Causes of Common Cold
Viruses cause infection by overcoming the body's complex defense system. The body's first line of defense in the respiratory tract is mucus, produced by the membranes in the nose and throat. Virus multiply in the outer mucus cell layer of the throat. This results in congestion of the walls of the throat which in turn manifest as an irritation or a tickle in the throat. This "tickly throat" compels the patient to cough in order to clear the irritation. This cough carries the virus from the patient and spread into the atmosphere. This in turn spreads the infection to other healthy people.
How are Colds Spread ?
Depending on the virus type, any or all of the following routes of transmission may be common:
- Touching infectious respiratory secretions on skin or personal objects which have been contaminated by the patient.
- Inhaling relatively large particles of respiratory secretions transported briefly in the air.
- Inhaling droplets, smaller infectious particles from coughing or sneezing by patients suffering from cold.