Routes of Transmission

Direct Contact Transmission

Direct contact transmission happens when pathogens are spread directly from one person to another.
This could be through physical touch, such as handshaking, or through sexual contact.
In healthcare settings, this can often occur when healthcare workers move from infected to uninfected patients without the proper use of personal protective equipment (PPE).
Vertical transmission is a type of direct transmission where pathogens are passed from mother to child during pregnancy, childbirth, or breastfeeding.

Indirect Contact Transmission

Indirect contact transmission occurs when an individual comes into contact with a contaminated object or surface.
Common objects include door handles, elevator buttons, and handheld electronic devices.
Also includes use of shared personal items such as towels, bed linen, combs, razors, or needles.

Droplet Transmission

Droplet transmission happens when an infected person coughs, sneezes, or talks, projecting pathogen-laden droplets into the air.
These can land on the mucous membranes of another person’s nose, mouth, or eyes, potentially causing infection.
Typically, droplets do not remain suspended in the air and only travel short distances, therefore close proximity to the infected person increases the risk of transmission.

Airborne Transmission

Airborne transmission involves pathogen-laden microscopic particles (much smaller than droplets) that stay suspended in the air for long periods.
These can be breathed in by other individuals, potentially leading to infection.
This type of transmission can occur over greater distances than droplet transmission—usually more than 1 meter.

Vector-Borne Transmission

Vector-borne transmission happens when a living organism, or ‘vector’, such as a mosquito, tick, or flea, transmits an infectious pathogen between humans or from animals to humans.
Malaria, for example, is a disease spread by the bites of infected mosquitos.
The tsetse fly, which spreads sleeping sickness, and the rat flea, which can spread Bubonic Plague, are other examples of vectors.

Understanding these routes of transmission is key to preventing and controlling the spread of infectious diseases in healthcare settings. Effective infection control measures can break the chain at any of these stages.