Overview

Listeriosis is a rare infection caused by bacteria called listeria. It usually goes away on its own, but can cause serious problems.

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 chilled, ready-to-eat foods, such as:

  • cooked sliced meats and cured meats
  • smoked fish and cooked shellfish
  • blue veined and mould-ripened soft cheeses, like camembert and brie
  • pâté
  • pre-prepared sandwiches and salads
  • some pre-prepared fruit, including melon slices
  • unpasteurised milk
  • dairy products made from unpasteurised milk

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

Although it’s less common, you can also catch listeriosis from:

  • someone else who has it – for example, if you eat food they've handled when they've not 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 or being sick
  • diarrhoea

If you're pregnant, you may also have a stomach ache or notice your baby moving less than usual.

Babies with listeriosis may be irritable and feed less than usual.

Risks of listeriosis

Listeriosis is not usually serious for most people.

But some people have a higher risk of serious problems, including:

  • people who are pregnant
  • newborn babies
  • people aged 65 or over
  • people with a condition that weakens their immune system, such as cancer or kidney disease
  • people having treatment that weakens their immune system, such as chemotherapy or steroid tablets
  • people with diabetes who are unable to keep their blood sugar level down, even with treatment (uncontrolled diabetes)

If you get listeriosis while you're pregnant, there is a risk it could cause miscarriage or stillbirth.

In babies, older people and people with a weakened immune system, listeriosis can sometimes lead to serious and life-threatening problems such as sepsis or meningitis.


Ask for an urgent GP appointment or get help from NHS 111 if:

  • you're pregnant and think you have listeriosis
  • you have a condition that weakens your immune system (like cancer or kidney disease) and think you have listeriosis
  • you're having treatment that weakens your immune system (like chemotherapy or steroid tablets) and think you have listeriosis
  • you think your baby might have listeriosis

If you're pregnant, you can also call your midwife for advice.

Call 999 or go to A&E if you or your child:

  • have a severe headache and stiff neck
  • find it uncomfortable to look at bright lights
  • have a fit (seizures)
  • feel suddenly confused
  • feel very sleepy or difficult to wake
  • have a rash that does not fade when a glass is rolled over it – the rash may be blotchy, like bruises or small pinpricks

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

Treatment for listeriosis

For most people, listeriosis is mild and gets better in a few days.

You can usually look after yourself at home by resting and drinking plenty of fluids.

If you're at a higher risk of getting seriously ill (for example, you're pregnant or have a weakened immune system), you may need antibiotics.

Find out how to treat diarrhoea and vomiting at home

How to avoid listeriosis

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

Do:

  • wash your hands regularly with soap and water
  • wash fruit and vegetables before eating them
  • keep chilled, ready-to-eat foods cold – try to make sure your fridge is working properly and is set to 5C or below
  • keep raw and ready-to-eat foods separate
  • use foods by their use-by date
  • follow storage instructions on food labels and use opened food within 2 days (unless the packaging says otherwise)
  • eat ready-to-eat foods within 4 hours of taking them out of the fridge
  • make sure all hot food is cooked or reheated until it's steaming hot all the way right through

Don't:

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

Foods to avoid if you're at risk

If you're pregnant or have a weakened immune system, you should avoid eating foods that have the highest risk of causing listeriosis.

These include:

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

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

Find out which foods to avoid during pregnancy

Smoked fish and listeria

Due to a listeria outbreak linked to smoked fish, people at higher risk of serious infection should only eat smoked fish products that have been thoroughly cooked.

When cooking smoked fish products at home, make sure they are steaming hot all the way through.

Find out more about the listeria outbreak in smoked fish from the Food Standards Agency



The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website nhs.uk
Last Updated: 01/06/2022 09:52:56