Difference between revisions of "Gasterophilus spp."

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(Created page with 'thumb|right|150px|Horse Bot Fly - Dennis Ray - Wikimedia Commons *Also known as the horse bot fly *Obligate parasites of equids *Spend most of life …')
 
 
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[[Image:Horse Bot Fly.jpg|thumb|right|150px|Horse Bot Fly - Dennis Ray - Wikimedia Commons]]
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{{OpenPagesTop}}
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*Also known as the horse bot fly
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{{Taxobox
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|name              =''Gasterophilus spp.
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|kingdom            = Animalia
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|phylum            = [[:Category:Arthropods|Arthropoda]]
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|class              =[[:Category:Insecta|Insecta]]
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|sub-class          = Diptera
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|order              =
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|super-family      =
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|family            =[[Oestridae]]
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|sub-family        =
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|genus              = Gasterophilus
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|species            =
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}}
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[[Image:Horse Bot Fly.jpg|thumb|right|150px|''Horse Bot Fly'' <br> Dennis Ray 2005, Wikimedia Commons]]
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Also known as: '''''Bot Fly — Bots'''
  
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*Obligate parasites of equids
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==Introduction==
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The species ''Gasterophilus'' is of the family [[Oestridae]], and is more commonly referred to as the 'Bot fly.'  It is an obligate parasite found on horses, donkeys, mules, zebras and elephants. 
  
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*Spend most of life cycle in the equine stomach
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Infection is particularly common in horses, with around 30-60% infected during the winter months.
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**Of little pathogenic significance
 
  
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*Three important species (in the UK)
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Within the United Kingdom there are three species of veterinary importance;
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**''G. intestinalis'' which is the most common
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''G. intestinalis'' which is the most common, and ''G. nasalis'', and ''G. haemorrhoidalis'' which are rare.
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**''G. nasalis''
 
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**''G. haemorrhoidalis'' which is rare
 
  
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*Two other important veterinary species
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''G. nigricornis'' and ''G. inermis'' are also of veterinary significance, but not currently within the UK.
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**''G. nigricornis''
 
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**''G. inermis''
 
  
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[[Image:Gasterophilus larvae.jpg|150px|thumb|right|''Gasterophilus larvae'' <br> Lamiot 2007, Wikimedia Commons]]
  
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'''Recognition'''
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==Identification==
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*Medium to large flies at 10-20mm long
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Gasterophilus are medium to large flies at 10-20mm long, and are thought to look similar to drone bumble bees.
  
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*Look similar to drone bumble bees
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They have clear wings with brown patches, and produce creamy-white eggs, around 1-2mm in length
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**Body covered with dense yellow hair
 
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**Dark coloured hairs produce a banding pattern
 
  
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*Clear wings with brown patches
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Adults have non-functional mouthparts so cannot feed.
  
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Both ''G. haemorrhoidalis'' and ''G. nasalis'' have spikes on the ventral surface of the larval segments arranged in two rows. ''G. intestinalis'' have mouth parts that are not uniformly curved dorsally and the body spikes present have blunt ended tips.
  
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'''Life cycle'''
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==Life Cycle==
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*Adults are most active in '''late summer'''
 
  
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*Eggs are laid on the body and hatch spontaneously or are stimulated to hatch through an increase in warmth and moisture from the animal self-grooming. They are laid in different areas according to species
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Eggs are laid on the body of the host and either hatch spontaneously or are stimulated to hatch through an increase in warmth and moisture from the animal self-grooming. They are laid in different areas according to species;
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**''G. intestinalis'' eggs are laid in the hair of the shoulders and fore legs
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''G. intestinalis'' eggs are laid in the hair of the shoulders and forelegs. ''G. nasalis'' eggs are laid in the intermandibular area. ''G. haemorrhoidalis'' eggs are laid around the lips
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**''G. nasalis'' eggs are laid in the intermandibular area
 
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**''G. haemorrhoidalis'' eggs are laid around the lips
 
  
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*Creamy-white eggs
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L1 are extremely small and motile, and begin development in the mouth, tongue and gums of the host.  The development of L1 into L2 occurs on the pharynx.  L2 then attaches to the base of the tongue and slowly migrates to the stomach.
  
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*1-2mm in length
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L3 attaches to the squamous gastric mucosa along the margo plicatus, in the case of ''G. intestinalis''. ''G. nasalis'' attaches to the dorsoproximal part of the duodenum, and ''G. haemorrhoidalis'' attaches to the gastric epithelium within the stomach.
  
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*Larvae crawl into the mouth and penetrate the tissues of the tongue and buccal mucosa
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The larvae then remain and develop within the stomach for around 10-12 months.  They mature in the following spring or early summer (generally between May and September), detach from their surface and are passed out in the host faeces. ''G. haemorrhoidalis'' also attaches to the rectal mucosa before being passed out.
  
