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Listeriosis is an infection that usually develops after eating food that's been contaminated by listeria bacteria (Listeria monocytogenes)

11 December 2018


Listeriosis is a rare infection caused by bacteria called listeria. It usually goes away on its own, but can cause serious problems if you're pregnant or have a weak immune system.

How you catch listeriosis

Listeriosis is usually caught from eating food containing listeria bacteria.

You can get it from lots of types of food, but it's mainly a problem with:

  • unpasteurised milk
  • dairy products made from unpasteurised milk
  • soft cheeses, like camembert and brie
  • chilled ready-to-eat foods, like prepacked sandwiches, pâté and deli meats


These foods don't always cause listeriosis. If you have eaten them recently, you don't need to do anything unless you get symptoms of the infection.

You can also catch listeriosis from:

  • someone else who has it – for example, if you eat food they have handled when they haven't washed their hands
  • close contact with farm animals – especially sheep and cows that are giving birth

Symptoms of listeriosis

In most people, listeriosis has no symptoms or only causes mild symptoms for a few days, such as:

  • a high temperature of 38C or above
  • aches and pains
  • chills
  • feeling sick or vomiting
  • diarrhoea

If you have these symptoms, you can usually look after yourself at home.

Find out how to treat sickness and diarrhoea yourself ↗

Call your midwife if you're pregnant and think you have listeriosis

You may need a blood test to check for the infection.

You'll be given antibiotics if you have listeriosis because it could cause serious problems like a miscarriage ↗ if not treated.

Ask for an urgent GP appointment if:

  • you think you have listeriosis and you have a condition that weakens your immune system (like diabetes)
  • you think you have listeriosis and you're having treatment that weakens your immune system (like chemotherapy)
  • you think your baby might have listeriosis

If it's not treated, severe listeriosis can cause serious infections like meningitis ↗ in babies and people with a weak immune system.

Call 999 or go to A&E if you get:

  • a severe headache and stiff neck
  • discomfort when looking at bright lights
  • fits (seizures)
  • sudden confusion
  • a rash that doesn't fade when a glass is rolled over it – the rash may be blotchy, like bruises or small red pinpricks

These could be symptoms of meningitis ↗ caused by listeriosis, which needs to be treated in hospital straight away.

How to avoid listeriosis

There are some simple things you can do to reduce your risk of getting listeriosis:


  • wash your hands regularly with soap and water
  • wash fruit and vegetables before eating them
  • store ready-to-eat foods as recommended by the manufacturer
  • make sure all hot food is steaming hot all the way through


  • do not eat food after its use-by date, even if it looks and smells normal

Foods to avoid if you're pregnant

If you're pregnant, you should avoid eating foods that have the highest risk of causing listeriosis.

These include:

  • some uncooked soft cheeses – including brie and camembert
  • all types of pâté – including vegetable pâté
  • unpasteurised milk or dairy products
  • any undercooked food

Find out which foods to avoid during pregnancy ↗


If you're pregnant, you should also avoid close contact with farm animals that are giving birth or have recently given birth.