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Microbiology > Protozoa > Flashcards

Protozoa Flashcards

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Biology 101 flashcards
1
Q

Protozoa have typically been classified as _____

A

parasites

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2
Q

what is a parasite

A

an organism that lives on or within another organism and benefits from the association while harming its host

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3
Q

what are the types of parasites

A

-protozoa= single celled eukaryotes
- helminths = multicellular animals (worms) (eukaryotes)

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4
Q

what are the modes of transmission for protozoa

A
  • vector - living transmitter of disease, most often arthropods
  • resevoir - sources of parasites in environment not active transmitters of disease
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5
Q

how does the parasite grow/ replicate

A

intracellular or extracellular

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6
Q

describe protozoa

A
  • diverse group of eukaryotic microbes
  • related by their simple organization: unicellular or multicellular without specalized tissues
  • most are free living in aquatic environments or on decaying organic matter
  • some are parasitic
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7
Q

what is encystation

A

formation of a cyst
- resting state with a wall and low metabolic activity

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8
Q

what is the function of cysts

A
  • protection from changes in environment
  • sites for nuclear reorganization and cell division
  • transfer from one host to another
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9
Q

what is excystation

A

escape of vegetative form from cyst

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10
Q

what is excystation triggered by

A

return to favorable environment

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11
Q

what is a trophozoite

A

-vegetative form released by parasitic species
- excystation often triggered by entry into new host

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12
Q

are all protozoa motile

A

no

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13
Q

motile species use one of the following:

A
  • cilia
  • flagella
  • pseudopodia
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14
Q

what are the means of reproduction for protozoa

A
  • asexual: binary fission- mitosis -> cytokinesis
  • sexual : conjugation- exchange of gametic nuclei between paired protozoa of opposite mating types
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15
Q

what types of protozoa are zooflagellates

A
  • giardia lamblia
  • trichomonas vaginalis
  • trypanosomes
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16
Q

what does giardia lamblia cause

A

giardiasis- gastro intestinal disorder

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17
Q

what does trichomonas vaginalis cause

A

sexually transmitted disease

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18
Q

what are trypanosomes

A

-hemoflagellates
- important blood pathogens

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19
Q

what is the most common cuase of epidemic waterborne diarrhea

A

giardiasis

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20
Q

what is the mechanism of action of giardiasis

A

-forms cysts and trophozoites
- trophozoites attach to intestinal epithelium and interfere with nutrient absorption

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21
Q

what is the transmission of giardiasis

A
  • cyst contaminated water
  • animal resevoirs
  • asymptomatic human carriers
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22
Q

what are the clinical manifestations of giardiasis

A

-acute giardiasis- severe diarrhea, epigastric pain, cramps, voluminous flatulence, and anorexia
- chronic gastritis- intermittent diarrhea with periodic appearance and remission of symptoms

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23
Q

what is the treatment prevention and control of giardiasis

A
  • antiprotozoal agents- metronidazole
  • avoid contaminated water of purify first
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24
Q

what is the prevalence of trichomonas vaginalis

A

15% of women have it

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25
Q

is there a cyst stage in trichomonas vaginalis

A

no only trophozoites

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26
Q

what are the clinical manifestations of trichomonas vaginalis

A
  • accumulation of leukocytes at site of infection
  • in females- yellow purulent vaginal discharge and itching
  • in males usually asymptomatic or burning urination
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27
Q

what is the treatment prevention and control of trichomonas vaginalis

A
  • observation of parasite in vaginal discharge, semen or urine
  • antiparasite therapy- metrodiazole
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28
Q

where is trichomonas tenax found and what is it associated with

A

in the mouth
- associated with poor oral hygiene

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29
Q

what are hemoflagellate diseases caused by

A

flagellated protozoa

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30
Q

what are the two major groups of flagellated protozoa

A

-leishmanias
- trypanosomes

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31
Q

how are hemoflagellate diseases transmitted

A

by bites of infected arthropods

32
Q

what is african trypanosomiasis

A
  • african sleeping sickness
  • chronic blood stream infection with bouts of parasitemia
  • CNS invasion after months to years
33
Q

how is african trpanosomiasis transmitted

A

by tsetse flies
- resevoirs are domestic cattle and wild animals

34
Q

what are the clinical manifestations of african trypanosomiasis

A
  • interstitial inflammation and necrosis within lymph nodes and small blood vessels of brain and heart, leading to lethargy and death within 1 to 3 years
35
Q

how is african trypanosomiasis diagnosed

A

observation of motile parasites in the blood

36
Q

when is drug therapy used for african trypanosomiasis

A

during systemic stage

37
Q

why is vaccine not useful in african trypanosomiasis

A

antigenic variation

38
Q

what is chagas disease

A

american trypanosomiasis
- most people affected in childhood
- early disease is mild
- small percentage develop complications 10-20 years later

39
Q

what is chagas disease transmitted by

A

kissing bug
- resevoirs are domestic cattle and other animals

40
Q

what complications are brought on by chagas disease

A

heart disease and other disorders due to destruction of parasitized cells in the liver, spleen, lymph nodes and CNS
- megaesophagus, megacolon
- cardiomyopathy

