Difference between revisions of "Filaroides osleri"

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=== '''''FILAROIDES (= Oslerus) OSLERI''''' ===
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{{OpenPagesTop}}
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*''F. osleri'' is atypical of the Metastrongyloidea in almost every way.
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Also known as: '''''Dog lungworm — Oslerus osleri'''''
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*Adults (approximately 1cm) are found in dogs clustered in fibrous nodules (few mm - 2cm) on tracheal wall (near bifurcation of trachea).
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{{Taxobox
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*This means that small numbers of L1 are found in the sputum, and can either be passed to the skin during grooming, or can be passed in the faeces (dead-end for life-cycle).
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|name              = ''Filaroides osleri
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*Transmission from bitch to pups occurs during grooming via transfer of sputum.
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|kingdom            =Animalia
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*Horizontal transmission rarely, if ever, happens.
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|phylum            =[[Nematodes|Nematoda]]
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*Infection is usually asymptomatic, but if symptoms are present, there is a chronic, dry, debilitating cough - performance of greyhounds may be affected.
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|class              =Secernentea
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|sub-class          =
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|order              =Strongylida
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|super-family      =[[:Category:Metastrongyloidea|Metastrongyloidea]]
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|family            =Filaroididae
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|sub-family        =
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|genus              =Filaroides
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|species            = ''Filaroides osleri
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}}
  
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=== ''Filaroides'' Infections ===
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==Introduction==
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*''F. osleri'' is usually associated with particular boarding kennels.
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''Filaroides osleri'' is a [[:Category:Metastrongyloidea|metastrongyloid]] nematode that lives in '''granulomatous nodules''' located on the mucosal surface of the '''distal trachea, tracheal bifurcation and first division bronchi''' in '''dogs''' and wild canid species.
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*Diagnosis and treatment are difficult.
 
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*The Baermann apparatus is used to recover L1 from faeces.
 
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*Larvae are, however, few in number and have sluggish movements.
 
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*They may, therefore, be very difficult to demonstrate in faeces or sputum.
 
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*Endoscopy (to visualise the tracheal nodules) is often required to confirm diagnosis.
 
  
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Fenbendazole is licensed for the treatment.
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==Identification==
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The adults are pale, thin [[:Category:Nematodes|nematodes]]. The female is larger than the male, at around 9-15mm in length.
  
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==Life Cycle==
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This is a direct life cycle, so forms the exception in the superfamily [[:Category:Metastrongyloidea|'''Metastrongyloidea''']]. The females are ovo-viviparous. The eggs are laid, and hatch within the trachea. They then transform into the larvae, which are coughed up and swallowed. They enter the intestine, and are passed out in the feces.
  
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* = ''Oslerus osleri''
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The bitch may transfer the larvae to the pup '''during grooming''', or infection may come about via '''ingestion of the larvae'''. The larvae '''mature and travel to the lungs'''.
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*Colonise the [[Trachea Inflammatory - Pathology#Infectious causes of tracheitis|trachea of dogs]]
 
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*Larva and adults accumulate in submucosal nodules of up to 1cm diameter at the tracheal bifurcation.  
 
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*Minimal inflammatory host reaction to the nematodes when they are alive - the size of the nodule is related to the number and size of the nematodes within it.
 
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*When the parasites die, an intense foreign body reaction develops
 
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*Tracheal nodules can cause coughing, usually in young dogs <18 months old.
 
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*Severe infestation can cause significant occlusion of the airway.
 
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*Uncommon, but sometimes seen in coughing greyhounds
 
  
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The prepatent period is '''10-18 weeks'''.
  
