Amoebozoa is a major taxonomic group containing about 2,400 described species of amoeboid protists.
Amoebiasis, also known as amebiasis or entamoebiasis, is an infection caused by any of the amoebozoans of the Entamoeba group. Symptoms are most common upon infection by Entamoeba histolytica. Amoebiasis can present with no, mild, or severe symptoms. Symptoms may include abdominal pain, mild diarrhoea, bloody diarrhea or severe colitis with tissue death and perforation. This last complication may cause peritonitis. People affected may develop anemia due to loss of blood.
Invasion of the intestinal lining causes amoebic bloody diarrhea or amoebic colitis. If the parasite reaches the bloodstream it can spread through the body, most frequently ending up in the liver where it causes amoebic liver abscesses. Liver abscesses can occur without previous diarrhea.
Increased white blood cell count is present in severe cases, but not in mild ones.
Cysts of Entamoeba can survive for up to a month in soil or for up to 45 minutes under fingernails.