The phrase "Common Cold" is a bit of a misnomer, as there are over 100 different cold viruses that cause the symptoms associated with the "Common Cold". Rhinoviruses are the most common, causing up to one-half of colds. The common cold is the description of an illness caused by a virus infection located in the nose, while also invading the ears, sinuses, and bronchial tubes.
Colds usually last for an average of one week, with mild cases lasting between 2 and 3 days, and severe cases lasting upwards of about 2 weeks.
General symptoms like headache, feverishness, and chilliness are also common, as well as a general unwell feeling.
Cold viruses can multiply only when inside living cells. While cold viruses cannot multiply on an environmental surface, they are still infectious if they are transported into the nose. These viruses live only in the noses of humans and not in animals, with the exception of higher primates such as the chimpanzee.
A cold virus is transmitted by depositing itself into the front of the nasal passages by contaminated fingers, or by droplets from coughs and sneezes present in the air. Small doses of the virus (between 1 and 30 particles) are sufficient to produce infection. The virus is then carried to the back of the nose and deposits itself on the adenoid area simply by breathing. From the time a cold virus enters the nose, it takes approximately 8-12 hours for the viral reproductive cycle to complete, and produce a new cold virus.
Many symptoms of the common cold are actually triggers from the body's immune and nervous systems. The body's immune system contains a variety of natural substances called "inflammatory mediators", which help protect the body from infection. When activated by a cold virus infection, inflammatory mediators cause dilation and leakage of blood vessels (causing redness and inflammation), as well as mucus gland secretion (that annoying runny nose.) They also activate sneeze and cough reflexes, as well as stimulating pain nerves.
You may be asking "If it's supposed to help get rid of the cold, why does it make me feel miserable?" Good question, and I wish I had an answer. Unfortunately, activity from the inflammatory mediators is NOT necessary for recovery from cold virus infection. They're just side effects. 25% of people who acquire a cold virus infection do not develop symptoms, and they recover from the infection just as well as those who have the symptoms. I envy those 25%, because I'm sitting here writing this node with a sore throat, an annoying cough, and a runny nose.
Common cold treatments include:
- Antihistamines - Used to block Histamines, which cause the majority of common cold symptoms.
- Nonsteroidal Antiinflammatory Drugs - Examples include ibuprofen and naproxen. Used to treat inflammation, pain, and fever. Also used to block the production of the "prostaglandin" brand of inflammatory mediators.
- Decongestants - Used to open the nasal passages by shrinking blood vessels in the mucous membrane of the nose - the primary cause of nasal congestion associated with colds.
- Anticholinergics - Used to block the action of the parasympathetic nervous system on mucus gland secretion, reducing nasal discharge. Not used to treat sneezing, because it has no effect on histamines.
- Cough Suppressants - Cool Stuff! They're actually natural narcotics that force the brain to chill on the cough reflexes.