On pages 109-110, Dr. Moalem focuses on the purpose of sneezes, and why in particular we sneeze. According to Dr. Moalem, a sneeze "occurs when the body's self-defense system senses a foreign invader trying to get in through your nasal passages". By sneezing, the invasive pathogens are expelled with force away from the body. However, Dr. Moalem brings up the point that a person who has the common cold tends to sneeze more than if they weren't infected. Why would that be?
Further consideration lead to the discovery that the disease caused the victim to sneeze; therefore there was a purpose in doing so. By triggering the sneeze reflex, the cold virus can spread the infection through air to other potential victims.
Hence, sneezing, one of the most common symptoms of an infectious disease, is the product of host manipulation. What other, if any, symptoms do people infected with the common cold display, and how would the mechanism expressed specefically aid in the virus/bacteria in surviving and reproducing? Focus on symptoms related to the common-cold only.
The common cold is a picornavirus meaning that it has ssRNA that can serve as mRNA. (Campbell 387). A picornavirus is also thought to be less virulent. It reproduces like any other virus, by creating a pore in the cell membrane and then injecting RNA.
ReplyDeleteBeing a virus it needs a host cell to survive and reproduce. Dr. Moalem on page 118 also notes that for the common cold, it needs close proximity to transfer from one human to another.
Here are a few symptoms related to the common cold (other than sneezing): runny nose, itchy throat (which leads to a cough), watery eyes, mild fatigue, and a mild fever. (http://www.mayoclinic.com/health/common-cold/DS00056/DSECTION=symptoms). The symptoms that would aid the cold virus in surviving a reproducing are the runny nose, itchy throat, and watery eyes. The mild fever and fatigue is the body's immune system trying to fight the virus. By raising the body temperature the body makes itself in hospitable to the virus.
A runny nose would aid a cold virus because when a person's nose runs they feel the need to wipe it. More often than not people wipe their nose on the back of their hand. Watery eyes are also very similar. People feel the need to wipe their eyes if they are watery. If they do not wash their hands before they touch something else, the virus could have transferred to another surface or another persons body. If it is to a surface, sooner or later another person will touch it effectively transferring the virus. The transfer of the virus allows the cold to survive and reproduce.
A cough (itchy throat) is more similar to sneezing. When a person coughs the virus is airborne and then goes up another persons nose, effectively transferring the virus. The transfer of the virus allows the cold to survive and reproduce.
(Sriya Potham, spotham4@students.d125.org)