Pathogens

Greg James describes the effects of bacterial growth, and how to prevent foodborne illness

A pathogen is a microorganism that causes a disease. There are four main types of pathogen:

PathogenExample in animalsExample in plants
VirusesHIV potentially leading to AIDSTobacco mosaic virus
BacteriaSalmonellaAgrobacterium
FungiAthlete's footBlack rose spot
ProtistsMalariaFew known

Transmission

Transmission can occur in a number of important ways, as shown in the table below:

TypeExamples
Direct contactContact such as shaking hands or touching contaminated surfaces.
WaterDirty water can transmit many diseases, such as the cholera bacterium.
Aerosol (airborne)When a person who is infected by the common cold sneezes, they can spray thousands of tiny droplets containing virus particles into the air that others breathe in.
AirWhen a person who is infected by the common cold sneezes, they can spray thousands of tiny droplets containing virus particles to infect others.
Contaminated foodUndercooked or reheated food can cause bacterial diseases like Escherichia coli (e coli) which is a cause of food poisoning.
Vector (insects)Any organism that can spread a disease is called a vector. Some farmers think tuberculosis in their cattle can be spread by badgers.
Body fluidsThese can be exchanged during sexual intercourse.