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− | {{unfinished}}
| + | #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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− | [[Image:Toxocara cati.jpg|thumb|right|150px|''Toxocara cati'' - Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine]]
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− | [[Image:Toxoscaris leonina.jpg|thumb|right|150px|''Toxoscaris leonina'' - Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine]]
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− | [[Image:Toxocara canis.jpg|thumb|right|150px|''Toxocara canis'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
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− | [[Image:Toxoscaris leonina 2.jpg|thumb|right|150px|''Toxoscaris leonina'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]] | |
− | *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 5 years
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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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