Protozoa 1 Flashcards

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1
Q

an organism (parasite) that lives completely at the expense of another organism (host)

A

definition of parasite

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2
Q

a relationship between two organisms in which one (parasite) gets benefit (food, physical support) from the other (host). Parasite can have minor or major effects on the survival of its host.

A

definition of parasitism

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3
Q

antigen masking
antigen sharing
antigenic variation
intracellular location

A

strategies of parasites to avoid killing by host

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4
Q

what are the two families under parasite?

A

protozoa and metazoa (helminths)

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5
Q

sarcodina (amebas)
sporozoa (sporozoans)
mastigophora (flagellates)
ciliata (ciliates)

A

protozoa

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6
Q

entamoeba histolytica
- with pseudopodia

A

sarcodina (amebas)

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7
Q

toxoplasma
babesia
plasmodium
sarcocytis
cryptosporidium

  • undergo sexual and asexual reproduction
  • intracellular parasites
A

sporozoa (sporozoans)

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8
Q

giardia
trichomonas
trypanosoma
leishmania

A

mastigophora (flagellates)

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9
Q

balantidium coli

  • a giant intestinal ciliate of humans and pigs
  • the only human ciliated parasite
A

ciliata (ciliates)

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10
Q

what are the protozoans that are not in any of the 4 groups?

A

microsporidia
- opportunistic parasites of immunocompromised patients

blastocytis
- life cycle and infectious stage remain unknown
- polymorphic shape in stool or lab culture

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11
Q

flagellates, amebae, and ciliates multiply by…..

sporozoans reproduce by….

A

binary fission

schizogony (multiple fission)

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12
Q

sporozoans undergo sexual recombination which leads to…

A

genomic and antigenic variation

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13
Q

some parasitic protozoa able to evade host’s immune response because…

A

they are intracellular and/or undergo antigenic variation

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14
Q

latent and relapse infections occur with….

A

toxoplasma gondii (tissue cysts)
plasmodium vivax
plasmodium ovale (hypnozoites in liver)

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15
Q

infections by intracellular protozoa are difficult to treat because….

A

drugs must cross plasma membrane. no vaccines are available for any human parasitic disease

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16
Q

a host in which sexual reproduction of a parasite takes place

A

definitive host

17
Q

a host in which asexual reproduction of a parasite takes place

A

intermediate host

18
Q

a host in which the parasite survives but without undergo further development

A

paratenic host

19
Q

a host which harbours the parasite and serves as a source of infection to other susceptible hosts. reservoir hosts do not get the disease carried by the pathogen or it is asymptomatic and non-lethal

A

reservoir host

20
Q

an organism which transmits the infection from an infected organism to a human or another organism

A

vector

21
Q

a host in which the parasite undergoes development before transmitting the parasite to another host; apply to definitive and intermediate hosts

A

biological vector

22
Q

a host in which no development of the parasite happen before transmitting the parasite to another host; apply to paratenic host

A

mechanical vector

23
Q

arthropods are the main vectors responsible for biological transmission - by biting the host

A

biological vector

24
Q

an animal that carries a pathogen from one host to another without being infected itself

eg. fly picks up pathogen from fecal matter and carries it on its body. fly transfers pathogen to food. person eats contaminated food and then gets sick.

A

mechanical vector

25
Q

risk factors:

poor hygiene and sanitation
limited access to clean water
crowded living environment
poor nutritional status
low immune status
age factor (too young and too old)
travelling
consume raw or undercooked meat or drink unboil water

