Hookworm/Ascaris/Strongyloides, Trichinella

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what are the next three roundworms?: -Ascaris
-Hookworm
-Strongyloides
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?: ascariasis
what is ascaris' common name?: roundworm
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
-infertile
how big are ascaris ova that are -corticated fertile -decorticated fertile -infertile: 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 -heavy -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
mabendazole
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?: -ancylostomiasis
-necatoriasis
-hookworm infection (profound)
Where is hookworm infection found?: Everywhere
-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?: -Mebendazole
-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?: -Strongyloidiasis
-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?: -Humans
-Dogs
-Monkeys
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?: Short
Sexy
Slit
on what basis are hookwrom and stercoralis rhabditiform larva diffntiated?: -Buccal cavity
-Genital primordium
-Tail
What are the characteristics of hookworm and s. stercoralis -Buccal cavity -Genital primordium -Tail: 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
-nausea
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?: worldwide
what are the hosts of trichinella?: humans
hogs
rats
bears
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.
DEAD END.
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?: -eosinophilia
-general leukocytosis
what 4 serological tests are done for trichinosis?: flocculation
latex agglutination
fluorescent antibody
elisa
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.

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