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==Clinical Signs==
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The primary clinical sign is a '''chronic cough'''. Progressively enlarging granulomatous nodules may obstruct airflow and lead to signs such as '''exercise intolerance, dyspnoea or even death'''.
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'''Spontaneous pneumothorax''' can occur extremely rarely.
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==Diagnosis==
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The tracheobronchial nodules may occasionally be detected '''radiographically''' as large, space-occupying masses protruding into the tracheal lumen near the bifurcation.
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'''Bronchoscopic visualisation''' is the best way to detect the mucosal nodules.
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'''Bronchial washings''' may then reveal larvated ova and larvae with a kinked tail.
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'''Feces''' can be examined for larvae, but this is less rewarding.
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'''Zinc-sulphate centrifugation/flotation''' is preferred to the Baermann method as the larvae are lethargic and do not migrate out of the fecal mass.
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==Treatment==
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Endoscopic examination and '''removal of the nodules''' is essential for a successful outcome.
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A good clinical response may be seen using extended courses of '''ivermectin, fenbendazole, albendazole and levamisole'''. This does not always clear the nodules on follow-up bronchoscopy.
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In a '''breeding colony''', bitches should be '''treated before whelping''', and pups should be separated from older infected dogs to prevent horizontal transmission by ingestion of infected feces. In infected dogs, good hygiene is essential, and pups could be '''hand-raised''' or foster-reared on uninfected bitches.
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{{Learning
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|literature search = [http://www.cabdirect.org/search.html?rowId=1&options1=AND&q1=%22Filaroides+osleri%22&occuring1=title&rowId=2&options2=OR&q2=%22Osterus+osleri%22&occuring2=title&rowId=3&options3=AND&q3=&occuring3=freetext&x=51&y=13&publishedstart=yyyy&publishedend=yyyy&calendarInput=yyyy-mm-dd&la=any&it=any&show=all ''Filaroides osleri'' publications]
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|Vetstream = [https://www.vetstream.com/canis/search?s=nematode Nematodes]
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}}
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==References==
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Taylor, M.A, Coop, R.L., Wall,R.L. (2007) '''Veterinary Parasitology''' ''Blackwell Publishing''
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King, L. (2004) '''Textbook of respiratory disease in dogs and cats''' ''Elsevier Health Sciences''
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Pinckney, R. D. (2000) '''Canine Filaroides infection in Companion and Exotic Animal Parasitology''' ''IVIS publication''
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{{review}}
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{{OpenPages}}
  
 
[[Category:Metastrongyloidea]][[Category:Dog_Nematodes]]
 
[[Category:Metastrongyloidea]][[Category:Dog_Nematodes]]
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[[Category:To_Do_-_Parasites]]
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[[Category:Expert_Review - Small Animal]]
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[[Category:Respiratory Parasitic Infections]]
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[[Category:Respiratory Diseases - Dog]]

Latest revision as of 19:09, 29 September 2018


Also known as: Dog lungworm — Oslerus osleri

Filaroides osleri
Kingdom Animalia
Phylum Nematoda
Class Secernentea
Order Strongylida
Super-family Metastrongyloidea
Family Filaroididae
Genus Filaroides
Species Filaroides osleri

Introduction

Filaroides osleri is a metastrongyloid nematode that lives in granulomatous nodules located on the mucosal surface of the distal trachea, tracheal bifurcation and first division bronchi in dogs and wild canid species.

Identification

The adults are pale, thin nematodes. The female is larger than the male, at around 9-15mm in length.

Life Cycle

This is a direct life cycle, so forms the exception in the superfamily Metastrongyloidea. The females are ovo-viviparous. The eggs are laid, and hatch within the trachea. They then transform into the larvae, which are coughed up and swallowed. They enter the intestine, and are passed out in the feces.

The bitch may transfer the larvae to the pup during grooming, or infection may come about via ingestion of the larvae. The larvae mature and travel to the lungs.

The prepatent period is 10-18 weeks.

Clinical Signs

The primary clinical sign is a chronic cough. Progressively enlarging granulomatous nodules may obstruct airflow and lead to signs such as exercise intolerance, dyspnoea or even death.

Spontaneous pneumothorax can occur extremely rarely.

Diagnosis

The tracheobronchial nodules may occasionally be detected radiographically as large, space-occupying masses protruding into the tracheal lumen near the bifurcation.

Bronchoscopic visualisation is the best way to detect the mucosal nodules.

Bronchial washings may then reveal larvated ova and larvae with a kinked tail.

Feces can be examined for larvae, but this is less rewarding.

Zinc-sulphate centrifugation/flotation is preferred to the Baermann method as the larvae are lethargic and do not migrate out of the fecal mass.

Treatment

Endoscopic examination and removal of the nodules is essential for a successful outcome.

A good clinical response may be seen using extended courses of ivermectin, fenbendazole, albendazole and levamisole. This does not always clear the nodules on follow-up bronchoscopy.

In a breeding colony, bitches should be treated before whelping, and pups should be separated from older infected dogs to prevent horizontal transmission by ingestion of infected feces. In infected dogs, good hygiene is essential, and pups could be hand-raised or foster-reared on uninfected bitches.


Filaroides osleri Learning Resources
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Vetstream
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(CABI log in required) 		Filaroides osleri publications


References

Taylor, M.A, Coop, R.L., Wall,R.L. (2007) Veterinary Parasitology Blackwell Publishing

King, L. (2004) Textbook of respiratory disease in dogs and cats Elsevier Health Sciences

Pinckney, R. D. (2000) Canine Filaroides infection in Companion and Exotic Animal Parasitology IVIS publication


This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing.



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