A

gastrointestinal parasitic infections

26
Q
  • trophozoites secrete proteolytic enzymes to invade intestinal mucose: cause flask-shaped ulcer and bloody diarrhea (dysentery)
  • trophozoites spread via blood from large intestine to other organs: liver (amoebic liver abscess), peritoneum, lung, and brain

diagnosis:
detect cysts or trophozoites in stool or tissue biopsy

infectious stage: cyst

A
  • intestinal amoebiasis
  • extra-intestinal amoebiasis
27
Q
  • trophozoites attach to GI surface: malabsorption, inflammation, watery diarrhea, greasy diarrhea (fatty stool = steatorrhea; trophozoites attach on duodenal surface, impairing fat digestion and absorption)
  • infectious stage: cyst
  • diagnosis:
    detect trophozoites or cysts in stool, entero test
A

giardisis: gastrointestinal infection

28
Q
  • a non-invasive method to obtain intestinal fluid sample (upper GI tract) for detection of Giardia lamblia and other enteric pathogens
  • patient swallows a string with a weighted gelatin capsule
  • one end of string is taped to patient’s face
  • capsule dissolves in stomach and string is weighted at its distal end passes into duodenum
  • after 4hr, the string and any adsorbed gastrointestinal fluid (bile, blood, mucus) is withdrawn through the mouth
  • examine fluid under microscope for pathogens
A

entero test (string test)

29
Q

infect GI tract especially jejunum:
- mild/self-limited water diarrhea in normal person
profuse watery diarrhea, malabsorption in immunocompromised, very young or old individuals

infect respiratory tract
- pulmonary infiltrates with dyspnea

infectious stage: oocyst

diagnosis:
detect spherical oocysts using acid fast stain

A

cryptosporidiosis: gastrointestinal and respiratory tract infections

30
Q
  • watery diarrhea, anorexia, fatigue, weight loss, infection altered mucosal architecture and shorten intestinal villi due to inflammation
  • self-limited, chronic in immunocompromised people

infectious stage: oocyst

diagnosis:
detect spherical oocysts using acid fast stain

A

cyclosporiasis: gastrointestinal infections

31
Q
  • unspecific: diarrhea, abdominal discomfort, weight loss, nausea, vomiting, malaise
    -self-limited

infectious stage: oocyst

diagnosis: detect ellipsoidal-shaped oocysts in stool

A

cystoisosporiasis: gastrointestinal infection

32
Q
  • intracellular protozoa which reside at small intestine of humans
  • cause acute gastroenteritis: diarrhea, chills, vomiting
  • self-limited

infectious stage and transmission:
- ingest sarcocysts in undercooked beef: S. hominis
- ingest sarcocysts in undercooked pork: S. suihominis

diagnosis: detect oocysts in stool

A

intestinal sarcocystosis: S. hominis and S. suihominis

33
Q
  • ingested oocytes release sporozoites which pass through gut wall, infect endothelial cells of blood vessels and develop, then spread to muscles (skeletal, cardiac, neural tissue) to develop into sarcocysts
  • muscle pain, transitory oedema, fever

infectious stage and transmission: ingest oocysts of non-human Sarcocystis sp.

diagnosis: detect sarcocysts in muscles

A

muscular sarcocystosis: non-human sarcocystis sp. infections

34
Q
  • recurrent diarrhea alternating with constipation, rarely ulcerative colitis with bloody diarrhea

infectious stage: cyst

diagnosis: detect trophozoites and cysts in stools

A

balantidiasis: gastrointestinal infection

35
Q
  • watery diarrhea, abdominal pain, excessive flatulence

diagnosis: stool examination for cyst-like or vacuole form

A

blastocystosis: gastrointestinal infection

36
Q
  • by ingestion of spores in food or water
  • inhabit intestinal tract, causes watery diarrhea and abdominal pain
A

microsporidia

37
Q
  • found at vagina, vulva, and cervix of woman
  • found at prostate, seminal vesicles, and urethra of man
  • symptoms in woman: causes vaginitis, vulva, cervix inflammation, with frothy yellow or cream-colored vaginal discharge, vaginal itching, painful urination
  • symptoms in man: cause prostate, seminal vesicles, and urethra inflammation, with a thin, white urethral discharge, pain after ejaculation, painful urination

diagnosis: detect pear-shape flagellates in vaginal or prostate discharge

A

trichomoniasis: sexually transmitted disease