Amoebiasis

A. Sandhya -

If a person is suffering from nausea, vomiting, abdominal cramping, gas (flatulence), intermittent constipation and stomach pain, (fever may be not common), loose stool (dysentery) with blood and mucus,  the person should see a doctor who will advise to carry out the testing of a stool sample to ensure that the person is suffering from Amoebiasis
The stool sample is sent to the laboratory and examined under a microscope to confirm that the gut (intestines) is infected with the parasite Entamoeba histolytica.

According to an estimation, around 1 in 10 people in the world is suffering from Amoebiasis. This infection is very common in areas of Central and South America, Africa, and Asia.

Entamoeba histolytica is a single-celled Protozoan parasite that lives in the large intestine and causes internal inflammation by destroying the tissue of the large intestine. As it destroys the tissue, the species got the name histolytica (histo = tissue, lytic = destroying). It is an internal parasite that looks like an amoeba and lives in the large intestine of humans. So, it got its name Entamoeba

Transmission of cysts to man occurs through contaminated food or water or hands. When they are ingested, they reach the small intestine, where the cysts will dissolve resulting in the release of the parasitic forms. Now, the parasitic forms migrate to the large intestine and start to feed on the contents of it. At this stage, the parasite is called trophozoite. In the large intestine, after attaining maximum size, they multiply and increase in number and develop hard coats surrounding their bodies. Such forms of parasite are called cysts which are passed outside along with the faeces. There, they can survive for weeks, or even months. Some trophozoites can also enter the intestinal wall and travel to extraintestinal sites (especially the liver, lungs and brain) through blood.

Symptoms

Most infections are asymptomatic but clinical manifestations in Acute Amoebiasis show the symptoms like, nausea and vomiting, severe amoebic dysentery that is accompanied by blood or mucus in stools, abdominal cramping, flatulence, loss of weight, and an intermittent fever. Patients may also experience symptoms that are vague and not specific to the ailment itself.
In Chronic Amoebiasis, gastrointestinal symptoms, fatigue, weight loss and occasional fever will occur.
In Extra intestinal Amoebiasis, where the parasite spreads to other organs, most commonly the liver,  it causes amoebic liver abscess with infections, right upper quadrant abdominal pain, severe illness and fever.

Diagnosis

A number of stool samples of patients on different days are tested in the laboratory to determine the presence of cysts and ingested erythrocytes (RBC) in stools. The diagnosis will be determined positive, when an infected person's stool contains the cysts and ingested erythrocytes.

To check for lesions on the liver, an ultrasound or CT scan may be advised. If lesions appear, a needle aspiration may be needed to see if the liver has any abscesses. An abscess in the liver is a serious consequence of Amoebiasis and it indicates that the amoeba has damaged the liver.

To check for the presence of the parasite in the large intestine (colon), colonoscopy may be necessary.

Treatment

In the case of patients who do not exhibit any symptoms, doctors will prescribe luminal agents such as Diloxanide Furoate or Liodoquinol.

  • In the case of uncomplicated Amoebiasis, a 10-day course of anti-parasitic drugs like Paromomycin or Metronidazole will be prescribed by the doctor get rid of the parasites and to destroy any traces of parasite in intestinal tissue and other surrounding organs.
  • If a patient shows the presence of liver abscess, a five-day course of antibiotics may also be necessary.
  • Anti-diarrheal medication is needed to prevent further loss in fluids.
  • If the colon or peritoneal tissues have perforations, surgery may be necessary
  • Excessive intake of solid food is not advisable to avoid intestinal cramping.
  • Alcoholic drinks should also be avoided, as they may cause complications
  • No vaccine is available to treat Amoebiasis.

Risk Factors

Amoebiasis is contagious. Poor hygienic conditions, sharing the personal belongings of infected individuals, such as towels, traveling to an area where amoebiasis is prevalent are at high risk for this type of parasitic infestation.

Prevention

  • To avoid contacting Amoebiasis, hygienic conditions should be followed.
  • Sharing the personal belongings of infected individuals should be avoided
  • Hands should be thoroughly washed with soap and water before eating.
  • Nails should be regularly cut and kept clean to refrain from the deposition of the parasitic eggs.