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| | The prepatent period is 2-3 months. | | The prepatent period is 2-3 months. |
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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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| − | {| style="width:75%; height:200px" border="1"
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| − | !
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| − | !'''Horses'''
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| − | !'''[[Lungworm - Donkey|Donkeys]]'''
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| − |
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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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| − | '''NOTE''': Clinical signs - chronic cough at rest or during exercise, single animal or group of horses, autumn or early winter.
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| − | *''Dictyocaulus arnfieldi'' causes [[Respiratory Parasitic Infections - Pathology#Dictyocaulus arnfieldi|cough in horses]]
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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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| − |
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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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| − |
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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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| − |
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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
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| − | *Gross pathology:
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| − | **Raised areas of over-inflated pulmonary tissue surrounding small bronchus, containing worms and mucopurulent exudate
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| − | **Hyperplastic bronchial epithelium
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| − | **Coiled worms in small bronchi
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| − | **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:Trichostrongyloidea]][[Category:Horse_Nematodes]] | | [[Category:Trichostrongyloidea]][[Category:Horse_Nematodes]] |
| | [[Category:To_Do_-_Max]] | | [[Category:To_Do_-_Max]] |
| | [[Category:Respiratory Parasitic Infections]] | | [[Category:Respiratory Parasitic Infections]] |
Dictyocaulus arnfieldi from horse faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona
| Also known as:
|
Equine lungworm
|
Scientific Classification
| Class
|
Nematoda
|
| Superfamily
|
Trichodectidae
|
Hosts
Donkeys, and occasionally horses.
Identification
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.
The embryonated eggs are 80-100µm in length.
Life Cycle
The lifecycle is not greatly known, but it is currently thought to be similar to that of Dictyocaulus viviparus.
The prepatent period is 2-3 months.
