About communicable diseases

Learn what a communicable disease is, how they are classified and spread, and how some can be prevented.

What communicable disease is

A communicable disease is an illness that spreads from one person to another. People also call them infectious diseases. Diseases that are spread from people to animals are called zoonotic diseases.

Different communicable diseases spread in different ways. Common ways are through viruses or bacteria in food or water, blood or other body fluids, insect bites or air.  

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Types of communicable disease

Communicable diseases can be grouped in different ways, depending on how they spread and if we can prevent cases by using vaccines.

We monitor some diseases Australia-wide. We call these ‘nationally notifiable diseases’ and we classify them according to:

  • how they most easily transmit
  • their most significant symptoms
  • how they are grouped for investigation and diagnosis.

These classifications are broadly understood nationally and internationally, but are not regulated.

See more about  nationally notifiable diseases and their classifications.

The federal Biosecurity Act 2015 classifies some diseases as ‘listed human diseases’. Examples include human influenza or coronavirus with pandemic potential, smallpox and viral haemorrhagic fevers. A listed human disease is one that can spread and may cause significant harm to human health. Measures can be imposed to help stop the spread of these diseases. An example is requirements for pre-departure testing or health screening at Australia's international borders.

Learn more about laws related to communicable diseases in Australia.

Significant health issue

Communicable diseases are a significant health issue in Australia and around the world. The health problems facing Australia today are diverse:

  • foodborne diseases
  • bacterial infections that no longer respond to antibiotics
  • sexually transmitted infections
  • diseases spread by animals (zoonotic diseases), insects or parasites
  • vaccine-preventable diseases.

Reducing the spread

We work to reduce the spread of communicable diseases and their impact on Australian society. See more on what we’re doing about communicable diseases.

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