ParasitologyTest1NonpathogenicAmoebas

Card Set Information

Author:
victimsofadown
ID:
283081
Filename:
ParasitologyTest1NonpathogenicAmoebas
Updated:
2014-09-15 02:57:29
Tags:
ParasitologyTest1
Folders:
ParasitologyTest1
Description:
ParasitologyTest1
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user victimsofadown on FreezingBlue Flashcards. What would you like to do?


  1. Compare E. hartmanni to E. histolytica (life cycle, morphology, disease)
    • Also known as "small race" and "large race"
    • Life cycle, general morphology, and overall appearance are identical to E. histolytica
    • E. hartmanni is smaller (12-15um vs 20-30um trophozoites and 5-9um vs 10-20um cysts)
    • about 1/3 patients with amoebiasis harbor E. hartmanni
    • E. hartmanni is non-pathogenic
    • *NOTE- very important to distinguish between these amoebas to avoid unnecessary treatment
  2. Compare E. coli to E. histolytica (life cycle, distribution, morphology, disease)
    • Coexist often
    • trophozoites are difficult to tell apart
    • E. coli is a commensal, it feeds on bacteria and other protozoa
    • E. coli is more widely distributed (better survival in putrefaction) and reaches 100% in some areas
    • E. coli is larger (15-40um vs 20-30um trophozoites and 10-33um vs 10-20um cysts)
    • E. coli cysts have up to 8 vesicular nuclei (vs E. histolytica's 4)
    • E. coli chromatoidal bars are needle-like, E. histolytica's are rounded
    • The life cycles are identical
    • No treatment is needed for E. coli, it is a commensal (no disease state)
  3. Compare E. polecki to the other amoebas (life cycle, size, morphology)
    • Typically infects pigs and monkeys
    • Size is 11-15um (9-18um) - between E. histolitica and E. coli
    • Cysts only have one nucleus! (1% have 2 nuclei)
  4. Compare E. gingivalis to the other amoebas (discovery, location, disease, life cycle, prevalence)
    • First amoeba of humans to be described
    • Lives in mouth, not intestine
    • Abundant in those with unhealthy mouths, but not the cause
    • Multiplies rapidly in the presence of food
    • Live well on uncleaned dental devices
    • No cyst stage
    • Trophozoite is 10-20um (between E. hartmanni and E. histolytica)
    • Trophozoite is transparent
    • Numerous blunt pseudopods allow quick movement
    • Food vacuoles contain oral epithelial cells, bacteria, and microorganisms
    • Transmission can only be from person to person (no cysts)
    • Up to 95% of those with unhygienic mouths may be infected
  5. Give details about Endolimax nana (size, location, nuclear appearance, locomotion, life cycle, morphological characteristics, disease)
    • Smallest of the intestinal dwelling amoebas of humans - 8um (6-15um)
    • small vesicular nucleus and large endosome
    • Slow movers (pseudopods are short and blunt)
    • Encystment is similar to E. coli and E. histolytica
    • Small oval cyst has no chromatoid bars and 4 nuclei
    • Metacyst excysts in small intestine while colonization begins in the large intestine
    • Feed mostly on bacteria with high incidence of infection (>30% in some populations)
    • Commensal
  6. Give details about Iodamoeba butschlii (life cycle, distribution, location, size, morphology,
    • Infects other primates and pigs
    • Infection by contamination (as others)
    • Its distribution is worldwide, but only 4-8% in humans (much less than E. nana or E. coli)
    • Mature form lives in large intestine
    • Trophozoite is usually 10um (5-18um)
    • Nucleus is large with large, ovoid endosomes
    • Food vacuole contains mostly bacteria
    • Cysts are uninucleate, commonly with a large vacuole containing glycogen (stains dark brown w/ Iodine)
  7. Which genera of amoeba are typically free-living?  Where are they normally found?  What disease do they cause?
    • Naegleria and Acanthamoeba
    • Water and soil
    • *NOTE- are facultative parasites of humans
    • Cause PAM (Primary Amoebic Meningoencephalitis)
  8. What are the symptoms of PAM?
    • PAM (Primary Amoebic Meningoencephalitis)
    • Sudden onset of headache, fever, stiff neck, lethargy, and coma
  9. Describe the life cycle of Naegleria fowleri in detail
    • Flagellated <-> amoeboid (trophozoite) <-> cyst
    • Cyst stage: Trophozoites encyst due to unfavorable conditions (food deprivation, crowding, dessication, accumulation of waste, cold temperatures (<10C)
    • Trophozoite stage: reproductive stage
    • grows fastest around 42C (binary fission)
    • nucleus surrounded by halo
    • single blunt lobopod
    • Flagellate stage: Occurs when trophozoites are exposed to change in ionic concentration
