Question: what makes a virus more lethal?

Sonia Rodriguez answered on 10 Jul 2020: last edited 11 Jul 2020 2:28 pm

That’s a very good question. There are several factors that can affect the lethality of a virus. One is the type of cell they infect. It’s more dangerous a virus that can infect your liver or blood than a virus that infects the external cells of your skin. Other important factor is how fast the virus multiply and its effect on the infected cells. If the virus multiplies very fast, more cells will be affected and all the machinery of the infected cell will be used to produce new virus. If the production of the virus is too fast, the cells don’t have enough resources for their normal functions. Moreover, some viruses cause the death of the cells they infect or make the cells send signals that affect the activity of other non-infected cells.
One of the known deadliest virus is ebola. This virus starts infecting only blood cells, but these infected cells send signals that damage the blood vessels. This facilitates the infection of other cell types very quickly and causes liver damage and internal bleeding. We could use warts as the opposite example. The viruses that cause warts can only infect the top layer of the skin and they multiply slowly, so they are quite harmless.