Listeriosis is an infectious, foodborn, but not contagious disease. It is caused by bacteria called Listeria monocytogenes that can be found in stale water, soil and poorly prepared food. The bacteria can live in the intestines of humans and animals for a long time without causing an infection.

It can rarely be cured with antibiotics, even when diagnosed early, in most cases it is fatal.

Listeria is more common in cattle, goats and sheep and can cause farm outbreaks though it is normally sporadic.