Entamoeba histolytica a very dangerous parasite

Entamoeba histolytica is the causative agent of amoebiasis, this protozoan is distributed throughout the world, but the highest prevalences are reported in Latin America, Africa and India. The most endemic areas are the tropical and subtropical countries, where there are sociodemographic factors and accessibility problems to basic services, such as lack of potable water in housing, overcrowding and lack of sewage networks, as well as poverty extreme Around 500 million people have been reported infected worldwide, of which 10% have intestinal clinical symptoms and 2 to 20% extraintestinal, causing a mortality rate ranging between 40,000 and 110,000 cases per year. According to WHO, it represents one of the main causes of death by protozoa worldwide, placing it in fourth place.

This parasite was recognized by Lösh in a patient with dysentery in 1875 in St. Petersburg; however, the author did not establish the cause-effect relationship between the amoeba and the patient’s symptoms. Koch, in the year of 1883, reviewing autopsies, in an epidemic of cholera, showed the presence of amoebas in the submucosa of the intestinal wall, in the capillaries near the wall of hepatic abscesses and in the exudate of lesions of the liver. This author is considered the first to affirm that the amoeba was the etiological agent of tropical dysentery, and that the liver abscess was a sequel to amoebic dysentery.

How can you get it?

Although it can occur in any person, the highest incidence as already mentioned is in tropical places, with poor environmental sanitation and warm climate. Amoebiasis is transmitted through water, food, utensils or directly orally when the infected person does not wash their hands after going to the bathroom and puts it in their mouth, since the human being is the main reservoir of the parasite.

What are the characteristics of this parasite?

This amoeba shares similar characteristics with two other species: E. dispar and E. moshkovskii, which is why it is currently called the Entamoeba complex or Entamoeba histolytica / dispar / moshkovskii. However, E. histolytica is the only one capable of producing damage to the human organism due to its extraintestinal cycle.

What are the symptoms of this infection? Even though this wide variety of clinical manifestations of the disease and the destructive capacity of the trophozoites of E. histolytica in the affected tissues, especially in the large intestine and in the liver, is still largely unknown, the intrinsic mechanisms of the amoeba and the host factors that lead to the production of the lesions.

Intestinal amoebiasis can be asymptomatic or cause dysentery or extraintestinal disease, the most frequent form of presentation is amoebic liver abscess. Patients with symptomatic intestinal amoebiasis or amoebic colitis report colicky abdominal pain of several weeks of evolution, sometimes have weight loss and diarrhea, which can be watery with plenty of mucus and little fecal matter with or without blood, when it exists. speaks of amoebic dysentery.

How is the clinical diagnosis of amoebiasis?

This is confirmed by coprological examination, usually with microscopic confirmation of characteristic cysts or trophozoites in the stool. However, microscopic examination has several limitations. The most important one is the inability to distinguish E. histolytica from E. dispar and E. moshkovskii. In addition, fecal samples can frequently present cysts from other species such as: Entamoeba coli, Entamoeba hartmanni, Iodamoeba butschlii or Endolimax nana, which can complicate the diagnosis.

The development of molecular techniques such as the Polymerase Chain Reaction (PCR) has allowed the differentiation of these species. This technique is very useful for epidemiological studies and, due to its great sensitivity, it allows detecting cases that could not be identified when applying conventional tests, as well as diagnosing mixed infections.

Knowing that one of the key elements for the diagnosis of this parasite, is to have microscopes that have the best possible technology, in Kalstein we put at your disposal, microscopes that will allow you to offer a better stool analysis. That’s why we invite you to take a look at our incubators available at: HERE