Difference between revisions of "Ascaridoidea"

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#REDIRECT[[:Category:Ascaridoidea]]
 
 
{{toplink
 
|backcolour =
 
|linkpage =Parasites
 
|linktext =PARASITES
 
|pagetype=Bugs
 
|sublink1=Nematodes
 
|subtext1=NEMATODES
 
}}
 
<br>
 
== General Appearance ==
 
[[Image:Toxocara cati.jpg|thumb|right|150px|''Toxocara cati'' - Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine]]
 
[[Image:Toxoscaris leonina.jpg|thumb|right|150px|''Toxoscaris leonina'' - Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine]]
 
[[Image:Toxocara canis.jpg|thumb|right|150px|''Toxocara canis'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 
[[Image:Toxoscaris leonina 2.jpg|thumb|right|150px|''Toxoscaris leonina'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 
*Non-bursate
 
*Big fleshy worms; typically 5-40cm long (depending on age, sex and species)
 
*Three lips around the mouth
 
*A single-bulbed pharynx
 
 
 
== General Life-Cycle ==
 
*Adult females in small intestine lay eggs
 
*Eggs have a thick protective shell
 
*Some also have a sticky outer albuminoid coat
 
*Eggs passed in faeces
 
*L1 → infective L2 inside the egg
 
*Infection is by ingestion of the embryonated egg (egg in which a larva has formed)
 
*Eggs can remain viable in humid environment for up to 5 years
 
*After hatching in the intestine, the larvae of most species (but not all) undergo hepato-tracheal migration:
 
**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)
 
 
 
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.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
[[Ascaridida]]
 
 
 
Occlusion of pancreatic ducts sometimes happens [[Pancreas Parasitic - Pathology|Pancreas - parasitic]]
 
 
 
In [[Peritoneal Cavity Parasitic - Pathology]]
 
 
 
*''Parascaris equorum'' in [[Respiratory Parasitic Infections - Pathology#In Horses|rhinitis and lungs]]
 
*Ascarid larvae in [[Muscles Inflammatory - Pathology#Nematodes|myositis]]
 

Latest revision as of 10:53, 26 April 2010