Parasites Flashcards
(16 cards)
Trichuris trichiura (whipworm)
-intestinal nematode
-human ingest eggs-> larvae hatch in intestine->penetrate villi->must develop in cecum to adults (attach to cecum)
less than 100 worms=asymptomatic
-Symptomatic: colon damage, abdominal pain, vomiting, diarrhea, prolapsed rectum
-Southeastern U.S., poor sanitation, humid (hatch faster)
-BARREL-SHAPED EGGS in feces
-NO EONSINOPHILIA
-mebendazole, treat infected and wash vegetables
Ascaris lumbricoides
intestinal nematode
- human ingest eggs-> hatch in duodenum->must get to lungs->coughed up and then swallowed-> small intestine
- asymptomatic (20 worms)
- symptoms: hemorrhage, pneumonia, malnutrition, intestinal blockage in children (bolus)
- highest in children (5-9years)
- eggs in stool(resistance and viable for 6 yrs), larvae in sputum
- mebendazole/albendazole
Toxocara canis/cati (round worm of cats and dogs)
- dog and cat main host (crosses placenta)
- infection from eggs (ingest)-> can migrate anywhere
- Visceral larval migrans
- granuloma in the liver
- very high eosinophilia
- ocular larval migrans (larvae trapped in eye)
- test by ELISA for toxocara
- thiabendazole (s-l), laser to remove ones in eye
- scoop laws
Enterobius vermicularis (pinworm)
intestinal nematode
- live/mate in cecum
- migrates to anus to deposit eggs
- intense itch, scratch can re-infect
- children-> lack of sleep, poor appetite, nervousness
- US and canada, prisons, dorms, clothes/bedding can hold eggs
- scotch tape test-> ID eggs
- Pyrantel Pamoate, mebendazole, treat family
- clean clothes/bedding, hygiene
Stronglyloides sterocoralis (threadworms)
intestinal nematode
-larvae penetrate unbroken skin-> get to lungs->break through alveoli to get swallowed-> small intestine-> eggs hatch into rhabditoform larvae (feed)
-direct life cycle (in soil)-> filariform larvae (infective)
-indirect life cycle (in us)-> free-living female and males
-autoinfection-> develop into filariform and invade gut (in IC’s)
-heavy infection: chronic dysentery, bronchitis, bacterial enteritis from intestinal damage
-cosmopolitan distribution (warm moist climates), mainly the south US
rhabditoform larvae or eggs in feces
-invermectin, thiabendazole (treat family and pets)
-economically depressed areas, reduce contact with dog/cat waste, human waste
Ancylostoma duodenale/necator americanus (hook worm)
-intestinal nematode
-filariform larvae (infectious)
-eggs in feces-> rhabditiform-> filariform larvaepenetrate skin->lungs-> cough and swallow-> attach in small intestine-> suck blood
-malnutrition, anemia, weakness, N&V, diarrhea
cutaneous phase (papule at site of bite)
-pulmonary phase-> larvae migrating through lungs, bronchitis if in large numbers
-intestinal phase-> suck blood
-infants/children-> mental retardation from malnutrition
-pregnant women
-improper disposal of feces, warm climates, humid, no shoes
-decal occult blood test
-mebendazole, iron,albendazole
ancyclostoma brailiense (another hook worm)
dog/cat hook worm
- cutaneous larvae migrans-> migrate subcutaneously
- southern U.S
- ID serpentine tunnels, hands, buttocks, feet
- thiabendazole, ivermectin
- deworm pets, plastic sheets on ground
trichinella spiralis
tissue nematode
-swine
-infected from CYSTS
-poorly cooked pork
-live in small intestine (mate)->invade lymph-> produce larvae-> encyst in skeletal muscle (rhabdomyolysis)
-host reaction-> calcify cysts
- phase 1: invades mucosa: abd. pain, diarrhea, N&V
-phase 2: larvae migrating: local edema, fever, eosinophilia, myocarditis
-phase 3: penetrate skeletal muscle: intense muscular
pain
-ethnic festivals,
-larvae in muscle via biopsy
-mebendazole, albendazole
-cook pork
Diphyllobothrium latum (fish tapeworm)
- infectious form: pleurocercoid larvae
- copepod (procercoid)-> minnow eats copepod-> encysts in muscle (called pleurocercoid)-> eaten by game fish-> human ingests undercooked game fish
- Pernicious anemia-> competes for B12
- Russia, sweden, fisherman, Pacific, Minnesota, Wisconsin
- ID proglottids in stool
- Praziquantel (calcium agonist), suppl. B12
- cook/freeze fish
Taenia saginata (beef tapeworm)
- infectious form: cysticercus
- proglottids pass through feces or unassisted climb out
- eggs in soil-> cattle eat (intermediate host)-> Oncosphere attaches to intestinal wall in cow-> lymph-> muscle fibers-> cysticercus-> human eats undercooked beef
- concomitant immunity (AB antibodies)
- rarely have symptoms
- ID gravid proglottids in feces, ID taenia eggs
- praziquantel, prevent soil contamination, inspect/freeze beef
Taenia solium (pork tapeworm)
- infectious form: cysticercosis eggs
- human intermediate host, proglottids not mobile
- cysticerci can develop in humans from ingested eggs
- main host, pigs/cows
- Cysticercosis, ocular cysticercosis, neurocysticercosis (sudden epilepsy)
- Mexico/Central-south america, sub-saharan africa, east asia
- ID gravid proglottids in feces, cysticercosis ID by soft tissue X-ray or CT scan
- Praziquante (intestinal worms), albendazole (cysticercosis)
Schistosoma spp.
- life cycle in snails to humans
- infectious form: cercariae
- human excretes eggs in feces (M/J) or urine (H)
- Miracidia hatch in water-> asexually multiple in snail-> cercariae formed-> infect human-> heart/lungs/heart/veins
- antigenic mimicry: take over antigen and wear them
- papule at bite site
- Acute phase: lay eggs-> fever, discomfort, pain
- Chronic phase: eggs in intestine-> fibrosis, eggs in liver/spleen-> granuloma
- dams, Egypt
- praziquantel, molluscicides in water (kills snails), sanitation, hygiene
schistosoma mansoni
veins around intestines, Biomphalaria snails
Africa, S.A, caribbean,
eggs in feces (lateral spikes)
schistosoma haematobium
veins in bladder, ulcerate bladder, mucosa->hematuria
Bullinus snail
Africa/Near East
eggs in urine
schistosoma japoricum
mesenteric veins, Oncomelania snails
China, Philippines
eggs in feces
Swimmers itch (cercarial dermatitis)
Bird schistosome -Cercariae enter skin of human -inflammation/ rash (pus filled papule) -tourists -history of water, if get an itch -antihistamine lotion vigorous rubbing with towel can reduce probability of penetration
