Life Cycle of Amoebic Dysentery

Amoebic dysentery is just one symptom of an illness known as amoebiasis. It is caused by an intestinal parasite known as Entamoeba histolytica. While the parasite can live within the large intestine of humans without causing any disease, it may cause a number of symptoms including colitis, dysentery and diarrhea.

Distribution

• The illness occurs worldwide, but is more frequently seen in areas with poor sanitation. Africa, India, South America and Mexico have significant numbers of cases of the disease.

Initial Infection

• Infection occurs when food, water or other items such as cooking utensils that have been contaminated with feces that contain mature cysts of Entamoeba histolytica come in contact with the mouth of a potential host. Once in the intestinal tract, the cysts open, releasing trophozoites that then migrate to the large intestine.

Reproduction

• In the large intestine, the trophozoites multiply by means of binary fission. They also produce more cysts. Both trophozoites and cysts will eventually pass through the intestinal tract and are eliminated from the body in the feces.

Invasion of the Intestinal Mucosa

• In some cases, trophozoites will invade the lining of the intestine. If trophozoites enter into the bloodstream they may also infect the brain, liver and lungs.

Contamination

• The trophozoites that are passed in the feces will inevitably die. However, cysts will continue to survive outside the host and can contaminate food, water or other items which can infect the new host, thereby continuing the life cycle.