Micro Test II

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Micro Test II
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Micro Test II
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Parasitology and Fungi
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  1. What are the three lifestages of parasites?
    Egg, larve (immature), Adults
  2. Define deifnitive host
    one in which the parasite reproduces
  3. Define intermediate host
    Development occurs here, no reproduction though
  4. Which parasites fall under the catagory of protozoa?
    • Entamoeba Histolytica
    • Giardia Lamblia
    • Trichomonas Vaginalis
    • Trypanosomes
    • leishmainia tropica
    • Leishmania Braziliensis
    • Balantidum Coli
  5. Entamoeba Histolytica Causes What?
    Amebic Dysentary
  6. Giardia Lamblia Causes what?
    Giardiasis aka "beaver fever"
  7. Trichomonas Vaginalis causes what?
    trichomoniasis
  8. Trypanosoma Brucei causes what?
    African Trypanosomiasis or "African Sleeping Sickness"
  9. Trypanosoma Cruzi causes what?
    Chagas disease (Mexico, South, and Central America
  10. Leishmania Donovani causes what?
    visceral leishmaniasis or "Kala-azar"
  11. Leishmania Tropica causes what?
    cutaneous leishmaniasis or "Oriental sore"
  12. Leishmania Braziliensis causes what?
    Mucocutaneous Leishmaniasis aka "espundia"
  13. Balantidum Coli Causes what?
    Ciliary Dysentery
  14. Plasmodium causes what?
    malaria
  15. Plasmodium vivax causes what?
    most common type of malaria aka "Benign Tertian Malaria"
  16. Plasmodium Malarie causes what?
    A less common form of malaria called quartan or malarial malaria
  17. Plasmodium Falciparum causes what?
    Common in the tropics, more serious form of malaria --> Cerebral malaria
  18. Toxoplasma gondii causes what?
    Toxoplasmosis
  19. Cryptosporidum Parvum causes what?
    ingestion of cysts causes diarrhea kind of like giardia
  20. What are the three types of sporozoa?
    • Plasmodium (all of the malarias)
    • Toxoplasma
    • Cryptosporidium Parvum
  21. How are roundworms tranmitted?
    by ingestion of the ova
  22. largest nematode parasitizing the human intestine

    Although infections may cause stunted growth,
    adult worms usually cause no acute symptoms

    ·     
    High worm burdens may cause abdominal pain and
    intestinal obstruction 

    ·     
    Migrating adult worms may block bile duct

    ·     
    During the lung phase of larval migration,
    pulmonary symptoms can occur

    Who am I?
    Ascaris Lumbricoides
  23. Ova (eggs) are ingested
    Larvae hatch in duodenum and move into blood vessels
    Larvae move to lungs to molt and mature
    In 3 weeks larvae are coughed up and swallowed
    Upon reaching small intestine develop into adult worms
    Female produces about 200,000 eggs daily
    Eggs pass out in feces
    Eggs in soil are viable for up to 3 years
    Ascaris Lumbricoides
  24. Life cycle
    Eggs are ingested 
    Eggs hatch in small intestine
    Larvae then migrate to the cecum and mature into adults
    Adult female produces up to 10,000 eggs daily which are shed in feces
    The adult worms live in the cecum and ascending
    colon.  They are fixed in that location, with the anterior portions threaded into the mucosa
    Trichuris trichiura - the whip worm
  25. Pathology
    Fewer than 100 worms rarely cause clinical symptoms, and the majority of infections are asymptomatic
    Heavy worm burden results in 

