Amoebic dysentery is caused by which organism?

AIIMS CRE, SNO-2024

Applied Microbiology & Infection control

Easy

Appeared in: AIIMS CRE, SNO-2024

Explanation

Amoebic dysentery, or amebiasis, is a parasitic infection of the intestines.
The causative agent is the protozoan Entamoeba histolytica.
Infection occurs through the fecal-oral route, typically by ingesting cysts from contaminated food or water.
While many infections are asymptomatic, invasive disease leads to colitis with symptoms like abdominal pain, cramping, and bloody diarrhea.
In some cases, the parasite can spread to other organs, most commonly causing liver abscesses.

Option A: Plasmodium vivax is a protozoan parasite, but it causes malaria, not amoebic dysentery.
Option C: Giardia lamblia is a protozoan that causes an intestinal infection called giardiasis, which is characterized by watery diarrhea, but it is distinct from amoebic dysentery.
Option D: Escherichia coli is a bacterium. While certain pathogenic strains can cause severe diarrhea (sometimes bloody), amoebic dysentery is specifically caused by the amoeba E. histolytica.

Visual 1: Micrograph - A microscopic image showing the trophozoite stage of Entamoeba histolytica, highlighting the ingested red blood cells which is a key diagnostic feature.
Visual 2: Diagram - The life cycle of Entamoeba histolytica, illustrating the transmission from cyst to trophozoite stage and the fecal-oral route of infection.
Visual 3: Infographic - A comparison chart of common gastrointestinal pathogens (E. histolytica, Giardia, E. coli, Salmonella), showing their type, disease, symptoms, and mode of transmission.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Etiology of Amoebic Dysentery as background academic context rather than a clinical decision trigger.
Nurses must implement strict contact and hygiene precautions for patients with amoebic dysentery to prevent nosocomial spread, as the cysts are transmitted via the fecal-oral route.
Patient education is a critical nursing role, focusing on handwashing, safe food preparation, and purification of drinking water, especially for patients traveling to or living in endemic areas.
Monitoring for complications is vital. Nurses should assess for signs of severe dehydration, electrolyte imbalance, and extraintestinal spread, such as right upper quadrant pain which could indicate a liver abscess.

How to Approach the Question

First, identify the key term in the question stem: 'Amoebic dysentery'. This is a specific disease name.
The question asks for the 'organism' that 'caused' it. This is a direct factual recall question about microbiology.
Scan the options. Each option is a different microorganism.
Recall or deduce the pathogen associated with 'amoebic' dysentery. The name itself provides a strong clue that the causative agent is an amoeba.
Evaluate each option: Plasmodium causes malaria, Giardia causes giardiasis, and E. coli is a bacterium. Entamoeba histolytica is the amoeba known to cause dysentery.
Select the option that correctly matches the disease with its causative agent.

Concept Tested & Keywords

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