HealthInfo West Coast-Te Tai Poutini

Yersinia

Matenga yersinia

Yersinia is a bacterium (germ) that causes gastroenteritis. Yersinia bacteria are most often found in pigs.

You can catch the Yersinia infection (or Yersiniosis) if you eat contaminated raw or undercooked pork. You can also get it if you do not wash your hands after handling raw meat or infected surfaces such as chopping boards and knives.

You usually get symptoms 3 to 7 days after being infected. Symptoms usually last between 3 days and 3 weeks.

The symptoms include diarrhoea that can be bloody, stomach pain or cramp and a slight fever. They sometimes include feeling sick and vomiting.

Treating Yersinia

There is no specific treatment for Yersinia. The treatment aims to relieve symptoms. You should rest and drink plenty of fluids to prevent dehydration. See the self-care section on the gastroenteritis page for more details.

Health providers may prescribe antibiotics in severe cases of Yersinia.

Getting help for Yersinia

You should see your general practice team if you have bloody diarrhoea or a fever or if your symptoms have not gone away after 7 days. You should also see your general practice team if you are very unwell or have a weakened immune system.

You should take your tamaiti (child) to your general practice team if they

• are not drinking
• are passing less urine than usual
• have a dry mouth or sunken eyes
• seem drowsy.

Avoiding spreading Yersinia

You can be infectious for 2 to 3 weeks after your diarrhoea starts. To reduce the risk of spreading the infection, it is important to have good hand hygiene, particularly after going to the toilet. This includes washing your hands with soap and water.

Try to avoid preparing food if you have Yersinia. If you do prepare food, make sure you wash and dry your hands well first. Follow this food safety advice. Make sure all meat, poultry and fish are well cooked. Thoroughly clean chopping boards, kitchen surfaces and knives after preparing raw meat before using them for other foodstuffs.

Stay away from work, community gatherings and school or preschool until you or your tamaiti have been free of symptoms for 48 hours. This includes the last time you had diarrhoea.

You should wait for at least 2 weeks after the last episode of diarrhoea before you go swimming in a pool.

Written by HealthInfo clinical advisers. Last reviewed May 2025.

Sources

Page reference: 49683

Review key: HIGTE-81185