Protozoa I Flashcards
______ = one that requires a temporary period as a parasite (mosquito, tick, etc.)
Temporary parasite
What is the most common clinical form of Entamoeba histolytica amoebiasis? How does it look?
- colitis
- flask-shaped ulcers in the muscularis layer of the large intestine mucosa
______ = insects, ticks and mites which either are parasitic or transmit parasites as vectors
Arthropods
_______ = an organism that may resort to parasitic activity, but does not absolutely rely on any host for completion of its life cycle
Facultative parasite
Which is larger: metazoa or protozoa?
metazoa
_____ = Both partners benefit.
Mutualism
How is giardiasis from Giardia lamblia diagnosed?
- cysts in formed stools OR
- cysts or trophozoites in liquid stools
What is the cause of primary amebic meningoencephalitis (PAM) (the “brain-eating” ameba) that is typically lethal?
Naegleria fowleri
Commensalism = ______
Sharing the table. One partner benefits but the other is not hurt.
______ = live within the body and tissues of their hosts
Endoparasite
_____ = an organism (often an arthropod) that is responsible for transmitting the parasitic infection
Vector
What does Naegleria fowleri cause?
- primary amebic meningoencephalitis (PAM) (the “brain-eating” ameba)
- *** typically lethal
______ = not suitable for parasite development, but severe disease might ensue nonetheless
Accidental host
How is Acanthamoeba spp diagnosed?
microscopic examination of stained smears of biopsy specimens (brain tissue, skin, cornea) = positive for trophozoites and cysts
What does Acanthamoeba spp cause?
- Granulomatous amebic encephalitis, particularly in immunosuppressed patients
- Keratitis, particularly associated with corneal injuries, and is assoc. with wearing contact lenses
_____ = a host that harbours the adult or sexually mature parasite and in which the parasite reproduces sexually
Definitive host
Paratenic or transport hosts = _____
one in which no parasite development occurs (carries)
Mutualism = ______
Both partners benefit.
______ = live on, but not in their hosts
Ectoparasite
What is the infectious dose of Giardia lamblia?
less than 10 cysts
_____ = any disease or infection that is naturally transmissible from vertebrate animals (often vertebrates) to humans. Animals thus play an essential role in maintaining the infections in nature.
Zoonosis
Host specificity = _____
the degree to which a parasite requires a particular host
What is a trophozoite?
a growing stage in the life cycle of some sporozoan parasites, when they are absorbing nutrients from the host (the multiplying, mobile form)
Intermediate host = ______
one that harbours the immature or asexual stages of the parasite and where asexual reproduction often occurs
Who are the high risk hosts of Entamoeba histolytica?
- homosexual men
- institutionalized pts/nursing home pts/day care kids
- travelers
- recent immigrants
Dx?
- Infection of small intestine that causes diarrhea/ dysentery (severe in AIDS and immunocompromised)
- fecal-oral transmission
- intracellular parasite
Cryptosporidiosis from Cryptosporidium spp.
Symbiosis = ______
any two organisms living in close association, commonly one living in or on the body of the other (contrast with free living)
Dx?
- Watery diarrhea can be accompanied by dehydration, weight loss, abdominal pain, fever, nausea and vomiting
- also found in other digestive tract organs, the lungs, and possibly conjunctiva
Cryptosporidiosis from Cryptosporidium spp.
What is the tx for giardiasis from Giardia lamblia?
metro
Dx?
- foul smelling, greenish vaginal discharge
- itching, burning
- strawberry cervix
Trichomoniasis from Trichomonas vaginalis
_____ = one in which no parasite development occurs (carries)
Paratenic or transport hosts
______ = the degree to which a parasite requires a particular host
Host specificity
Name 4 parasitic diseases that have a high mortality rate.
- Malaria
- Sleeping Sickness
- Chagas
- Visceral Leishmaniasis
Accidental host = ______
not suitable for parasite development, but severe disease might ensue nonetheless
Zoonosis = ______
any disease or infection that is naturally transmissible from vertebrate animals (often vertebrates) to humans. Animals thus play an essential role in maintaining the infections in nature.
_______ = Sharing the table. One partner benefits but the other is not hurt.
Commensalism
Temporary parasite = ______
one that requires a temporary period as a parasite (mosquito, tick, etc.)
_____ = unicellular eukaryotes
Protozoa
Nematodes = elongated worms with rigid cuticula (_____)
roundworms
What kind of exudate is found in the liver of those with Amoebiasis from Entamoeba histolytica?
“anchovy paste” exudate
How is Naegleria fowleri diagnosed?
microscopic examination of CSF + for motile trophozoites
How is Cryptosporidiosis from Cryptosporidium spp. diagnosed?
oocycts on acid-fast stain
What is the tx for Trichomoniasis from Trichomonas vaginalis?
metro (for pt and prophylactically for the partner)
Which is larger: a nematode or malaria?
nematode
______ = one that harbours the immature or asexual stages of the parasite and where asexual reproduction often occurs
Intermediate host
How is Entamoeba histolytica diagnosed?
look for cysts in feces
What are the s/s of Giardia lamblia?
