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Myiasis Producing Flies (view source)
Revision as of 21:06, 7 November 2008
, 21:06, 7 November 2008no edit summary
[[Image:Horse Bot Fly.jpg|thumb|right|150px|Horse Bot Fly - Dennis Ray - Wikimedia Commons]]
[[Image:Horse Bot Fly.jpg|thumb|right|150px|Horse Bot Fly - Dennis Ray - Wikimedia Commons]]
*Also known as the horse bot fly
*Also known as the horse bot fly
*Obligate parasites of equids
*Spend most of lifecycle in equine stomach
**Cause little pathogenesic significance
*Three important species (in the UK)
**''G. intestinalis'' which is the most common
**''G. nasalis''
**''G. haemorrhoidalis'' which is rare
*Two other important veterinary species
**''G. nigricornis''
**''G. inermis''
'''Recognition'''
'''Recognition'''
*Medium to large flies at 10-20mm long
*Look similar to drone bumble bees
**Body covered with dense yellow hair
**Dark coloured hairs produce a banding pattern
*Clear wings with brown patches
'''Life Cycle'''
'''Life Cycle'''
*Adults are most active in late summer
*Eggs hatch spontaneously or are stimulated to hatch through an increase in warmth and moisture from the animal self-grooming
**''G. intestinalis''
***Creamy-white eggs
***1-2mm in length
***Eggs laid in the hair of the shoulders and fore legs
**''G. nasalis''
***Eggs laid in the intermandibular area
*''G. haemorrhoidalis''
***Eggs laid around the lips
*Larvae crawl into the mouth and penetrate the tissues of the buccal mucosa which takes a few weeks
*Larvae then emerge and are swallowed
*Larvae pass into the stomach and attach to the gastric mucosa
**Larvae are now known as '''bots'''
*Each species attaches to a specific part of the stomach
**''G. intestinalis'' attaches to the cardiac region
**''G. nasalis'' attaches to the pylorus
*After 10-12 months in the stomach, the larvae detach and are passed out in the faeces
**''G. haemorrhoidalis'' attaches to the rectal mucosa before being passed out
*Larvae pupate on the ground
*Adults hatch after 1-2 months and survive for a few days up to two weeks
**Adults have non-functional mouthparts so cannot feed
*There is only one generation per year in temperate regions of the world
'''Pathogenesis'''
'''Pathogenesis'''
*Adult cause annoyance when egg laying
**Disturbance and panic can ensue
*Larvae cause a marked inflammatory reaction when attached to the gastric mucosa
**Ring like thickening around the base of each attached larvae
*Large numbes of larvae may interfere with the passage of food and action of the sphincters
*''G. haemorrhoidalis'' can cause mild irritation to the rectal wall
**Host reaction to larvae in the mouth is minimal
'''Control'''
'''Control'''
*Treatment of horses with [[Ectoparaciticides|insecticides]] over winter
**Breaks the life cycle as all the population are present as bots in the stomach
*If eggs are present in late summer, the horse's coat can be sponged with an [[ectoparasite|insecticide]]
**Stimulates hatching
**Kills larvae
===''Dermatobia hominis''===
===''Dermatobia hominis''===