Exam 2

• Digenea


  A subclass of Trematoda in the phylum Platyhelminths, which includes flukes (trematodes)
• Characteristics of flukes

  flat, non-segmented, has two suckers, leaf-like shape
• acetabula


  cup-shaped muscular suckers found on the oral or ventral surface of the flukes.
• hermaphroditic flukes


  -organ-dwelling flukes

  -contain both male and female reproductive organs
• Blood flukes (schistosomes)

  -contact with contaminated water, blood flukes penetrate skin and get into bloodstream

  -male and female exist as pairs
• Fasciola hepatica

  sheep liver fluke
• Fasciolopsis buski


  giant intestinal fluke
• F. hepatica and F. buski


  eggs are too similar to differentiate
• Clonorchis sinensis eggs resemble what two other organism's eggs?

  Heterophyes heterophyes and Metagonimus yokagawai
• Clonorchis sinensis

  Chinese liver fluke
• Paragonimus westermani


  Oriental lung fluke
• Schistosoma mansoni egg


  large lateral spine
• Schistosoma japonicum egg

  Small lateral spine (may be hidden)
• Schistosoma haematobium egg

  large terminal spine
• Schistosoma haematobium


  bladder fluke, can cause hematuria
• Top 3 most serious parasitic infections

  1. malaria

  2. schistosomiasis

  3. Entamoeba histolytica
• flagellates


  a type of protozoa that moves using flagella
• Ciliates


  a type of protozoa that moves using hair-like cilia
• Amoebae


  a type of protozoa that moves using pseudopods
• Coccidia


  a type of protozoa that are nonmotile
• Karyosome (Endosome)


  dot of chromatin in nucleus
• endoplasm


  inner fluid adjacent to nucleus
• ectoplasm


  outer, gelatinous cytoplasmic material
• Vacuoles


  Stores food, water, wastes, and other materials, contain glycogen
• Chromatoidal bars (chromatid bodies)

  rod shaped structures of condensed RNA, found in cytoplasm
• Encystation


  The process by which a trophozoite morphs into a cyst
• Excystation


  Transformation of a cyst stage into a trophozoite stage.
• Entamoeba histolytica


  always pathogenic, causes amebic colitis/dysentery
• Entamoeba histolytica trophozoite


  - RBC inclusions

  - Central karyosome
• Entamoeba coli


  -cysts typically have 4-8 nuclei

  -eccentrically located, irregular karyosome
• Entamoeba gingivalis

  associated with poor oral hygiene
• Naegleria fowleri


  -primary amoebic meningoencephalitis ("the brain-eating amoeba")

  -associated with water activities
• Primary Amoebic Meningoencephalopathy


  - signs & symptoms same as those of meningitis & encephalitis

  - progressively worsens over 3 to 7 days leading to death

  - caused by Naegleria, which live in warm bodies of water, mud & in artificial water systems

  -enters respiratory system by inhalation of contaminated water
• Acanthamoeba keratitis


  -transmitted via swimming in contaminated water while wearing contacts

  -associated with unsanitary contact lenses

  -contaminated contact solution
• Balantidium coli


  largest protozoan parasite of humans

  moves by cilia
• Giardia lamblia

  only know pathogenic intestinal flagellate, causes traveler's diarrhea
• describe the appearance of Giardia lamblia trophozoite

  -teardrop shape

  -bilaterally symmetrical

  -looks like an old man

  -2 karyosomes resemble eyes
• How is Giardia lamblia transmitted?

  -usually contaminated drinking water, untreated water from streams and lakes

  -can be seen in daycare settings
• Name two flagellates that have no known cyst stage

  Dientamoeba fragilis

  Trichomonas vaginalis
• Trichomoniasis


  an STD caused by Trichomonas vaginalis that results in infections of the vagina, urethra, prostate and bladder