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128 Cards in this Set
- Front
- Back
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what are the roundworms (nematodes) you get by ingestion? |
Enterobius vermicularis |
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what roundworm causes pinworms?
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Enterobius vermicularis
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what roundworm causes Ascariasis?
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Ascaris lumbricoides |
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what nematode causes whipworm?
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Trichuris trichiura
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what nematode causes visceral larva migrans?
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Toxocara canis/cati
Trichinella spiralis Anisakis spp. Dracunculus medinensis |
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what nematode causes trichinosis?
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Trichinella spiralis
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what nematode causes Anisakiasis/herring disease?
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Anisakis spp.
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what nematode is the Guinea fire worm (fiery serpent)?
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Dracunculus medinensis
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what roundworm infecs are acquired via the skin?
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Necator americanus & Ancylostoma duodnale
Ancylostoma caninum & A. braziliense Strongyloides stercoralis Wuchereria bancrofti Loa Loa Onchocerca volvulus Dirofilaria immitis |
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which roundworms are the intestinal worms?
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Necator americanus & Ancylostoma duodnale
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what roundworms cause cutaneous larva migrans?
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Ancylostoma caninum & A. braziliense
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what roundworm causes Strongyloidosis?
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Strongyloides stercoralis
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what nematode causes filariasis --> elephantiasis?
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Wuchereria bancrofti
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what nematode is the eye worm and causes calibar swellings?
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Loa Loa
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what nematode is responsible for river blindness?
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Onchocerca volvulus
(W. Africa) |
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what nematode causes dog heart worm (coin lesion)?
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Dirofilaria immitis
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what nematode causes dog heart worm (coin lesion)?
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Dirofilaria immitis
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where can you get Toxocara canis/cati?
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Dog & cat ASCARID worms
(10-12 cm long) shed eggs in feces, ending up in the dirt |
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how does Toxocara become infectious?
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Eggs embryonate in soil for 2-3 weeks; thereafter they are infectious for dogs (& cats) & humans
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how is Toxocara canis/catis transmitted?
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Eggs INGESTED mainly by kids 1-4 yrs old, who indulge in PICA (= eating dirt, etc)
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what happens once Toxocara is ingested?
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When ingested by humans --> larvae penetrate human gut, reach blood stream, then migrate as larvae to various human tissues; they do not develop beyond migrating larvae
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are Toxocara canis infections common?
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Infection rate in the 50 million dogs inhabiting the US is great; > 80% of puppies & 20% of older dogs involved.
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what age grp shows clinical manifestations of Toxocara canis?
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Clinical manifestations occur mostly among children 1 - 6 yrs old.
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why do ppl get disease from Toxocara canis infections?
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Disease results from organ invasion by larvae via blood stream & hypersensitivity to larval antigens
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what organ systems are affected in Toxocara canis infections?
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Liver, lungs, heart, skeletal muscle, brain, eye & skin involved most frequently
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what kind of damage can Toxocara canis larvae cause?
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Larvae cause necrosis, bleeding, formation of eosinophilic granulomas & fibrosis
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what are the symptoms of intense Toxocara canis infec?
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Children with more intense infection may have fever & big liver
More seriously ill patients may have skin rash, enlarged spleen, asthma, recurrent pulmonary infiltrates, abdominal pain, sleep & behavioral changes Illness (VISCERAL LARVA MIGRANS) may persist for months. May die of respiratory failure, arrhythmia, brain damage |
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how do you diagnose Toxocara canis?
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demonstrating larva in liver biopsy or at autopsy
Lab findings: increased eosinophils in peripheral blood, & increased IgE Serodiagnosis using EIA is 75% sensitive & 90% specific |
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how do you treat Toxocara canis?
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albendazole, mebendazole, diethylcarbamazine, or thiabendazole used
- no treatment if no symptoms |
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how do you prevent Toxocara canis?
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Worming of pets begins @ 3 wks of age, repeat every 3 mos in 1st year, then 2x/ yr afterward.
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where is Trichinella spp?
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everywhere!
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how do ppl get trichinosis?