    Anemia --consume blood cells with anterior end buried in mucosa
    --Damage to epithelia layer can lead to secondary bacterial infection
    --In extreme cases of heavy infection prolapse of the rectum can occur
    Trichuris trichiura - The whip worm
  26. The worm is considered the pinworm, humans are considered to be the only hosts
    Enterobius vermicularis
  27. Life cycle
    Gravid adult female worm is nocturnal 
    Migrates out of intestine to lay up to 20,000eggs on perianal skin at night
    Eggs are transferred to fingernails by scratching
    Eggs are then ingested 
    Larvae hatch in small intestine and migrate to colon where mature into adults
    Enterobius vermicularis
  28. Epidemiology     
    Worldwide, but appears to be more common in temperate than tropical countries
    The most common helminthic infection in the United States (estimated 40 million persons infected)
    Infections more frequent in school- or preschool- children and in crowded conditions
    Enterobius vermicularis
  29. Pathology
    Frequently asymptomatic.  The most typical symptom is perianal itching, especially at night, which may lead to secondary bacterial infection
    Occasionally, invasion of the female genital tract causing vulvovaginitis
    Enterobius vermicularis
  30. These are Roundworms transmitted by direct penetration of infectious larvae
    • American Hookworms: 
    • Ancylostoma duodenale
    • Necator americanus
    • Ancylostoma braziliense
    • Strongyloides stercoralis
  31. Life cycle
    Adult female in small intestine lays 10 to 20,000 eggs daily
    Eggs in feces
    Larvae hatch, feed on bacteria
    Rhabditiform larva molts to filariform larva
    Filariform is infective
    Filariform larva penetrates bare skin
    Moves to lung, are swallowed
    American Hookworms: Ancylostoma duodenale and Necator americanus
  32. Pathology
    Larval penetration of skin usually causes little damage, possible dermatitis
    Larvae may cause pulmonary symptoms, rarely pneumonitis
    Adult worms in small intestine attach to mucosa with strong cutting plates, beginning feeding on blood. 
    Anemia, malnutrition
    American Hookworms: Ancylostoma duodenale and Necator americanus
  33. Life cycle
    Larvae penetrate skin and wander
    Life cycle is not complete in humans, continue to wander aimlessly = creeping eruption (visceral larval migrans)
    Intense itching and eosinophilia (excessive eosinophils)
    Ancylostoma braziliense - Dog and cat hookworm
  34. Female in small intestine is ovoviviparous - develop within eggs that remain within the mother up until they hatch or are about to
    Eggs are deposited in mucosa, hatch and move to lumen
    Larvae are excreted in feces, or cause auto infection
    Become free-living adults in soil
    Free living adults produce eggs that develop into infectious filariform larvae
    Larvae penetrate skin, move through blood to lungs
    Molt in lungs, are swallowed and become adults in small intestine
    Strongyloides stercoralis - alternates between free-living and parasitic forms
  35. Roundworm Tissue Parasites
    • Anisaka
    • Trichinella Spiralis
    • Onchocerca volvulus
  36. Larvae are ingested by humans in flesh of raw fish
    Produce intestinal obstruction, pain, nausea and vomiting
    higher incidence in areas where raw fish is eaten (e.g., Japan, Pacific coast of South America, the Netherlands) 
    No effective drug treatment – surgical only
    Anisaka
  37. Life cycle
    Encysted larvae are ingested and during digestion reach small intestine where molt to become adults
    Adult females produce 100s of larvae
    Shortly followed copulation adult male dies, following larval production adult female dies
    Larvae are carried via blood to muscle where they encyst
    If the host is not consumed, larvae calcify and die
    Humans are a dead end host
    Trichinella Spiralis
  38. Pathology
    Light infections may be asymptomatic 
    Larval migration into muscle tissues can cause facial edema, conjunctivitis, fever, myalgias, rashes, and blood eosinophilia
    Occasional life-threatening manifestations include myocarditis, central nervous system involvement, and pneumonitis
    Trichinella Spiralis
  39. Wuchereria bancrofti causes what and is vectored by what?
    Elephantitis and the mosquito
  40. Life cycle
    Females in lymph duct are ovoviviparous and produce 1000s of immature larvae known as microfilariae
    Microfilariae released into the lymph and swept into blood through the thoracic duct
    Mosquitoes ingest microfilariae in blood meal
    Microfilariae mature in mosquito to final infective larval stage
    Wuchereria bancrofti
  41. Pathology
    When females release microfilariae intense lymphatic inflammation occurs with chills and fever
    Lymph nodes become obstructed resulting in swelling
    Males – scrotum, legs
    Women – legs
    Microfilariae exhibit periodicity in the blood, they can be demonstrated during certain times of the day, while other times they seem to disappear from peripheral circulation
    Draw blood at night to observe microfilariae
    Wuchereria bancrofti
  42. onchocerca volvulus causes what?
    river blindness
  43. onchocerca volvulus is vectored by what?
    black fly, Simulium
  44. Life cycle
    Adult worms locate under the skin, become encapsulated by host reactions to form nodules
    Adult female releases microfilariae 
    Microfilariae migrate through skin, to eyes
    onchocerca volvulus
  45. Pathology
    Larvae migrate through skin causing inflammation “lizard skin”
    Larvae may migrate to eyes and cause blindness
    onchocerca volvulus
  46. Platyhelminthes- The Flat Worms
    Trematoda - flukes

