on the clinical illness that results from it.''
{Link without Title}
Eating very spicy food can help alleviate congestion, although it may also irritate the already-tender throat. Coffee, or its active component, caffeine, has also been shown to improve mood and mental performance during rhinovirus infection.
Cold medicine (aspirin, acetaminophen / paracetamol, ibuprofen, etc) should never be taken along with alcohol.
Antibiotics are ineffective against the common cold and all other viral infections. They are useful in treating any secondary
Bacteria l infections that sometimes occur, but treatment with antibiotics ''before'' these coinfections develop is counterproductive, as it produces drug resistance, and can even promote infections by killing off normal bodily flora.
Publications in the
1960s and
1970s suggested that large doses of Vitamin C could both prevent and reduce the effects of the common cold. A particularly vociferous proponent of this theory was Nobel Prize winner
Linus Pauling , who heavily advocated the intake of large doses of
Vitamin C to prevent infection. In
1970 he wrote the bestseller ''Vitamin C and the Common Cold''. A
Meta-analysis published in 2005 found that vitamin C reduced the incidence of colds by 50% in six trials with physically stressed participants, but it had no effect on the incidence of colds in ordinary people. Regular vitamin C supplementation shortened the duration of colds in children by 14% and in adults by 8%. Findings from therapeutic trials have been conflicting, yet it is worth noting that none of the therapeutic trials carried out so far has examined the effect of vitamin C on children, although the regular supplementation trials have shown a substantially greater effect on episode duration in children.
See Also: Zinc gluconate
Zinc -containing preparations have been claimed to be effective in the treatment of cold infections. There have been a number of
Clinical Studies of the efficacy of zinc, some of which have shown an effect and some of which have shown no effect.
A
Chemistry of all zinc lozenge formulations tested from 1984 through 2004, showed a
Statistically Significant Dose Response when the amount of
Ion ic zinc, rather than total zinc, was considered.
There are concerns regarding the safety of long-term use of cold preparations in an estimated 25 million persons who are
Haemochromatosis Heterozygote s. Another concern with use of very high-dose zinc for more than two weeks is
Copper depletion, which leads to
Anemia .
Although widely available and advertized in the
United States , the safety and efficacy of zinc preparations have not been evaluated or approved by the
Food And Drug Administration , and they are not likely to have any utility against colds due to removal of
Ionic zinc through additive food acids (
Citric Acid ,
Ascorbic Acid and
Glycine ). Consequently, a "cure for the common cold", using zinc acetate lozenges without additive food acids , is not available due to marketing rather than scientific considerations.
In the
United Kingdom , the
National Health Service includes zinc lozenges in a list of not recommended treatments.
{Link without Title}
Zicam Cold Remedy is a non-drip nasal gel containing Zincum Gluconicum to "Reduce the duration; Reduce the severity of the common cold." Research on the nasal gel has shown that if taken within 24 hours of the initial cold symptoms it can shorten a cold to just five days.[http://www.zicam.com/pdf/Zinc_nasal_gel_treatment_common_cold_symptoms.pdf] The nasal gel works best when taken within 24 hours of the first symptoms of a cold, and has not been proven to be effective if it is not initially used within the first 48 hours of the first symptoms of a cold. [http://www.zicam.com/pdf/ClevelandClinicZicamStudy.pdf] A $75,000,000 lawsuit against the company that makes Zicam Cold Remedy filed by people who claimed that the nasal gel caused them to lose their sense of smell
was settled out of court for $12,000,000 but the company did not admit fault.[http://www.zicamsideeffects.com/claim/zicam-suit.html
Common colds interfere with school attendance and can cause lost days on the job, resulting in considerable costs to the economy. In addition, a lot of money is spent on
Over-the-counter and home remedies.
Arguably the most common communicable disorder that humans can be afflicted with, the cold is considered something of a common cultural point of reference. Thus, catching a cold is often used as a
Plot Device in various stories, movies, and television series.
Most companies offer a number of paid sick days per year to avoid errors during work and transmission to co-workers.
