Listeria is caused by bacteria that lives in soil, water, dust and animal waste. Meats that aren’t properly processed, unpasteurised milk and raw vegetables contaminated by manure or soil are most likely to give you listeria. The main symptoms are nausea, muscle aches, fevers and diarrhoea. For most healthy people, the disease does not pose a threat and usually passes in a few days.
In some cases, especially in pregnant women, seniors and people with weak immune systems, the symptoms can be life threatening. Known as listeriosis, symptoms include headaches, stiff neck, confusion, loss of balance and convulsions. Listeriosis affects the nervous system and is fatal in 20% of cases.