- diarrhea, abdominal pain, bloating, gas
- foul-smelling, greasy stools that tend to float
- nausea, and vomiting
- *** think FAT-rich GHIRARDELLI chocolates for FATTY stools of GIARDIA***
Ectoparasite = _______
live on, but not in their hosts
______ is the only ciliate that infects humans.
Balantidium coli
Endoparasite = ______
live within the body and tissues of their hosts
______ = “Any two organisms living in close association, commonly one living in or on the body of the other, are symbiotic, as contrasted with free living.”
Symbiosis
_____ = One partner harms or lives on the expense of the other (host).
Parasitism
______ = flatworms that include flukes and tapeworms (dorsoventrally flattened)
Platyhelminthes
_____ = elongated worms with rigid cuticula (roundworms)
Nematodes
Dx?
- extracellular parasite that adheres to epi
- sexual or genital contact transmission
- no cysts
Trichomoniasis from Trichomonas vaginalis
Definitive host = ______
a host that harbours the adult or sexually mature parasite and in which the parasite reproduces sexually
Dx?
- extracellular parasite of the small intestine
- fecal-oral transmission via cysts
- the most common cause of non-bacterial diarrhea in the US
Giardia lamblia
Dx?
- extracellular parasite but can become invasive –> blood -> liver, lungs –> abscesses
- Toxic to cells- causes lysis
- fecal-oral transmission of cysts –> large bowel infection –> diarrhea (bloody), dysentery, colitis, RUQ pain
Amoebiasis from Entamoeba histolytica
Reservoir host = _____
an animal that harbours the same species of parasites as man and constitute a source of infection to him. Serves as an alternate animal host from which the parasite can be transmitted to humans (zoonosis) or domestic animals
Nematodes = _____ with _____ (roundworms)
elongated worms with rigid cuticula
How is Trichomoniasis from Trichomonas vaginalis diagnosed?
trophozoites on wet mount antigen detection PCR
Host = ______
an organism that harbours or nourishes another organism (parasite).
Facultative parasite = _____
an organism that may resort to parasitic activity, but does not absolutely rely on any host for completion of its life cycle
_______ = a parasitic organism that cannot complete its life-cycle without exploiting a suitable host
Obligate parasite
How do Entamoeba histolytica multiply? Where?
binary fission in the small intestine
Platyhelminthes = _______ that include (dorsoventrally flattened)
flatworms that include flukes and tapeworms
______ = an animal that harbours the same species of parasites as man and constitute a source of infection to him. Serves as an alternate animal host from which the parasite can be transmitted to humans (zoonosis) or domestic animals
Reservoir host
Platyhelminthes = flatworms that include flukes and tapeworms (______ flattened)
dorsoventrally
What is the clinical presentation of Giardia lamblia?
asymptomatic –> severe diarrhea, malabsorption
A ______ is an organism which lives upon or within another living organism at whose expense it obtains some advantage.
parasite
Obligate parasite = ______
a parasitic organism that cannot complete its life-cycle without exploiting a suitable host
Vector = _____
an organism (often an arthropod) that is responsible for transmitting the parasitic infection is known as the vector (typically reserved for cases where development ensues in the organism)
Balantidium coli is the only _____ that infects humans.
ciliate
Dx?
- diarrhea, abdominal pain, bloating, gas
- foul-smelling, greasy stools that tend to float
- nausea and vomiting
- giardiasis from Giardia lamblia
- *** think FAT-rich GHIRARDELLI chocolates for FATTY stools of GIARDIA***
What form of Entamoeba histolytica is infectious? Why?
the cyst bc it’s hardy/resistant
Which is larger: fungi or protozoa?
protozoa
_____ = an organism that harbours or nourishes another organism (parasite).
Host
Protozoa = ______
unicellular eukaryotes
What is a major risk factor for parasites?
poverty
What causes:
- granulomatous amebic encephalitis, particularly in immunosuppressed patients
- Keratitis, particularly associated with corneal injuries, and is assoc. with wearing contact lenses?
Acanthamoeba spp
What is the tx for Cryptosporidiosis from Cryptosporidium spp.?
nitazoxanide in immunocompetent hosts
Parasitism = ______
One partner (the parasite) harms or lives on the expense of the other (host).
What is the tx for Amoebiasis from Entamoeba histolytica? What about asymptomatic carriers?
active = metro carriers = iodoquinol
Why is Giardia lamblia so hard to control?
Zoonosis - Domestic dogs, beavers, elk, deer may serve as hosts
Arthropods = ______
insects, ticks and mites which either are parasitic or transmit parasites as vectors
This is the growing stage in the life cycle of some sporozoan parasites, when they are absorbing nutrients from the host (the multiplying, mobile form).
trophozoite
