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Created page with '== Lungworm == === ''DICTYOCAULUS ARNFIELDI'' === ==== General ==== *Lungworm of equidae; adult worms found in smaller bronchi. Frequently incriminated as the cause of a chronic …'
== Lungworm ==
=== ''DICTYOCAULUS ARNFIELDI'' ===
==== 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.


{| style="width:75%; height:200px" border="1"

!
!'''Horses'''
!'''[[Lungworm - Donkey|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.
[[Category:Trichostrongyloidea]][[Category:Horse_Nematodes]]
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