    Name Them
    • Fasciola hepatica
    • Clonorchis Sinensis
    • Fasciolopsis Buski
  47. Large
    leaf-shaped parasites of herbivores, that can infect humans accidentally
    Fasciola hepatica
  48. Life cycle
    Adult flukes live in the bile duct, eggs are passed out of the liver with the bile and into the intestine to be voided with feces
    Larvae penetrate snails
    Motile larvae called cercariae leave snail and encyst as metacercariae on water plants
    Metacercariae ingested by animal, migrate to liver
    Fasciola hepatica - Liver Fluke
  49. Pathology
    The liver is damaged by the migration of flukes
    Worms in bile ducts cause inflammation, pain, chills and fever
    Fasciola hepatica - Liver Fluke
  50. The Chinese liver fluke
    Worms mature in the bile ducts and produce up to 4000 eggs a day for at least 6 months
    Clonorchis Sinensis
  51. Life cycle
    Eggs excreted in feces
    Eggs hatch in water and larvae penetrate snails
    Larvae mature in snails and cercariae leave snail to penetrate fish
    Metacercariae encyst in fish flesh
    Humans consume undercooked/raw fish
  52. Life cycle
    Eggs in feces hatch in water
    Larvae penetrate snails
    Cercariae move to plants (usually water chestnuts)
    Metacercariae encyst under leaves
    Humans or pigs eat water chestnuts
    Fasciolopsis Buski
  53. Mature in blood stream of definitive host

    Unlike other flukes, schistosomes are dioecious (separate male and female worms)

    Schistosoma mansoni

    S. haematobium

    S. japonicum

    All 3 species have similar life cycles

    What are all of these Called?
    The Blood Flukes
  54. Life cycle
    Males and females live in host blood vessels (each species prefer different veins)

    Females release 3,000 eggs/day

    Eggs pass through tissue to reach intestine or bladder

    Eggs reach fresh water in urine or feces

    Eggs hatch in fresh water

    Infective larval stage penetrates snail

    Snail excretes infective cercariae form with a forked tail

    Cercaria penetrate the skin of a vertebrate host, mature into adults and reside in veins


    Adults may live 20-30 years
    • Schistosoma mansoni
    • S. haematobium
    • S. japonicum
  55. Swimmer’s itch – dermatitis from penetration of skin by cercaria
    In 1-2 months of infection develop fever, chills, cough 
    Most serious damage is done by the eggs

         Eggs lodged in venules and tissue cause immune system                         to respond to foreign invader
           As eggs accumulate enlarged spleen (splenomegaly), ascites (accumulation of fluid in abdominal cavity)
          High eosinophilia
    • Schistosoma mansoni
    • S. haematobium
    • S. japonicum
  56. live in the small intestine of the human by attaching to the
    intestinal wall by means of a head called a scolex

    The body is composed of segments called
    proglottids

    Each proglottid contains a set male and female organs that
    produce eggs
    Cestoda - Tapeworms
  57. The beef tapeworm
    Taenia saginata
  58. The pork tapeworm
    Taenia solium
  59. The fish tapeworm
    • Diphyllobothrium latum
    • Echinococcus granulosus
  60. Life cycle

