Helminths Flashcards
Enterobius vermicularis
pinworm
most common in temperate zone
life cycle in humans; auto infection
gravid female migrates out of anus
local irritation and itching esp at night when eggs are laid
treat whole family –> reinfections are common
Tx with Pyrental Pamoate
Trichuris trichiura
whipworm
ingestion of fully embryonated eggs
heavy inf = ulceration and hemorrhage of cecal mucosa
can see rectal prolapse in children with heavy inf
may resemble IBD
see football shaped eggs in feces
Tx with Mebendazole
Ascaris lumbricoides
large roundworm ingestion of embryonated eggs eggs need to be outside of host for 2-3wks to become infective larva migrate to lungs to mature sensitive pt may dev asthma heavy inf = bowel obstruction
Necator americansus / Ancylostoma duodenale
hookworm
attach to intestinal lining and sucks blood
iron def proportional to worm burden
may see pneumonia and eosinophilia as worm migrates
can have dermal, pulmonary, GI, and hematologic dz
Strongyloides stercoralis
small roundworm
parasitic and free living form
filariform larvae –> skin –> lungs –> small intestine
autoinfection –> diff of rhabdiform to filariform
fatal hyperinfection in immuncomp
Trichinella spiralis
trichinosis eating bad pork --> encrysted larvae mature in intestines larvae --> muscle --> nurse cells --> destruction --> paralysis (PMN infiltrate) strong IgE response mycard and encephalitis lemon-shaped capsule
Toxacara
dogs and cats humans are incidental hosts --> kids playing in dirt Ocular larva migrans Visceral larva migrans (heavy inf) inner cities in US
Wuchereria bancroftii and Brugia malayi
mosquito vector
adults –> lymphatics –> elephantiasis
embryos –> microfilariae –> released when vector feeds
tropical pulmonary eosinophilia
Onchocerca volvulus
river blindness
black flies
see microfilariae in cornea and ant chamber
subcut nodules
Loa Loa
african eye worm
migrates through SC tissue –> not painful
mango flies
Dracunculus medinensis
Guinea worm extinct soon live in intestine gravid female migrates to skin --> ulcer use stick to wind it out release larvae when in contact with water crustaceans are interm host
Schistosomes (S. japonicum, hemtobium, and mansoni)
blood flukes
humans –> def host
snails –> interm hosts
snails –> cercariae –> motile and penetrate human skin –> mature in veins
produce LOTS of eggs that are deposited in tissues –> fibrosis –> main pathogenesis
TNF + egg prod
are covered in MHC
Taenia saginata
tapeworm head: scolex / has hooks hermaphrodite humans only def host cysticercus --> larva invade striated muscle can survive a LONG time
Taenia solium
humans both def and interm host
cysticercus can def in muscle, brain, liver, etc
can cause cerebral cysticercosis –> Hispanics and the SW US
Echincoccus granulosus
dogs def host humans are incidental small tapeworms fluid-filled cysts in over, lungs cysts contain hydatid sand
