helminths Flashcards
Many helminths undergo part of their life cycle
outside of the human host
Helminths:
Some are transmitted only from ______
Others are capable of _____ (e.g. strongyloidiasis)
Some are transmitted only from human to human (e.g. enterobiasis)
Others are capable of auto-infection (e.g. strongyloidiasis)
- Found predominantly in fecally contaminated soil
- Transmitted by fecal-oral route or by direct penetration of the skin
- Many species infect children in developing countries, leading to malnutrition, growth retardation and cognitive deficits
nematodes- round worms
Ascariasis: Clinical Presentation
(mos)often asymptomatic unless obstruction or perforation due to large burden of worms; can cause malnutrition
Intestinal phase:
Ascariasis: Clinical Presentation
(mos-yrs)migrate into biliary tree causing cholangitis, cholecystitis, hepatic abscesses
Hepato-biliary phase:
Ascariasis: Clinical Presentation
wks-mos) hypersensitivity pneumonitis (Loeffler’s
Migratory phase:
ascariasis diagnosis and treatment
diagnosis is through the passage of eggs or worms and albendazole as the treatment
Human disease only: passed from human to human (usually via children)
Very common in cosmopolitan areas in temperate climates
Eggs laid in perirectal area, child scratches area then sucks thumb or contaminates food with the eggs
Eggs hatch in ileum, worm migrates to anus to lay eggs
Causes pruritis ani, perianal eczema; insomnia
pinworm
pinworm treatment
treat the whole family. use albendazole
stronglyloides difference to other helminths in the infection phase?
what could we see?
what develops in the setting of immunosuppression?
they hatch inside you and leads to autoinfection
- what could we see?–>we see mild eosinophilia
- what develops in the setting of immunosuppression?–> hyperinfection
treatment of strongyloides
ivermectin
Complex developmental cycles involving snails and humans or other mammals
Can be acquired by ingestion or by penetration of intact skin
Host tissue is ingested via suckers
trematodes- flatworms
Infection is acquired through the skin while bathing in fresh water
Similar life cycles and acute disease; chronic disease and long term consequences are different for each species but it is the eggs that cause the issue
trematodes- schistosoma
Schistosomiasis: clinical manifestations
(hours) pruritic papular rash after swimming, “swimmer’s itch”
Cercarial dermatitis:
Schistosomiasis: clinical manifestations
(1-2 mos) fever, chills, headache, LAD, HSM, eosinophlia; due to adults releasing eggs into tissues
Acute schistosomiasis (Katayama fever):
pipe stem fibrosis
it is the chronic disease we see with shictosomiasis and it is due to the repeated exposure/infection reaction to eggs
this occurs in the liver
dults migrate through portal system; eggs migrate through intestinal wall, embed in it or are swept back into portal system
Causes blood in the stool; pipe stem (periportal) fibrosis; portal HTN
S.masoni
Mao’s troops unable to launch amphibious assault on Taiwan due the development of Katayama fever while encamped on the Yangtze river
Similar to Mansoni
Worst of the 3, largest numbers of eggs with extensive granulomas
S. japonicum
Ancient Egyptians believed manhood was heralded by blood in the urine
Eggs laid in venous plexus of bladder, migrate through bladder wall or embed
Causes hematuria, recurrent UTIs; increased risk of squamous cell carcinoma of the bladder
S. Hematobium
what type of cancer do we see in shistosomiasis
bladder cancer
diagnosis of shistosomiasis and treatment
serology and treatment is praziquantel
Flat segmented worms composed of a head (scolex) and a series of segments (proglottids)
They absorb nutrients from the host’s gut through their tegument
Adult ones usually do not cause significant pathology in the human intestine
But when humans serve as intermediate hosts they can cause significant morbidity
cestodes: tapeworms
tapeworm transmission
poorly cooked pork
taeniasis
same as tapeworm but in beef
taeniasis treatment
praziquantel
Cysticercosis
it is when we eat the eggs of the tapeworm and it migrates to the muscles, brain and eyes
diagnosis of Cysticercosis and treatment
CT/MRI and albendazole. steroids and antiseizure (if brain spread)
Echinococcus: Hydatid Disease
dog tapeworm
Echinococcus: clinical presentation
liver (65%) and lung (25%) affected with cysts growing and evading immune response over the years
hydated diagnosis and treatment
imaging
for hepatic cysts- PAIR
for multiple cysts- surgical
+ albendazole
anti-parasite drugs MOA
act by paralyzing worms
