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170 Cards in this Set
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Intestinal Nematodes |
Anclostoma duodenale, Ascaris lumbricoides, Enterobius vermicularis, Necator americanus, Strongyloides stercoralis, Trichinella spiralis, Trichirus trichiura
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Tissue and blood nematodes
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Brugia malayi, Loa loa, Onchocerca volvulus, Wuchereria bancrofti
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Oral cavity of roundworms
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Buccal cavity
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The outer surface of roundworms; this surface resists digestion
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Cuticle
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Third stage larva, infective, non- feeding, sheathed. Has a long slender esophagus
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Flariform larva
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Embryo stage of filarial parasite, usually in the blood or tissue of definitive host. Ingested by arthropod intermediate host
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Microfilaria
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Roundworms
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Nematodes
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First stage larva, non-infective, feeding. Has an hourglass shaped esophagus
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Rhabitiform larva
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Body parts of nematodes
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Nerve cord, digestive tract, complex reproductive organs
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How to diagnose Ascaris lumbricoides
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Eggs in feces
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Where do Ascaris lumbricoides develop to become infective?
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1 month in soil
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How long do Ascaris lumbricoides remain infective?
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Years
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How do humans acquire Ascaris lumbricoides?
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Ingesting infective eggs
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Can Ascaris lumbricoides leave the body?
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Yes; through nose, mouth or anus
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How does Ascaris lumbricoides move about a human body?
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Larva from the eggs penetrate the intestinal wall and migrate to the lungs, larva are coughed up and swallowed and return to the intestine to mature
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Where would you find Ascaris?
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Appalachia
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What species is often found with Ascaris?
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Trichuris trichiura
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Largest adult nematode?
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Ascaris. 22-35 cm
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Most common intestinal worm infection worldwide, 2nd most common in US
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Ascaris
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How many eggs do female Ascaris lay a day?
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250,000
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Fertile eggs
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Corticated
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Pinworm or Seatworm
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Enterobius vermicularis
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Diagnostic and infective stage of Enterobius vermicularis
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Egg
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How does Enterobius vermicularis/ pinworm/ Seatworm lay eggs?
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Migrates out the anus to deposit eggs on perianal folds
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How long does infectivity of Enterobius vermicularis/ pinworm/ Seatworm last?
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A few days
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When and how are eggs of Enterobius vermicularis/ pinworm/ Seatworm sought?
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Tape prep in the morning
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Can Enterobius vermicularis/ pinworm/ Seatworm eggs be found in air?
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Yes
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Most common worm infection in US
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Enterobius vermicularis/ pinworm/ Seatworm
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When does Enterobius vermicularis/ pinworm/ Seatworm migrate in body? What does it cause?
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At night, bed wetting, sleeplessness, itching
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Hookworm
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Necator americanus
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Where is hookworm found
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North and South America, Asia and Africa
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North and South America, Asia and Africa
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Old world Hookworm
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Anclyostoma duodenale
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Where is Anclyostoma duodenale found?
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North Europe, S America, Asia, Africa and the Caribbean
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How can Ancylostoma infect?
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Flariform larvae can infect orally and possibly by transmammary or transplacental passage
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Diagnostic stage of hookworm
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Egg in feces
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Development of hookworm
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Egg develops to rhabitiform larva in soil (1-2 days); matures to flariform larva (infective)
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How does hookworm infection occur?
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When flariform larva penetrates the skin; usually on the feet
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How does hookworm migrate through the body?
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Larva migrates through lungs, coughed up and swallowed and returns to intestines to mature
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Hookworms are often found with
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Ascaris and Trichuris
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How does Strongyloides stercoralis infection occur?
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Larva penetrates skin
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How does threadworm larva move around the body?
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Larva migrates through the blood to the lungs, and from the lungs to the intestine. Larva may also be found in the sputum.
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Where does Strongyloides stercoralis reside in the body?
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In the intestinal mucosa
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Where is Strongyloides found? (Types of regions)
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Worldwide in warm areas, tropics and subtropics
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How big is Strongyloides?
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Only 2-3 mm
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Strongyloides Identification
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Eggs not usually seen, look similar to Hookworm eggs; recovered with Enterotest capsule Larva must be differentiated from Hookworm Flariform- Strongyloides has short buccal cavity and hourglass shaped esophagus
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Trichosis
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Trichinella spiralis
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What does hookworm consume?
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Blood, heavy infections can result in severe blood loss 100 mL/ day
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What percentage of human population is infected with hookworm?
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25%
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What happens if hookworm fecal exam is delayed?
