Parasites - Helminths Flashcards
what do helminths most commonly cause?
eosinophilia**
-IgE helps clear them
Ascaris lumbricoides
-Giant Roundworm
- larvae travel to lungs –> migrate up trachea –> swallowed
- intestinal OBSTRUCTION***
- Loeffler pneumonitis*** from eosinophilic rxn in lungs
- eggs seen on stool exam***
Pinworm - Enterobius vermicularis
-aka “seatworm”
- most common intestinal worm infection
- migrate to perianal skin to lay eggs at night
- perianal pruritis***
- scotch tape test***
- flattened edge with eggs***
Hookworm - Necator americanus, Ancylostoma duodenale
-US
- larvae in soil penetrate skin
- lungs –> bronchi –> swallowed
- creeping eruption (cutaneous larva migrans)***
- anemia
Threadworm - Strongloides sterocalis
-southeast US
- larvae in soil penetrates skin
- lungs –> bronchi –> swallowed
- migrate to duodenum –> duodenitis (GI symptoms)
- increase risk with HTLV-1*
Trichinosis - Trichinella spiralis
- eating undercooked meat and larvae migrating to muscles***
- pork, walrus, bear meat containing encysted larvae
-curly S on smear** (pic on test)
Guinea Worm - Dracunculus medinensis
- consuming unpurified water containing copepods (contain larvae)
- migrates to skin
-extract worm slowly (matchstick)
Onchocerca volvulus - Filarial Worms
- River blindness**
- microfilariae enter skin and eyes
- transmitted by blackfly*** or buffalo gnat
- highly oxygenated water (fast moving stream/rivers)
- Africa, latin america, Middle east
Loa loa - Filarial worms
- transmitted by deer fly and mango fly
- worm found in eye, but RARELY causes blindness***
- calabar swellings*
- Africa, India
Lymphatic Filariasis
-Wuchereria bancrofti, Brugia malayi, Brugia timori
- transmitted by mosquito bites
- tropical parasites*
- larva affect lymphatic system (obstruct flow)**
- lymphedema, elephantitis**
Toxocara canis/cati
-Dog and Cat roundworm
-MULTIPLE systems affected** –> migrate through body
Cestode (tapeworm)
-longer than Ascaris, but does NOT cause obstruction***
Taeniasis***
- Taenia solium (pig)
- Taenia saginata (cow)
-tapeworm
- can ingest eggs
- can ingest larva in raw meat
- “radial tire” eggs that attach in gut
- solium (pig)
- BAD
- ingest EGGS (cysts) –> mobile larva –> cysticerocosis** –> neurocysticercosis and seizures**
- “swiss cheese brain”** - saginata (cow)
- ingest larva from meat –> NO cysticerocosis
- less mobile larva
Echinococcus granulosus
-dog tapeworm
- tapeworm
- hydatid cyst*** in brain or kidneys
- fluid/parasites in hydatid cyst is allergenic –> anaphylactic shock if rupture***
Diphyllobothrium latum
- tapeworm
- eat infected fish
- Anemia and B12 deficiency –> megaloblastic anemia***
- hypersegmented neutrophils
- CNS issues
