Pathogens and Disease

Pathogens and Disease

A pathogen is a microorganism that causes disease — the main types are bacteria, viruses, fungi, and protists.

How pathogens spread

Pathogens can spread by direct contact, through water, through the air (droplet infection), or via a vector like an insect carrying the pathogen between hosts.

The body's defences

The skin acts as a physical barrier. If pathogens get inside, white blood cells attack them directly, produce antibodies to target them specifically, or produce antitoxins to neutralise toxins they release.

Practice

Name two ways pathogens can spread from person to person.