More Protozoa

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  1. Define trophozoite.
    motile form
  2. Define bradyzoite.
    resting form in tissue cysts
  3. Define cysts.
    resting form, may be passed in feces
  4. Define oocyst.
    passed in feces
  5. Define tachyzoite.
    destructive form
  6. Who does Giardia affect?
    anything that is mammal
  7. What species can serve as reservoirs in nature for Giardia?
  8. Is there an intermediate host for Giardia?
  9. Where does Giardia infect its host?
    small intestines
  10. What clinical signs are there with Giardia infection?
    • diarrhea
    • cramping
    • anorexia
    • flatulence
    • weight loss
  11. What is the infective form of Giardia?
  12. How does Giardia enter the body?
    through food or water
  13. What is the prepatent period of Giardia?
    1 - 2 weeks
  14. How is Giardia diagnosed?
    • trophozoites are found in fresh direct fecal smears
    • IFA
    • EISA
    • Small cysts can be found on centrifugal floataion with zinc sulfate as the flotation medium
  15. What is the treatment for Giardia?
    • Metronidazole
    • Dogs and ruminants: fenbendazole
    • Albendazole for large animals
  16. How much metronidazole would a 44 pound dog need if you are asked to dose it at 50 mg/kg QD x 5d to treat Giardia?
    20, 000 mg
  17. Are pet owners more commonly infected with Giardia than people who have no pets?
    no epidemiologic relationship between pet owners and human infection
  18. Is there a vaccine for Giardia?
  19. What flagellate causes venereal disease, abortion, and infertility in cattle?
    Tritrichomonas fetus
  20. How is tritrichomonas fetus diagnosed?
    • see organisms on cytology from vagina/prepuce
    • serology of bulls
    • culture of preputial flush
  21. What organism causes canker in birds?
    avian trichomonas
  22. How is avian trichomonas diagnosed?
    • crop wash
    • DQ stained smear of lesion
  23. What is the reservoir of Balantidium coli?
  24. Association with what species increases the risk of Balantidium infection in humans?
  25. Which protozoan we discussed has the largest cyst form?
  26. What is commensal?
    living with, on, or in another, without injury to either
  27. Are most species of amoeba harmful?
    no, most are non-pathogenic
  28. What type of test will give you the best chance of finding intestinal protozoan trophozoites?
    fresh direct fecal smears
  29. What type of test will give you the best chance of finding Giardia cysts?
    centrifugal flotation
  30. What is the definitive host of Toxoplasma gondii? Where does it live in the definitive host?
    • cats
    • jejunum and ileum
  31. What is the intermediate host of Toxoplasma gondii? How is the intermediate host affected?
    • amphibians, fish, reptiles, birds, and all species of mammals
    • lymph nodes, heart, skeletal muscle, brain
  32. How can the intermediate host become infected with Toxoplasma gondii?
    • ingestion of bradyzoites in meat
    • ingestion of oocyts
  33. How is the definitive host infected with Toxoplasma gondii?
    cats ingests tissue cysts containing bradyzoites (usually by eating mice)
  34. What are the three life forms of Toxoplasma gondii?
    • oocysts
    • tachyzoites
    • tissue cyst containing bradyzoites
  35. How big are toxoplasma oocysts?
    10 - 12 microns (small)
  36. What happens after a cat eats an infected mouse? Describe the life-form changes.
    • cat ingests bradyzoites from mice
    • bradyzoites "hatch"(turn into tachyzoites) and penetrate the epithelial cells of the small intestines
    • reproduction occurs
    • cat sheds unsporulated oocysts
  37. Are Toxoplasma oocysts infective immediately upon being released into the environment? takes 1 - 3 days in the environment for the oocysts to become infective
  38. Is Toxoplasma considered a dange in immunocompetent individuals? What happens to the organism in an immunocompetent intermediate host?
    • no
    • there are no clinical signs
  39. What three organ systems are most commonly affected in the cat?
    • lungs
    • neurological
    • ocular
  40. Are cats showing signs of disease caused by toxoplasmosis usually shedding oocysts?
  41. Is there a Toxoplasma antigen test?
  42. How long will a positive antibody titer (concentration) for Toxoplasma last in the cat? What precent of healthy cats are seropositive?