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Hatching of eggs with larva
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Which worms have a long buccal cavity?
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Hookworms
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Threadworm
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Strongyloides stercoralis
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Diagnostic stage of threadworm
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Rhabitiform larva
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Where do Strongyloides stercoralis eggs hatch?
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In the intestinal mucosa
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Whose larva can develop to infective stage in the intestine and reinfect the host?
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Strongyloides stercoralis
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Can live non parasitically in soil
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Threadworm
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Hookworms are often found with
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Ascaris and Trichuris
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How does Strongyloides stercoralis infection occur?
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Larva penetrates skin
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How does threadworm larva move around the body?
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Larva migrates through the blood to the lungs, and from the lungs to the intestine. Larva may also be found in the sputum.
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Where does Strongyloides stercoralis reside in the body?
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In the intestinal mucosa
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In what regions is Strongyloides found?
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Worldwide in warm areas, tropics and subtropics
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How big is Strongyloides?
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Only 2-3 mm
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Strongyloides Identification
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Eggs not usually seen, look similar to Hookworm eggs; recovered with Enterotest capsule Larva must be differentiated from Hookworm Flariform- Strongyloides has short buccal cavity and hourglass shaped esophagus
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Trichosis
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Trichinella spiralis
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What does hookworm consume?
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Blood, heavy infections can result in severe blood loss 100 mL/ day
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What percentage of human population is infected with hookworm?
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25%
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What happens if hookworm fecal exam is delayed?
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Hatching of eggs with larva
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Which worms have a long buccal cavity?
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Hookworms
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Threadworm
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Strongyloides stercoralis
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Diagnostic stage of threadworm
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Rhabitiform larva
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Where do Strongyloides stercoralis eggs hatch?
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In the intestinal mucosa
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Whose larva can develop to infective stage in the intestine and reinfect the host?
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Strongyloides stercoralis
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Can live non parasitically in soil
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Threadworm
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Hookworms are often found with
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Ascaris and Trichuris
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How does Strongyloides stercoralis infection occur?
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Larva penetrates skin
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How does threadworm larva move around the body?
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Larva migrates through the blood to the lungs, and from the lungs to the intestine. Larva may also be found in the sputum.
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Where does Strongyloides stercoralis live?
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In the intestinal mucosa
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Where is Strongyloides found?
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Worldwide in warm areas, tropics and subtropics
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How big is Strongyloides?
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Only 2-3 mm
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Strongyloides Identification
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Eggs not usually seen, look similar to Hookworm eggs; recovered with Enterotest capsule Larva must be differentiated from Hookworm Flariform- Strongyloides has short buccal cavity and hourglass shaped esophagus
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Trichosis
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Trichinella spiralis
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Zoonotic disease, carnivorous mammals are the primary host
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Trichosis
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Diagnostic stage is larva encysted in striated muscle "nurse cells"
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Trichinella spiralis
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What does hookworm consume?
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Blood, heavy infections can result in severe blood loss 100 mL/ day
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What percentage of human population is infected with hookworm?
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25%
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What happens if hookworm fecal exam is delayed?
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Hatching of eggs with larva
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Which worms have a long buccal cavity?
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Hookworms
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Threadworm
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Strongyloides stercoralis
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Diagnostic stage of threadworm
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Rhabitiform larva
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Where do Strongyloides stercoralis eggs hatch?
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In the intestinal mucosa
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Whose larva can develop to infective stage in the intestine and reinfect the host?
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Strongyloides stercoralis
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Can live non parasitically in soil |
Threadworm
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Ascaris lumbricoides egg |
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Ascaris lumbricoides egg |
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Ascaris lumbricoides egg |
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Enterobius vermicularis |
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Enterobius vermicularis |
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Enterobius vermicularis |
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Hookworm |
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Hookworm |
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Hookworm |
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Ascaris infection |
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Hookworm egg |
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Hookworm egg |
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Hookworm larva |
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Hookworm larva |
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Strongyloides stercoralis |
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Strongyloides stercoralis |
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Strongyloides stercoralis |
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Trichuris trichuria egg |
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Trichuris trichuria egg |
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Trichuris trichuria egg |
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Wucheria bancroft |
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Wucheria bancroft |
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Brugia malayi |
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Brugia malayi |
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How does Strongyloides infect a human?
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Larva penetrates skin
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How does Strongyloides move about the body?
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Larva migrates the blood to the lungs, and from the lungs to the intestine , larva may also be found in sputum
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How big are Strongyloides stercoralis?