    • transformation occurs quickly (a few minutes)
    • 2 flagella at one end (no pseudopod)
  10. How do most Naegleria fowleri infections occur? Describe what happens.
    • Most cases are contracted in lakes/swimming pools
    • Flagellated trophozoites are forced deep into the nasal passages
    • Trophozoites enter the nervouse system and migrate to the brain where inflammation occurs
    • PAM proceeds rapidly, death within 5-7 days
  11. What are the treatments for N. fowleri
    • Qinghausu and Amphotericin can kill the parasite, but almost all patients die
    • *NOTE- in Nigeria a person suspected of PAM is forced to wash 5x per day, including sniffing water up the nose
  12. How can you differentiate between Naeglaeria and Acanthamoeba? (physically, disease state, method of infection)
    • Naegleria cysts have a single wall, circular
    • Acanthomoeba cysts have two walls, polygonal
    • Naegleria has a single lobopod
    • Acanthamoeba forms small spiky pseudopod and move slowly (filopodia)
    • Acanthamoeba cysts are found in affected tissue
    • Naegleria do not encycst in humans
    • Acanthamoeba infection is less severe than Naegleria, not usually affecting CNS 
    • Acanthamoeba infections are often from contact lenses (homemade saline solution)
    • Naegleria infections are often from swimming
  13. Describe Acanthamoeba (disease, life cycle, morphology, size, method of infection, disease state, treatment)
    • Causes PAM
    • life cycle is very similar to Naegleria except NO flagellated stage
    • small spine-like pseudopod (filopoda)
    • double-walled cysts that are polygonal (15-20um)
    • Trophozoites are 25-50um
    • Most victims wear contact lenses with a homemade saline solution
    • PAM-like symptoms, but rarely affects CNS
    • Acanthamoebic keratitis can lead to blindness
    • Treatment is difficult, although sulfonamides respond favorably
  14. What are the characteristics of phylum Ciliophora? (morphological, reproduction, location
    • Posession of cilia, pellicle, macronucleus w/ micronuclei
    • Binary fission and conjugation
    • Majority are free living
    • Balantidium genus is parasitic
  15. Describe Balantidium coli (life cycle, size, locations, epidemiology/effects of hosts, morphology, feeding, color, reproduction)
    • only ciliate that infects humans (sometimes monkeys, rats, and pigs)
    • Both trophozoite and cyst stage
    • largest protozoan parasite of humans (trophozoite 50-130um long and 20-70um wide)
    • round cysts are 40-60um
    • Very common in tropical zones (esp. Philippines), also in temperate regions
    • Epidemiology and effects are similar to E. histolytica
    • Macronucleus is large and sausage-like, micronucleus is very small
    • 2 contractile vacuoles present- one in middle and one at posterior (for excretion)
    • ingest particles within the cytostome (cytophage at posterior end leads to cytostome)
    • Food vacuoles contain  erythrocytes, cell fragments, starch granules, and fecal matter
    • trophozoites are yellowish or greenish in color
    • Multiply by binary fission where posterior daughter cell forms a new cytostome after division
    • Conjugation occurs infrequently
  16. Give a detailed description of B. coli cysts
    • Round cysts (40-60um)
    • Heavy cell wall (possibly 2 membranes)
    • Macronucleus, contracticle vacuole, and cilia can be seen within the cyst wall
  17. Describe B. coli transmission/life cycle in detail
    • Cysts are infective stage
    • can live in pig feces for weeks (pig is normal source of infection for humans)
    • Nonpathogenic to pigs, so very common (20-100%)
    • Infection occurs from ingestion of contaminated food/water 
    • Excystation occurs in the small intestine
    • Balantidiosis is rare (<1% in human pop)
  18. Where is infection common for B. coli? How can it be prevented?
    • Common where malnutrition is widespread, pigs share habitation with humans, and fecal contamination of food and water occur
    • For prevention avoid food/water contaminated by piggies
  19. Describe the symptoms and diagnosis for B. coli. The treatment?
    • Clinically, balantidiosis is indistinguishable from amoebic dysentary (flask-shaped ulcers in large intestine, bloody dysentary results)
    • HAS NOT been reported outside GI tract (too big)
    • Fatalities are rare
    • Balantidiosis is easily diagnosed with large cysts in feces (asymptomatic)
    • Symptomatic cases typically only have trophozoites in feces
    • treated with metronidazole or oxytetracycline (like E. histolytica).  
    • Clinical symptoms last ~10 days.

What would you like to do?

Home > Flashcards > Print Preview