MIcro Exam III – Lectures 14-16 – Flashcards

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question
What are cell walls of fungi composed of?
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Chitin and glucan.
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What does the cell membrane of a fungi contain?
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Ergosterol.
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T/F Most fungi are aerobes.
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True.
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T/F Fungi typically infect immunosuppressed.
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True.
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How do fungi disperse spores?
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Throwing them - raise up fungal head (conidia and other names).
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Which form of fungi is single cell?
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Yeast - asexual budding, divide by fission. Single cell - typically in you.
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Which form of fungi grows as long hyphae?
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Mold - free living, multi-cellular. May have conidia - asexual reproductive elements.
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How are fungi diagnosed?
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Growth/culture, Microscopy (may digest keratin w/ KOH), Antibody/antigen/Molecular Biology.
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How is microscopy done for diagnosing fungi?
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Digestion of keratin w/ KOH.
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How are fungi classified by body location?
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Superficial, cutaneous, subcutaneous, systemic.
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Where are superficial fungal infections located?
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Hair/skin, non-destructive.
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Name 2 superficial fungal infections?
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Tinea nigra - black patches on soles of hands/feet, Tinea versicolor - altered pigmentation - usually hypo.
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Where do cutaneous fungal infections reside?
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Skin, hair nails.
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What do cutaneous fungi secrete and what does it do?
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Keratinase - crumbles the skin/nails, loss of hair.
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Name some examples of cutaneous fungi?
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Tinea corpis, Tinea curis, Tinea pedis, Tinea capitis, Tinea unguium, Candida albicans.
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How are cutaneous fungi treated?
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Imidazoles & Griseofulvin.
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What causes oral thrush?
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Candida albicans. Patches of white exudate w/ reddish base. Can also cause vaginal infections.
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What do subcutaneous fungal infections cause?
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Deeper layers of skin/muscle/CT.
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What causes rose gardener's disease?
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Sporothrix scheckii - skin lesions, can be systemic.
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What is a long term subcutaneous infection?
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Chromomycosis.
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What does Cryptococcus neoformans cause?
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Inhaled into lungs, not dimorphic, goes systemic if immunosupressed.
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T/f Cryptococcus neoformans is not dimorphic?
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True - YEAST only.
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How are systemic fungi treated?
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Amphotericin B - Systemic treatment.
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Histoplasmosis capsulatum, Blastomycosis dermatidis and Cocoidiomycosis immitis are examples of what?
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Systemic fungi.
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What part of the cell wall is targeted for fungal infection?
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Glucan synthesis, chitin synthesis.
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What is the target for caspofungin and micafungin?
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Cell wall - Glucan synthesis.
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What is nikkomycin a target for?
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Chitin synthesis - cell wall.
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What is the mechanism of Azoles?
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Cell membrane of fungi - ergosterol synthesis. Fluconazole and ketconazole.
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What is the mechanism of Polyenes?
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Affect the egosterol pathway - Amphotericin B and Nystatin.
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What is Aphotericin B?
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A Polyene.
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What is the target for Griseofulvin?
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Inhibits mitotic spindle formation - used for superficial and dermatophytes.
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What is the target for Flucytosine?
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Nucleic acid synthesis Inhibitors.
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What is the target for Sordarins and Azasoradins?
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Protein synthesis inhibition.
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What is Blastomyces dermatitidis cause?
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Blastomycosis - resp. infection inhaled - Ohio and Miss. river valleys and Great Lakes.
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How is Blastomyces dermatitidis treated?
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Anphotericin B.
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What does Coccidioides immitis cause?
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Mild lung infection - found in the desert SW US. Lesions in lung. Coccidiodomycosis.
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How does Coccidioides immitis treated?
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Amphotericin B.
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What does Histoplasma capsulatum cause?
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Histoplasmosis - most recover, problem w/ immunocompromised - causes TB like granulomas. Endemic in Miss and Ohio RV - bird bat droppings.
