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Created page with '==== Epidemiology ==== *Main source of infection = donkeys (remain infected for years) - contaminate horse pasture. *Infection can cycle in horses. {| style="width:75%; height:…'
==== 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.

*''Dictyocaulus arnfieldi'' causes [[Respiratory Parasitic Infections - Pathology#Dictyocaulus arnfieldi|cough in horses]]

==== 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 and Bronchioles Inflammatory - Pathology#Infectious causes of bronchitis or bronchiolitis|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 [[Hindgut Fermenters - Horse - Anatomy & Physiology|horses]], the worms usually fail to achieve sexual maturity
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