Entamoeba histolytica

• Can be asymptomatic
  
• Abd pain, cramping, colitis, diarrhoea (frequent bloody stools)
  
• Dysentery (can be fatal)
  
• Amoebic abscesses in lung, liver, etc)

• Resistant cysts (survive outside body)
• Trophozoites (feeding forms) in large intestine, caecum.
• Feed on mucosal surface, cause extensive ulcers via cytotoxin.

• Infection via ingestion of cysts, release trophozoite in duodenum.
  
• Can become invasive, via blood or direct spread to other organs.
  
• Cysts shed into faeces, infective

• Infected patients pass trophozoites (non-infective) and cysts in stools
  
• Asymptomatic patients can be carriers
  
• Vectors: water, food contamination from infected ppl.
• Flies, cockroaches, anal sex

• Metronidazole or tinidazole.
  
• Liver abscess can be aspirated, drugs injected directly.

• Good hygiene, safe water and food.

• 1 of 2 major causes of dysentery.
  
• Major cause morbidity in poor hygiene/inadequate water areas.

Category: Microbiology Notes