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| | '''[[Oestrus ovis|''Oestrus ovis'']] | | '''[[Oestrus ovis|''Oestrus ovis'']] |
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| | + | '''[[Gasterophilus spp.|''Gasterophilus spp.'']] |
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| | </big> | | </big> |
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| − | ===''Gasterophilus spp.''===
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| − | [[Image:Horse Bot Fly.jpg|thumb|right|150px|Horse Bot Fly - Dennis Ray - Wikimedia Commons]]
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| − | *Also known as the horse bot fly
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| − |
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| − | *Obligate parasites of equids
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| − |
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| − | *Spend most of life cycle in the equine stomach
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| − | **Of little pathogenic significance
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| − |
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| − | *Three important species (in the UK)
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| − | **''G. intestinalis'' which is the most common
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| − | **''G. nasalis''
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| − | **''G. haemorrhoidalis'' which is rare
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| − |
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| − | *Two other important veterinary species
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| − | **''G. nigricornis''
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| − | **''G. inermis''
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| − | '''Recognition'''
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| − | *Medium to large flies at 10-20mm long
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| − |
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| − | *Look similar to drone bumble bees
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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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| − |
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| − | *Clear wings with brown patches
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| − |
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| − |
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| − | '''Life cycle'''
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| − | *Adults are most active in '''late summer'''
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| − |
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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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| − | **''G. intestinalis'' eggs are laid in the hair of the shoulders and fore legs
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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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| − |
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| − | *Creamy-white eggs
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| − |
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| − | *1-2mm in length
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| − |
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| − | *Larvae crawl into the mouth and penetrate the tissues of the tongue and buccal mucosa
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| − |
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| − | *Larvae then emerge after a couple of weeks and are swallowed
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| − |
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| − | *Larvae pass into the [[Forestomach - Anatomy & Physiology|stomach]] and attach to the gastric mucosa
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| − | **Larvae are now known as '''bots'''
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| − |
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| − | *Each species attaches to a specific part of the stomach
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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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| − |
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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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| − | **''G. haemorrhoidalis'' attaches to the rectal mucosa before being passed out
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| − |
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| − | *Larvae pupate on the ground
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| − |
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| − | *Adults hatch after 1-2 months and survive from a few days to 2 weeks
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| − | **Adults have non-functional mouthparts so cannot feed
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| − |
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| − | *There is only '''1 generation per year''' in temperate regions of the world
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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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| − |
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| − | *Larvae cause a marked inflammatory reaction when attached to the gastric mucosa
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| − | **Ring like thickening around the base of each attached larvae
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| − |
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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]] | | [[Category:Parasites]][[Category:Flies]][[Category:Myiasis Producing Flies]] |