3.1.1 - Communicable (Infectious) Diseases

What is a communicable disease?

A disease caused by a pathogen which can be passed between animals or plants e.g. flu

What is a pathogen?

A micro-organism that causes infectious diseases e.g. bacteria

How do bacteria cause disease?

Once inside the body, they divide rapidly by binary fission. They kill cells and produce harmful toxins.

Give three ways in which pathogens can be spread

• By air - flu, tuberculosis and the common cold are spread by droplet infection

• By water - fungal spores in water spread plant diseases

• By direct contact - common in plant diseases and sexually transmitted infections

Give four ways in which the spread of pathogens can be reduced

• Hygiene - handwashing, disinfectants, tissues

• Reducing contact with infected individuals - quarantine

• Removing vectors - use of pesticides and insecticides, removal of habitats

• Vaccination