Over 200 types of viruses cause common colds. Among all these viruses, rhinoviruses are said to cause about 10% to 40% of all cases. Rhinoviruses thrive at 32.7 degrees Celsius (91 degrees Fahrenheit), which is the temperature inside the human nose. Coronaviruses account for about 20% to 30% of common colds, mostly with short incubation periods. Other viruses that cause colds are respiratory syncitial virus (RSV) , adenoviruses, paramyxoviruses, coxsackieviruses, and orthomyxoviruses among others.
Contrary to common belief, cold weather does not directly cause colds, although some colds viruses easily grow during cold weather. Allergies and physical stress also do not cause colds, but they seem to be factors in making a person more susceptible to the infection.
Mode of transmission
Common colds are transmitted from person to person through direct contact, or through contaminated surfaces, called fomites, such as table tops, door knobs, faucets and other surfaces that are commonly touched.
Colds are also passed on through aerosol transmission. Coughing or sneezing produces several hundreds to thousands of virus-laden droplets that are suspended in the air. Large droplets fall to the ground or nearest surface, which become fomites. Smaller and lighter droplets remain suspended in the air and may travel distances dependent on their sizes. When these droplets are inhaled, the virus they carry multiply inside the body and cause illness.
About one to three days after exposure to a causative agent, the first symptoms of colds appear. These are sneezing, runny nose, and itchy throat. The nose and sinuses may become congested, and a cough may develop as mucus secretion along the respiratory tract increases. Sometimes, fever and headache may accompany these symptoms.
Young children and infants usually experience a more severe course than adults. A cold episode may last for as short as 2 days and as long as 2 weeks. But most people recover spontaneously after one week of illness.
Common colds sometimes lead to other bacterial infections such as otitis and sinusitis, and more severe illnesses such as bronchitis and pneumonia. Colds may also result to exacerbation of pre-existing respiratory conditions such as asthma, chronic bronchitis, and emphysema.
There is no specific cure for colds, since the illness is usually self-limiting and will run its course. Pain relievers such as paracetamol and ibuprofen are prescribed to relieve fever and headache. Antihistamines and decongestants can relieve nasal congestion. These medications, however, will not shorten the course of a cold. Gargling with warm salt solution or sucking on lozenges can soothe an itchy throat caused by post-nasal drip.
Children under 12 years old who are suffering from viral infections like common colds should never be given aspirin because it has been linked with Reye's Syndrome. As much as possible, avoid giving over-the-counter cold medications to children under 6 years old, as the Food and Drug Administration (FDA) of the United States has not found them efficacious and safe for those ages.
Drinking plenty of fluids, sleeping and resting offer relief for a person with common colds. Although steam inhalation is a common remedy for colds, experts have found out that it does not effectively alleviate symptoms and, therefore, do not recommend it.
Antibiotics will not help in common colds because it is a viral infection. However, doctors may prescribe antibiotics when bacterial complications arise.
There are preventive measures one can take to avoid getting sick with the common cold.
- Strengthen the immune system by practicing a healthy lifestyle.
- Eat a balanced diet, drink plenty of fluids, and get adequate rest and sleep.
- Exercise alleviates stress and also strengthens the immune system.
- Do not smoke, and avoid second-hand smoke.
- Breastfeed children. Breastmilk is proven to strengthen the immune system, as children who have been breastfed experience lesser episodes of illness.
- Natural and vitamin supplements are often used to prevent colds, although their efficacy is still controversial. Vitamin C and zinc supplements, as well as herbal supplements such as echinacea are claimed to prevent common colds and other infections.
- Practice good hygiene.
- Wash hands frequently. Frequent hand-washing prevents the spread of many diseases, as the hands are said to be the most common transmitter of organisms.
- Do not cover your nose and mouth with your hands when coughing or sneezing. Instead, use a disposable tissue or the crook of your elbow to cover the nose and mouth.
- Sanitize with isopropyl alcohol or hand sanitizer when there is no water.
- Avoid touching your face, because this brings germs close to your eyes, nose and mouth, through which they enter and cause illness.
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