A pathogen is an organism that has the potential to cause disease.
- They are typically micro-organisms- very small living creatures
- micro-organisms are classified into 5 different groups: viruses,bacteria,fungi,algae,protozoa (protocists)
- The cycle of transmission involves
- Escape from the host or reservior of infection
- Transport to the new host
- Entry to a new host
- Escape from the new host
An infection is the invasion and multiplication of pathogenic microbes in an individual or popualtion
Disease is when the infection causes damage to the individual's vital function or systems.
- Infections do not always lead to disease