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*Larvae then emerge after a couple of weeks and are swallowed
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[[Image:Gasterophilus.jpg|200px|thumb|right|''Gasterophilus'' <br> Notafly 2008, Wikimedia Commons]]
  
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*Larvae pass into the [[Forestomach - Anatomy & Physiology|stomach]] and attach to the gastric mucosa
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The larvae then penetrate the soil, where they transform into pupae and the flies hatch 30 to 40 days later.
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**Larvae are now known as '''bots'''
 
  
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*Each species attaches to a specific part of the stomach
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They are only found on pasture, as they do not survive well on stable bedding.  The pupae are known to be sensitive to frost, moisture and flooding, so the environmental conditions present play a significant role in the success of the parasite.
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**''G. intestinalis'' attaches to the cardiac region
 
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**''G. nasalis'' attaches to the pylorus
 
  
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*After 10-12 months in the stomach, the larvae detach and are passed out in the faeces
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{{Learning
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**''G. haemorrhoidalis'' attaches to the rectal mucosa before being passed out
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|flashcards = [[Myiasis_Producing_Flies_Flashcards|Myiasis Producing Flies Flashcards]]
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|literature search =[http://www.cabdirect.org/search.html?q=title%3A%28%22Gasterophilus%22%29+ ''Gasterophilus'' spp. publications]
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|Vetstream = [https://www.vetstream.com/canis/Content/Disease/dis60301.asp Myiasis]
 +
}}
  
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*Larvae pupate on the ground
 
  
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*Adults hatch after 1-2 months and survive from a few days to 2 weeks
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{{review}}
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**Adults have non-functional mouthparts so cannot feed
 
  
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*There is only '''1 generation per year''' in temperate regions of the world
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{{OpenPages}}
  
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[[Category:Oestridae]]
  
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'''Pathogenesis'''
 
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*Adults cause annoyance when egg laying
 
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**Disturbance and panic can ensue
 
  
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*Larvae cause a marked inflammatory reaction when attached to the gastric mucosa
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[[Category:Expert_Review]]
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**Ring like thickening around the base of each attached larvae
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[[Category:Horse Parasites]]
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*Large numbers of larvae may interfere with the passage of food and action of gastric sphincters
 
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*''G. haemorrhoidalis'' can cause mild irritation to the rectal wall
 
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*Host reaction to larvae in the mouth is minimal
 
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'''Control'''
 
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*Treatment of horses with [[Ectoparasiticides|insecticides]] over winter
 
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**Breaks the life cycle as all the population are present as bots in the [[Forestomach - Anatomy & Physiology|stomach]]
 
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*If eggs are present in late summer, the horse's coat can be sponged with an [[Ectoparasiticides|insecticide]]
 
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**Stimulates hatching
 
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**Kills larvae
 
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[[Category:Parasites]][[Category:Flies]][[Category:Myiasis_Producing_Flies]]
 

Latest revision as of 17:32, 4 June 2016


Gasterophilus spp.
Kingdom Animalia
Phylum Arthropoda
Class Insecta
Sub-class Diptera
Family Oestridae
Genus Gasterophilus
Horse Bot Fly
Dennis Ray 2005, Wikimedia Commons

Also known as: Bot Fly — Bots

Introduction

The species Gasterophilus is of the family Oestridae, and is more commonly referred to as the 'Bot fly.' It is an obligate parasite found on horses, donkeys, mules, zebras and elephants.

Infection is particularly common in horses, with around 30-60% infected during the winter months.

Within the United Kingdom there are three species of veterinary importance; G. intestinalis which is the most common, and G. nasalis, and G. haemorrhoidalis which are rare.

G. nigricornis and G. inermis are also of veterinary significance, but not currently within the UK.

Gasterophilus larvae
Lamiot 2007, Wikimedia Commons

Identification

Gasterophilus are medium to large flies at 10-20mm long, and are thought to look similar to drone bumble bees.

They have clear wings with brown patches, and produce creamy-white eggs, around 1-2mm in length

Adults have non-functional mouthparts so cannot feed.

Both G. haemorrhoidalis and G. nasalis have spikes on the ventral surface of the larval segments arranged in two rows. G. intestinalis have mouth parts that are not uniformly curved dorsally and the body spikes present have blunt ended tips.

Life Cycle

Eggs are laid on the body of the host and either hatch spontaneously or are stimulated to hatch through an increase in warmth and moisture from the animal self-grooming. They are laid in different areas according to species; G. intestinalis eggs are laid in the hair of the shoulders and forelegs. G. nasalis eggs are laid in the intermandibular area. G. haemorrhoidalis eggs are laid around the lips

L1 are extremely small and motile, and begin development in the mouth, tongue and gums of the host. The development of L1 into L2 occurs on the pharynx. L2 then attaches to the base of the tongue and slowly migrates to the stomach.

L3 attaches to the squamous gastric mucosa along the margo plicatus, in the case of G. intestinalis. G. nasalis attaches to the dorsoproximal part of the duodenum, and G. haemorrhoidalis attaches to the gastric epithelium within the stomach.

The larvae then remain and develop within the stomach for around 10-12 months. They mature in the following spring or early summer (generally between May and September), detach from their surface and are passed out in the host faeces. G. haemorrhoidalis also attaches to the rectal mucosa before being passed out.

Gasterophilus
Notafly 2008, Wikimedia Commons

The larvae then penetrate the soil, where they transform into pupae and the flies hatch 30 to 40 days later.

They are only found on pasture, as they do not survive well on stable bedding. The pupae are known to be sensitive to frost, moisture and flooding, so the environmental conditions present play a significant role in the success of the parasite.


Gasterophilus spp. Learning Resources
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Vetstream
To reach the Vetstream content, please select 		Canis, Felis, Lapis or Equis
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Flashcards
Test your knowledge using flashcard type questions 		Myiasis Producing Flies Flashcards
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Literature Search
Search for recent publications via CAB Abstract
(CABI log in required) 		Gasterophilus spp. publications



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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