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64 Cards in this Set

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  • Back
What does Phylum Apicomplexa consist of?
The intestinal coccidia
what are the 4 species of intestinal coccidia?
1. Blastocystis hominis
2. Isospora belli
3. Cryptosporidium parvum
4. Cyclospora cayetanensis
what are general characteristics of coccidia?
-used to be sporozoa
-have a sexual stage in the life cycle - oocysts
-most sever inf. in immunocomp.
How big is the blastocystis hominis cyst?
usually about 10u, can range from 5-32 though.
-Has three sporocysts surrounding surrounding central pallor
What is the significance of Blastocystis hominis?
Commensal in 10-16% of people, but only causes diarrhea if there are >5 per field
-Normal to find in a specimen.
What sets B. hominis apart from the other 3 coccidia?
It's the only one with a cyst; the other three are oocysts.
What is the morphology of Isospora belli?
-Oocyst that's 25-35 x 10-15u
-has 1-2 sporocysts
-may stain acid fast
Where is Isospora belli significant?
-Endemic in brazil, Columbia and Chile.
-Asymptomatic, may cause diarrh.
-Causes dysentary in immunocomp.
what is the most significant of the coccidia?

What does it cause?
Milwaukee's very own claim to fame, Cryptosporidium parvum

Causes: Cryptosporidiosis
Where is Cryptosporidium found?
Worldwide in drinking H2O and swimming pools - oocysts resist chlorine.
What are the hosts of Crypto parvum?
Humans and other animals
What is the morphology of cryptospordium?
IT'S TINY! 4-6u oocyst
Have to use acid fast stain to be able to see it - that's why it took forever to identify in 1993 outbreak.
What features are seen in the oocyst?
an Attachment organ, up to 4 sporozoites.
What are symptoms of Cryptosporidiosis, seen in three levels of the infection?
-Mild inf: flu-like symp.
-Acute inf: frothy, explosive diarrhea
-Chronic inf. may disseminate to other organs w/ 50% death rate.
What 2 bases is Cryptosporidium diagnosed on?
1. Morphological
2. Immunological
What two methods are used for morphological diagnosis of Cryptosporidium?
1. Sheather's sugar flotation
2. Modified acid fast stain
why are the two methods used?
Sheathers - concentrates the diarrhea, not ethyl b/c the oocyst is too light.
Mod AFstain so you can see it.
what conditions should you work under to identify cryptosporidium?
Biological safety cabinet!!!
What 2 medicines are used to treat cryptosporidium?
How is Cryptosporidium prevented?
1. H2O filtration
2. Good hygiene
What is cyclospora cayetanensis similar to, but how is it different?
Similar to Cryptosporidium, but bigger. 8-10u
Where is Cyclospora cayetanensis found and transmitted?
Found in Warm/moist climates
Waterborne - likes storage tanks
Guatamala rasberries
lettuce and basil
What are the hosts of Cyclospora cayetanensis?
Humans and maybe cattle
How is Cyclospora identified and diagnosed? what symptoms does i cause?
Very similar to Cryptosporidium for all, except bigger. Acid fast stain.
How is Cyclospora cayetanensis treated?
How is it prevented?
Bactrim is them put together
To prevent: Avoid contaminated water and wash your berries
What organism comprises the Tissue coccidia?
What subphylum is this again?
Subphylum Apicomplexa
Toxoplasma gondii
what disease does Toxoplasma gondii cause?

Where is it found?
What are the definitive hosts of T. gondii? Why?
Domestic or wild cats - they house the mature parasite
What are the intermediate hosts of T. gondii? Why?
Humans, rodents, cattle, others
They house the larval or sexually immature parasites but are necessary to lifecyle.
What testing is most important for diagnosing Toxoplasmosis?
What kind of parasite is seen for morphologically identifying Toxoplasma?
Tachyzoite - 3-6u
What type of parasite is Toxoplasma to humans?

What type of specimen is it seen in?
Obligate intracellular parasite.

