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15 Cards in this Set
- Front
- Back
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What does helminth mean? |
worm *nemathelminthes (roundworms) *platyhelminthes (flatworms) |
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What are some general characteristics of helminths? |
-parasitic and non parasitic -live extracellularly (in GI tract/organs) -Passive or active ingestion (diffuse or phagocytosis) -SEXUAL repro. (some are hermaphroditic) -DO NOT multiply within host (offspring must leave host) |
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What is the direct life cycle of helminths? |
Direct (1 host=sheep) Eggs passes in feces 3rd stage larvae migrate to grass to be ingested as L3 Develop into L4 and L5 and adult in sheep |
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What is the indirect life cycle of helminths? |
2 hosts = dog and flea Adult worms in small intestine, segments of adult worms passed in feces Eggs ingested by larval flea (outside) Larval flea develops into adult (outside) Adult flea ingested by dog *mosquito (indirect life cycle) |
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What are the characteristics of Nematodes (roundworms)? Spaghetti |
-Free-living or parasitic (soil, plant, animal) -Elongate/cylindrical -Alimentary canal present (digestive system) -Separate sexes -Life cycle can be direct or indirect |
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What are the characteristics of the sexes of Nematodes? |
Female-ovaries Male-some have bursa to hold onto female, ALL have spicules When male and female connect to each other they are stuck together for life |
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How can you identify the sex of a Nemtode? |
Bursate (male) (sometimes) Vulva mouth (shape, teeth) Esophagus size |
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What is L1 stage called? |
mff or microfilaria |
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What is the stage L5 called? |
immature adult |
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What are the two primary stages of the Nematode life cycle? |
E-L1-L2-L3-L4-L5-Adult 1. Direct: infective larva=usually L3, infective larva in an egg=usually L2 2. Indirect: L1 infective to IH, L3 infective to the final host Egg in feces-> L1,L2,L3 in feces-> L3 in grass-> L3, L4, L5, adult, eggs in host |
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What can affect where the stages end up shifting (inside or outside of host)? |
If a paratenic host is added that can affect where the egg, and larval stages will be *mice are usually the paratenic host |
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How do Nematodes ensure that their offspring with get into a host? |
Periparturient rise Survival of eggs with larva Paratenic hosts Transmammary, transplacental Arrested development (will sit in tissues until animal becomes pregnant and immune system is lowered) Bad weather: hypobiosis |
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What is periparturient rise? |
An increase in number of worms right before birth of host offspring so they can be excreted and eaten by the host offspring.
*this is not seen in cattle since they have pies for poop |
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Example of indirect life cycle |
Cat=final host Snail/slug=intermediate host (but cats dont usually eat these) Bird=Transport host or paratenic host in this case since intermediate host isnt being eaten |
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What is the life cycle of Ancylostoma caninum? |
Direct (5 modes of infection-transmammary is important, transplacental is rare) Arrested development Lung migration L3 is consumed by dog (infective stage) Found attached small intestine villi with hooks Symptoms: hemorrhaging, anemia, pale gums -zoonotic-get under human skin but not to blood |
