Disease: a description of syptoms either physical, mental or a combination of both. This definition suggests a malfunction of body or mind which has an adverse effect on good health. Implications of which could be mental, physical or social.
For a micro organisms to be considered a pathogen it must:
- Gain entry to the host,
- colonise the tissues of the host,
- resist the defences of the host,
- cause damage to the host tissues.
Pathogens include, bacteria, fungi and viruses.
Once a pathogen has gained entry to the host and colonised it tissues then it has successfully infected. If there are visible symptoms then disease occurs. If the pathogen is transferred from one individual to the next then is is an example of transmission.
Pathogens infect their host…