The disease is often mild, causing diarrhoea and abdominal pain, but a more severe form (amoebic dysentery) can occur. Symptoms of amoebic dysentery include severe stomach pain, blood and mucus in the faeces, and high temperature or fever. Occasionally the infection invades the liver and causes an abscess.
Entamoeba histolytica is estimated to be responsible for between 50,000 and 100,000 deaths every year worldwide.
Transmission of the parasite occurs when a person eats or drinks something that has been contaminated with infected faeces. Entamoeba histolytica is therefore more likely to affect people who live in developing countries, where sanitation and hygiene is poor. People in England & Wales with E. histolytica infection have usually acquired it when travelling abroad.