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| − | {{toplink
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| − | |backcolour =
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| − | |linkpage =Insecta
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| − | |linktext =INSECTA
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| − | |pagetype=Bugs
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| − | |sublink1=Parasites
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| − | |subtext1=PARASITES
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| − | }}
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| − | <br>
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| − | ==Introduction==
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| − | Myiasis is the parasitism of living animals by dipteran larvae. Myiasis can be oligatory or facultative (optional) and is described as cutaneous, nasal or somatic.
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| − | ==Oestridae==
| + | #REDIRECT[[:Category:Myiasis Producing Flies]] |
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| − | *The larvae of Oestridae spp. are '''obligatory''' parasites
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| − | *The three important species of veterinary interest are ''Hypoderma'', ''Oestrus'' and ''Gasterophilus''
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| − | ===''Hypoderma'' spp.===
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| − | *Also known as warble flies
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| − | *Important cattle parasites
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| − | **Also parasitise horses, small ruminants and sometimes humans
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| − | *The two main species in cattle are ''H. bovis'' and ''H. lineatum''
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| − | *''H. diana'' parasitises deer
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| − | *Infestation is largely confined to the Northern Hemisphere
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| − | '''Recognition'''
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| − | *Large 13-15mm long
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| − | *Similar to bumble bees in appearance
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| − | **Yellow abdomen
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| − | *Band of black hairs
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| − | *One pair of wings
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| − | '''Life Cycle'''
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| − | *Adult flies emerge on warm, sunny days between June and August
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| − | *White eggs are laid around the belly and legs of the animal
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| − | **Eggs are attached to hairs by cement and a small terminal clasp
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| − | **''H. lineatum'' lays a whole row of eggs as it approaches the animal stealthily
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| − | **''H. bovis'' only deposits a single egg before the animal runs away (''''gadding''') as it makes a loud buzzing noise
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| − | *The adult lives for 3 weeks
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| − | *Females can lay several hundred eggs in their life
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| − | *A few days after eggs are laid, larvae emerge and crawl down the hairs into the hair follicles
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| − | *Larvae penetrate the skin through wounds made by [[Biting Flies - WikiBlood|biting flies]]
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| − | *Larvae migrate through the subcutaneous tissue towards the diaphragm
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| − | **Enzymatic secretions and mouth hooks aids larval migration
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| − | *After 3 months larvae reach '''winter resting sites''' where they remain from November to Feburary/March whilst moulting to the L2 stage
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| − | **Epidural fat in the spinal canal for ''H. bovis''
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| − | **Wall of the oesophagus for ''H. lineatum''
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| − | *Larvae then migrate back to the subcutis along the midline of the back where they bore a breathing hole through the skin and moult to the L3 stage
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| − | **Larvae are palpable as distinct swellings called '''warbles'''
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| − | *L3 larvae emerge after 4-10 weeks where they fall to the ground and pupate under loose vegetation
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| − | *Adult flies emerge from the pupa after one month where they copulate, lay eggs and die within two weeks
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| − | *''H. lineatum'' are on the wing 6-8 weeks before ''H. bovis''
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| − | *There is only '''one''' generation of warble flies per year
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| − | '''Pathogenesis'''
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| − | *Causes[[Muscles Inflammatory - Pathology#Arthropods| myositis]]
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| − | *Production losses
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| − | **Condemnation and down-grading of hides
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| − | **Reduced milk yield and reduced weight gain
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| − | **Injury from stock panic
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| − | **Trimmed meat losses from ''H. lineatum''
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| − | ***'Butcher's Jelly' around warbles which is green due to mass [[Eosinophils - WikiBlood|eosinophil]] attraction
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| − | *Paraplegia resulting from:
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| − | **Toxin release
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| − | **Pressure on the spinal cord (''H. bovis'')
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| − | **Bloat from pressue on the oesophageal wall (''H. lineatum'')
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| − | '''Control'''
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| − | *Total eradication should be aimed for
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| − | *Old methods include popping out warbles
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| − | **But could lead to anaphylactic shock
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| − | *[[Ectoparasiticides]]
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| − | **Systemic organophosphorus [[Ectoparasiticides|insecticides]] in pour-on formula
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| − | **Avermectins and milbemycins in pour-on and injectible formulations
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| − | *Timing is crucial for treatment
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| − | **Larvae residing in winter resting sites, if killed, can lead to bloat and paraplegia
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| − | **It is safe to treat in the '''autumn''' before larvae reach their winter resting sites and in the '''spring''' when the warbles have migrated to the midline of the back
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| − | **Ivermectin can be given at any time without risking host infection as larval antigen is released much slower
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| − | '''Legislation in the UK'''
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| − | *'Warble Fly Order 1978' requires all clinically affected animals to be treated
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| − | *Notifiable disease
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| − | *'Warble Fly Infected Area Order 1983'
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| − | *For more information on the warble fly orders, see[http://www.defra.gov.uk/animalh/diseases/notifiable/brucellosis/surveillance.htm| here]
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| − | ===''Oestrus ovis''===
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| − | *Also known as the sheep nasal bot fly
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| − | '''Recognition'''
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| − | '''Life Cycle'''
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| − | '''Pathogenesis'''
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| − | *[[Respiratory Parasitic Infections - Pathology#Oestrus ovis|Apthology in the nasal cavity]]
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| − | '''Control'''
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| − | ===''Gasterophilus'' spp.===
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| − | *Also known as the horse bot fly
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| − | '''Recognition'''
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| − | '''Life Cycle'''
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| − | '''Pathogenesis'''
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| − | '''Control'''
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| − | ===''Dermatobia hominis''===
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| − | '''Recongition'''
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| − | '''Life Cycle'''
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| − | '''Pathogenesis'''
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| − | '''Control'''
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| − | ==Calliphoridae==
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| − | '''Recongition'''
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| − | '''Life Cycle'''
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| − | '''Pathogenesis'''
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| − | '''Control'''
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| − | ==Screw Worm Myiasis==
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| − | '''Recongition'''
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| − | '''Life Cycle'''
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| − | '''Pathogenesis'''
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| − | '''Control'''
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| − | ==''Wohlfahrtia'' sp.==
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| − | '''Recongition'''
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| − | '''Life Cycle'''
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| − | '''Pathogenesis'''
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| − | '''Control'''
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| − | ==Links==
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| − | *[[Viruses]]
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| − | *[[Ectoparasiticides]]
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