How does infection occur?
An infected person excretes cysts in their feces - resistant forms of amoeba that survive in the external environment for weeks. They get into water, on vegetables and herbs, on hands and objects. After ingestion, motile forms emerge from the cyst in the intestine. In most people, the amoeba remains in the intestinal lumen without damaging it, and the person becomes an asymptomatic carrier. In some infected people, the parasite secretes enzymes that dissolve the mucous membrane, penetrates the wall and forms characteristic ulcers with undermined edges. From there, amoebas can enter the blood vessels and reach the liver through the bloodstream.
- Drinking raw water from taps, ditches, wells
- Unwashed vegetables, herbs, fruits, watered with contaminated water
- Dirty hands and household items
- Flies as carriers of cysts
- Asymptomatic carriers as a source of infection
- Traveling to countries with hot climates and poor sanitation
Symptoms of the intestinal form
The incubation period is usually one to four weeks. Unlike bacterial dysentery, amebiasis often begins gradually, and the temperature may be normal or slightly elevated. The stool becomes more frequent up to several times a day, mucus and blood appear in it, giving the characteristic appearance of raspberry jelly. I am concerned about cramping pain, often in the right half of the abdomen, and painful urges. Without treatment, the disease takes an undulating course: exacerbations are replaced by periods of relative well-being, and the intestinal mucosa is gradually damaged more and more.
- Gradual onset without fever
- Frequent stools with mucus and blood
- Cramping pain in the abdomen
- Painful urge to defecate
- Bloating, rumbling, decreased appetite
- Weight loss and weakness with prolonged course
- Wave-like alternation of exacerbations and lulls
Extraintestinal amoebiasis and liver abscess
The most common complication is amoebic liver abscess. It can develop months after intestinal manifestations, and sometimes it becomes the first sign of the disease, and by this time the diarrhea has already passed or did not exist at all. Typical symptoms include high fever with chills, constant pain in the right hypochondrium, which intensifies with breathing and radiates to the right shoulder, enlarged liver and tenderness when pressed. Less commonly, amoebas infect the lungs, brain, or skin around the anus. All these conditions require hospital treatment.
- Fever with chills and sweating
- Constant pain in the right hypochondrium radiating to the shoulder
- Enlarged and painful liver
- Weight loss and severe weakness
- Cough and chest pain due to rupture into the pleura
- Perforation of intestinal ulcer with peritonitis
- Intestinal bleeding and amoeba - tumor formation
Diagnostics
The main method is to examine fresh feces for protozoa, and the material must get to the laboratory as quickly as possible, otherwise the mobile forms are destroyed. The analysis is repeated several times. It is important that under a microscope it is difficult to distinguish dysentery amoeba from the harmless Entamoeba dispar, therefore additional methods are used: determination of antigen in feces, PCR, serological tests for antibodies. If a liver abscess is suspected, ultrasound, supplemented if necessary by computed tomography, is crucial. Colonoscopy is performed according to indications when it is necessary to exclude ulcerative colitis.
- Examination of fresh stool for protozoa, repeatedly
- Determination of amoeba antigen in stool or PCR
- Serological tests for antibodies
- Coprogram and feces for occult blood
- Complete blood count, ALT and AST
- Ultrasound of the abdominal cavity and liver
- Colonoscopy with biopsy if indicated
Treatment and prevention
Treatment is prescribed by a doctor and is usually carried out in two stages: first, a drug that acts on amoebas in tissues, then a luminal drug that destroys cysts in the intestines and prevents relapse and infection of others. Skipping the second stage is a common reason for the disease to return. Liver abscess in most cases responds to drug therapy; drainage is not always required and is performed at the discretion of the surgeon. Antidiarrheal drugs that slow down the intestines may worsen the condition in amebiasis. Carriers without symptoms are also treated to interrupt transmission.
- Antiprotozoal drug as prescribed by a doctor
- Mandatory second stage - luminal drug against cysts
- Hospitalization for liver abscess and severe course
- Abscess drainage according to indications
- Control stool analysis after the course
- Boiled or bottled water
- Thorough washing of vegetables, herbs and hands
- Examination of family members and carriers