University Of Michigan researcher Dr. A. Mark Fendrick published 2003 study on effects of the common cold: The study found that the common cold leads to more than 100 million physician visits annually at a conservative cost estimate of $7.7 billion per year. More than one-third of patients who saw a doctor received an antibiotic prescription, which Fendrick says not only contributes to unnecessary costs, but also has implications for antibiotic resistance from overuse of such drugs.
The study found that Americans spend $2.9 billion on over-the-counter drugs and another $400 million on prescription medicines for symptomatic relief. Additionally, cold sufferers spend $1.1 billion annually on an estimated 41 million antibiotic prescriptions, even though the drugs have no effect on a viral illness.
The study reports that an estimated 189 million school days are missed annually due to a cold. As a result, parents missed 126 million workdays to stay home to care for their children. When added to the workdays missed by employees suffering from a cold, the total economic impact of cold-related work loss exceeds $20 billion.
Colds were known in
Ancient Egypt ; there were
Hieroglyph s representing the cough and the common cold. The Greek physician
Hippocrates gave a description of the disease in the
5th Century BC . The common cold was also known among the ancient
American Indian Aztec and
Maya civilizations. A mixture of
Chili Pepper ,
Honey , and
Tobacco was one common Aztec treatment for colds.
In the
18th Century ,
John Wesley wrote a book about curing diseases; it advised cold baths as prevention and stated that chilling causes the common cold. The work was widely reprinted in the
19th Century . Another book by
William Buchan in the 18th century also gave wet feet and clothes as the cause of the common cold.
The idea of microscopic infectious agents causing disease arose in the second half of the
19th Century .
Initially,
Bacteria were suspected to be the cause of the common cold, and
Vaccine s were produced based on this theory; these were still prescribed in the
1950 s.
s by
Alphonse Dochez , first in
Chimpanzee s, and then in human volunteers using a
Double-blind setup. Nevertheless, in
1932 a major textbook on the common cold by
David Thomson still presented bacteria as the most likely cause.
In Britain, the
Common Cold Unit was set up by the civilian
Medical Research Council in
1946 . The unit worked with volunteers who were infected with various viruses. The rhinovirus was discovered there. In the late
1950 s, researchers were able to grow one of these cold viruses in a tissue culture (it would not grow in fertilized chicken eggs, the method used for many other viruses). In the
1970 s, the CCU demonstrated that treatment with
Interferon during the incubation phase of rhinovirus infection protects somewhat against the disease, but no practical treatment could be developed. The unit was closed in 1989, just two years after it demonstrated the benefit of zinc gluconate lozenges in the prophylaxis and treatment of rhinovirus colds.
{Link without Title}
The term "cold", as it relates to climatic temperature is somewhat misleading. (This is not limited to English; many other European languages contain the root word for "cold" in their words for the common cold.) Climate may affect transmission by some means, such as by causing people to stay indoors and increasing the proximity to infected persons, but the cause of the infection remains viral. Some allergies, bacterial respiratory infections, and even climate changes can also cause common-cold-like symptoms that can last for days.
It is not definitely known whether cold weather or a humid climate can affect transmission by other means, such as by affecting the immune system, or ICAM-1 receptor concentration, or simply increasing the amount and frequency of circulation needed to carry
White Blood Cells to the area of infection.
It is perhaps the case that "cold" refers to a "cold condition;" i.e., the hot, cold, dry, and wet "conditions" described by the ancient Anatolian physician
Galen . Colds are somewhat more common in winter since during that time of the year people spend more time indoors in close proximity to others, and natural ventilation is generally less prevalent in cold weather, which increases the infection risk.
Moreover, if cold weather is directly linked to the spread of the common cold, then it would be easy to prove by comparing the infection rates of people who live in colder climates (such as Iceland or Greenland) with people who live in warmer climates (such as countries close to the equator). Studies have shown no significant increase in infection rates in people who live in colder climates.
In '''' the best treatment that 24th century medicine can muster for the common cold is
Earl Grey Tea and rest, implying that no "cure" has yet been found.
In the original 1966 '''', Spock says to McCoy: "Doctor, you may yet cure the common cold."
''Mr. Putter & Tabby Catch the Cold'' by Cynthia Rylant. Harcourt Paperbacks 2003 ISBN 0152047603
The common cold famously defeated the aliens in
H. G. Wells ' ''
The War Of The Worlds ''.