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Infection begins with ingestion of undercooked pork or bear meat containing encysted larvae;
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how does Trichinella survive in you after you eat it?
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encysted larvae liberated from meat by digestive enzymes, develop in
small intestine mucosa |
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what's the Trichinella life cycle?
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Larvae released in intestines --> mature to adults, mate --> females produce live-born larvae -->penetrate intestinal wall --> enter blood stream --> all areas of body --> encapsulate in striated muscle
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what are symptoms of Trichinella infec?
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Few symptoms while intestinal phase:
Some diarrhea, abdominal discomfort developed infection: periorbital edema, muscle pain & tenderness, headache, weakness, Myocarditis, CNS involvement, death may occur Eosinophilia myositis & vasculitis |
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how long can Trichinella larvae persist in body?
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viable for years!
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what are Trichinella symptoms dependent on?
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tissue invaded, parasite load, general health of patient
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how do you diagnose Trichinella?
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Symptoms
Muscle biopsy (encysted larvae) Serology |
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Trichinella tx?
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Rx of adult worms in small intestine with mebendazole may halt production of new larvae
-no tx for larvae in muscle! |
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what are general char of trematodes/flukes?
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Leaf-like and flat
Human (or another animal) is definitive host for all Two intermediate hosts for most (schistosomes have one) |
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what's the normal trematode life cycle?
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Eggs shed from human into fresh water (lake, pond, etc.) --> miracidia larvae hatch and infect mollusks (snails) --> cercaria larvae from snail enters water --> metacercaria invade 2nd intermediate host which is ingested by man
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what's schistosoma alteration to normal trematode life cycle?
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cercaria infect man through skin with no second intermediate host.
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where can you find Schistosoma japonicum?
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S. japonicum: S. E. Asia,
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where can you find Schistosoma hematobium?
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S. hematobium: Nile valley, Central Africa, Middle East,
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where can you find Schistosoma mansoni?
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S. mansoni: Africa, S. America, Caribbean, Phillipines
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how do ppl get Schistosome infec?
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Cercaria leave snail and penetrate human skin
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where can you find Schistosomes in human body?
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Large eggs are deposited in vessels of humans
-G.I tract: S. mansoni and S. japonicum -Urinary bladder (bladder cancer) and lower G.I.tract: S. hematobium “Swimmer’s Itch” (schistosomal dermatitis) - a diff Schistosoma sp. |
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is it a good thing to have Schistosomes in your body?
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-Adults living in blood vessels of mesentary where they cause probs in liver and spleen
-In liver, eggs cause inflamm rxn --> extensive fibrosis |
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where can you find Schistosoma hematobium eggs?
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urine!
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how do you diagnose Schistosoma?
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eggs! in urine- hematobium or feces- japonicum and mansoni
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describe Schistosoma japonicum egg:
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S. japonicum: (85 x 60 µ), rounded with small lateral spine
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describe Schistosoma hematobium egg:
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S. hematobium (150 x 55µ), oval with pointed terminal spine
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describe Schistosoma mansoni egg:
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S. mansoni: (150 x 50 µ), oval with long pointed lateral spine
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what's the most common form of Schistosomiasis?
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Schistosoma mansoni
GI – involves mesenteric vessels… causes probs in liver and spleen |
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how can you decrease infection w/ Schistosoma?
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Proper fecal and urine sanitation
Avoid contact with water Eradicate snails Treat infected individuals |
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what is Fasciolopsis buski and where is it found?
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Giant intestinal fluke (found only in china, Vietnam, Thailand, parts of Indonesia, Malaysia & India
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what's Fasciola hepatic and where's it found?
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Sheep liver fluke (found in Russia, Japan, Egypt, & many latin American countries; rare in US)
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what is Opisthorchis (Clonorchis) sinensis -? where is it found?
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Chinese liver fluke (found only in China, Japan, Korea, & Vietnam)
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what's Paragonimus westermani -- ? where is it found?
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Lung fluke (Occurs in Asia, Africa, India, & Latin America)
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what are general char of tapeworms/cestodes?
