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62 Cards in this Set

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  • Back
what are the next three roundworms?
Describe the life cycle identical between ascaris, hookworm and strongyloides.
-Larvae are in blood/lymphatics.
-Larvae migrate to the lungs, alveoli, ascend respir. tract; cough up/swallow larvae into small intest. adults develop, fertilize, and ova laid there.
after ova are laid in intestine what happens in Hookworm?
-Pass to feces, then to soil.
-Rhabditiform larvae hatch, feed on organic debris in soil.
-Filariform larvae develop
-Filariform penetrate human skin and get into bloodstream.
what's the infectious stage of hookworm?
-filariform larvae
after ova are laid in the intestine, what does Ascaris do then?
-pass into feces/soil.
-embryonated ova are ingested by humans, pass to small intestine.
-rhabditiform larvae hatch
-they penetrate intestinal wall
after ova are laid in the intestine, what does Strongyloides do then?
-Rhabditiform larvae hatch in intestine.
-They pass into feces, then soil.
Filariform larvae develop and penetrate human skin.
Which two have similar entrance ways into human hosts?
strongyloides and hookworm - both penetrate human skin.
what is an alternate autoinfection path of strongyloides?
-instead of developing outside of intestine, filariform larvae devel. inside.
-then penetrate intestine, and migrate to lungs.
what disease does Ascaris lumbracoides cause?
what is ascaris' common name?
where is Ascaris found?
warm, moist climates, esp in the Appalachian mountains
What are the hosts of aScaris?
humans - both children and adults.
how long are ascaris adults?
30 freakin centimeters! holy cow
-remember the gross white mass of wormy worms
how big are the ascaris ova?
about 60 x 45 u
what additional morphology is seen of ascaris ova?
three stages - -corticated/decorticated fertile
how big are ascaris ova that are
-corticated fertile
-decorticated fertile
Corticated and de are 45x35 to 70x50

Infertile is 90 x 40
whats the main morphologic difference seen between ascaris fertile and infertili ova?
Fertile = double hyaline shell, bile-stained, embryo does not extend to the shell.
Infertile = thin, SINGLE hyaline shell, amorphous mass extends all the way out to it.
Now we're talking disease;
How does symptomology in Ascariasis vary?
By infection strength - light, heavy, and very heavy.
What are symptoms of ascarias -light infection
-very heavy
light: May be asymptomatic
heavy: abdom. pain, allergic symptoms (asthma, swollen lip)
v. heavy: intestinal obstruction of adults that resists peristalsis
how is ascariasis diagnosed?
(3 signs)
1. presence of ova in the feces.
2. possible eosinophilia
3. possible adults in stool/vomit/nasal cavity
how is ascariasis treated?
pyrantel pamoate
what does pyrantel pamoate do?
relaxes the muscles of adults so they can't resist peristalsis.
what are the two types of HOOKWORM?
what are their common names?
-Necator americanus
-New World hookworm
-Ancylostoma duodenale
-Old World hookworm
what are three names of diseases caused by hookworm?
-hookworm infection (profound)
Where is hookworm infection found?
-endemic in chinese elderly fem.
-a lot in Asia
what are the hosts of hookworm?
-Humans mostly
-sometimes other primates
what is the hookworm ovum very similar to?

what 3 things differentiate it?
decorticated ascaris ovum

1. ascaris has a DOUBLE hyaline sheath, hookworm's is single.
2. Hookwm is not bile-stained b/c its shell wont absorb it.
3. Hkwm has a 2-8cell embryo
what's less mature, rhabditiform or filariform larva?

what's the purpose/form of each?
Rhabdit = feeding form
-has large, bulging esophagus and open buccal cavity
Filarif = infective
-has small esoph, buccal cav enclosed in cuticle.
What is the size of
-Hookworm rhabditiform larva
-Hookworm filariform larva
Rhab: 250 u
Filar: 400-600 u
what are 3 stages of a hkwm inf?
what are the symptoms in each?
1. Skin penetration - local erythema, severe itching, often seen on the feet.
2. Larva lung migration: allergy symptoms
3. Adult in sm. intest: abdominal pain, diarrhea, Fe deficiency anemia
how is hookworm treated?
-Pyrantel pamoate
What is Trichostrongylus?
A very very rare human parasite.
OVa is similar to hookworm, but a bit longer and has multiple cell divisions per embryo (not 2-8).
What is the actual name for threadworm?
Strongyloides stercoralis
What are 2 names for the disease caused by S. stercoralis?
-Cochin-china diarrhea
what is the geographic distrib of strongyloides stercoralis?
similar to hookworm - east, in asia/china, everyhwere.
what are the hosts of s. stercoralis?
What is the ovum of S. stercoralis similar to?
Hookworm - identical in fact.
How do you know if you've got S. stercoralis or hookworm?
-Hookworm is id'd by presence of ova in feces
-S. stercoralis is id'd by the presence of LARVAE in feces.
what's the pneumonic for remembering strongyloides' characteristics?
on what basis are hookwrom and stercoralis rhabditiform larva diffntiated?
-Buccal cavity
-Genital primordium
What are the characteristics of hookworm and s. stercoralis
-Buccal cavity
-Genital primordium
Hookworm: long, small, pointy

Strongyl: short, large, blunt
what's the tail diffnc between hkwm/strongyl filariform larvae?
Hookworm: pointed tail
Strongyl: slit tail
In what patients is strongyloides forced into autoinfection?
patients on immunosuppressant therapy - not AIDS patients.
What are the 3 stages of strongyloidiasis?
-penetration of skin
-larval lung migration
-adult in small intestine
what symptoms develop after adults develop in sm. intestine?
-v. DRAMATIC inflamm response
-abdominal cramps
-diarrhea w/ mucus
how is strongyloidiasis diagnosed?
-rhabdit larvae in stool
-ova in duodenal intubation spec
-eosinophilia maybe
-anemia maybe
how is strongyloides treated?
MUST USE thiabendazole, not the others.
what nematode larvae is charactized by its tendancy to migrate from lymphatics to striated muscle?
trichinella spiralis
where do humans get trichinosis from?
ingesting undercooked pork meat.
where geographically is trichinosis found?
what are the hosts of trichinella?
how do you identify trichinella spiralis morphologically?
by the larva in muscle cells.
never see adults, and they don't have any ovum
how do trichinella reproduce?
moms give birth to little baby trichinellas - no ovum
what's the life cycle of trichinella?
-hogs have it, humans ingest their muscles.
-the larvae get into the small intestine, develop into adults.
-adults fertilize, females deposit larvae in lymphatics
-larvae enter blood, go to striated muscle and encyst.
What are the 3 stages of trichinosis infection?
1. Adult invasion of sm. intest
2. Migration of larvae
3. Encystation
What symptoms are seen in the adult stage of inf?
nausea, diarrhea, abdom pain, but pretty vague - not diagnostic.
what symptoms of trichinosis are seen during larval migration?
fever - consistent, days
periorbital edema - larvae around the eyes
-muscle pain
-pneumonia/allergic response
-petechial lesions in skin hemorrhage
what are 4 ways trichinosis is diagnosed?
1. Symptoms - during stages
2. Muscle biopsy
3. WBC diff
4. Serological testing
what is seen in the wbc diff for trichinosis?
-general leukocytosis
what 4 serological tests are done for trichinosis?
latex agglutination
fluorescent antibody
how is trichinosis treated?
nothing's very good
mebendazole if anything
how is trichinella prevented?
cook pork well
freeze it
don't use same meat grinder as for beef.