    Cattle consume gravid proglottids or eggs in contaminated feeds
    The eggs hatch and the larvae migrate to muscle
    Larvae encyst in muscle as cysticerci
    Taenia saginata
  61. Pathology
    produces only mild abdominal symptoms. 
    The most striking feature consists of the passage of proglottids
    Taenia saginata
  62. Life cycle
    Morphology and life cycle are similar to T. saginata
    Proglottids and eggs eliminated in feces
    Pigs consume gravid proglottids or eggs in contaminated feed
    The eggs hatch and the larvae migrate to muscle
    Larvae encyst in muscle as cysticerci
    Cysticercus consists of scolex within a large "bladder;" hence, cysticerci are often referred to a "bladder worms”
    Taenia solium
  63. Pathology
    Cysticercosis
    Only occurs with pork tapeworm, T. solium
    Infective larvae migrate into muscles and tissue of human host and develop into cysticerci
    adult worms rarely cause symptoms
    The main symptom is often the passage of proglottids 
    The most important feature is the risk of development of cysticercosis 
    Cysticerci can develop in brain or eye
    This can cause meningitis, visual disturbance and acute inflammation
    Taenia solium
  64. Life cycle
    Eggs are eliminated in feces
    Eggs hatch in water, larvae are called coracidium
    Coracidium are ingested by copepods
    Copepods are eaten by fish
    Larvae mature to sparganum and encyst in fish muscle
    Infection from undercooked fish
    Diphyllobothrium latum
  65. Pathology
    Infections can be a long-lasting (decades) 
    Most infections are asymptomatic 
    Manifestations may include abdominal discomfort, diarrhea, vomiting, and weight loss
    Vitamin B12 deficiency with anemia may occur. 
    Tapeworm absorbs large amounts of B12
    Diphyllobothrium latum
  66. Life cycle
    Adult worms infect canines and release eggs in small intestine
    Eggs eliminated in feces and ingested by sheep, cattle, pigs etc.
    Humans are accidental hosts, transmission is usually by contact with infected dog
    Dogs may be infected by eating viscera of livestock
    Echinococcus granulosus
  67. Human infection
    Larvae move into liver or lung and form hydatid cyst
    Cyst contains infectious worms called hydatid sand
    Echinococcus granulosus
  68. Pathology
    infections remain silent for years before the enlarging cysts
    cause symptoms in the affected organs
    Hepatic involvement can result in abdominal pain, a mass in the hepatic area, and biliary duct obstruction
    Pulmonary involvement can produce chest pain and cough
    Rupture of the cysts can produce fever, eosinophilia, and anaphylactic shock, as well as cyst dissemination
    In addition to the liver and lungs, other organs (brain, bone, heart) can also be involved, with resulting symptoms
    Echinococcus granulosus
  69. Pathology
    Immunocompetent persons is generally an asymptomatic infection 
    In patients with AIDS, is the most common cause of intracerebral mass lesions and is thought to be caused by reactivation of chronic infection  
    Results from an acute primary infection acquired by the mother during pregnancy 
    Invades CNS and may cause blindness, encephalitis, mental
    retardation
    Toxoplasma gondii
  70. Transmission
    Ingestion of undercooked infected meat containing oocysts
    Ingestion of the oocyst from fecally contaminated hands or food
    Transplacental transmission
    Toxoplasma gondii
  71. Very low host specificity
    Definitive host  = domestic cat and wild cats
    Life stages
    Sporozoites are infectious form
    Sporozoites are within oocyst that passes out in feces
    Toxoplasma gondii
  72. Similar to P. vivax
    Common in Africa
    Produces fewer merozoites
    Relapse is common
    Plasmodium Ovale
  73. Common in the tropics, most serious disease
    Multiple sporozoites infect one RBC- creating “signet ring” formation
    Daily fever, becoming tertian (36 to 48 hours) 
    Chills, nausea
    Infection restricted to liver and spleen
    Blackwater fever is characterized by intravascular hemolysis and kidney failure
    Cerebral malaria can ensue- mental status changes, coma, death
    Plasmodium Falciparum
  74. Less common than P. vivax
    No enlarged RBCs
    Distinctive banding pattern
    Asexual forms in RBCs appear as rosettes
    No relapses
    Fever occurs in 72 hour pattern
    Called quartan or malarial malaria
    Plasmodium Malariae
  75. Most common cause of malaria called benign tertian malaria
    Infected red cells have unique pink dots = Schuffner’s dots
    Stage in RBC is ring shaped
    Infected RBC is large
    Characterized by fevers that typically occur every other day
    Relapse from latent liver infection common
    Plasmodium Vivax
  76. In the vertebrate host two cycles occur
    Exoerythrocytic stage – in liver
    Erythrocytic stage – in RBCs
    Merozoites in RBCs produce waste product called malarial pigment
    Lysis of RBCs cause anemia and jaundice of malaria
    Plasmodium
  77. Lifestages
    Sporozoites released from mosquito into human host, go to liver
    Undergoasexual reproduction (schizogony) to produce merozoites
    Merozoites = infect and destroy red blood cells causing symptoms of malaria
    Gametocytes = produced as result of erythrocytic stage in RBC, taken up by female mosquito
    Plasmodium
  78. Large ciliated trophozoite form
    Cyst form is present
    Transmission
    Fecal contaminated water, particularly associated with infected pig feces
    Pathology
    Abdominal pain, watery, bloody stools
    Balantidium coli
  79. Life stage is protozoa form, no cyst
    Transmission
    Vectored by the sandfly
    Pathology
    Lesions in the junction of the pharynx result in the break down of the palate of the mouth and nose 
    Leishmania tropica
  80. Life stage is protozoa form, no cyst
    Transmission
    Vectored by the sandfly
    Pathology
    Invades liver, spleen, kidney
    Causes enlarged liver, spleen, wasting, and finally death (in untreated) in 2-3 years
    Following treatment a condition known as post-kala azar dermal leishmanoid = a granulomatis reaction on the skin about 2-3 years after treated
    Leishmania donovani
  81. Life stage is protozoa form called trypanosome, no cyst
    Transmission
    vectored by the reduviid bug (kissing bug) via defecation by bug into wound
    Pathology
    Acute Chagas’ disease 
    Small red nodule called chagoma at bite site
    Heart, liver, spleen and lymph nodes are infected
    Symptoms include anemia, nervous disorders, muscle and bone pain, heart failure
    Death may ensue after 3 to 4 weeks
    Most common in children
    Chronic Chagas’ disease
    Symptoms are primarily nervous dysfunction with may continue for years
    Individual may be virtually asymptomatic and suddenly die of heart failure
    Trypanosoma cruzi
  82. Life stage is protozoa form called trypanosome, no cyst
    Transmission
    vectored by the Tse-Tse fly 
    Pathology
    In vertebrate host trypanosomes live in blood, lymph nodes, spleen and CSF
    Do not invade or live in cells, but rather in tissue spaces particularly in CNS
    Within a few days animals becomes emaciated, uncoordinated, and paralyzed… then dies
    Humans tend to experience mental dullness, tendency to sleep finally coma and death
    Trypanosoma bruce
  83. Trophozoite has 4 flagella
    NO CYST form
    Transmission
    Trophozoites are passed sexually causing urogenital infections
    Pathology
    Green discharge, itching in females; urethritis in males
    Trichomonas vaginalis
  84. Two life stages
    Trophozoite- the active feeding stage
    Cyst-similar to endospore, resistant to environment and infective
    Transmission
    Cysts ingested in contaminated water, particularly near beaver populations, beavers are reservoir
    Pathology
    Cysts excyst in intestine, reproduce and cover intestinal wall
    Interfere with fat absorption, causing fatty stools and diarrhea
    Giardia lamblia
  85. Two life stages
    Trophozoite- the active feeding stage, pseudopods
    Cyst- similar to endospore, resistant to environment and infective
    Transmission
    Cysts ingested in contaminated water, food- use of nightsoil increases chance of contamination.  Can be vectored by flies.
    Pathology
    Cysts excyst in intestine causing bloody diarrhea, if trophozoites enter blood move to liver causing hepatic
    amebiasis- a collection of pus in the liver.
    Entamoeba histolytica
  86. Single celled eukaryotes
    Divide by binary fission or budding
    Yeasts
  87. Fungi that produce mycelia
    Multicellular
    Composed of hyphae - long, branching filament that, with other hyphae, forms the feeding thallus of a fungus called the mycelium
    Molds
  88. Hyphae are either 

