Which option lists the three modes of disease transmission used in infection control?

• A. Contact, Droplet, and Airborne transmission
• B. Bloodborne, Vector-borne, and Fomite transmission
• C. Direct, Indirect, and Ambient
• D. Mechanical, Chemical, and Biological

Answer: (A)

Understanding how diseases spread in healthcare settings centers on three main modes of transmission that drive infection-control measures: contact, droplet, and airborne.

Contact transmission occurs when pathogens move through direct touch with an infected person or through touching contaminated surfaces (fomites) and then touching the face. Droplet transmission happens via larger respiratory droplets expelled when someone coughs or sneezes, which travel short distances and reach the nose, mouth, or eyes. Airborne transmission involves very small particles that can remain suspended in the air and travel longer distances, requiring precautions like N95 respirators and specialized ventilation.

This trio is the standard grouping used in infection control, guiding what protective measures to apply in different scenarios. Other groupings mix concepts that aren’t the three primary transmission modes—for example, bloodborne or vector-borne refer to how pathogens reach the body rather than how they spread in a setting, and ambient or mechanical/chemical/biological don’t describe the main modes of person-to-person transmission.