Which mechanisms describe direct transmission?

• A. Direct contact and droplet spread.
• B. Vehicle borne and vector borne.
• C. Direct contact and vector borne.
• D. Fomite and waterborne.

Answer: (C)

Direct transmission means the infectious agent moves straight from one host to another without an intermediate object or organism. The two mechanisms that accomplish this are direct contact (such as skin-to-skin or sexual contact) and droplet spread (respiratory droplets produced when an infected person talks, coughs, or sneezes that reach the mucous membranes of a nearby person).

Vector-borne transmission, as well as vehicle-borne, fomite, and waterborne routes, involve an intermediary (a living vector or an inanimate vehicle), so they are indirect transmission. Therefore, the pair that describes direct transmission is direct contact and droplet spread.