disease vectors

Disease vectors are organisms that transmit pathogens from one host to another without themselves being the cause of disease.

Mosquitoes are vectors for malaria and dengue; ticks carry Lyme disease.

The term extends figuratively to anything that spreads harm: Social media can be a disease vector for misinformation.

In epidemiology, controlling vectors—through pesticides, nets, or habitat reduction—is often more practical than treating infections directly.