Cholera is an acute diarrhoeal illness caused by a bacteria. The disease infects the small bowel and causes painless, watery diarrhoea. It is known to infect only humans.  Cholera is usually transmitted via infected water that has been contaminated by faeces and less commonly via food, particularly shellfish.  The disease is found throughout the world particularly in countries where sanitation is poor, particularly parts of Africa, India and South East Asia.  The incubation period can be 12 hours up to 5 days after exposure.

75% of people affected with cholera will have no or mild symptoms and the illness is self limiting.
In healthy travellers, the illness is most likely to be mild.
More severe illness is more likely in those who live in poverty and are unable to access safe water and food.
More severe illness is more likely in those with underlying health problems such as immunosuppression, liver disease or malnutrition.
In more severe disease, rapid onset of watery diarrhoea and vomiting can lead to extreme dehydration. For severe illness medical attention should be urgently as individuals can die quickly if they are not treated promptly with intravenous fluid replacement.