    Septate- walls that divide hyphae intocells
    Aseptate- no walls
    Molds
  89. Sexual spores are free zygotes
    Asexual spores are enclosed in sac-like structure called a sporangium
    Phycomycetes
  90. Sexual spores enclosed in sacs called asci
    Asexual spores are exogenous, formed at the end of the hyphae
    Ascomycetes
  91. Sexual spores found on basidia
    Basidiomycetes
  92. No sexual stage
    "fungi imperfecti"
    Deuteromycetes
  93. Found worldwide, concentrated in U.S. in Midwest and Eastern U.S.
    Found in soil contaminated with bat and bird feces (frequently in caves)
    Spores are inhaled 
    Histoplasmosis (Spelunker's Disease)
  94. Found in Southwestern U.S. (NM, AZ)
    Inhale arthrospore (spores united in the form of a string of beads, formed by fission
    Most infections are asymptomatic, maybe only slight fever
    Coccidiomycosis (Valley Fever)
  95. Spores are inhaled into lungs where they transform to a yeast form of the microbe
    50% of individuals are symptomatic, with flu-like illness with productive cough
    Blastomycosis
  96. Amphotericin B- binds to sterols, preferentially to the primary fungal cell membrane sterol, ergosterol.  
    Disrupts cell, causing lysis
    Treatment for systemic fungi
  97. Occupational hazard for greenhouse workers, gardeners
    Fungi enter via skin lesion, transform to yeast form
    Nodules and skin lesions appear along lymphatic system 
    Sporotrichosis- “rose handler’s disease”
  98. Invade dead keratinized tissue (hair, nails)
    Major genera include:
    Trichophyton
    Microsporum
    Epidermophyton

