amoeba infects humans and other primates. The active (trophozoite)
stage exists only in the host and in fresh feces; cysts survive
outside the host in water, soils and on foods.. When swallowed they
cause infections the excyst ( become the trophozoite stage) in the
intestines. Amebiasis (or amoebiasis) is the name of the infection
caused by E. histolytica .
sometimes last for years may cause 1) no symptoms, 2) vague gastrointestinal
distress, 3) dysentery (with blood and mucus). Most infections occur
in the digestive tract but other tissues may be invaded. Complications
include 4) ulcerative and abscess pain and, rarely, 5) intestinal
blockage.. The amoeba's enzymes help it to penetrate and digest
human tissues and it secretes other toxic substances. Eating of
one cyst can cause an infection.
cases are diagnosed by finding cysts in the stool. Since cysts are
not shed constantly, a minimum of 3 stools should be examined. Serological
tests exist for long-term infections. It is sometimes difficult
to distinguish the E. histolytica cyst from the cysts
of non-pathogenic intestinal protozoa by its appearance.
is transmitted by faecal contamination of drinking water and foods,
but also by direct contact with dirty hands or objects and by sexual
amoebas remain in the gastrointestinal tract of the hosts but ulceration
of the gastrointestinal mucosal surfaces occurs in less than 16%
of cases. In fewer cases, the parasite invades the soft tissues,
most commonly the liver. Amoebomas are rare masses that lead to