Increasing understanding about the cause of disease

• Public health is the prevention of disease and the spread of disease in a community. Causes of disease have to be understood before cures can be developed. If the causes are discovered than the spread of disease can be reduced.
• 2 main theories about the cause of disease:

  1. Miasma theory
  2. Germ theory of disease
• Miasma theory of disease:

  Diseases were caused by the presence of miasma or 'bad air'. It was a kind of poisonous gas, which were suspended in minute particles of decaying matter. It was characterised by a foul smell. If your were breathing in miasma you were going to get ill. Disease was spread through the air. Industrialisation had created foul-smelling areas in cities. Improving housing and sanitation would mean public health would improve
• The germ theory of disease:

  Scientists became interested in decaying matter and in the maggots and flies that lived on and in it. Development of microscopes (Joseph Lister in 1830) enabled them to observe micro-organisms in rotting materials. Decaying matter created the micro-organisms, and that micro-organisms in the air were attracted to decaying material
• Which theory was correct?

  1860 - Louis Pasteur, conducted a series of experiments proving that micro-organisms existed in the air and were not created by decaying material. Germs caused disease in silkworms and humans. Not everyone believed him. Robert Koch proved this in the 1880s and 1890s. Germs caused most of the killer diseases.