Definition of virulent

The word "virulent" originated from the Latin word "virulentus," which was used to describe poisonous or deadly substances. During medieval times, scientists and physicians began applying this term to describe the potency and severity of infectious diseases. They noticed that certain types of illnesses were incredibly dangerous and caused progressively worsening symptoms, sometimes leading to death. These diseases were dubbed "virulent" as a way to emphasize the intensity of their symptoms and impact on the human body. In the centuries that followed, the meaning of "virulent" expanded to include not just infectious diseases but any substance or agent that causes swift and destructive harm, such as poisons, toxins, and viruses. Today, the word "virulent" continues to convey the idea of extreme danger and lethality, whether it is used to describe a microbe, a toxin, or a disease.