What type of life cycle does Entamoeba histolytica have?
DIRECT life cycle. ingestion of cyst w/ digestion of cyst wall in SI, releasing 4 motile, amoeboid trophozoites → trophozoites divide by binary fission in the cecum & colon (E. histolytica resides in crypts of LI) → establishment of intestinal infection may be followed by invasion of other organs including liver, lung, & brain.
What is the route of transmission for Entamoeba histolytica?
Pathology of Entamoeba histolytica?
Single cell protozoan in intestinal contents > trophozoa parasitize mucosa & encyst in unfavorable conditions > cysts are infective. Usually cause little to no pathology in domestic animals, BUT.... DOG- localizes in cecum & only rarely invades the tissues & produces clinical signs of acute or chronic amoebiasis. HUMANS (& nonhuman primates) - trophozoites invade cecal, colonic, or rectal mucosa & generate flask-shaped ulcers. May also invade other organs, including liver, lung, & brain
Clinical signs of Entamoeba histolytica?
FLASK-SHAPED ULCERS, Abdominal pain, intermittent diarrhea, anorexia, malaise....signs may wax & wane. Feces contain blood & mucus; tenesmus if parasites in rectum. (In histo class, use flasks)
How do you diagnose Entamoeba histolytica?
Cysts in formed feces, Trophozoites in diarrheic stools, ELISA, IFAT, hemagglutination tests, PCR, DNA probes
Describe the life stages of Entamoeba histolytica?
Cyst & trophozoite stage
Describe the appearance of Entamoeba histolytica- trophozoite stage.
Single nucleus w/ central endosome & food vacuoles containing RBCs
Describe the appearance of Entamoeba histolytica- cyst stage.
Captive reptiles, esp snakes & carnivorous lizards (NOT so much in turtles aka herbivorous chelonians)
What type of life cycle does Entamoeba invadens have?
DIRECT life cycle. Fecal-oral contamination, cyst wall digested by small intestine
What is the route of transmission for Entamoeba invadens?
Pathology of Entamoeba invadens?
Most pathogenic in snakes & carnivorous lizards, usually nonpathogenic & found in the intestine, & sometimes stomach, liver, spleen, kidneys, & lungs in herbivorous chelonians (turtles & tortoises).... LIFE THREATENING=pulmonary & CNS involvement
Clinical signs of Entamoeba invadens?
Amebiasis (amoebic dysentery) - diarrhea!
How do you diagnose Entamoeba invadens?
Fecal float, ELISA, IFAT, PCR & DNA probes, hemagglutination tests
Describe life stages of Entamoeba invadens
Trophozoite & cyst
Describe the appearance of Entamoeba invadens, trophozoite form
Nucleus w/ central endosome
Describe the appearance of Entamoeba invadens, cyst form
What type of life cycle does Balantidium coli have?
Direct fecal-oral transmission. infective cysts passed in feces → infective cysts are ingested → trophozoites escape from cysts & travel to lumen of cecum & colon (rarely are able to invade the mucosa) → trophozoites encyst in distal gut prior to excretion in feces
What is the route of transmission for Balantidium coli?
Pathology of Balantidium coli?
Balantidium coli is able to initiate lesions in some hosts via invasion of mucosa & generation of deep ulcers. Ulcers are minute at early stages, but ulcerative colitis may result in fatality. In severe infections, large areas of epithelium may be destroyed. Perforation of the bowel is a rare, but reported sequela
Clinical signs of Balantidium coli?
Can be asymptomatic, recurrent watery diarrhea, nausea, epigastric pain, vomiting, & intestinal colic in severe cases
How do you diagnose Balantidium coli?
Identification of trophozoites in diarrheic stools or cysts in formed stools via simple fecal flotation. Histopathology is confirmatory
Describe life stages of Balantidium coli?
Trophozoite & cyst
Describe the appearance of Balantidium coli, trophozoite
Large, kidney-shaped macronucleus. Small micronucleus. Presence of cytostome (mouth). 50-150um in length. Body surface covered w/ rows of cilia