Only can see in a biopsy or exudate from tissue.
What are 2 ways Toxoplasmosis can be transmitted to humans?
1. from Oocysts in cat feces

2. From Bradyzoites in raw meat
-Humans ingest them and macrophages phagocytize.
What's an important and concerning happening in the life cycle of toxoplasma?
Tachyzoites in blood can cross the placenta and enter the CNS of a fetus, causing congenital infection.
what are 3 types of Toxoplasma that humans can have?
1. Acquired toxoplasmosis
2. Congenital
3. Recrudescent
what symptoms are seen in acquired toxoplasmosis?
Mild, flu-like, might not know.
What symptoms of acquired toxoplasmosis are seen in IMMUNOCOMPROMISED?
Much more severe:
What is the most severe form of toxoplasmosis?

What tissues are affected?
CNS: mental retardation/seizures
Eyes: blindness
Blueberry muffin petechiae on forehead.
What is recrudesent toxoplasmosis?

What tissue is affected?
Infection that arises though the patient had it years earlier

Flares when immunity is compromised.
How is toxoplasmosis diagnosed?
Microscopic - tissue biopsy in histology lab

What 4 serological tests are used for diagnosing toxoplasmosis?
1. Indirect flouresc. Ab
2. Elisa
3. Torch panels
4. Ophthalmology exam
What is a TORCH panel?
TO = toxoplasma
R = Rubella
C = cytomegalovirus
H = herpes
All have smlar symptoms, so tests for them all.
How is toxoplasmosis treated?
Pyramethamin and SUlfandiazine, but you don't really need to know this Keren.
How do you prevent Toxoplasmosis?
Cook meat well
Don't go near cat poop
What phylum of Protozoa is not very well understood and has 5 genera you don't need to memorize?
Phylum Microspora
Who are Microsporidian infections seen in usually?
Immunocompromised, rare otherwise.
Who are usual hosts of microspora?
Humans, insects, animals
What is the morphology of Microscpora?
Small; 1-4u, seen with electron micrograph.
What 5 diseases do Microspora cause?
1. Enteritis, cholecystitis
2. Keratitis
3. Nephritis
4. Hepatitis, peritonitis
5. Sinusitis, pneumonitis
What is cholecystitis?
Inflammation of the gallbladder. Keratitis = corneal inflamm.
Conjunct = around the eye
How is Microsporan infection diagnosed?
-Acid fast stain (partially AF)
-Electron microscopy is best
What are the 4 Acid fast protozoa in Phylum apicomplexa and Microspora then?
Changing pace now..
What subphylum comprises Atrial Amoeba?
Subphylum Sarcodina (amoeba)
What 2 species are in subphylum Sarcodina?
1. Naegleria fowleri
2. Acanthamoeba
Where is Naegleria fowleri primarily found?
In lake bottoms in warm places like Florida.
How do you get Naegleria fowleri?
by diving to lake bottoms
What type of life cycle does N. fowleri have?
Trophozoites live in water
Get in nasal pssgs of humans
Penetrate cribiform plate
Enter brain, produce enzymes, turn brain to jelly.
What disease does Naegleria fowleri cause?
Primary amoebic meningoencephalitis
What are the symptoms of prim. amoebic meningoencephalitis?
-Blocked nose
-Severe frontal headache
-Nausea, fever
-Death in 4-5 days
Boy in florida got it... sad
How is N. fowleri diagnosed?
By finding trophs about 10-20u in spinal fluid CSF, along w/ RBCs and WBCs
How is N. fowleri encephalitis treated and prevented?
Amphotericin B
Don't swim in Florida
What is a very similar organism to N. fowleri?
Acanthamoeba - caused corneal infection in bball player cuz he didn't wash his contacts gross
What disease does Acanthamoeba commonly cause?
How is Acanthamoebiasis diagnosed?
Immunoflourescent Ab
Morphology - see an ameboid w/ a vacuole.