B3-089 Helminth Infections Flashcards
round worms
nematodes
tapeworms
cestodes
flukes
trematoda
platyhelmithes
trematoda & cestoda
aschelminthes
nematoda
largest group of helminths infecting humans
nematodes
life cycle involves an insect
filarial nematode
ocassionally transmitted to humans but humans are a dead end host
zoonotic nematodes
pinworm
enterobius vermicularis
pin worm females are cream colored and have __________ tails
sharply pointed tails
clear, thin shelled ovoid eggs flattened into a D shape
enterobius vermicularis
why should you treat all family members for enterobius vermicularis?
the eggs remain viable for days so reinfection is common
nocturnal pruritis around anus
enterobius vermicularis
treatment for enterobius vermicularis
mebendazole
diagnosis of enterobius vermicularis
anal cellophane tape test
no vector no incubation
enterobius vermicularis
trichuris trichiura
ascaris lumbricoides
the hookworms
strongyloides stercoralis
what do these have in common?
nematodes that require soil incubation prior to becoming infective
**puts populations with unclean water, inadequate sanitation, and poor hygiene at risk
whipworm
trichuris trichiura
adults are thin/threadlike anterior that embeds in the intestine and bulbous posterior that contains eggs
trichuris trichiura
thick shell eggs with translucent knob ends
trichuris trichiura
for most helminths, low burden is associated with what symptoms
asymptomatic
high burden can cause growth retardation, colonic mucosal damage, blood loss, anemia
rectal prolapse is a severe complication
trichuris trichiura
treatment of trichuris trichiura
mebendazole
improve sanitary conditions
diagnosis trichuris trichiura
eggs in stool
mild eosinophilia
ascaris lumbricoides
the hookworms
stronglyoides stercoralis
have what in common?
nematodes that have a pulmonary migration stage
intermediate burden may cause a hypersensitivity reaction to pulmonary migration and Loeffler’s syndrome
ascaris lumbricoides
heavy burden causes obstruction of appendix, bile, pancreatic duct, intestine, abdominal pain, malabsorption
ascaris lumbricoides
treatment ascaris lumbricoides
mebendazole
Loeffler’s syndrome is characterized by
eosinophilia, O2 desaturation, migratory pulmonary infiltrates, larvae in sputum
ascaris lumbricoides diagnosis
eggs in stool
elliptical, rough/mamillated thick walled eggs. viable up to 6 years
ascaris lumbricoides
hookworms
strongyloides stercoralis
what do these organisms have in common?
nematodes that cause cutaneous infections
which hookworm has cutting plates
necatur americanus
whick hookworm has teeth
ancylostoma duodenale
seen in warm, wet environments where people walk shoeless
hookworms
symptoms include: ground itch, Loeffler’s syndrome, peripheral and gut eosinophilia
hookworms
heavy burden causes iron deficient anemia, hypoalbuminemia, epigastric pain, abnormal peristalsis, mortality in infants
hookworms
treatment hookworms
mebendazole
heavy burdens of hookworms can lead to
cardiac insufficiency and mental stunting of children due to blood loss at the attachment site
thin shelled eggs
hookworm
diagnosis of hookworm
eggs in feces
eggs pass in cat/dog feces, larvae hatch in soil, larvae penetrate skin
zoonotic hookworms
pruritic, raised, red, serpiginous track in dermis
southern US atlantic and gulf states
cutaneous larval migrans caused by zoonotic hookworm
has auto-infection cycle
strongyliodes stercoralis
female conceives parthenogenetically
strongyliodes stercoralis
ground itch
loeffler’s
abdominal pain, diarrhea
urticarial rash with Larva currens
strongyliodes stercoralis
disseminated hyperinfection:
immunosuppression
abdominal pain
enterocolitis
shock
recurrent Gram negative bacteremia
strongyliodes stercoralis
treatment: strongyliodes stercoralis
ivermectin
larva currens
red, raised, serpiginous lesions on buttocks and lower back
diagnosis strongyliodes stercoralis
larvae in stool (no eggs)
adult worms in aspirate/jejunal biopsy
trichinella spiralis
anisakis
toxocara
what do all these organisms have in common?
zoonotic nematodes
**humans are accidental and dead-end hosts
caused by macroscopic adult nematodes and their offspring,
lifecycle includes an insect vector,
dead worm is not expelled (inflammatory response)
filariasis
distribution: wuchereria bancrofti
tropical asia, africa, americas
vector: wuchereria bancrofti
culex, anopheles mosquito