13.1 - entamoeba Flashcards
pathogenic member of entamoeba
entamoeba histolytica
entamoeba histolytica causes
amoebic dystentery
amoebic dysentery
an inflammatory form of diarrhoea in which the stool contains red and white blood cells - blood and pus
entamoeba histolytica found in
tropical and underdeveloped parts of the world
infection of entamoeba histolytica
90% of infections are asymtpomatic (asymptomatic cyst passer)
entamoeba histolytica extra intestinal disease
the ability go the trophozoites to invade beyond the bowel and productione abscesses in other organs of the body
three other species of human entamoeba with identical morphologies
entamoeba dispar
entamoeba Bangladeshi
entamoeba moshkovskii
all non pathogenic
other entamoeba colonisers of the human bowel
entamoeba hartmanni
entamoeba polecki
entamoeba coli
life cycle of E histolytica
exists in two forms
- hardy cyst
- trophozoite - motile invasive form
E histolytica cysts
survive for weeks in the environment and passage through the acidic environment of the stomach
ingested in food or water which has been contaminated by faeces
excitation may occur in the small bowel, releasing trophozoites which have the potential to invade the colonic mucosa
trophozoites or cysts are passed in the faeces, the cysts may go on to infect other individuals
amoebic dysentery clinical features
range from mild diarrhoea to dysentery to colitis
invades and damages colonic mucosa
abdominal pain and variable fever
stool
visible blood
trophozoites, on microscopy, are seen to have ingested erythrocytes
amoebic dysentery internal effects
ulceration of the intestinal wall varies from mild and superficial to extensive (colitis)
perforation and peritonitis may result
trophozoites in the portal circulation
trophozoites may enter portal circulation and be carried to the liver where they produce abscesses containing ‘anchovy sauce’ pus
abscesses may form in the spleen, lung or brain
