Queensland Health investigating listeria outbreak

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17 September 2023

Health authorities across Australia are continuing to investigate three separate genetically related clusters of Listeria infection.

The Queensland cases under investigation are from South East Queensland.

Queensland’s Chief Health Officer Dr John Gerrard said there had been no reported deaths.

“There is potential for further cases to be notified as part of this outbreak as it can take up to two months for symptoms to appear after eating food contaminated with listeria,” Dr Gerrard said.

“We are investigating several potential food sources, with tests currently under way.

“We expect more results to come through in the coming week.”

Year to date, there have been eight cases of listeriosis reported in Queensland, which is similar to the nine cases reported in the same period in 2019, before the COVID-19 pandemic.

Listeriosis is a serious infection in humans caused by the bacteria Listeria monocytogenes. It usually causes only a mild illness but may progress to septicaemia and/or meningitis (known as invasive listeriosis).

People at highest risk of severe illness include the elderly, pregnant women and people with a weakened immune system, such as diabetics, cancer and transplant patients, people who are HIV positive, and people with a history of alcohol abuse.

Listeriosis is primarily a foodborne disease transmitted by ingestion of contaminated food such as ready-to-eat processed meats (e.g. packaged or freshly deli sliced meats like ham and salami), soft cheeses, pre-prepared salads, raw vegetables, pâté and shellfish.

Symptoms of listeriosis

Symptoms of listeriosis can include fever, headache, muscle aches, nausea, vomiting, diarrhoea and neck stiffness.

Symptoms may appear within 24 hours of eating contaminated food, but it can take up to two months for symptoms to develop.

What to do if you are concerned

If you are concerned that you may have listeriosis, please see your GP immediately.

If in doubt, always call Triple Zero (000).

Preventing listeriosis

There are a number of things you can do to prevent listeriosis, including:

  • Cooking food thoroughly, especially meat, poultry and fish
  • Washing fruits and vegetables thoroughly before eating
  • Avoiding soft cheeses, such as camembert and brie, and pate
  • Avoiding pre-prepared salads and meats
  • Keeping raw meat, poultry and fish separate from other foods in the refrigerator and freezer
  • Cleaning and disinfecting all surfaces that come into contact with raw meat, poultry and fish
  • Washing your hands thoroughly after handling raw meat, poultry and fish

More information on listeriosis is available on the Queensland Government website.