Parascaris equorum: Difference between revisions

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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).

Causes transient nasal discharge when migrating through lungs
- Foals and weanlings

@@ Line 1: / Line 1: @@
-{{OpenPagesTop}}
+=== ''PARASCARIS EQUORUM'' ===
-{{Taxobox
-|name               = ''Parascaris equorum
-|kingdom            =
-|phylum             =
-|class              = [[Nematodes|Nematoda]]
-|sub-class          =
-|order              =
-|super-family       = [[:Category:Ascaridoidea|Ascaridoidea]]
-|family             =
-|sub-family         =
-|genus              =
-|species            = ''Parascaris equorum
-}}
-==Introduction==
 [[Image:Parascaris equorum.jpg|thumb|right|150px|''Parascaris equorum'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 [[Image:Parascaris equorum2.jpg|thumb|right|150px|''Parascaris equorum'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 [[Image:Parascaris equorum3.jpg|thumb|right|150px|''Parascaris equorum'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 [[Image:Parascaris equorum4.jpg|thumb|right|150px|''Parascaris equorum'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
-''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.
+==== General ====
+*Ascarid, small intestine.
+*Mostly in young horses, especially foals <6months old.
-Predilection site: '''Small intestine
+==== Morphology ====
+*Stout worms, up to 50cm long.
+*Three large lips around mouth.
-==Hosts==
+==== Life-Cycle ====
-Horses and donkeys.
+*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.
-==Identification==
+==== Pathogenicity ====
-''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.
+*''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.
-== Life-Cycle ==
+==== Epidemiology ====
-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.
+'''High Fecundity of Female ''Parascaris''''':
+*Infected foal may pass millions of eggs per day.
-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.
+'''Resistance of Eggs in Environment''':
+*Thick, pitted shell ensures prolonged survival (>1year).
+*Sticky outer shell aids passive spread.
-The prepatent period of ''P. equorum'' is 10-16 weeks.
+'''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?).
-May cause [[Ascarid Impaction - Horse|'''Ascarid Impaction''']] in horses.
+==== Control ====
+*Regular anthelmintic treatment.
+*Remove faeces from paddocks - collect every 2weeks (takes 2weeks to reach L2 stage).
-{{Learning
-|flashcards = [[Horse_Nematode_Flashcards|Horse Nematode Flashcards]]
-|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]
-|Vetstream = [https://www.vetstream.com/canis/search?s=nematode Nematodes]
-}}
-{{review}}
+*Causes transient [[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|nasal discharge]] when migrating through [[Lungs Inflammatory - Pathology#Infectious causes of pneumonia|lungs]]
+**Foals and weanlings
-{{OpenPages}}
 [[Category:Ascaridoidea]][[Category:Horse_Nematodes]]
-[[Category:Expert_Review]]
+[[Category:To_Do_-_Max]]
-[[Category:Respiratory Parasitic Infections]]