Difference between revisions of "Parascaris equorum"

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=== ''PARASCARIS EQUORUM'' ===
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{{Taxobox
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==== General ====
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|name              = ''Parascaris equorum
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*Ascarid, small intestine.
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|kingdom            =
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*Mostly in young horses, especially foals <6months old.
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|phylum            =
 
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|class              = [[Nematodes|Nematoda]]
 
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|sub-class          =
 
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|order              =
 
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|super-family      = [[:Category:Ascaridoidea|Ascaridoidea]]
 
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|family            =
 
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|sub-family        =
 
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|genus              =
 
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|species            = ''Parascaris equorum
 
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}}
 
  
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==Introduction==
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==== Morphology ====
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[[Image:Parascaris equorum.jpg|thumb|right|150px|''Parascaris equorum'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
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*Stout worms, up to 50cm long.
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[[Image:Parascaris equorum2.jpg|thumb|right|150px|''Parascaris equorum'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
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*Three large lips around mouth.
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[[Image:Parascaris equorum3.jpg|thumb|right|150px|''Parascaris equorum'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 
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[[Image:Parascaris equorum4.jpg|thumb|right|150px|''Parascaris equorum'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 
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''P. equorum'' is a [[Nematodes|nematode]] that primarily affects younger horses, usually under two years of age, as their immune response is not as developed as older horses.
 
  
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Predilection site: '''Small intestine
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==== Life-Cycle ====
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*Direct.
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*Infection - ingestion of embryonated egg (L2).
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*Egg (100µm diameter, brown, thick pitted shell).
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*Larvae → hepatotracheal migration (liver → heart → lungs → intestine, 3weeks).
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*Prepatent period = 10-12weeks.
  
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==Hosts==
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==== Pathogenicity ====
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Horses and donkeys.
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*''Larvae'' - eosinophilic tracts and haemorrhages in liver and lungs. Clinically, latter may lead to cough and nasal discharge.
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*''Adult worms'' - may cause unthriftiness, weight loss; impaction and intestinal perforation rarely.
  
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==Identification==
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==== Epidemiology ====
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''P. equorum'' is a large stout nematode, with the female capable of growing up to 40cm in length.  The adults have a mouth surrounded by three large lips.  The egg is spherical, brown and has a thick outer shell.
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'''High Fecundity of Female ''Parascaris''''':
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*Infected foal may pass millions of eggs per day.
  
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== Life-Cycle ==
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'''Resistance of Eggs in Environment''':
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The adults live unattached in the small intestine.  In heavy infections, they may form large balls, which can cause intestinal obstruction. Under optimal conditions L2 can develop in 14 days.  The host ingests the embryonated egg.  L2 larvae then pass through the intestinal wall, and transform into L3.  The larvae then migrate to the liver via the hepatic portal vein, where they stay for around a week.  They enter the vena cava and travel to the pulmonary alveoli, where they transform to L4.
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*Thick, pitted shell ensures prolonged survival (>1year).
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*Sticky outer shell aids passive spread.
  
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The larvae travel up bronchi to the trachea and are coughed up and swallowed.  Finally they return to the stomach and small intestine, where they mature into adults.
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'''Susceptible Animals''':
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*Foals (<4months) - transmission from one year's foals to the next, infection normally occurring during the first month of life.
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The prepatent period of ''P. equorum'' is 10-16 weeks.
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*Adult horses - few worms only (carriers?).
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May cause [[Ascarid Impaction - Horse|'''Ascarid Impaction''']] in horses.
 
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{{Learning
 
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|flashcards = [[Horse_Nematode_Flashcards|Horse Nematode Flashcards]]
 
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|literature search = [http://www.cabdirect.org/search.html?rowId=1&options1=AND&q1=%22Parascaris+equorum%22&occuring1=title&rowId=2&options2=AND&q2=&occuring2=freetext&rowId=3&options3=AND&q3=&occuring3=freetext&x=32&y=11&publishedstart=yyyy&publishedend=yyyy&calendarInput=yyyy-mm-dd&la=any&it=any&show=all ''Parascaris equorum'' publications]
 
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|Vetstream = [https://www.vetstream.com/canis/search?s=nematode Nematodes]
 
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}}
 
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{{review}}
 
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{{OpenPages}}
 
  
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==== Control ====
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*Regular anthelmintic treatment.
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*Remove faeces from paddocks - collect every 2weeks (takes 2weeks to reach L2 stage).
 
[[Category:Ascaridoidea]][[Category:Horse_Nematodes]]
 
[[Category:Ascaridoidea]][[Category:Horse_Nematodes]]
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[[Category:Expert_Review]]
 
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[[Category:Respiratory Parasitic Infections]]
 

Revision as of 22:05, 26 April 2010

PARASCARIS EQUORUM

General

  • Ascarid, small intestine.
  • Mostly in young horses, especially foals <6months old.

Morphology

  • Stout worms, up to 50cm long.
  • Three large lips around mouth.

Life-Cycle

  • Direct.
  • Infection - ingestion of embryonated egg (L2).
  • Egg (100µm diameter, brown, thick pitted shell).
  • Larvae → hepatotracheal migration (liver → heart → lungs → intestine, 3weeks).
  • Prepatent period = 10-12weeks.

Pathogenicity

  • Larvae - eosinophilic tracts and haemorrhages in liver and lungs. Clinically, latter may lead to cough and nasal discharge.
  • Adult worms - may cause unthriftiness, weight loss; impaction and intestinal perforation rarely.

Epidemiology

High Fecundity of Female Parascaris:

  • Infected foal may pass millions of eggs per day.

Resistance of Eggs in Environment:

  • Thick, pitted shell ensures prolonged survival (>1year).
  • Sticky outer shell aids passive spread.

Susceptible Animals:

  • Foals (<4months) - transmission from one year's foals to the next, infection normally occurring during the first month of life.
  • Adult horses - few worms only (carriers?).

Control

  • Regular anthelmintic treatment.
  • Remove faeces from paddocks - collect every 2weeks (takes 2weeks to reach L2 stage).
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