Concept explainers
To describe:
Why an individual may get a common cold or twice a year but measles was a one time-occurrence?
Introduction:
There is a wide range of airborne viral diseases such as measles, mumps, chicken pox, and rubella can affect humans. Measles induces systemic infections and also induce a variety of serious problems, such as pneumonia, inner ear infections, and encephalomyelitis. Measles may last for a week with cough, fever, and a rash may persist.
The respiratory diseases range from mild, self-limiting, like common cold to lethal entities such as pulmonary embolism, lung cancer, acute asthma, and bacterial pneumonia.
Explanation of Solution
Cold is considered as a common respiratory illness due to its rapid onset. The causative agent of common cold is Rhinovirus. Rhinoviruses are single stranded plus-sense RNA viruses and they are a genus of the Picornaviridae family. There are other viruses that can cause cold in humans, such as Coronavirus, Coxsackie virus, Adenovirus, Orthomyxovirus, and respiratory syncytial viruses. Since a wide range of viruses causes the common cold the human defense system cannot able to develop immunity to all of them. Therefore, chances of getting cold is frequent.
In contrast, a single virus, called Paramyxovirus, causes the measles. Since, a single virus causes the disease; the human immune system may produce a lifelong immunity against that particular disease. Therefore, if an individual experienced measles, it may be a one-time occurrence.
Want to see more full solutions like this?
Chapter 30 Solutions
Brock Biology of Microorganisms - MasteringBiology With eText - Access