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Flatworms (members of Platyhelminthes)
Head (scolex) equipped with structures for attachment = suckers, some with hooklets (“armed”), & one with pair of lateral grooves only Proglottids (individual segments) are diagnostic for some Entire chain of proglottids is called a “strobila” All are hermaphroditic (both male and female in each proglottid) All tapeworms have larval stages; most require 1 or more intermediate hosts 6-hooked hexacanth embryos in embryonated eggs of all |
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what tapeworm doesn't require 1 or more intermediate hosts?
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Hymenolepsis nana
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what species of tapeworm doesn't have 6-hooked hexacanth embryo in embryonated egg?
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D. latum which is operculated like a fluke egg
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what's strobila?
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chain of proglottids
**tapeworms!! |
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what's the most common tapeworm in the US?
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Hymenolepsis nana
*more common in kids |
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describe Hymenolepsis nana life cycle:
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Simple life cycle; no intermediate host required. Eggs ingested
Embryo released Invades mucosa & develops larva called cysticercoid Larva enters lumen & attaches, develops to adult Adult lays eggs |
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what kind of host is human in Hymenolepsis nana infection?
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Human can be both definitive & intermediate host, thus autoinfection may occur.
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what worm can you become autoinfected w/?
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Hymenolepsis nana
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how is Hymenolepsis nana transmitted?
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Spread fecal- oral route, or by ingestion of infected arthropod
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what are the hosts for H. nana infection?
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-Rodent = reservoir host
-arthropod (beetle) can serve as intermediate humans- definitive and intermediate host |
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how do you diagnose H. nana?
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Thin shelled eggs in stool (30-45 µ) with hexacanth embryo, polar thickenings and filaments.
Adults: small (<40 mm), tiny armed scolex (20-30 µ), hooklets |
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how do you treat H. nana?
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Praziquantel (or niclosamide)
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where is Diphyllobothrium latum found in nature?
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Found in temperate zones (even Scandinavia)
Found in U.S. – Northern midwest lakes |
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what's the only operculate tapeworm found in man?
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Diphyllobothrium latum
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what are the intermediates in Diphyllobothrium latum?
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Two intermediates: copepod and freshwater fish
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how is Diphyllobothrium latum transmitted?
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Humans ingest raw/inadequately cooked fish
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what are the symptoms of Diphyllobothrium latum?
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Vague abdominal symptoms (diarrhea, etc), megaloblastic anemia (competition for B12)
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how do you diagnose Diphyllobothrium latum?
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-Based on ID of eggs or proglottids passed in stool
-Eggs (65 µ), operculate, aboperculate knob -Proglottids are broader than long (often chain of proglottids passed) -Scolex has bothria (slits) instead of suckers |
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what's the beef tapeworm?
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T. saginata
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what's the intermediate host for Taenia saginata?
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Cattle are intermediate host
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how common is Taenia saginata?
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Worldwide but rare in U.S.
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symptoms of Taenia saginata?
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vague abdominal symptoms; passing of proglottids; gravid proglottids may crawl from anus
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how do you diagnose T. saginata?
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proglottids are longer than wide (15-20 uterine branches), scolex has no hooks
Eggs (40 µ), striated shell, hexacanth embryo (can’t differentiate from T. solium) |
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what's the definitive host for T. saginata?
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humans
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how does Taenia saginata present itself in meat?
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Bladder cyst - cysticercus - in beef muscle
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how can you get Taenia saginata?
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eating raw or undercooked beef
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what's the Taenia saginata life cycle?
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Scolex evaginates & attaches to small intestinal mucosa by suckers
Strobila develops (usually one/patient) Proglottids become larger as they become filled with eggs Do not lay eggs, but proglottids drop off, rupture & eggs in feces, or remain intact & passed in feces - crawl like inch worm Cattle ingest eggs (e.g., cowboy defecates in pasture) Ingested eggs invade & reach beef muscle & form cysticerci |
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what's a defining char of Taenia saginata?
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Scolex of Taenia saginata has 4 suckers and no hooklets
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what's the pork tapeworm?
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Taenia solium
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what are the hosts for Taenia solium?
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intermediate- pig
definitive- human |
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how common is Taenia solium?