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How is Histoplasma capsulatum treated?
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Aphotericin B.
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What does Cryptococcus neoformans cause?
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Opportunistic - usually asymptomatic, can cause pneumonia and cryptococcal meningitis. Spread by soil, pigeon droppings (CACA).
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What are the fungi that is monomorphic?
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Candida albicans, Cryptococcus neoformans, Aspergillus.
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What does Candida albicans cause?
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Opportunistic, cutaneous, oral, vaginal.
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How is Cryptococcus neoformans treated?
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Aphotericin B - for over 6 mos.
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How is Candida albicans treated?
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Nystatin or Amphotericin B.
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What does Aspergillus cause?
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Most common invasive mold, worldwide because they are saprobes, causes mycetoma in lungs, Type I Hypersensitivity rxn.
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How is Aspergillus treated?
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Aphotericin B.
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What does Tinea cause?
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Yeasts, Cutaneous.
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How are Tineas treated?
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Topical azones, dandruff shampoo. Causes chronic persisten skin pigment changes.
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How is Sporothrix shcenckii treated?
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Potassium Iodide.
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What does Pneumocystis jirovecii cause?
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Only a problem for immunosuppressed - cause pneumocystis pneumonia.
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How is Pneumocysts jirovecii treated?
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Trimethorpim-sulfamethoxazole.
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What other problems can fungi cause?
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Allergy - Type I Hypersensitivity, Toxins - aflatoxin, Mycormycosis - hard tissue necrosis in patients w/ poorly controlled diabetes.
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How does a cyst help a protozoa?
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Allows them to resist the env.
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What is the feeding form of a protozoa called?
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Trophozoite.
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What are protozoa?
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Single celled eukaryotes.
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T/F Protozoa are part of the normal flora.
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False.
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How are protozoas grouped?
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By how they move and their life cycle.
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Describe Trichomonas vaginalis.
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Flagellate, STD, can live in oral cavity too - no disease. Many are asymptomatic, 5-20% of women, 2-10% of men.
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What is the reservoir for Trichomonas vaginalis?
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Men.
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How is Trichomonas vaginalis treated?
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Metronidazole.
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T/F Giardia is resistant to chlorine.
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True - need to filter/boil.
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T/F Giardia can't spread person to person.
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False - it can spread.
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How is Giardia treated?
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Metronidazole.
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Where is Giardia found?
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Lakes, streams, mountain resorts.
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What is the reservoir for Giardia lamblia?
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Beavers/muskrats.
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T/F Giardia is a Ciliophora.
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False - flagellate.
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Name an amoeba.
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Entamoeba histolytica.
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What does Entamoeba histolytica cause - where does it live?
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Diarrhea - can exist in oral cavity.
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How is Entamoeba histolytica spread?
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Institutions - fecal/oral of cysts & in homosexual male population - asymptomatics can also pass it.
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How is Entamoeba histolytica prevented?
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Chlorination of water/filtration.
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T/F Entamoeba histolytica can spread to liver/lung/brain in immunosuppressed.
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True.
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How is Entamoeba histolytica treated?
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Metronidazole.
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Name a sporozoa?
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Toxoplasma gondii, Malaria.
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What is the reservoir for Toxoplasma gondii?
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Cats - cysts in feces - get it from eating infected mice.
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What are the symptoms of Toxoplasma gondii?
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Flu like symptoms.
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Who is at risk for Toxoplasma gondii?
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Immunosuppressed and pregos - can cause abortion or neuro problems in the baby.
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How is Toxoplasma gondii detected?
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Serology/screening/amniotic PCR.
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What is the vector for malaria?
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Mosquito.
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What do mosquitoes transmit to you with malaria?
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Sporozites - they go to the liver and reproduce - may have dormant liver phase.
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What happens in the malarial lifecycle?
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Sporozites go to liver, then hepatocytes rupture and morozoites enter the bloodstream and infect RBCs.