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2-3mm
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US infection rate of Trichinella spiralis
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~4%
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Distribution of Trichinella spiralis
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World-wide in meat eating populations, but rare in the tropics
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Trichuris trichiura
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Whipworm
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How to diagnose Trichuris trichiura
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Eggs in feces
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Where do Trichuris trichiura eggs mature?
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In soil, infective in one month
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How do humans acquire Trichuris trichiura infection?
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Eating eggs
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How does whipworm travel through body?
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Larva hatch in small intestine, develop in villi and mature in colon
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Who has Barrel shaped eggs with plugged ends and a smooth surface
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Trichuris trichiura
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Which worm produces living embryos, microfilariae, that migrate into lymphatics , blood or skin
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Filariae
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Filariae intermediate host is who and does what
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Arthropod ingests microfilariae
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Where do adult Strongyloides live?
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In the intestinal mucosa
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Who shows periodicity and why
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Microfilariae become more prevalent at certain times during the day- these seem to correlate with the feeding patterns of the arthropod hosts
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Where is Strongyloides found?
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In warm areas, tropics and subtropics
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Strongyloides Identification
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Eggs: not usually seen, look similar to hookworm eggs, may be recovered using Entero-Test capsule. Larvae: must differentiate between Strongyloides rhabitiform larva and Hookworm Filariform larva.
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Characteristics of Strongyloides larva
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Short buccal cavity, hourglass shaped esophagus
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Zoonotic disease, carnivorous mammals are the primary hosts
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Trichosis
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Diagnostic stage of Trichinella spiralis
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Larva encysted in striated muscle "nurse cells"
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How does Trichinella spiralis infection occur?
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Undercooked infected meat is eaten
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How long must infected meat be frozen to kill Trichinella spiralis?
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20 days
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Trichinella spiralis movement through the body
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Larva is freed when meal is digested, rapidly develop into adults. Adults live on intestine. Female releases larva into submucosa. Larva disseminate via the blood stream
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Knott's technique
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Blood can be concentrated and the RBCs lysed before staining to concentrate microfilariae
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How is microfilariae identified
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By the presence or absence of a sheath around the larva and whether there are nuclei present in the tip of the tail and if there is a pattern to their distribution
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Diagnostic stage of Filariae
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Microfilariae
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Adults live in subcutaneous tissue, migrate actively
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Loa loa; eyeworm
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Loiasis/ Calabar swellings
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Loa loa
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Elephantiasis a
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Wucheria bancrofti
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Adults live in the lymphatics, blockage causes extreme edema
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Wuchereria bancrofti
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Wucheria bancrofti intermediate host
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Mosquito
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Microfilariae have a sheath but have no nuclei in tail tupmicto
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Wucheria bancrofti
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Microfilariae are found in the blood
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Wucheria bancrofti
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Tightly coiled, sheath present, nuclei tightly packed, terminal and sub- terminal nuclei extend to tip of the tail. Adults live in lymphatics. Mosquito arthropod host.
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Brugia malayi
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Eyeworm
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Loa loa
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Loa loa arthropod host
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Chrysops (Deerfly)
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Sheath present nuclei present in tail, continuous
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Loa loa
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Diagnostic stage of Filariae
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Microfilariae
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Adults live in subcutaneous tissue, migrate actively
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Loa loa; eyeworm
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Loiasis/ Calabar swellings
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Loa loa
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Elephantiasis a
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Wucheria bancrofti
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Adults live in the lymphatics, blockage causes extreme edema
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Wuchereria bancrofti
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Wucheria bancrofti intermediate host
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Mosquito
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Microfilariae have a sheath but have no nuclei in tail tupmicto
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Wucheria bancrofti
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Microfilariae are found in the blood
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Wucheria bancrofti
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Tightly coiled, sheath present, nuclei tightly packed, terminal and sub- terminal nuclei extend to tip of the tail. Adults live in lymphatics. Mosquito arthropod host.
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Brugia malayi
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Eyeworm
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Loa loa
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Loa loa arthropod host
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Chrysops (Deerfly)
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Sheath present nuclei present in tail, continuous
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Loa loa
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Black fly is the arthropod host. Major cause of blindness in Africa
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Onchocerca volvulus
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Adults live in subcutaneous tissue, nodules form around the adult
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Onchocerca volvulus
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River blindness
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Onchocerciasis
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Black fly is the arthropod host. Major cause of blindness in Africa
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Onchocerca volvulus
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Adults live in subcutaneous tissue, nodules form around the adult
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Onchocerca volvulus
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River blindness
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Onchocerciasis
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