The patient may have eight to 12 bowel movements each day, and he may experience a constant nagging, irritating feeling that he needs to move his bowels. There is fever only about one-third of the time. Amebas can spread through the bloodstream to other parts of the body, when they do so pockets of infection and pus forms in many different organs. About one percent of the time, they tend to infect the liver, and the condition is called hepatic amebiasis. In rare cases, amebiasis causes an amebic dysentery, with sudden symptoms of fever, chills, and severe diarrhea.
Symptoms can last from a few days to several weeks.
The infection begins when a person swallows ameba cysts, which may contaminate food or water, especially in tropical areas of the world. Ameba cysts survive the body's stomach acids and travel into the intestines. There they may peacefully colonize the inside of the large intestine without causing any symptoms or some amebas may begin to invade the wall of the large intestine. When this happens, there is abdominal pain, blood-stained diarrhea, and sometimes fever. There is also the danger of amebas spreading to infect other body organs.