infectious

adjective4

1. •
   Caused by an agent that enters the host's body (such as a bacterium, virus, parasite, or prion); often, also, transmitted among hosts via any of various routes (for example, contact, droplet-borne, airborne, waterborne, foodborne, fomite-borne, or bloodborne).

   • Cancer is usually not infectious.
   • More infectious diseases like the flu are usually less potent.
2. •
   Able to infect others; capable of transmitting pathogens.

   • Despite feeling better, the patient is still infectious.
3. •
   Spreading quickly from one person to another.

   • Her enthusiasm for work can be really infectious.
4. •
   Memorable and invoking excitement or interest.

   • Pop music is more infectious than elevator music.