    Tinea infections- Tinea is the name given to a fungal skin infection. Synonymous with dermatophyte (are contagious)
    Tinea pedis – athlete’s foot
    Tinea corporis – trunk or extremities
    Tinea capitis – head, causes hair loss
    Tinea unguium – nails
    Dermatophytoses
  99. Yeast is part of normal flora.
    Heat, humidity, and sweat help it proliferate in some people
    Tinea versicolor is not contagious
    KOH wet mount looking for yeast cells
    Wood’s lamp - lamp emits ultraviolet light. If there is an infection on the area where the Wood's lamp is illuminating, the area will fluoresce. Normally the skin does not fluoresce, or shine, under ultraviolet light 
    Tinea versicolor- caused by yeast
  100. Part of normal flora in mouth, gut, vagina
    Pathogen when normal conditions are altered- antibiotics, depressed immunity 
    Thrush, skin infections
    Candidiasis
  101. Large encapsulated yeast
    Microbe enters the host via respiratory route 
    After some time in the lungs C. neoformans spreads to extrapulmonary tissues
    It has a predilection for the brain, infected persons usually contract meningoencephalitis 
    Cryptococcosis 
  102. It is not yet established whether it is a fungus or a protozoan.
    Antigenic differences have been found in strains derived from the various mammalian hosts. 
    In normal individuals, asymptomatic infection of the lungs occurs in early life.
    The organism persists in an
    inactive or latent state unless the host becomes immunocompromised
    Pneumocystis carinii

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