Diseases and surveillance

Listeriosis

Listeriosis is an infection caused by bacteria in contaminated food. It can be serious. Safe food practices and avoiding high-risk foods for people at greater risk are the best protection. We provide guidelines and monitor and report on listeriosis, including national case numbers.

At a glance

About listeriosis

Listeriosis is caused by the bacterium Listeria monocytogenes. It is usually spread through eating contaminated food.

Listeriosis can cause symptoms similar to gastroenteritis, but the bacteria can spread beyond the gut and cause a serious invasive disease, including brain infection.

Getting listeriosis while pregnant can cause serious disease or death for the unborn or newborn baby.

People at greater risk of severe disease – especially pregnant people – should avoid eating high-risk foods.

Why it matters to public health

Listeriosis is rare, but it can be deadly, even with treatment.

Listeriosis in pregnant people can have severe effects on the developing baby or newborn, including death.

Listeriosis outbreaks happen when many people are infected from a common source. Outbreaks in Australia can have serious impacts.

Because of these major impacts, we:

Symptoms

If you’re looking for advice about your own health or treatment options, see healthdirect or speak with a qualified healthcare professional. Our role is to provide public health advice – information and guidance that helps prevent disease, protect communities and improve wellbeing at a population level. 

Symptoms of intestinal listeriosis are usually mild and resolve without treatment within a few days.

Symptoms include:

Invasive listeriosis usually begins with mild symptoms similar to the flu. It can progress to severe illness such as sepsis or meningitis. 

Meningitis (inflammation of the lining of the brain) symptoms include:

Serious complications can include long-term brain damage or death.

In pregnant people, invasive listeriosis usually has mild or no symptoms, and severe illness is rare. But it can cause other serious complications, including:

  • miscarriage
  • stillbirth
  • serious infection of the newborn baby.

Read more about the symptoms, diagnosis and treatment of listeriosis.

healthdirect’s symptom checker can help you decide whether to see a health professional.

Check your symptoms

Onset of symptoms

The time between eating contaminated food and symptoms starting depends on the type of disease:

  • Intestinal illness usually starts within 24 hours.
  • Invasive illness usually starts within 2 weeks.
  • In pregnancy, symptoms usually start within 4 weeks – but this can be up to 70 days.

How it spreads

Listeriosis is usually caused by eating contaminated food. Listeria bacteria can grow and multiply even in the fridge. 

Most healthy people won’t get sick if they eat foods contaminated with Listeria. But some people are more likely to be infected and develop invasive listeriosis.

Certain types of food – especially cold, pre-prepared, ready-to-eat foods – are more likely to be contaminated.

High-risk foods include:

  • pre-cooked cold meats, including chicken
  • chilled raw or smoked seafood, including smoked salmon and ready-to-eat prawns
  • soft cheeses, including brie and camembert
  • pate or meat spreads
  • pre-cut or pre-prepared fruit, including fruit salads
  • pre-prepared or pre-packaged cold salads
  • frozen vegetables, unless cooked
  • rockmelon
  • soft serve ice cream
  • raw seed sprouts
  • unpasteurised (raw) milk or juices.

The infection can also pass to the baby during pregnancy or birth.

People who have recovered from listeriosis can be infected again.

Infectious period

Listeriosis does not usually spread from person to person, except from a pregnant person to their developing baby or newborn.

Prevention

There is no vaccine against listeriosis. 

People who are at greater risk of severe disease should avoid eating high-risk foods.

The best ways to protect against listeriosis are to:

Australia has strict food safety standards and programs for Listeria testing in commercially prepared high-risk foods. Foods that have unacceptable levels of Listeria may be recalled from sale.

Read more ways to prevent listeriosis.

Priority groups and settings

Some people are at greater risk of getting listeriosis or of getting very sick from it.

If you are at greater risk, it is especially important to take steps to protect yourself.

People at greater risk of severe disease

Those at greater risk of severe illness include:

  • pregnant people and their unborn babies
  • newborn babies
  • older adults
  • people who are immunocompromised.

People at greater risk of exposure

People are more likely to be exposed to Listeria if they eat high-risk foods.

Diagnosis and treatment

Invasive listeriosis is diagnosed through laboratory testing of: 

Babies can be diagnosed through laboratory testing of the amniotic fluid or placenta (after delivery).

You can use healthdirect’s directory to find a health service near you.

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People with invasive listeriosis are cared for in hospital.

Healthcare professionals may prescribe antibiotics to people with:

  • severe symptoms
  • a high risk of complications – including pregnant people.

Read more about how to manage or treat listeriosis.

Surveillance and reporting

Listeriosis is a nationally notifiable disease – these are diseases that present a risk to public health.

Health authorities in each state and territory report new confirmed cases to us daily through the National Notifiable Diseases Surveillance System.

We also collect and analyse data on listeriosis cases through the OzFoodNet Network. This includes details about people’s risk factors and food consumption history.

This is part of our surveillance activities, which help us monitor case numbers around the country, understand disease patterns and identify outbreaks. 

We analyse the data and report on case numbers and other data through our data visualisation tool, where you can filter and search the latest information.

Outbreaks

State and territory health departments investigate outbreaks by:

  • interviewing people with listeriosis to find a common source
  • identifying other people who might have been exposed to the same source
  • testing foods
  • assessing food handling procedures
  • working with food safety agencies and distributors to trace where the food came from.

Outbreak control measures might include:

  • providing education of safe food practices and hand hygiene
  • issuing public health orders to food businesses – this might include improvements to food processing procedures
  • recalling contaminated food
  • sending out national or regional media alerts.

OzFoodNet monitors and reports on listeriosis outbreaks.

Read more about how the Australian Government plans for outbreaks.

Support

For information about listeria in your state or territory, see:

If you need mental health support, see a list of organisations, websites and services that offer support, counselling and information.

Latest resources

Listeriosis – CDNA National Guidelines for Public Health Units

These guidelines for Public Health Units provide nationally consistent guidance on how to respond to listeriosis. They are part of a Series of National Guidelines (SoNGs) published by the Communicable Diseases Network Australia (CDNA).

Listeriosis – Laboratory case definition

The Public Health Laboratory Network (PHLN) has developed standard case definitions for the diagnosis of key diseases in Australia. This document contains the laboratory case definition for listeriosis.

Listeriosis – Surveillance case definition

This document contains the surveillance case definition for listeriosis, which is nationally notifiable within Australia. State and territory health departments use this definition to decide whether to notify us of a case.
Related resources
Last updated:
Disease groups:
  • Gastrointestinal
  • Foodborne