Amoebic dysentery disease is a severe form of amebiasis and is caused by the parasite, Entamoeba histolytica. Amebiasis is common in tropical areas with poor sanitation. It is spread by fecal matter contamination. A study in Current Gastroenterology reports that E. histolytica infects 50 million people worldwide and 100,000 people die from the disease annually. In the United States the disease is rare and is most common in recent immigrants. Amebiasis is not often the cause of traveler's diarrhea, although travel to countries where the disease is endemic poses a risk for contracting the disease.
Entamoeba histolytica
Entamoeba histolytica has a life cycle consisting of an active parasite and a dormant parasite, or cyst. The cysts can live outside the body and can be transmitted by person-to-person contact, or indirectly in contaminated water or food. Once in the body, the cysts hatch into active parasites that multiply in the intestine.
Symptoms
The Centers for Disease Control and Prevention reports that symptoms of amebiasis develop within two to four weeks after infection and only appear in 10 to 20 percent of infected people. Mild symptoms include diarrhea, stomach pain and cramping. When the parasite invades the tissue of the colon it causes colitis, and people may exhibit more severe symptoms, such as gastrointestinal bleeding, severe abdominal pain and acute fever. If left untreated symptoms can reappear.
Complications
The parasite that causes amebiasis can sometimes infect the liver and cause abscesses. The symptoms of a liver abscess may include weakness, nausea, vomiting, weight loss, pain in the right upper abdomen where the liver resides, swelling of the liver and jaundice. An article in a Danish journal reports that liver abscesses occur in one-third of patients with amebiasis. A review in Clinical Infectious Diseases says that liver abscesses are ten times more common in men than in women. Spread of the parasite to the lungs and brain has been rarely reported. Additionally, there have been some reports of deadly necrotizing infections in people with amebiasis.
Treatment
The Merck Manuals Online Medical Library says that amebiasis is treated with the amebicides, metronidazole or tinidazole. It aslso mentions that tinidazole produces fewer side effects. Other drugs, such as paromomycin, iodoquinol or diloxanide may be required to kill the cysts and prevent a relapse of symptoms.
Prevention
To prevent infection by E. histolytica when traveling, drink only bottled or boiled water, avoid consuming unpasteurized dairy products and fresh fruit and vegetables. The review in Clinical Infectious Diseases notes that raw vegetables can be washed with soap and then soaked in vinegar for 15 min before being eaten. To prevent the spread of amebiasis, practice good hygiene and thoroughly wash hands with soap after going to the bathroom, changing diapers and before preparing food.
