Viruses cause sickness through two basic means and yet the contributions of each mechanism to pathology are generally unclear. Today I want to explore the literature a bit and see if I can somehow compare the weight of these two basic pathological devices in the progression of viral pathology. I submit to you that while a virus may incite dysfunction and cellular or even organismal death through one of two following basic modes, these are by no means the only roles of viruses in biology:

1) Viral replication variably stresses critical cellular machinery; this results in mis-function, and dysfunction of your vital tissues.



2) The virus elicits immune responses which variably culminate in cellular damage throughout your body.

Let’s look at the first case: direct viral damage. For those of you with college level biological knowledge, you are may remain under the impression that viruses destroy their hosts by proliferating to the point of literally bursting open their hosts, like the parasitic Face-Huggers of the film, Aliens. This direct lytic mechanism is, in fact, surprisingly rare among viral infections in animals. There are just a few anecdotes of animal viruses assisting in the permeabilization of host membranes, for example. Generally if direct lysis occurs in animals, it is usually after a prolonged period of latency whereby the virus lurks within the host’s genome. What is more likely is that viruses in eukaryotic tissue have evolved to be less directly virulent, promoting longer-term, rather than immediate cellular failure.



Think about it. Virions cannot survive for very long outside of a body. They certainly cannot replicate without a host; and generally, they are well-suited to a fairly specific host-type. Since virions are highly simple structures, they rely of a very few genes to accomplish a great deal and this inherently restricts and regulates their spread among species. And while in pools of bacteria, viruses must play a numbers game and infect as many as possible, as quickly as possible, literally to the point of bursting open the cell so as not be out-divided. But such an approach is not so effective in slow-moving, slowly dividing, cellularly complex animals like you, the hairless ape. So in the case of a typical cold, flu, or even the coronavirus epidemic of late, lytic action is unlikely to be a primary contributor to most viral pathologies.