Parasites 2 Flashcards
Give examples of lumens, hook worm and tissue worm varieties of nematoda and their associated transmission route.
luminal: ascaris lumbricoides- egg via fecal oral
hookworm: Stronglyoides stercoralis- larva invade skin
tissue worm: Toxocara canis- egg via fecal/oral
What is the organism and transmission of pinworm?
Enterobius vermicularis resides in the adult colon and transmission is by direct person to person transmission via ingestion of eggs; commonly in daycare centers or in infected bed clothes (up to 3wks)
once eggs hatch in the intestine, the adults migrate to the colon
(gravid female emerges from anus to lay eggs (a LOT)
What are the symptoms, dx. and tx of pin worm?
symptoms of intense perianal itch, secondary infection due to scratching, restlessness, insomnia
confirm with scotch tape yes, observations of eggs
tx: pyrantel permeate, mebendazole, albendazole, thorough house cleaning
What is the organism and transmission of whipworm?
Trichuris trichina
humans are the only host and whip worm is spread by ingestion of embryonated eggs (not person-person) commonly when human waste is used as fertilizer
common in places where obligate soil stage is warm; hatched eggs migrate to the colon
What are the symptoms, dx, and tx of whipworm?
pathology in the degree of worm burden
low to moderate: usually none, bleeding, bacteria
high: disrupted colonic mucosa, bloody stool, prolapse, anemia
heavy burden in children leads to impaired growth/cognitive ability
dx. by eggs in stool, tx. 3d ivermectin, mebendazole or albendazole
some evidence for acquired immunity, hand wash, cook raw fruits and vegetables
What is the transmission and distribution of Ascaris lumbricoides?
very common infection of the upper intestine due to ingestion of eggs from soil; 25% of people infected world wide esp. in tropical and subtropical, US and south, requires maturation in soil
once in venous circulation, is brought to the lungs, coughed up and swallowed when infection
a result of human waste used as a fertilizer (humans are the definitive host)
Describe the pathology the accompanies ascariasis. How is it dx and tx.
usually low or moderate worm burden
heavy worm loads can lead to intestinal obstruction
stressed worms known to migrate to nose, ear, and through peritoneal body wall
chronic infection can lead to malnutrition with poor mental and physical development
allergic inflammation can occur with larval migration through the lungs
dx: eggs in stool; tx: mebendazol, albendazole or ivermectin
What are the organisms of hookworm and how is it transmitted.
Nectar americanus (Global) Ancylostoma duodenal (Asia)
located with the small intestine, humans are the only host and transmission occurs with, common in children and farmers that do not wear shoes
after skin infection, larvae migrate to the lungs, are coughed up and swallowed before maturing in the intestine; eggs in feces must mature in the soil
What are symptoms, dx. and tx. of hookworm?
initial pruritis at penetration sites, often between toes; exsanguination leading to anemia and decreased physical and mental development in children; bronchitis or other pulmonary symptoms possible with large worm load
dx by anemia na eggs in stool, tx. pyrantel permeate, albendazole and mebendazole
How is strongyloides transmitted?
filariform larvae penetrate skin directly from soil, or by auto infection
What are the symptoms, dx. and tx. of strongyloides?
chronic malabsorption, dysentery, rash of the buttocks, asthmatic pathology with prolonged/repeated infection
which is detected by staining of feces or sputum for worm, serology
treat all cases with ivermectin, thiabeazole
How is Trichinosis transmitted.
adults invade intestine, larvae invade muscle and transmission occurs due to raw/undercooked meat containing encysted larvae
humans are dead end hosts, meat eating mammals are the definitive hosts; larvae migrate via lymphatics and develop into encapsulated spiral
What are the symptoms of trichinosis? How is it dx and tx?
mild nausea, cramps etc from adult worms
localized inflammation occurs around an individual cyst with degeneration of muscle cel architecture (pain, weakness, cardiac and neural dysfunction and conjunctivitis)
eosinophilia, periorbital edema, myositis and fever can be confirmed with serological tests
tx. with mebendazole or albendazole and corticosterioids for symptoms
How is Toxocara canis transmitted?
adult worms are free in the upper intestine of dogs (definitive host) most commonly transmitted between puppies and children; eggs must develop in warm soils
in humans it is distributed in all tissues and larvae burrow through the intestine and wander for months (visceral larva migrans)
What are the symptoms, dx. and tx. for toxocariasis?
light infection: self limiting
heavy: can lead to severe necrosis in any location including liver, pulmonary and eyes; neurological symptoms as a result of visceral larvae migrans
asthmatic and immune hypersensitivity is common
no eggs in stool because infection does not progress to adults, ELISA can cross react with Ascaris
tx. with albendazole or mebendazole, corticosteroids for symptoms; DEWORM dogs
