Diseases notes - Pathogens

Pathogens

• A pathogen is a disease inducing organism
• The host is the infected organism
• A disease is an abnormal condition of an organism which impares bodily functions
• Pathogens include: 

Bacteria

• Bacteria are simple, prokaryotic cells
• They contain no nucleus
• Not all of them are pathogenic
• They can tolerate a lot of conditions and multiply rapidly
• Many release toxins

Cholera is an example of a bacterium in the syllabus. They release toxins which affect the digestive system causing severe diarrhoea. Tuberculosis is another example of a bacterium, it affects the lungs. 

Viruses

• Not strictly cells
• They are particles compromising of a protein coat containing genetic material and enzymes
• They are all  pathogenic
• They live as an obligate parasite, by invading host cells to reproduce

Influenza is a virus which affects the lungs and trachea. The host's immune system then releases chemicals which cause fever, muscle aches and fatigue. 

Fungi 

• Fungi are the most complex eukaryotic cells
• Have a nucleus and other membrane bound…