Chapter 2 Flashcards
What is the general structure of entamoeba
vesicular nucleus, small endosome at or near center, no goli nor mitochondria
What is the only pathogenic strain of entamoeba
Entamoeba histolytica
What illness does E. histolytica cause and what are the symptoms
amebiasis: mild loose stools, stomach pain and cramping
amebic dysentery: sever form, stomach pain, bloody stool, fever
Where in the body are E. Histolytica trophozoites found
trophozoites feed on mucosal secretions, invade tissue, lesions in cecum, appendix or colon
What is E. histolytica often confused with
E. hartmanni
How can E. Histolytica kill you
ulcers might get secondary infections, perforated colon.
rarely: attacks liver, perforates it, lungs or brain
Describe the life cycle of E. histolytica
in the large intestinal wall precysts (non-invasive)–> encystation create cysts that are passed out with feces–>cysts are ingested by host–> excystation in SI, metacystic amoeba reproduces by binary fission forming invasive trophozoites–>can transform to precysts, start over
How is E. histolytica diagnosed
stool samples by microscopy, floating stool sample, look for cysts
How is amebiasis treated
paromomycin for intestinal trophs and metronidazole for trophs and extraintestinal amoebiasis
How does metronidazole combat parasites
inhibits nucleic acid synthesis by disrupting DNA
How does paromomycin combat parasites
increases error rate in ribosomal translation, binds to RNA loop
Where in the world is E. histolytica found
cosmopolitan, moslty tropics and high density pops, young travelers
How is E. histolytica transmitted
contaminated water or food, filth flies and roaches can be mechanical vectors, night soil, oral anal sex
how can you avoid E. histolytica infection
bottled water, carbonated water, avoid unpeeled fruit and vegetables, street food
Where is Entamoeba coli found and what illness does it cause
lives in intestine, feeds on bacteria, protists and yeast, commensal, often confused with E. histolytica, non pathogenic
Where is Entamoeba gingivalis found
in the mouth
What stages does E. gingivalis have
only trophozoite stage, no cyst stage
How is E. gingivalis transmitted
direct contact, kissing, in primates, cats and dogs
Where in the body is endolimax nana found
in human cecum, feces
What animals are Iodamoeba buetschlii found in
pigs, humans other primates,
What environment is Naegleria fowleri found
warm freshwater and soil
What illness does Naegleria fowleri cause
PAM: primary amebic meningoencephalitis
rare: severe brain infection mostly fatal
How is Naegleria fowleri transmitted
enters through nose, swimming in ponds, lakes, warm freshwater, hot springs, poorly maintained pools
What stages are present in Naegleria fowleri
trophozoites and cysts
Where in the world are Naegleria fowleri
US: southern states, all over the world
Describe how PAM progresses
1-14 days: symptoms show: headache, fever, nausea, vomiting, and stiff neck.
Later: confusion, lack of attention, less balance, seizures and hallucinations
Death: in 3-7 days
How is Naegleria fowleri treated
not clear, all infections have been fatal, 2 survived with miltefosine
What illnesses does Acanthamoeba cause
chronic skin infection or CNS in immunocompromised
GAE, keratitis: eye infection
What organisms cause GAE
granulomatous amebic encephalitis- Acanthamoeba and Balamuthia mandrillaris
What stages does Acanthamoeba have
cysts and trophozoites
What is keratitis
inflammation and opacity of the cornea, can cause blindness
How are Acanthamoeba infections treated
keratitis with ketoconazole, corneal transport
GAE: fatal
What illnesses does Balamuthia mandrillaris cause
GAE, infects respiratory system or through skin, skin lesions
Where in an environment can Balamuthia mandrillaris be found
soil, dust, water
How is Balamuthia mandrillaris diagnosed?
mostly through autopsy
