Micro: Skin Parasites

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  1. Vector for Leishmaniasis
    Sandfly Phlebotomus and Lutozomya
  2. Commonly found in US soldiers returning from Afghanistan
    Cutaneous Leishmaniasis
  3. Infective form of Leishmaniasis for Man vs Fly?
    Promastogote vs Amastigote
  4. Describe the general invasion of Leishmania
    • Sandfly transmission
    • Promastigote invades macrophages
    • Transforms into nonmotile amastigote
    • Multiplies within cells of reticuloendothelial system (lymph, spleen, liver, bone marrow)
  5. Initial skin ulcer (oriental sore) that hears in a year but leaves depigmented scar is characteristic of what?
    Simple Cutaneous Leishmaniasis
  6. Immunity and Hypersensitivity type associated with Leishmaniasis
    Cell-mediated, Type IV (PPD-like test, positive only if cell-mediated immune system is intact, as in simple cutaneous Leishmaniasis)
  7. Nodular skin lesion that does not ulcerate; over time more lesions arise diffusely over body with a concentration near the nose.
    Diffuse Cutaneous Leishmaniasis
  8. Initial dermal ulcer at entry site that heals; months to years later ulcers in mucous membranes of nose and mouth aris; chronic leads to erosion (disfigurement) of nasal septum, soft palate, and lips over 20-40 years. Death by secondary bacterial infections.
    Mucocutaneous Leishmaniasis (L. braziliensis only)
  9. Treatment for Leishmaniasis
  10. Visceral Leishmaniasis (Kala-azar) species & most commonly infected/symptom?
    • L. donovani or L. chagasi
    • Infects malnourished children
    • MASSIVE SPLEENOMEGALY (increased abdominal girth, feeling of heaviness, appetite loss)
  11. Chagas' Disease is caused by what organism & vector?
    • Trypanosoma cruzi
    • Feces of the Reduviid (kissing) bug
    • (rodent, opossum, armadillo reservoirs)
  12. Hardened, red chagoma, followed by systemic spread with fever, malaise, swollen lymph nodes.
    Acute Chagas' Disease (T.cruzi)
  13. Organs primarily affected in Chronic Chagas' Disease
    • Heart (arrhythmias)
    • Megacolon
  14. Treatment for Acute Chagas' Disease
    Nifurtimox and Benznidazole (does not help for chronic form)
  15. Test for Leishmania
    Montenegro test (DTH) with leishmanin
  16. Causative agent of Cutaneous Larva Migrans, and frequent site of contraction
    • Dog or cat hookworm: Ancylostoma braziliensis
    • Sand/beach (animal feces)
  17. Intense skin itch and inflammation; creeping eruption. Characteristic of?
    Cutaneous Larva Migrans (remember no adult worm infection)
  18. Treatment for CLM?
    • Albendazole oral or topical
    • Ivermectin and thiabendazole are alternatives
    • Anti-histamines control itching
  19. Adult worm in subcutaneous tissues, releases eggs when wet; contracted from contaminated water supply.
    Dracunculus medinensis (Dragon or guinea worm)
  20. Treatment for Dracunculiasis
    • Benzimidazoles (Niridazoles, Metronidazole, Thiabendazole)
    • Stick winding
    • Match stick removal
    • Surgery
    • Education
    • Better water resources
  21. Fugitive or Calabar swellings, microfilaria in blood, continuous adult worm subcutaneous migration (including conjuctiva): characteristic of?
    Loasis (Loa Loa; Mango fly vector, equatorial Africa)
  22. Treatment of Loaisis
    DEC (Diethylcarbamazine), surgicial removal of worms
  23. Treatment of centipede bite
    Local measures: Sodium bicarbonate compresses or Epsom salt solutions
  24. Vector of Head Lice in school children
    Pediculus humanus var capitus
  25. Important vector in transmission of Ricketsia (typhus-trench fever) and spirochetes (relapsing fever)
    Body louse (Pediculus humanus var humanus)
  26. What is Phthirus pubis, and where is it acquired?
    • Crab louse
    • toilet seat, contaminated clothes
  27. Symptoms and treatment for Phthirus pubis
    • intense itching, secondary infections
    • gamma benzene hexachloride or copper oleate
  28. Infestation with fly larvae (maggots) that live in human tissue; Dermatobia hominis (human botfly); presents with a boil-like lesion; common in travelers returning from tropical countries.
    Furuncular Myasis
  29. Cimex lectularius
    Bed bugs
  30. Ascending flaccid paralysis, fever, generalized toxemis caused by what ticks?
    Dermocenter andersoni
  31. Pimple-like irritation in interdigital spaces of wrist, forearms, genitalia; intense pruritus. Characteristic of?
    Itch or Mange Mite (Scabies)
  32. Releases Alpha-latrotoxin nonhemolytic, neurotoxic venom
    Lactrodectus mactans (Black widow spider)
  33. Releases necrotoxin that may have hemolytic properties, and causes radiating necrotic spreading lesions with deep tissue damage; 2nd infections and gangrene may follow.
    Loxosceles laeta (Brown recluse)
  34. Proper course of treatment for Brown Recluse spider bite
    • most require no specific therapy
    • cleansing, tetanus prophylaxis, antibiotics
    • excision only if not healed naturally after 3 to 6 weeks
Card Set
Micro: Skin Parasites
Parasites and Ectoparasites causing skin infections, Micro Exam 2
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