A number of viruses often include a similar set of symptoms when they cause an infectious disease state (fever, headache, fatigue, runny nose). Why would they all cause the same symptoms if they're different viruses?
A) They all possess the same basic virulence genes and molecules, so they all trigger the same responses.
B) The symptoms are associated with the immune system's response, NOT the molecules from the pathogens themselves. Our responses against viruses are fairly similar, regardless of virus type, so the symptoms are similar.
C) Most viruses infect the upper respiratory tract. This leads to the common set of symptoms listed above. Only a few viruses infect areas away from this region.
D) Viruses specifically infect mainly epithelial membranes. As such, the virally induced reaction is similar in different areas of the body due to the same basic cell types (epithelial cells) being infected in each area.
E) All animal viruses must attach to and enter host cells. Since this step in the life cycle is identical in all viruses, the signs and symptoms that follow will also be identical.

Question

Quizplus · Accepted Answer

The symptoms are a response generated by the host immune system, not the molecules specific to the virus itself. Therefore, similar symptoms may be seen in response to different viruses because the immune response to viral infections is relatively consistent.

A Number of Viruses Often Include a Similar Set of Symptoms