Amobiasis and giardiasis |signs, symptoms and treatment

 Amoebiasis is caused by Entamoeba histolytica, a protozoa that is transmitted from one person ro another through fecally contaminated foods and drinks. Entamoeba histolytica is a protozoa that resides in the caecum and ascending colon. The organism is transmitted as cysts and once in the caecum and ascending colon  the hatch into trophozoites and multiply.

Giardiasis is caused by Giardia lamblia(also known as Giardia intestinalis or Giardia
It is also transmitted through contaminated foods and water. The organism is ingested as cyst. In the jejunum, it releases trophozoites which attach themselves to the jejunum mucosa. Colonization
and multiplication of the trophozoite lead to mucosal invasion, localized edema, and flattening of the villi, resulting in malabsorption states in the host especially fat. The major symptom of giardiasis is steatorrhea. steatorrhea is presence of  fat in stool which is caused by inability of the intestines to absorb fat due to giardia infection. THe patient's stool floats on water and makes it hard to flash down the toilet.

transmission of amoeba and giardia

Signs and symptoms of amobiasis.

  • Foul smelling stool,
  • Diarrhea alternating with constipation.
  • Abdominal discomfort after eating food.
  • Bloating after eating any food
  • General muscle fatigue.
  • back pain may occur,
  • blood in stool(amoebal dysentry)
  • Nausea and vomiting.
  • Headache.

signs of amoeba

In general amoebiasis does not cause a very serious illness that can stop one from going on with everyday work but brings a lot of general discomfort.

Complications of amoebiasis

Amebiasis may invade the liver and cause hepatic amoebiasis. They cause hepatic abcess. This may lead to compromized liver function.  

Perforation. Amoeba my cause local perforation and spread to the chest cavity. This  may lead to subphrenic abscesses and peritonitis.

Symptoms of giardiasis.

Acute onset

  • Diarrhea,
  • cramp-like abdominal pain,
  • bloating and flatulence
  • Malaise,
  • anorexia,
  • nausea,
  • belching


  •  foul-smelling diarrhea, copious, light-colored, fatty stools,
  • weight loss,
  • Periods of diarrhea alternating with constipation,
  • Steatorrhea,
  • lactose intolerance,
  • vitamin B12 and fat-soluble vitamin deficiencies.

Diagnosis of giardiasis

This is done through examination of fresh stool. Fresh specimen may show trophozoids and if preserved then itncan show cysts. If symptoms of giadiasis are present, then empirircal treatment is encouraged. 

Treatment of amobiasis and giardiasis.

Both diseases are treated using the same drug.

Desired outcomes of the treatment.

In amebiasis and giardiasis, the goals of therapy are initially to eradicate the parasite by use of specific amebicides and then to render supportive therapy.

The treatment should be a combination of a highly absorbed 5-nitro-imidazole and a poorly absorbed amoebocide. Note, even though most people prefer a single dose of secnidazole or tinidazole, these drugs are not effective in killing the luminal giardia and amoeba cysts.

regimens luminal  amoeba and giardia;

Giardiasis and amobiasis in children use Aminosidine 250mg three times daily for five days, and aminosidine 500mg three times daily for adults.

diloxanide 500mg three times daily for five days for adults. However, it might be hard to get diloxanide alone. Most of the time it is combined with metrotronidazole. In this case take diloxanide/metronidazole 500/400 three times daily for five days. For amoebiasis and giardiasis in children use diloxanide metronidazole 250/200mg three times daily for five days.

Systemic amoebiasis.

Use either of the following  regimen.

Metronidazole 200mg three times daily for five days in children and metronidazole 400mg daily for five days in adults.

Tinidazole 2g once daily for three days.

secnidazole 1 gram  daily for three days.

Prevention of amoebiasis and giardiasis.

Hygiene is the key to prevention. water should always be boiled before drinking.







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Dr Mathu

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