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How is malaria treated?
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Quinines and Doxycycline.
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What are parasites in the animal kingdom called?
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Metazoans.
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T/F Helminths are exogenous parasites.
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True.
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What is the protective cuticle on flatworms called?
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Tegument.
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What is reproduction like in the helminths?
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Large scale, much energy.
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What are round worms called?
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Nematodes.
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What does Trichinella spiralis live in?
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Pork/game - undercooked.
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Where do Trichinella spiralis go in your body?
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Muscles - larvae die and calcify there.
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T/F Trichinosis is fatal.
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True if it gets to your heart/brain/lungs, typically asymptomatic though.
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What are flatworms called?
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Platyhelminthes.
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What are Trematodes?
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Flatworms - flukes - leaf shaped body - Schistosomes.
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What is a tapeworm called?
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Cestodes - proglottids - absorb nutrients thru body - Taenia for example.
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T/F Arthoropods are ectoparasites.
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True. Can directly cause disease OR be intermediate hosts/vectors.
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T/F Arthoropods cause Type II Hypersensitivity.
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False - Type I.
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What kingdom do Microsporidians belong to?
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Fungi - even tho it seems like they belong as Protozoa.
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What is in the kingdom Chromista?
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Blastocystis hominis - role in human health is debated.
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What is the role of Blastocystis hominis in human health?
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Debated - not treated.
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What is antigenic variation?
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Changing coat - how protozoa and worms avoid your I/S. Plasmodium/Giardia.
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What is molecular mimicry?
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Looks like host antigen so you don't respond. Plasmodium.
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How do Taenia/Schistosomes conceal their antigenic sites?
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Coat themselves with host molecules - ex. MHC - to avoid your I/S.
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Who lives intracellularly to avoid your I/S?
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Plasmodium/Toxoplasma.
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Which protozoa immunosuppress and how?
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Schistosomes - suppress T and B cells.
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What part of your I/S fight parasites?
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IgE, Eosinophils, Th2.
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T/F Haemophilus are gram-positive facultative aerobes streptococci.
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False - Gram - facultatively coccobacilli.
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T/F Haemophilus is not part of your normal flora.
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False - normal flora of mouth - found in plaque biofilms, salive, mucosa.
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What infections do Haemophilus cause?
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Dentoalveolar infections, acute sialadenitis (salivary gland infection), infective endocarditis.
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Describe Actinobacillus.
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Gram - microaerohilic or capnophilic, coccobacilli.
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What is often a co-infection with Actinomyces?
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Actinobacillus.
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What virulence factos does Actinomyces have?
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Fimbria and others.
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What does Actinobacillus cause?
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Found in perio pockets - implicated in aggressive forms of perio disease.
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Describe Eikenella.
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Gram - fac. anaerobe coccobacilli.
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Where is Eikenella found?
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Plaque biofilms in healthy mouths & with perio disease.
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What does Eikenella cause?
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Dentoalveolar abscesses, infective endocarditis; possible chronic forms of perio disease.
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Describe Capnocytophaga.
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CO2 dependent Gram - rods.
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Where is Capnocytophaga found?
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Plaque, mucosa, saliva.
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Who does Capnocytophaga infect?
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Immunocompromised - destructive perio disease.
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What bacteria produces IgA protease?
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Capnocytophaga.
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Describe Porphyromonas gingivalis.
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Gram - anaerobic pleomorphic rods, non-motile.
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What bacteria degrades collagen?
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Porphyromonas gingivalis.
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What does Porphyromonas gingivalis cause?
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Perio disease, also part of normal flora.
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Where is Porphyromonas gingivalis found?
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Gingival crevice and subgingival plaque in small numbers.
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What are Porphyromonas gingivalis virulence factors?
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Produces proteases - a haemolysin, collagen degrading enzyes and cytotoxic metabolites, large capsule, fimbriae.
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Describe Prevotella.
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Gram - pleomorphic anaerobic rods.
