Listeria is a type of bacteria which infects humans and some animals through contaminated food.
Listeria can cause an infection called listeriosis - but what is this and is it dangerous?
Listeriosis is a rare infection caused by bacteria called listeria. Although it usually goes away on its own, it can cause serious problems if you are pregnant or have a weak immune system.
The NHS notes that 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 pre-packed sandwiches, pâté and deli meats
However, it is important to note that these foods do not always cause listeriosis and if you have eaten them recently, you do not 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 have not washed their hands
- close contact with farm animals – especially sheep and cows that are giving birth
What are the symptoms of listeriosis?
In most people, listeriosis has no symptoms or only causes mild symptoms for a few days, including:
- a high temperature of 38C or above
- aches and pains
- feeling sick or vomiting
The NHS explains that “if you have these symptoms, you can usually look after yourself at home.”
However, if you should get advice from 111 if :
- you're pregnant and think you have listeriosis
- you have a condition that weakens your immune system (like diabetes) and think you have listeriosis
-you're having treatment that weakens your immune system (like chemotherapy) and think you have listeriosis
- you think your baby might have listeriosis
“You may need a blood test to check for the infection and antibiotics to treat it,” adds the NHS.
You should 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 does not 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,” the NHS explains.
How to avoid listeriosis
To reduce your risk of getting listeriosis, you should:
- 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
“You should not eat food after its use-by date, even if it looks and smells normal,” notes the NHS.