Difference between revisions of "Dictyocaulus arnfieldi"

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{{OpenPagesTop}}
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== Lungworm ==
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{{Taxobox
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|name              =''Dictyocaulus arnfieldi
 
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|kingdom            =
 
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|phylum            =
 
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|class              =[[:Category:Nematodes|Nematoda]]
 
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|sub-class          =
 
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|order              =
 
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|super-family      =[[Trichostrongyloidea]]
 
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|family            =
 
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|sub-family        =
 
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|genus              =Dictyocaulus
 
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|species            ='''''D. arnfieldi'''''
 
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}}
 
 
[[Image:Dictyocaulus arnfieldi.jpg|thumb|right|150px|''Dictyocaulus arnfieldi'' from horse faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 
[[Image:Dictyocaulus arnfieldi.jpg|thumb|right|150px|''Dictyocaulus arnfieldi'' from horse faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
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Also known as: '''''Equine lungworm
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==== General ====
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*Lungworm of equidae; adult worms found in smaller bronchi. Frequently incriminated as the cause of a chronic cough.
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==== Morphology and Life-Cycle ====
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*Similar to lungworm in cattle, except:
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**embryonated eggs (80-100µm) passed in fresh faeces; and
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**prepatent period = 12weeks.
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==== Epidemiology ====
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*Main source of infection = donkeys (remain infected for years) - contaminate horse pasture.
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*Infection can cycle in horses.
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==Hosts==
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{| style="width:75%; height:200px" border="1"
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Donkeys, and occasionally horses.
 
  
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==Identification==
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!
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''D. arnfieldi'' are of the superfamily [[Trichostrongyloidea]].  Adults are slender, thread-like and white.  Females are larger than males at around 6.5cm in length.  The males have a small non-lobulated bursa.
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!'''Horses'''
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!'''[[Lungworm - Donkey|Donkeys]]'''
  
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The embryonated eggs are 80-100µm in length.
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|-  
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|'''Prevalence'''
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|10-20% 
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|75%
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|-
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|'''Adult worms'''
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|Few
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|Many
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|-
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|'''Eggs in faeces'''
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|Often zero
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|Many
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|-
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|'''Period of patency'''
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|<8months
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|5+ years
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|-
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|'''Clinical signs'''
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|Sometimes
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|Rarely
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|}
  
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==Life Cycle==
 
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The lifecycle is not greatly known, but it is currently thought to be similar to that of ''[[Dictyocaulus viviparus]]''.
 
  
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The prepatent period is 2-3 months.
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'''NOTE''': Clinical signs - chronic cough at rest or during exercise, single animal or group of horses, autumn or early winter.
  
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{{Learning
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*''Dictyocaulus arnfieldi'' causes [[Respiratory Parasitic Infections - Pathology#Dictyocaulus arnfieldi|cough in horses]]
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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=%22Dictyocaulus+arnfieldi%22&occuring1=title&rowId=2&options2=AND&q2=&occuring2=freetext&rowId=3&options3=AND&q3=&occuring3=freetext&x=42&y=10&publishedstart=yyyy&publishedend=yyyy&calendarInput=yyyy-mm-dd&la=any&it=any&show=all ''Dictyocaulus arnfieldi'' publications]
 
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|Vetstream = [https://www.vetstream.com/canis/search?s=nematode Nematodes]
 
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}}
 
  
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==== Pathogenicity ====
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*Raised areas of over-inflated pulmonary tissue (several cms in diameter) surrounding small bronchus containing worms and mucopurulent exudate.
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*Hyperplastic bronchial epithelium.
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*Peribronchial "cuffing".
  
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{{review}}
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==== Diagnosis ====
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*Clinical signs.
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*Grazing history (donkey contact or shared grazing).
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*Faecal examination (only detects patent infections = small proportion of lungworm infections in horses):
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**process sample immediately = McMaster method, embryonated eggs
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**process sample later = Baerman technique, larvae with tail spine.
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*Tracheobronchial washings (large eosinophils).
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*Response to anthelmintic treatment (e.g. resolution of clinical signs = retrospective diagnosis).
  
