Transmission

Definition

Transmission refers to the mechanism by which an infectious agent is spread from a source or reservoir to a susceptible host. It can occur through various pathways, including direct contact, indirect contact, and vectors.

5 Must Know Facts For Your Next Test

1. Direct transmission involves immediate transfer of the pathogen through physical contact such as touching or biting.
2. Indirect transmission occurs when pathogens are spread via inanimate objects called fomites, such as doorknobs or medical instruments.
3. Vector-borne transmission involves carriers like mosquitoes or ticks that transmit pathogens between hosts.
4. Airborne transmission happens when infectious agents are carried on dust particles or droplets that remain suspended in the air for long periods.
5. Droplet transmission occurs when respiratory droplets carrying pathogens are expelled during coughing, sneezing, or talking and land on mucosal surfaces.

Review Questions

• What is the difference between direct and indirect transmission?
• How does vector-borne transmission differ from droplet transmission?
• What role do fomites play in the spread of infectious diseases?

Related terms

Fomite: An inanimate object that can carry infectious agents from one individual to another.

Vector:

An organism, typically an insect, that transmits a pathogen from one host to another.

Reservoir:

A habitat where an infectious agent normally lives, grows, and multiplies.