    • positive titers last for years
    • this does not mean the cat is shedding oocysts (not shedding = no danger to humans)
    • 40%
  43. Does a positive test mean a cat is infected with Toxoplasma?
    no, it just means at some point in its life it ingested the infection
  44. Can a healthy cat test positive for Toxoplasma?
  45. List all the preventative measures pregnant women should take to avoid contracting toxoplasmosis.
    • avoid litter boxes
    • if they can't avoid litter boxes: wear gloves while scooping litter, clean litter box daily before oocysts can sporulate and become infective
    • meat should be cooked well
    • wash hands after handling raw meat
    • wash fruits and vegetables well
    • wear gloves while gardening
    • cover outdoor sand boxes
  46. What organism that causes abortion in ruminants was until recently believed to be Toxoplasma?
    Neospora caninum
  47. What are the three forms of Neospora caninum?
    • tachyzoites
    • bradyzoites
    • oocysts
  48. Who is the definitive host for Neospora caninum?
  49. Can Neospora caninum be spread vertically (from mother to baby)?
    yes...can cross placenta and infect fetus
  50. What is the intermediate host of Isospora? Eimeria?
    there is no intermediate host
  51. In general, are protozoan oocysts resistant in the environment? Are they infective immediately upon entering the environment?
    no and no
  52. What is the genus name of the parasite you have probably seen in fecals from puppies or kittens? Is it zoonotic?
    • isospora
    • yes
  53. Why do you sometimes see blood in feces from puppies or kittens infected with isospora?
    because they reproduce in intestinal cells which causes diarrhea, blood, and or mucus
  54. Is the life cycle of Isospora direct or indirect?
  55. What is the prepatent period of Isospora felis or canis?
    1 week
  56. Why would a veterinarian choose not to treat Isospora infection in a healthy, asymptomatic animal?
    because this type of animal typically has an immune system strong enough to take care of it itself...they develop an immunity over time
  57. How is it that Cryptosporidium can enter municipal water supplies?
    because occysts are found in about 65-97% of surface water (lakes, ponds, swimming pools, etc)
  58. How is Cryptosporidium diagnosed?
    • small oocysts found on fecal float
    • acid-fast staining
    • immunofluroescent staining
    • ELISA test for antigen
  59. What does Crytosporidium cause?
    • diarrhea
    • cramping
    • malaise
  60. Is there an intermediate host for Cryptosporidium?
  61. Is Cryptosporidium zoonotic?
  62. What species commonly carry Cryptosporidium?
    • calves under 4 weeks of age
    • small ruminants
  63. Describe what happens in "autoinfection" and why parasites that can undergo this phenomenon can be so dangerous.
    • autoinfection is the ability of a parasite to re-infect a host without ever passing out of the host.
    • this is dangerous because it can cause an overwhelming infection
  64. Of the ones we've discussed, which parasitic protozoan oocysts are the smallest?
  65. Is there an epidemiological relationship between being in the veterinary profession and contracting Cryptosporidium?
    yes...rates of infection are higher in the veterinary profession
  66. What is the causative organism of EPM?
    sarcocystis neurona
  67. What is the definitive host of sarcocystis?
  68. What kind of host is the horse for EPM?
  69. What species serve as intermediate host for EPM?
    • raccoon
    • aramdillo
    • skunk
  70. How do horses become infected with EPM?
    the sporocysts are ingested in opossum feces. they get into the GI tract and then the blood and then the CNS
  71. What species spreads EPM through its feces?
  72. How is it best to diagnose EPM in horses?
    antibodies in CSF (blood tests only indicate exposure)
  73. What kind of pollen has the "Mickey Mouse ears"?
    pine pollen
  74. What types of protozoa will we be studying?
    • flagellates
    • amoebae
    • ciliates
    • coccidians
  75. What are the different types of flagellates?
    • giardia
    • tritrichomonas
    • trichomonas
  76. What does the trophozoite of giardia look like?
    • tear drop
    • two nuclei "eyes"
    • 8 flagella (4 pairs)
  77. What type of reproduction does giardia have?
  78. Describe cyst ingestion of giardia.
    • trophozoites divide by longitudinal fission (asexual reproduction)
    • they proliferate in the small intestines
    • trophozoites are then passed in diarrhea but are incapable of causing infection and soon die
