Cholera is an acute diarrhoeal infection caused by the bacterium Vibrio cholera of serogroups O1 or O139. Humans are the only relevant reservoir, even though Vibrios can survive for a long time in coastal waters contaminated by human excreta.

Consumption of contaminated water and food, especially seafood eaten under-cooked, results in infection. After a short incubation period of less than five days, the typical symptoms might develop, characterised by vomiting and watery diarrhoea. In most cases, though, symptoms are mild or absent and infected individuals become carriers with no symptoms.

With timely treatment (fluid replacement and antibiotics), less than 1% of patients with symptoms die. The disease has not been endemic in Europe for a long time, and thanks to high hygiene standards the potential for imported cases to generate further ones is low.