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{{OpenPages}}
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==== Control ====
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*Do not keep horses on pastures grazed by donkeys (potential carriers).
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*Treat donkeys with appropriate anthelmintic in spring if grazed with horses.
  
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*Found in smaller [[Bronchi and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|bronchi]]
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*Cause of chronic cough
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*Donkeys are a reservoir mostly without any clinical signs
 +
*Gross pathology:
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**Raised areas of over-inflated pulmonary tissue surrounding small bronchus, containing worms and mucopurulent exudate
 +
**Hyperplastic bronchial epithelium
 +
**Coiled worms in small bronchi
 +
**Peribronchial cuffing
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**In caudal lung lobes
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*Histologically
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**Central coiled parasites and associated chronic catharral bronchitis
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**Goblet cell hyperplasia
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**Lymphoid cell infiltration
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*In [[Hindgut Fermenters - Horse - Anatomy & Physiology|horses]], the worms usually fail to achieve sexual maturity
  
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[[Category:Dictyocaulus]][[Category:Horse_Nematodes]]
 
  
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[[Category:Expert_Review]]
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[[Category:Trichostrongyloidea]][[Category:Horse_Nematodes]]
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[[Category:To_Do_-_Max]]
 
[[Category:Respiratory Parasitic Infections]]
 
[[Category:Respiratory Parasitic Infections]]

Revision as of 09:05, 22 July 2010

Lungworm

Dictyocaulus arnfieldi from horse faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona

General

  • Lungworm of equidae; adult worms found in smaller bronchi. Frequently incriminated as the cause of a chronic cough.

Morphology and Life-Cycle

  • Similar to lungworm in cattle, except:
    • embryonated eggs (80-100µm) passed in fresh faeces; and
    • prepatent period = 12weeks.

Epidemiology

  • Main source of infection = donkeys (remain infected for years) - contaminate horse pasture.
  • Infection can cycle in horses.


Horses Donkeys
Prevalence 10-20% 75%
Adult worms Few Many
Eggs in faeces Often zero Many
Period of patency <8months 5+ years
Clinical signs Sometimes Rarely


NOTE: Clinical signs - chronic cough at rest or during exercise, single animal or group of horses, autumn or early winter.

Pathogenicity

  • Raised areas of over-inflated pulmonary tissue (several cms in diameter) surrounding small bronchus containing worms and mucopurulent exudate.
  • Hyperplastic bronchial epithelium.
  • Peribronchial "cuffing".

Diagnosis

  • Clinical signs.
  • Grazing history (donkey contact or shared grazing).
  • Faecal examination (only detects patent infections = small proportion of lungworm infections in horses):
    • process sample immediately = McMaster method, embryonated eggs
    • process sample later = Baerman technique, larvae with tail spine.
  • Tracheobronchial washings (large eosinophils).
  • Response to anthelmintic treatment (e.g. resolution of clinical signs = retrospective diagnosis).

Control

  • Do not keep horses on pastures grazed by donkeys (potential carriers).
  • Treat donkeys with appropriate anthelmintic in spring if grazed with horses.
  • Found in smaller bronchi
  • Cause of chronic cough
  • Donkeys are a reservoir mostly without any clinical signs
  • Gross pathology:
    • Raised areas of over-inflated pulmonary tissue surrounding small bronchus, containing worms and mucopurulent exudate
    • Hyperplastic bronchial epithelium
    • Coiled worms in small bronchi
    • Peribronchial cuffing
    • In caudal lung lobes
  • Histologically
    • Central coiled parasites and associated chronic catharral bronchitis
    • Goblet cell hyperplasia
    • Lymphoid cell infiltration
  • In horses, the worms usually fail to achieve sexual maturity
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