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rare in US
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what stage of Taenia solium is infective?
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egg
cysticercus |
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what are symptoms of Taenia solium?
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-cystercerci in various organs (called Cysticercus cellulosae)
-Serious problem when larvae travel to brain or eye (cysticercosis) – headaches, seizures, psychiatric disturbances possible |
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what is special about a cysticercus?
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invaginated scolex
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how do you diagnose Taenia solium?
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Eggs or proglottids found in stool
Eggs: can’t be differentiated from T. saginata (above) Proglottids: similar to T. saginata except 7-13 uterine branches, scolex is armed (hooks) |
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what's a defining char of Taenia solium?
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Scolex of Taenia solium has 4 suckers plus a double row of hooks.
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what does black widow look like?
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black w/ red hourglass
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what kind of damage can black widow cause?
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systemic
toxin mediated |
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describe damage of brown recluse:
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forms severe localized lesion that ulcerates.. Systemic signs not as bad as black widow
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what damage can bed bugs cause?
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dermatitis lesions on skin
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what's the official name of dog ticks?
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Dermacenter variabilis
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what are general char of Insecta?
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3 body parts (head, thorax & abdomen), 3 pairs of legs, one pair of antennae, 1 or 2 pairs of wings (or no wings)
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contrast lice and fleas:
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Lice -Flattened dorsoventrally
Fleas- Flattened laterally |
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what's the body louse?
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Pediculus humanus
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where can you find body louse on person?
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Nits (eggs) deposited clothing
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how is body louse transmitted?
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host to host
also diseases ex: typhus |
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what's head louse?
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Pediculus capitis
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where can you find head louse?
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nits on hair - REMOVE!
*can see easier w/ wood's lamp or uv light |
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what's pubic louse?
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Phthirus pubis
“Crabs” |
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where can you find pubic louse?
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Pubic hair or occasionally of axillae, eyebrows, beard
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what are gen char of fleas?
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3 pair of clawed legs – attached at thorax
Large hind legs for jumping |
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why aren't fleas our friends?
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Transmit bacterial infections (plague, etc.), tapeworms (e.g., Hymenolepis diminuta)
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what's the dog or cat flea called?
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Ctenocephalides spp.
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what's in the Arachnida class?
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Ticks, mites, spiders and scorpions
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what are gen char of ticks?
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Chitinous shield
Mouth parts attached to fused body (globular body) Head and antennae are absent 4 pair legs in adults (3 in larvae) |
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are ticks our friends?
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NO! Transmit diseases (e.g., RMSF, Babesiosis,
-Anaplasma phagocytophilum (human granulocytic Ehrlichiosis), -Borrelia burgdorferi (Lyme disease) |
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what's the deer tick?
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Ixodes scapularis
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what's the lone star tick?
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Amblyomma americanum
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what's the lone star tick a vector for?
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-Ehrlichia chaffeensis (monocytic Ehrlichiosis)
-Francisella tularensis (tularemia) |
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what's dog tick a vector for?
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-Rickettsia rickettsia (Rocky Mountain Spotted Fever)
-Francisella tularensis |
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what's dog tick?
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Dermacentor variabilis
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is it a good idea to leave tick head inside you?
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no! can get bac infecs
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how do you take a tick out?
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To remove (1) grasp tick’s mouthparts against skin using pointed tweezers; (2) pull back slowly & steadily. Be patient, the long, central mouthpart (“hypostome”) inserted in the skin is covered with sharp barbs, sometimes making removal difficult & time-consuming.
DON'T USE FINGERNAIL POLISH OR HEAT! |
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what are gen char of mites?
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No chitinous shield
Short legs (larvae have 6, adults have 8) |
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how do mites infect you?
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Burrows in skin and lays eggs
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how are mites transmitted?
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Host to host in crowded conditions, poor hygiene
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what disease do mites cause? is it prevalent?
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scabies- endemic in US
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what's the itch mite?
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Sarcoptes scabiei
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what are symptoms of scabies?
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intense itching particularly in the interdigital folds leads to excoriation of the skin secondary to scratching, which produces crusts & secondary bacterial infection
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