Shigellosis and amoebiasis are two main types of dysentery. Dysentery is an infection of the intestine. This condition causes diarrhea, which contains either blood or mucus. The other symptoms of this condition include painful stomach cramps, vomiting, and high temperature.
The key difference between shigellosis and amoebiasis is their cause. Shigellosis is caused by Shigella bacteria, while amoebiasis is caused by an amoeba called Entamoeba histolytica.
CONTENTS
1. Overview and Key Difference
2. What is Shigellosis
3. What is Amoebiasis
4. Similarities – Shigellosis and Amoebiasis
5. Shigellosis vs Amoebiasis in Tabular Form
6. Summary – Shigellosis vs Amoebiasis
7. FAQ – Shigellosis and Amoebiasis
What is Shigellosis?
Shigellosis is a disease affecting the digestive system and is caused by Shigella bacteria. These bacteria are spread when someone comes into contact with the stool of an infected person or comes into contact with an item contaminated with the stool of an infected person. Common symptoms of shigellosis include diarrhea (watery, bloody, or containing mucus), stomach pain and cramps, vomiting, and fever.

Figure 01: Shigella Bacteria
Shigellosis can be diagnosed through physical examination and stool tests. Furthermore, treatment options for shigellosis may include resting, drinking fluids to prevent dehydration, and giving prescribed antibiotics to clear bacteria.
What is Amoebiasis?
Amoebiasis is an intestinal or bowel disease that is caused by a parasite called Entamoeba histolytica. This tiny parasite also spreads through infected human feces. The symptoms of amoebiasis include nausea, diarrhea, weight loss, stomach tenderness, and occasional fever. In rare cases, it can cause more severe infections such as liver abscesses.

Figure 02: Amoebiasis
Amoebiasis can be diagnosed through physical examinations, stool tests, and blood tests. Furthermore, metronidazole or tinidazole antibiotics are the first-line treatment for amoebiasis.
Similarities Between Shigellosis and Amoebiasis
- Shigellosis and amoebiasis are the two main types of dysentery.
- Both conditions are spread by infected human feces.
- These conditions can cause similar symptoms, such as diarrhea, nausea, and fever.
- Both conditions are diagnosed through physical examination and stool tests.
- They can be treated through medications like antibiotics.
Difference Between Shigellosis and Amoebiasis
Definition
- Shigellosis is an illness that affects the intestine caused by Shigella bacteria.
- Amoebiasis is an illness that affects the intestine and is caused by Entamoeba histolytica.
Risk Factors
- The risk factors for shigellosis include being a child, living in a group housing, living or traveling in an area lacking clean water, sexual contact that involves the anus, and experiencing homelessness.
- The risk factors for amoebiasis include people who traveled to tropical places with poor sanitary conditions, immigrants from tropical countries with poor sanitary facilities, people who used to be in facilities with poor sanitary conditions, and having anal sex.
Symptoms
- The symptoms of shigellosis include diarrhea that may contain water, blood, or mucus, stomach pain or cramps, a feeling of needing to pass stool even when on an empty stomach, fever, and an upset stomach.
- The symptoms of amoebiasis include severe abdominal pain, diarrhea containing blood or mucus, high temperature, loss of appetite, and weight loss.
Diagnosis
- Shigellosis can be diagnosed through health history, physical examination, and stool test.
- Amoebiasis can be diagnosed through stool microscopy, abscess fluid extraction under ultrasound guidance, stool antigen test, blood test, colonoscopy, and liver ultrasound scan.
Treatments
- Shigellosis can be treated through rest, taking enough fluids, giving diarrhea medicines such as loperamide, and giving antibiotics such as ciprofloxacin or azithromycin.
- Amoebiasis can be treated by taking fluid to prevent dehydration, giving antibiotics such as metronidazole or tinidazole, and luminal amoebicides such as diloxanide furoate, iodoquinol, and paramomycin.
The following table summarizes the difference between shigellosis and amoebiasis.
Summary – Shigellosis vs Amoebiasis
Dysentery is a gastrointestinal disease. Diarrhea is the primary symptom of dysentery. Shigellosis and amoebiasis are the two main types of dysentery. Shigellosis is a bacterial infection of the intestine caused by a bacteria called Shigella. Sometimes, it can also be caused by other bacteria such as Salmonella, Campylobacter, and Escherichia coli. On the other hand, amoebiasis is an intestinal infection caused by an amoeba called Entamoeba histolytica. This is the main difference between shigellosis and amoebiasis.
FAQ: Shigellosis and Amoebiasis
1. What is the main cause of shigellosis?
- Shigella bacteria is the main cause of shigellosis. The most common ways people get sick by shigellosis are from eating or drinking contaminated food or water and contact with someone who is infected. Shigella can also be spread during sexual activity with a sick person.
2. What organ does Shigellosis affect?
- Shigellosis is an infection of the lining of the intestines. Therefore, the intestine is the main organ that is affected by shigellosis. This bacterial infection can lead to the formation of pus or to the spread of bacteria in the bloodstream.
3. How can Shigellosis be treated?
- Shigellosis can be treated through fluid and salt replacement and by giving prescribed antibiotics such as ciprofloxacin and azithromycin. These antibiotics can shorten the time people have fever and diarrhea by about 2 days.
4. What are the symptoms of amoebiasis?
- The main symptoms of amoebiasis include diarrhea (which may be bloody or contain mucus), stomach pains, cramping, nausea, loss of appetite or weight loss, and fever.
5. What is the treatment for amoebiasis?
- The primary treatment for symptomatic amoebiasis includes hydration and using antibiotics such as metronidazole and/or tinidazole. The other treatments include luminal amoebicides such as diloxanidefuroate, iodoquinol, and paramomycin.
Reference:
1. “Shigella Infection (Shigellosis): Causes, Symptoms & Treatment.” Cleveland Clinic.
2. “Amebiasis.” MedlinePlus, U.S. National Library of Medicine.
Image Courtesy:
1.”Shigella Bacteria” (CC0) via Pixino
2. “Amoebiasis of intestine” By Department of Pathology, Calicut Medical College (CC BY-SA 4.0) via Commons Wikimedia
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