Yersiniosis (Yersinia infection): symptoms, treatment and preventing spread

The UK Health Security Agency (UKHSA) describes yersiniosis, also called Yersinia gastroenteritis, as a gastrointestinal infection caused by a type of bacteria called Yersinia. It is a form of food poisoning. The most common species causing disease in people is Yersinia enterocolitica.

The NHS describes food poisoning in general as an illness caused by eating something that has been contaminated with germs, which is rarely serious and usually gets better within a week. The NHS lists campylobacter, salmonella, E. coli and norovirus as the usual causes, with campylobacter the most common cause of food poisoning in the UK. UKHSA's guidance is specific to Yersinia.

UKHSA says Yersinia infection can cause a range of symptoms including watery diarrhoea, sometimes with blood in the stool, severe stomach pain, fever and vomiting. The symptoms begin 4 to 7 days after acquiring the bacterium, which can make it hard to link the illness to a particular meal.

The NHS lists the general symptoms of food poisoning as feeling sick or being sick, diarrhoea, tummy pain, a high temperature and feeling generally unwell, and says they usually start within a few hours or a few days of eating the food that caused the infection, although sometimes they do not start for a few weeks.

• Watery diarrhoea, sometimes with blood

• Severe stomach pain

• Fever

• Vomiting

UKHSA says Yersinia bacteria are usually acquired by eating or drinking contaminated food, including undercooked meat, unpasteurised milk products or contaminated water. The bacteria can also spread through person-to-person contact or direct contact with infected animals.

The NHS explains that, for food poisoning generally, food may be contaminated if it is not cooked or reheated thoroughly, not stored correctly, left out for too long, handled by someone who is ill or has not washed their hands, or eaten after its use by date. Following food hygiene guidance at home, including thorough cooking and correct chilling, is the main way to reduce the risk.

UKHSA says most people with Yersinia infection recover quickly, within 1 to 3 weeks, often without treatment. Rarely it can cause more severe illness with symptoms lasting up to 8 weeks that requires appropriate antibiotics. It advises seeking medical attention if your symptoms are not settling, if you are concerned about your health or if you have underlying conditions that reduce your immunity.

The NHS says that for food poisoning you can usually treat yourself or your child at home, and that the most important thing is to have lots of fluids to avoid dehydration. It advises speaking to a pharmacist if you have signs of dehydration such as dark, smelly pee or peeing less than usual, or if you are an older person or have a weakened immune system or another condition that increases the risk of dehydration.

The NHS says to call 111 if you are worried about a baby under 12 months, if your child stops feeding while ill, if a child under 5 has signs of dehydration, if signs of dehydration persist after using oral rehydration sachets, if you keep being sick and cannot keep fluid down, if you have bloody diarrhoea or bleeding from the bottom, or if you have diarrhoea for more than 7 days or vomiting for more than 2 days. Call 999 or go to A&E for vomit that contains blood or looks like ground coffee, a stiff neck with pain looking at bright lights, a sudden severe headache, sudden severe tummy ache, blue, grey, pale or blotchy skin, severe difficulty breathing, or confusion.

UKHSA says Yersinia infection can be confirmed by undertaking stool and blood tests. UKHSA advises seeking medical attention if symptoms are not settling or you have conditions that reduce your immunity, and a clinician can then decide whether tests are needed.

UKHSA refers people to the NHS for advice on managing gastroenteritis at home. The NHS advice is to stay at home and rest, drink lots of fluids such as water or squash with small sips if you feel sick, carry on breast or bottle feeding a baby, and eat when you feel able, which may be easier if you avoid fatty or spicy foods. Paracetamol can be taken if you are in discomfort, checking the leaflet before giving it to a child.

The NHS advises not having fruit juice or fizzy drinks, which can make diarrhoea worse, not making baby formula weaker, not giving children under 12 medicine to stop diarrhoea and not giving aspirin to children under 16. A pharmacist can recommend oral rehydration powder or medicine to stop diarrhoea for a few hours, such as loperamide, which is not suitable for children under 12.

UKHSA says that if you have Yersinia in your faeces you should stay off nursery, school or work until you have been symptom free for at least 48 hours, and avoid handling and preparing food and providing personal care for others until symptom free for at least 48 hours. People you live with who have symptoms such as diarrhoea but have not been tested should do the same.

To help avoid spreading the infection it advises washing your hands with soap and water frequently, washing any clothing or bedding that has poo or vomit on it separately on a hot wash, and cleaning toilet seats, flush handles, taps, surfaces and door handles every day.

Most Yersinia infections are managed at home with fluids, with advice from a pharmacist, NHS 111 or a GP when needed. Stool or blood tests, when required, are usually requested through your GP or hospital team. Private GP appointments can arrange tests too, but the exclusion advice and the red flag symptoms above apply whichever route you use.