The common cold is a viral infection of the upper respiratory tract. The rhinovirus, followed by the corona virus and the respiratory syncytial virus, is responsible for most cases of the common cold. Any virus that causes the common cold is generally referred to as the common cold virus. Common colds are hardly fatal, but they are irritating and troublesome  nevertheless and do require the patient to take some rest.

There are nearly 200 different types of viruses that are known to cause common cold. The symptoms of the condition can vary from person to person and usually depend upon the type of causative virus. For this reason, the rapid detection of the specific virus causing the infection is required to make optimal use of antiviral agents for common cold treatment.

The Transmission Of The Common Cold Virus

The inflammatory mechanism of the common cold is an example of the complexity of the virus-host relation. The common cold is an air borne infection. It spreads when the common cold virus is transmitted through the aerosols of nasal fluids. In some cases, especially when the infection is caused by the respiratory syncytial virus, the transmission of the virus is also caused through contact with contaminated surfaces.

Rhinoviruses can often survive for 18 hours on contaminated surfaces. When a person comes in contact with these surfaces, the infection is immediately transmitted to him. A rhino virus infection is highly transmissible during its first three days. People may just carry the virus and transmit it to others without experiencing any of the symptoms themselves.

The host’s immune response to the common cold virus is the basic reason for the symptoms observed during a common cold infection. The entry of the viral particles into the human body is known to trigger inflammatory mediators that produce the common cold symptoms.

The Body’s Response To The Common Cold Virus

The symptoms begin when the viral particles are attached to the epithelial linings of the upper respiratory tract. The subsequent inflammatory response then results in the secretion of lot of mucus in the upper respiratory tract.This fluid dilutes the common cold virus and expels it from the nose. The inflammatory reaction also expels the virus by irritating the nasal sensory cells and causing sneezing. If the virus penetrates the upper respiratory tract further, coughing also occurs in order to get rid of the virus.

Sometimes this acute viral infection may spread to the lower respiratory tract and cause secondary infections in the eyes and middle ears. If the host’s defenses increase, the clear fluid transforms into a thick fluid that is filled with the debris of dead cells and is yellow-green in color.

While the common cold usually lasts for about five to seven days, the postnasal discharge and the cough may continue to exist for a period of two weeks or more. As so much of the body’s energy is directed at fighting the virus, the host feels tired and miserable.

In most cases, a common cold is diagnosed by observing the patient’s medical history and generating cultures for the common cold virus. This condition is rather annoying than harmful, and the best way to fight it is to use antiviral agents, drink lots of fluids, and get plenty of rest.