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T/F Prevotella is part of the normal flora.
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True.
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Where is Prevotella found?
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Perio pockets, dental plaque, dentoalveolar abscess.
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Describe Fusobacterium.
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Gram - anaerobic.
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What causes halitosis?
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Fusobacterium - produce Ammonia and Hydrogen Sulfide.
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Where is Fusobacterium found?
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Gingival crevice and tonsils, perio infections, gingivitis, dentoalveolar abscess.
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Describe Leptotrichia.
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Gram - filaments anaerobes.
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Where is Leptotrichia found?
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Plaque - no known disease association.
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Describe Wolinella.
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Gram - anaerobic bacilli.
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What does Wolinella cause?
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Destructive perio disease.
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Describe Selomonas.
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Gram - anaerobic rods.
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What does Selomonas cause?
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Found in gingival crevice, no known disease association.
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Describe Treponema.
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Motile Gram - anaerobic helical/spirillum.
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What does Treponmea cause in the mouth?
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Found in gingival crevice, ulcerative ginigivits, destructive perio disease.
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Name the most common supragingival bacteria?
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Streptococci.
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Name the 4 most common species of Strep in the mouth.
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Mutans, Salivarius, Anginosus, Mitis.
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What 5 species make up subgingival plaque?
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Actinomyces, Prevotella, Porphyromonas, Fusobacterium, Veillonella.
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What role does saliva play in bacterial growth?
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Provides pellicel for adhesion, nutrient source, clumping, non-specific defense factors, maintain pH.
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What do bugs hydrolyze sucrose to?
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Dextrans, glucans, and fructans/levans.
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How do dextrans help bacteria?
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Make a sticky surface for other bugs.
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How do glucans help bacteria?
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Used to store energy.
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How do fructans/levans help bacteria?
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Additional storage - when broken down plaque gets more acidic.
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How do bacteria stick to teeth?
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Both are negatively charged, so you need Ca2+ ions make a bridge between enamel and pellicle and bug - or they use fimbriae pili, flagella to bind to glycoproteins of the pellicle.
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How do bacteria in a biofilm communicate?
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Quorum sensing molecules for communication - Control genes for polysaccharide production, reduce metabolism, Control production of virulent factors.
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What is the role of biofilms in gingivitis and periodontitis?
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Pellicle formation, bacteria attach to pellicle.
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What is the main etiological agent of perio disease?
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Flora inhabiting subgingival plaque.
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What is the specific plaque hypothesis?
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Key organisms cause the disease - fusobacteria and spirochetes in necrotizing ulcerative gingivits, Actinobacillus in perio disease.
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What is the non-specific plaque hypothesis?
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Disease caused by a wide range of non-specific organisms - virulence factors of many bacteria, some can substitute for others, so plaque cause disease no matter what it's composition.
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Which - non spec or spec plaque hypothesis is correct.
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Both?
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What is the ecological plaque hypothesis?
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Host mounts Imm. Resonse, inflammation leads to GCF, which feeds Gram - anaerobes. These suppress Gram + bacteria and shift the flora. This overwhelms host defenses.
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T/F Gram + bacteria are most prevalent in the ecological plaque hypothesis.
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False - Gram -.
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What 4 types of bacteria are normal oral flora?
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Gram + bacilli, Gram - bacilli (most concentrated), Veillonella, and Gram + cocci.
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What changes occur in plaque bacteria with perio disease?
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Changes from aerobic, non-motile, gram + cocci to Gram - anaerobic motile bacilli.
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What species increase in perio disease?
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Actinobacillus either alone or w/ Capnocytophaga spp. and Porphyromonas gingivalis.
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What bacteria predominate in ulcerative gingivitis?
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Fusobacterium nucleatum and oral spirochetes.
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What are microsporidians?
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Small, obligate intracellular parasites that lack mitochnodria.
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What is a cluster of hyphae that forms a mat called? 
answer
Mycelium
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