Amebiasis is an intestinal illness caused by the microscopic parasite Entamoeba histolytica, a type of amoeba. Dysentery resulting from this infection, called amoebic or amebic dysentery, is a more severe form of amebiasis. Most people infected with E. histolytica never become sick, but amebiasis is still the third-most common cause of fatal parasitic infection, according to Patient UK, with only schistosomiasis and malaria causing more deaths.
Risk Factors
Amebiasis and amoebic dysentery are uncommon in the United States, occurring mainly in people traveling to tropical areas with poor sanitary conditions or immigrants from these regions, says the U.S. Centers for Disease Control and Prevention (CDC). Men having sex with men also are more likely to become infected than other members of the population, as are people living in institutions with unsanitary conditions. The disease is most common in South and Central America, Southeast Asia and West Africa, according to Patient UK.
Infection
You can become infected with E. histolytica by putting something in your mouth that has touched the stool of someone infected with the parasite, explains the CDC. Poor hygiene is a primary contributor because food and drink can easily become contaminated by people not washing their hands. You can contract an E. histolytica infection by touching a surface contaminated with parasite eggs, known as cysts, if you later put your hand in your mouth. Even when people infected with E. histolytica amoebae do not have symptoms, they can still infect other people because they excrete the cysts through bowel movements, explains NetDoctor.
Symptoms
Only about 10 percent to 20 percent of people infected with E. histolytica develop symptoms, according to Patient UK. Symptoms of amebiasis might include gas, loose stools, occasional constipation and stomach pain and cramps. Dysentery is an inflammatory intestinal disorder that can result from this infection, with symptoms of severe and bloody diarrhea, nausea, vomiting and weight loss.
Complications
Serious complications can develop from infection with E. histolytica, according to NetDoctor. As the amoebae damage the walls of the large intestine, they not only cause ulcers and bleeding, but they also can break through the intestinal wall and cause peritonitis, an inflammation of tissue lining the abdominal wall and covering the abdominal organs. Rarely the amoebae forms cysts in the liver and cause liver abscesses, and sometimes they spread to the lungs or brain.
Treatment
Doctors usually treat amoebic dysentery with the drugs metronidazole, known as Flagyl, or tinadazole, known as Fasigyn, according to NetDoctor. Treatment typically lasts five to 10 days. This is followed by 10 days of diloxanide furoate to eliminate any amoebae in the digestive tract and prevent further chronic infection. Serious complications resulting from amoebic dysentery might require hospital treatment, including fluid and electrolyte replacement, blood transfusions and surgery.
