Dysentery can be either bacterial or amoebic, depending on the type of infection and the microorganism involved. When it comes to amoebic dysentery, the causes can be narrowed down to Entamoeba histolytica – a single-celled protozoan parasite that infects the large intestine, bringing about bloody diarrhea.

This microorganism breeds in specific reservoirs and is spread through certain carriers.

• Reservoirs

  Infected humans and people who carry the parasite asymptomatically are the only reservoirs.

• Carriers

  Food or water that has been contaminated with the infection through the feces (stool) of infected individuals act as the carriers of this infection.
  The infection can also spread through oral or anal sexual contact and due to poor personal hygiene.

Dysentery Causes – The Role Of Fomites

Any object that acts as a vehicle for transmitting amoebic dysentery is called as a fomite. For example, when a person with dysentery touches the door handle without washing his hands after defecating, he can transfer the organism onto the door handle.

When a second healthy person touches the door handle and later uses his hands for eating, the organism enters his digestive system and infects the bowels.

Dysentery Causes – How The Amoeba Causes Dysentery

Entamoeba histolytica enters the body in two forms, and this can determine the extent of the infection.

• Tropozoite (Free Amoeba)

  Active growing form that is readily killed by the digestive enzymes or the acidity of the stomach.

• Cyst (Egg-Like Stage)

  Infectious form that comes with a protective covering, is resistant to adverse environmental conditions, and is excreted in the feces of affected individuals.

Amoebic dysentery is caused when the cyst form of the parasite is ingested. Once inside the human intestinal tract, it bypasses the adverse acidic condition of the stomach, enters a favorable environment, and resumes its growth, causing damage to the intestine.

In severe cases, the organism invades the intestinal wall causing dysentery and may also reach other organs through the blood stream causing extra-intestinal complications like liver damage.

Some of the tropozoites get excreted in feces, ready to infect a second person. These cysts survive for long periods (up to two months) in the environment and contaminate adjacent water bodies or cultivation, serving as potential sources of infection and acting as primary dysentery causes.

The cysts can also remain inactive in the intestine for years and trigger the disease when a person’s immunity is low, during pregnancy, old age, or when patients are affected by cancer, diabetes, alcoholism, or a HIV infection.

Dysentery Causes – Predisposing Factors

When it comes to dysentery causes, some factors that play a key role are:

• Using untreated human waste as fertilizers
• Untreated sewage getting to drinking water
• Travelling to developing countries without adequate precautions
• Eating contaminated fruits and vegetables
• Drinking water without treating it beforehand
• Poor sanitation and personal hygiene
• Washing fruits or vegetables in contaminated water
• Living in crowded areas like refugee camps

Amoebiasis occurs worldwide, but dysentery symptoms are quite a common problem in Africa, Mexico, certain parts of South America, and South East Asia (including India). They account for about 70,000 deaths annually worldwide, so learning about the dysentery causes and taking active measures for dysentery prevention can keep you on the safer side of the fence. In case you do do contract this infection, consult your doctor for a confirmation of dysentery diagnosis as well as timely amoebic dysentery treatment.