What it means
A measure of how harmful a pathogen is. A highly virulent germ can cause serious illness even in small numbers, often because it makes toxins, invades tissue easily or escapes the immune system. Virulence is one link in whether an infection happens; the number of germs and the host's defenses matter too.
At a glance
| Spanish | virulencia |
|---|---|
| Also written | virulent |
Related terms
bacterium
A tiny one-celled living thing, seen only under a microscope, of which some kinds cause disease; the plural is bacteria.
infectious disease
An illness caused by a germ such as a bacterium, virus, fungus or parasite.
pathogen
A germ, such as a bacterium, virus, fungus or parasite, that can cause disease.