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45 terms

Unique or Misc. Characteristics - Parasitology Final

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Cryptosporidium parvum - oocysts stain red against blue background
acid fast positive
Cyclospora cayetanensis - stain light pink to dark red, or not at all
acid fast variable
Cyclospora cayetanensis (C. parvum is not)
oocyst wall is autofluorescent when vied bu UV microscopy
Cyclospora cayetanensis
common in AIDS patients, but not limited to immunocompromised persons
Cryptosporidium parvum
illness from this is self-limiting in immunosufficient persons, however, immunodeificient persons will experience severe diarrhea, fever, nausea, abdominal discomfort & weight loss. AIDS patients are very susceptible.
Cyclospora cayetanensis
modified safranin stain
diagnostic stage of Cryptosporidium parvum
mature & immature oocyst
diagnostic stage of Cyclospora cayetanensis
oocyst
diagnostic stage of Isospora belli
immature oocyst
oocyst
infective stage of Cryptosporidium parvum, Cyclospora cayetanensis, Isospora belli
modified safranin stain
developed by CDC
uses microwave oven to heat stain
permits oocyst to stain uniformly & consistently
Isospora belli
oppurtunistic infection in AIDs patients
Isospora belli, sporoblasts in oocyst stain deep red; may also see sporocysts
acid fast positive
Toxoplasma gondii
definitive host is a cat
serological test, important in detecting toxoplasmosis in neonates (IgM antibodies)
toxoplasma gondii diagnosed by what test?
oocyst
infective stage of toxoplasma gondii
Isospora belli
eosinophilia may occur even in asymptomatic patients, charcot leyden crystals frequently seen
toxoplasma gondii
can cause death of fetus
serum from patient who has has toxoplasmosis affects t. gondii organisms so they lose their affinity for methylene blue stain (not routinely used in clinical labs- older method to diagnose)
Sabin-Feldman dye test
Pneumocystis jiroveci
causative agent of atypical interstitial plasma cell pneumonia (PCP)
Pneumocystis jiroveci
silver stain
Enterocytozoon bieneusi
most common microsporidian causing enteritis in AIDS patients
characteristic feature of Enterocytozoon bieneusi
spores containing a polar tubule, which is an extrusion mechanism for injecting infective spore contents into host cells; spores are very resistant
definitive diagnosis for Enterocytozoon bieneusi
electron microscope often required to recognize & identify organisms (not practical in clinical lab)
Enterocytozoon bieneusi
diagnosed by modified trichome stain, serological testing not useful with AIDS patients (poor antibody response)
yes, 4-6 um
is cryptosporidium parvum acid fast? size?
variable, 8-10 um
is cyclospora cayetanesis acid fast? size?
yes
is isospora belli acid fast?
not usually
is enterocytozoon bieneusi acid fast?
Blastocystis hominis
strictly anaerobic & normally required bacteria for growth
Blastocystis hominis
protozoan of unclear classification
Blastocystis hominis
characterized by a large central body, that usually resembles a vacuole
Blastocystis hominiss
organism should be quantitated (rare, few, moderate, or many)
list 3 flagellates that are pathogenic
Trichomonas vaginalis
Dientamoeba fragilis
Giardia lamblia
List 3 flagellates with NO cyst stage
Trichomonas vaginalis
Trichomonas hominis
dientamoeba fragilis
specific gravity of zinc sulfate flotation technique
1.18
L. tropica major
wet or rural cutaneous leishmaniasis (leishmania tropica complex)
produces wet sore; lower limbs
found in rural areas
L. tropica minor
dry or urban cutaneous leishmaniasis
produces dry sore; facial area
found in urban areas
Montenegro skin test
diagnosis of Leishmania Tropica complex , delayed hypersensitivity reaction to a suspension of killed promstigotes administered intradermally; not species specific
definitive diagnosis of leishmania tropica complex
demonstration of amastigotes in tissues or promastigotes in culture
L. braziliensis complex
results in progressive ulceration & erosion of mucosal linings
L. mexicana complex
painless lesions usually occur singly; predominantly on ear; often heals spontaneously.

Chiclero ulcer - development of nodules which resemble leprosy
Death usually occurs due to secondary infection/malnutrition
Sexual
Asexual (except P. falciparum)
Erythrocytic phase
Exoerythrocytic phase - primarily occurs in the liver
life cycle of plasmodium species
trophozoite
schizont with merozoites
merozoites from ruptured schizont
diagnostic stages of plasmodium species
tetrad formation "maltese cross"
no malarial pigment
RBCs not enlarged or pale
no stippling
no malarial pigment
how babesia differs from plasmodium