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| + | #REDIRECT[[:Category:Ascaridoidea]] |
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| − | {{toplink
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| − | |backcolour =
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| − | |linkpage =Parasites
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| − | |linktext =PARASITES
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| − | |pagetype=Bugs
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| − | |sublink1=Nematodes
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| − | |subtext1=NEMATODES
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| − | }}
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| − | <br>
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| − | == General Appearance ==
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| − | *Non-bursate.
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| − | *Big fleshy worms; typically 5-40cm long (depending on age, sex and species).
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| − | *Three lips around the mouth.
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| − | *A single-bulbed pharynx.
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| − | == General Life-Cycle ==
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| − | *Adult females in small intestine lay eggs.
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| − | *Eggs have a thick protective shell.
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| − | *Some also have a sticky outer albuminoid coat.
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| − | *Eggs passed in faeces.
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| − | *L1 → infective L2 inside the egg.
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| − | *Infection is by ingestion of the embryonated egg (egg in which a larva has formed).
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| − | *Eggs can remain viable in humid environment for up to 5years.
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| − | *After hatching in the intestine, the larvae of most species (but not all) undergo hepato-tracheal migration:
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| − | **egg hatches in intestine → larva penetrates intestinal mucosa → hepatic portal blood → liver → venous blood → heart → lung capillaries → alveoli → ascends trachea → swallowed → small intestine (where the adults develop).
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| − | NOTE: there are important variations on this theme; for example, the migratory larvae of some species can cross the placenta or enter the mammary glands (examples of vertical transmission); while some species will utilise paratenic or intermediate hosts.
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| − | [[Ascaridida]]
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| − | Occlusion of pancreatic ducts sometimes happens [[Pancreas Parasitic - Pathology|Pancreas - parasitic]]
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| − | In [[Peritoneal Cavity Parasitic - Pathology]]
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| − | *''Parascaris equorum'' in [[Respiratory Parasitic Infections - Pathology#In Horses|rhinitis and lungs]]
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| − | *Ascarid larvae in [[Muscles Inflammatory - Pathology#Nematodes|myositis]]
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