The common cold typically refers to an upper respiratory disease, also known as viral upper respiratory tract infection (VURTI) or acute viral rhinopharyngitis. This sickness is one of the most prevalent and frequently experienced illnesses in all parts of the world, in all ages of human beings, hence its moniker, the common cold.

The causes of the common cold cannot be attributed to one source alone. Viruses, stress, and the weather are said to all factor in to enable the onset of the common cold in the body.

Common Cold Viruses

Rhinovirus

The rhinovirus was found to be the most prevalent common cold virus, out of the two hundred identified common cold viruses. According to a study conducted by Dr. Terho Heikkinen and Dr. Asko Järvinen in 2003, thirty to fifty percent of those who were afflicted with the common cold who were under observation were infected with the rhinovirus. This confirms the earlier study of Dr. Makela et. al. in 1997, which said that viral etiology, was found in sixty-nine percent of the patients that were under observation, and of this number, a majority were infected with rhinoviruses.

Other Viruses

Other viruses that cause the common cold are adenoviruses, coxsackieviruses, echoviruses, orthomyxoviruses, which cause influenza A and B, paramyxoviruses respiratory syncytial virus, and enteroviruses.

Yet, despite the numerous studies done on the causes of the common cold, these same studies show that twenty to fifty percent of the viruses that were found in the patients under observation could not be identified.

The Weather

Laymen most often relate the common cold to cold weather. However, studies are conflicting with regard to the weather's direct effect on the common cold.

The National Allergy and Infection Diseases Department of the United States Department of Health and Human Services however, explains this by the tendency of people to stay indoors during the onset of the winter or cooler months. By staying indoors, the chances of spreading and catching the common cold are more likely to occur.

Stress

A study conducted by Dr. Sheldon Cohen et al concluded that psychological stress made otherwise healthy individuals more susceptible to being infected with the common cold virus. The study however clarified that stress increased the risk of being infected with the common cold and did not significantly affect the onset of the symptoms after the infection occurs.