Rhinovirus - The Common Cold :: Essays Papers

Rhinovirus - The Common Cold Introduction: Rhinovirus, pictured above, is best known as the common cold. It is a member of the picornaviridae family along with more virulent viruses such as polio and hepatitis A. The viruses of this family are characterized as small (20-30nm genome) positive polarity RNA viruses consisting of one genome segment and a nonenveloped capsid. Unlike the its more lethal relatives, Rhinovirus is designed to attack a host numerous times during their lifetime. It is the perfect pathogen. It is estimated that adults suffer from 2 to 4 infections with the virus each year. The statistics below show the toll that the virus has on the United States Population: . There are nearly 62 million cases of the common cold annually in the US . 52.2 million of these cases affect Americans under age 17 . There are nearly 22 million school-loss days annually due to the common cold . There are approximately 45 million bed days annually associated with the common cold . Seventy-five percent of common colds suffered by children under 5 years are medically attended Source: Vital and Health Statistics Series 10, No. 200 The economic impact of the cold is estimated at 5 billion dollars, but is far greater in indirect costs when considering loss of productivity and school abscence. Encounter: It is virtually impossible to avoid Rhinovirus encounter because it is one of the few pathogens that is present in the environment year round. There are over 100 serotypes making it unlikely to have antibodies to each strain. It often enters the upper respitory tract via aerosolized droplets coming from an infectious individuals coughing or sneezing. It is also possible to spread the pathogen through saliva. However, studies have proven that contact transmission is the dominant mode of contraction. [9] This is possible because infected individuals can shed the virus 24 hours before symptoms and as long as 2 weeks after symptoms cease. Contrary to popular belief, there is no valid clinical evidence that exposure to cold or moisture will result in infection. Entry: Primary infection occurs in the nasal mucosa and occasionally the conjunctiva. Once exposed to the epithelial cells, the virus attempts to bind to intracellular adhesion molecule-1 (ICAM1). ICAM-1 is regularly used by the immune system to bind endothelial cells to leukocytes. However, as the picture above shows, Rhinovirus is able to take advantage of this property and recognizes it with its own receptors.