  79. Where do cysts for giardia attach in the small intestines? What does it do there?
    • brush border of small intestines
    • absorb food
  80. What do the "suckers" of the giardia cysts do to the small intestines and what does this cause?
    • damage villi where they attach
    • causes secretory diarrhea
  81. Which is the most common intestinal parasite in people in North America?
  82. What species does Balantidium coli infect?
    • dogs
    • primates including humans
  83. What kind of life cycle do Balantidium coli have?
    direct lifecycle
  84. Where do Balantidium coli infect?
    the large intestines
  85. What are the symptoms of Balantidium?
    • often asymptomatic
    • can cause diarrhea, abdominal pain, can be severe in debilitated humans
  86. How do animals get entamoeba histolytica?
    humans spread to pets
  87. What are the symptoms of entamoeba histolytica
    • diarrhea
    • ulcerative colitis
  88. What are the different coccidians?
    • isospora and wimeria
    • cryptosporidium
    • toxoplasma
    • sarcocystis
    • neospora
  89. How are coccidians spread?
    by ingestion
  90. How do you diagnose coccidians?
    • on float or direct smear
    • may be hard to find so seological tests exists
  91. Define sporocyst.
    passed in feces
  92. Define sporozoites.
    invade cells
  93. Define merozoite.
    dividing form
  94. Define meront.
    in tissue cysts
  95. Define microgamont.
  96. Define macrogamont
  97. What are the different life forms of toxoplasma in cats and what do they do?
    • oocyst (shed in feces)
    • tachyzoites (detrimental, motile form)
    • bradyzoites (resting form in tissue cysts)
  98. Which organ system in cats becomes infected with toxoplasma?
    any of them
  99. Are seropositive cats a risk to humans?
  100. Describe the life cycle in the intermediate host for toxoplasma.
    tachyzoites form and invade and multiply in any tissue. they for tissue cysts containing bradyzoites in muscle, organs and CNS
  101. What can toxoplasma cause in human babies?
    • abortion
    • blindness
    • retardation
    • seizures
  102. If a pregnant woman has a positive titer test for toxoplasma, what does that mean?
    she is protected
  103. What are the clinical signs of Neospora caninum?
    • neurological (ataxia, stiffness, circling, ascending paralysis, and rigid hyperextension of hind limbs)
    • muscle atrophy
    • seizures
    • head tilt
  104. Who is most commonly infected with Neospora caninum?
    puppies 5 - 6 weeks old
  105. What is the treatment for Neospora?
    • sulfonamides
    • clindamycin
  106. How is Neospora diagnosed?
    • histology
    • serology in large animals
    • PCR
  107. How do you prevent Neospora?
    avoid feeding dogs raw meat diets
  108. What are the different intestinal coccidia?
    • isospora
    • eimeria
    • cryptosportidium
    • sarcocystis
    • toxoplasma
  109. What kind of life cycle does isospora and eimeria have?
    direct life cycle (no intermediate host)
  110. When do isospora sporulate?
    1 - 2 days (eimeria takes longer)
  111. How do animals get isospora or eimeria?
    • host eats infective oocyst
    • sporozoites hatch and enter intestinal cells
  112. What animals get eimeria?
    • cattle
    • sheep
    • goats
    • swine
    • rabbits
    • poultry
    • horses
    • not found in dogs or cats
  113. What is the treatment for isospora and who do we treat?
    • sulfonamides and environmental control (strong ammonium hydroxide...resistant to most disinfectants)
    • neonates
  114. Where do cryptosporidium live in hosts?
  115. What is the treatment for cryptosporidium?
    supportive care
  116. Cryptosporidium can be fatal for what kind of people?
    immunocompromised people
  117. How do people typically get cryptosporidium?
    public water sources
  118. What kind of life cycle does sarcocystis have?
    predator-prey life cycle
  119. Define the predator-prey life cycle.
    • sporocysts passed from definitive host
    • sarcocysts live in muscles of intermediate host (prey species)
    • birds/insects transport hosts
  120. What does sarcocystis cause in rottweilers?
    • encephalitis
    • dermatitis
    • myocarditis
  121. What are the clinical signs of EPM?
    • ataxia, incoordination
    • muscle atrophy
    • facial paresis/paralysis
    • difficulty swallowing
    • collapse
    • seizures
  122. What does EPM stand for?
    equine protozoal myeloencephalitis
  123. What is the treatment for EPM?
    Marquis antiprotozoal paste
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More Protozoa
2012-03-09 03:59:01
Lab Tech

Lab Tech
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