Entamoeba histolytica: This parasite exists in the colon in two forms, the trophozoite or cyst form mobile and stationary.
trophozoite:
measures between 20-50 microns, has adjustable motility, this ectoplasm clear and well defined, with thin fingerlike pseudopodia and endoplasm finely granular, with eccentric nucleus and the central and punctiform karyosome. Live in the lumen, wall or both parts of the colon. Multiply by binary fission grow best under anaerobic conditions and require the presence of bacteria or tissue substrates for nutritional requirements. The trophozoite is the form of propagation (vegetative) of the parasite.
trophozoite:
measures between 20-50 microns, has adjustable motility, this ectoplasm clear and well defined, with thin fingerlike pseudopodia and endoplasm finely granular, with eccentric nucleus and the central and punctiform karyosome. Live in the lumen, wall or both parts of the colon. Multiply by binary fission grow best under anaerobic conditions and require the presence of bacteria or tissue substrates for nutritional requirements. The trophozoite is the form of propagation (vegetative) of the parasite.
Cyst
is the infective form and is predominant in the stools of asymptomatic carriers. The cysts are between 5-20μm. Cysts in stool can from one to four cores. Cysts survive outside the host for days or weeks, especially at low temperatures and humidity. Is the infecting stage in the life cycle of the parasite and thus infection is transmitted from one host to another, with the ingestion of contaminated food and water.
Life cycle:
If food or water infected with faeces containing cysts of E. histolytica, they can be ingested by an individual, these cysts contained in the feces resist stomach pH and pass into the intestine, the bowel will be excystation and release the trophozoite (vegetative form) and it will multiply. The infected individual may have symptoms or do not, then encyst and cysts are to be deleted to the environment by the deposition and they are going to infect other individuals. It can also happen that the infected individual trophozoites released into the environment but they are dying. Another possibility is that the amoeba puncture the intestine and reaches the liver is a liver abscess.
If food or water infected with faeces containing cysts of E. histolytica, they can be ingested by an individual, these cysts contained in the feces resist stomach pH and pass into the intestine, the bowel will be excystation and release the trophozoite (vegetative form) and it will multiply. The infected individual may have symptoms or do not, then encyst and cysts are to be deleted to the environment by the deposition and they are going to infect other individuals. It can also happen that the infected individual trophozoites released into the environment but they are dying. Another possibility is that the amoeba puncture the intestine and reaches the liver is a liver abscess.
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