41
Q

what are the treatments for chagas disease

A

no treatment available for late complications
- vaccines not useful because of antigenic variation

42
Q

what is leishmaniasis transmitted by

A
  • sand flies
  • animal resevoirs are canines and rodents
43
Q

where does leishmania survive and differentiate

A

macrophages

44
Q

what are the 3 forms of leishmaniasis infection

A

mucocutaneous, cutaneous and visceral

45
Q

what does the visceral form of leishmaniasis infection involve

A
  • tissue macrophage disfunction
  • intermittent fever and enlargement of spleen or liver
46
Q

what does recovery of leshmaniasis provide

A

permanent immunity

47
Q

describe the treatment, prevention and control of leishmaniasis

A
  • amphotericin B
  • vector and resevoir control and epidemiological surveillance
48
Q

what is amoebiasis and what is it caused by

A
  • amoebic dysentery
  • caused by entamoeba histolytica
49
Q

how is amoebiasis transmitted and what are the clinical symptoms

A
  • ingestion of cysts
  • asymptomatic to fulminationg dysentery, exhaustive diarrhea, and abscesses of liver, lungs and brain
50
Q

what is the treatment, prevention and control of amoebiasis

A
  • observatino of trophozoites in fresh warm stools or cysts in ordinary stools and serological tests
  • metronidazole
  • avoid contaminated water and food
51
Q

describe phylum apicomplexa

A
  • lack locomotor organelles
  • all have apical complex: arrangement fibrils, tubules, vacuoles and other organelles at one end of cell
52
Q

what is the apicomplexan life cycle

A
  • involves two different hosts
  • involves both asexual and sexual phases
53
Q

what are the sexual and asexual phases of the apicomplexan life cycle

A
  • schizogony is asexual phase: rapid series of mitotic events producing infective organisms
  • oocyst is sexual phase: thick walled, diploid structure, undergoes meiosis to produce haploid spores
54
Q

what are the important sporozoan genera

A

-plasmodium - malaria
- cryptosporidium - cryptosporidosis
- toxoplasma- toxoplasmosis

55
Q

what is malaria caused by

A
  • plasmodium falciparum
  • plasmodium vivax
  • plasmodium malariae
  • plasmodium ovale
56
Q

what is malaria transmitted by

A

bite of an infected female anopheles mosquito

57
Q

what is the resevoir, intermediate host, and definitive host of malaria

A

reservoir: humans
intermediate host: humans asexual reproduction
-definitive host: mosquito sexual reproduction

58
Q

what causes recurrent malaria

A
  • P vivax and P ovale form hypnozoites within liver cells
59
Q

what are the clinical manifestations of malaria

A

periodic attacks of chilld and fever

60
Q

how is malaria diagnosed

A

demonstration of parasites within wright or Giemsa stained RBCs and seroligcal tests

61
Q

how is malaria treated and prevented

A
  • antimalarial drugs- chloroquine
  • chemoprophylaxid for people travelling to endemic areas, netting, and insect repellants
62
Q

where is babesia found and what is it transmitted by

A
  • endemic to USA
  • transmitted by same Ixodes tick as Borrelia burgorferi
63
Q

what are the symptoms of babesia

A

subclinical to severe disease, summer flu

64
Q

how does babesia infect

A

protozoa infect RBCs and cause fever upon damage

65
Q

what is the resevoir for babesia

A

white footed mouse

66
Q

how is babesia diagnosed and treated

A
  • microscopy of Giemsa stained blood samples, PCR
  • clindamycin and quinine
67
Q

what is toxoplasmosis caused by and how is it transmitted

A
  • toxoplasma gondii
  • transmission of ingested and undercooked meat, congenital transfer, blood transfusion, tissue transplant and ingestion of cat feces
68
Q

what is the most common form of transmission for toxoplasmosis

A

undercooked meat containing tissue cysts

69
Q

what is the definitive host for toxoplasmosis

A

cat

70
Q

how does toxoplasmosis infect

A

invades macrophages

71
Q

what are the clinical manifestations of toxoplasmosis

A
  • asymptomatic or resmebles mononucleosis
  • can be fatal in immunocompromised hosts
  • congenital infections
72
Q

what is the treatment, prevention and control of toxoplasmosis

A
  • antiparasite therapy for immunocompromised patients
  • minimize exposure by avoiding raw meat and eggs
  • women screened for antitoxoplasma antibody at marriage or very early in pregnancy
73
Q

what is cryptosporidosis caused by

A

cryptosporidium parvum
-apicomplexan that forms cysts, sporozoites and merozoites

74
Q

what is cryptosporidosis resistant to

A

chlorine

75
Q

how is cryptosporidosis transmitted

A

-animal resevoirs and in contaminated food or water
- many birds and mammals shed oocysts in feces
- also spread person to person in crowded urban environments
- public water system risks
- swimming pools

76
Q

what are the clinical manifestations of cryptosporidosis

A
  • diarrhea, abdominal pain, nausea, fever and fatigue
  • self limiting
  • can be fatal in late stage AIDS patients and other immunocompromised individuals
77
Q

what is the treatment of cryptosporidosis

A
  • microscopic examination of stools
  • symptomatic/ supportive therapy

Microbiology (39 decks)

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