<P> The active ( trophozoite ) stage exists only in the host and in fresh loose feces ; cysts survive outside the host in water , in soils , and on foods , especially under moist conditions on the latter . The infection can occur when a person puts anything into their mouth that has touched the feces of a person who is infected with E. histolytica , swallows something , such as water or food , that is contaminated with E. histolytica , or swallows E. histolytica cysts ( eggs ) picked up from contaminated surfaces or fingers . The cysts are readily killed by heat and by freezing temperatures , and survive for only a few months outside of the host . When cysts are swallowed they cause infections by excysting ( releasing the trophozoite stage ) in the digestive tract . The pathogenic nature of E. histolytica was first reported by Lösch in 1875 , but it was not given its Latin name until Fritz Schaudinn described it in 1903 . E. histolytica , as its name suggests ( histo -- lytic = tissue destroying ) , is pathogenic ; infection can be asymptomatic or can lead to amoebic dysentery or amoebic liver abscess . Symptoms can include fulminating dysentery , bloody diarrhea , weight loss , fatigue , abdominal pain , and amoeboma . The amoeba can actually ' bore ' into the intestinal wall , causing lesions and intestinal symptoms , and it may reach the blood stream . From there , it can reach different vital organs of the human body , usually the liver , but sometimes the lungs , brain , spleen , etc . A common outcome of this invasion of tissues is a liver abscess , which can be fatal if untreated . Ingested red blood cells are sometimes seen in the amoeba cell cytoplasm . </P>
<P> The active ( trophozoite ) stage exists only in the host and in fresh loose feces ; cysts survive outside the host in water , in soils , and on foods , especially under moist conditions on the latter . The infection can occur when a person puts anything into their mouth that has touched the feces of a person who is infected with E. histolytica , swallows something , such as water or food , that is contaminated with E. histolytica , or swallows E. histolytica cysts ( eggs ) picked up from contaminated surfaces or fingers . The cysts are readily killed by heat and by freezing temperatures , and survive for only a few months outside of the host . When cysts are swallowed they cause infections by excysting ( releasing the trophozoite stage ) in the digestive tract . The pathogenic nature of E. histolytica was first reported by Lösch in 1875 , but it was not given its Latin name until Fritz Schaudinn described it in 1903 . E. histolytica , as its name suggests ( histo -- lytic = tissue destroying ) , is pathogenic ; infection can be asymptomatic or can lead to amoebic dysentery or amoebic liver abscess . Symptoms can include fulminating dysentery , bloody diarrhea , weight loss , fatigue , abdominal pain , and amoeboma . The amoeba can actually ' bore ' into the intestinal wall , causing lesions and intestinal symptoms , and it may reach the blood stream . From there , it can reach different vital organs of the human body , usually the liver , but sometimes the lungs , brain , spleen , etc . A common outcome of this invasion of tissues is a liver abscess , which can be fatal if untreated . Ingested red blood cells are sometimes seen in the amoeba cell cytoplasm . </P>
where does excystation of mature entamoeba histolytica cysts occur
where does excystation of mature entamoeba histolytica cysts occur
digestive tract
digestive tract