Amoebic dysentery vs. Bacillary dysentery

Acute diarrhea is categorized as noninflammatory (watery, nonbloody) or inflammatory (bloody). The term dysentery refers to bloody diarrhea.

Bloody diarrhea caused by Shigella is often called bacillary dysentery. Other bacterial causes of dysentery are, Vibrio parahaemolyticus, Enteroinvasive E.coli (EIEC), Enterohemrorrhagic E.coli (EHEC), Campylobacter sps, and Salmonella sps. Bloody mucous containing diarrhea caused by bacterial pathogens is often accompanied by inflammatory cells (neutrophils). Other symptoms include fever, abdominal cramping, tenesmus, and pain in defecation.

Amoebic dysentery (also known as amoebiasis) is caused by an invasive protozoan parasite, Entamoeba histolytica.

Character Amoebic dysentery Bacillary dysentery
Number 6-8 motions a day Over 10 motions a day
Amount (Volume) Relatively copious Small amount
Appearance and Amount Blood mucus, semi formed Blood mucus, mainly watery
Odour Offensive (fishy odour) Odourless
Colour Dark red (altered blood) Bright red (fresh blood)
Reaction Acidic Alkaline
Consistency Not adherent to the container Adherent to the container
RBCs In clumps Discrete, sometimes in clumps due to rouleaux formation
Pus Cells Few Numerous
Macrophages Few Numerous, many of them contain RBCs hence may be mistaken for E. histolytica
Eosinophils Present Scarce
Charcot-Leyden (C-L) crystals* Present Absent
Pyknotic bodies** Present Absent
Ghost Cells*** Absent Present
Parasites Seen Trophozoites of E. histolytica Absent
Bacteria Seen Many motile bacteria Scanty, nonmotile  (Shigella is nonmotile bacteria)
Growth on MacConkey Agar Various intestinal flora may grow Pure growth of Shigella spp. may be seen

 Further notes: 

Charcot Leyden Crystals
Charcot Leyden Crystals
  • *Charcot-Leyden crystals are hexagonal bipyramidal structures, formed from the breakdown of eosinophils and may be seen in the stool or sputum of patients with parasitic diseases.
  • **Pyknotic bodies are the nuclear remains of tissue cells and leukocytes, they may present in the stools of persons suffering from amoebiasis.
  • ***Ghost cell is a swollen/enlarged epithelial cell with only cytoplasmic outline but without a nucleus.


  1. Manson-Bahr, P. E., & Ormerod, W. E. (1971). Amoebic and bacillary dysentery and the enteric fevers. The Practitioner, 207(238), 154–163. 
  2. Cook G. C. (1977). Dysentery-bacillary and amoebic. Nursing mirror and midwives journal, 144(12), 54–57. 
  3. Dans, L. F., & Martínez, E. G. (2007). Amoebic dysentery. BMJ clinical evidence, 2007, 0918.

Acharya Tankeshwar

Hello, thank you for visiting my blog. I am Tankeshwar Acharya. Blogging is my passion. As an asst. professor, I am teaching microbiology and immunology to medical and nursing students at PAHS, Nepal. I have been working as a microbiologist at Patan hospital for more than 10 years.

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