The E. histolytica parasite causes amebiasis, an inflammation of the small intestine. Amebiasis can be found worldwide but occurs most often in developing countries, particularly those in tropical climates. In industrialized nations, the disease is most common among immigrants, institutionalized populations, and those who have traveled recently to a developing area.

Here are some of the most commonly asked questions about the diagnosis, treatment, and prevention of amebiasis.

  1. How do people get amebiasis? The E. histolytica parasite passes through the fecal-oral route; this means that people contract the disease by accidentally ingesting infected fecal matter. This occurs most commonly through contaminated drinking water. The CDC estimates that only 10-20 percent of people infected with E. histolytica actually become ill.
  2. What are the symptoms of amebiasis? Many cases of amebiasis will be asymptomatic, meaning an infected person will not show any symptoms. Mild symptoms can include diarrhea, nausea and vomiting, abdominal pain, and loss of appetite. Amebiasis can become acute or chronic in the form of amebic dysentery; symptoms of this more serious condition include stomach pain, bloody stool, and fever. In very rare cases, E histolytica infection can spread and result in abscesses in the liver, brain, or lungs, which is known as extraintentinal amebiasis.
  3. How is amebiasis diagnosed? If you present any of these symptoms, you should see your doctor, especially if you have recently traveled to a developing country where amebiasis is more common. Your doctor will most likely need to collect several stool samples, as the E. histolytica parasite can be difficult to detect. A very similar and much more common parasite, E. dispar, is commonly mistaken for E. histolytica; therefore, E. dispar infection can often be confused for E. histolytica infection. If your doctor believes the infection may have spread beyond the intestines, you may also need to provide a blood sample for further testing.
  4. What is the typical treatment for amebiasis? If an E. histolytica infection is confirmed, your doctor will prescribe antibiotics. Typically, only one antibiotic will be needed if the infection has not made you sick; if you have experienced symptoms of amebiasis, you will likely require two separate antibiotics. E. dispar infection typically does not make people ill and thus requires no treatment.
  5. How can I prevent amebiasis? Proper personal hygiene is key in preventing amebiasis. Always wash your hands thoroughly with soap and warm water after using the bathroom or changing a diaper and before handling or preparing food. If living or traveling in an area where amebiasis is more common, you should avoid tap water, ice cubes, unpasteurized dairy products, and fresh fruits and vegetables that you did not prepare yourself using clean water. You should drink bottled water or tap water that has been boiled for at least one minute or that has been filtered and treated.
  6. What kinds of diagnostic tests are used to test for amebiasis? Stool samples will be used to detect E. histolytica/dispar antigens. The most common E. histolytica/dispar antigen test is an enzyme-linked immunosorbent assay (ELISA), like the IVD E. histolytica/dispar Stool Antigen Detection Microwell ELISA.

References

Centers for Disease Control (CDC). “Parasites – Amebiasis- Entamoeba histolytica infection.” Available at
https://www.cdc.gov/parasites/amebiasis/general-info.html

Centers for Disease Control (CDC). “DPDx – Laboratory Identification of Parasitic Disease of Public Health Concern.” Available
https://www.cdc.gov/dpdx/amebiasis/index.html

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