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Created page with 'thumb|right|150px|Pollenia rudis (Calliphoridae) - Richard Bartz, Munich - Wikimedia Commons [[Image:Lucilia cuprina.jpg|thumb|right|150px|''Lucilia c…'
[[Image:Calliphoridae.jpg|thumb|right|150px|Pollenia rudis (Calliphoridae) - Richard Bartz, Munich - Wikimedia Commons]]
[[Image:Lucilia cuprina.jpg|thumb|right|150px|''Lucilia cuprina'' - Wikimedia Commons]]
[[Image:Blow fly head.jpg|thumb|right|150px|Blowfly Head Close Up - Martin Pot - Wikimedia Commons]]
*The ''Calliphoridae'' family are '''facultative''' parasites

*Cause '''blowfly strike'''

*If the fly lays eggs on an animal, the animal is said to be '''blown'''

*The damage the larvae cause to the animal is known as '''strike'''

*Worldwide distribution

*Affects sheep mostly
**Rabbits can also be affected


'''Species of veterinary importance in Europe'''
*''Lucilia sericata''; Greenbottle

*''Phormia terra-novae''; Blackbottle

*''Calliphora erythrocephala''; Bluebottle

*''Calliphora vomitoria''; Bluebottle


'''Species of veterinary importance in the Tropics'''
*''Lucilia cuprina''; South Africa and Australia

*''Chrysomya spp.''; Africa, Asia and Australia

*''Wohlfahrtia''; Fleshfly


'''Recognition of Adults'''
*Medium sized flies under 10mm long

*Metallic sheen to abdomen
**Colour depends on species

*Clear wings


'''Recognition of Larvae'''
*Smooth maggots

*10-15mm long

*Spiracles and stigmatic plates on the tail can be used for species differentiation


'''Life cycle'''
*Eggs laid in wounds, soiled fleece and on carrion
**Females attracted by the odour emitted
**Clusters of yellow-cream eggs laid

*Larvae hatch 24 hours later and crawl down onto the skin
**Feed rapidly
**Grow rapidly
**Moult twice before becoming full maggots
**Process takes 1-2 weeks

*Larvae fall to the ground to pupate

*Adult emerges in under 1 week (during summer)

*The female reaches sexual maturity after a protein meal
**Lays eggs in batches of 100-200

*Adult flies survive for 1 month

*'''Four generations can develop between May and September '''
**In warmer climates, up to 9 or 10 generations can develop per year

*Flies can survive the winter as pupae and emerge the next spring


'''Epidemiology'''
<br>Blowflies are divided into categories depending on their ability to initiate strike
*Primary flies are capable of initiating a strike on living sheep. Larvae can penetrate intact skin
**''Lucilia''
**''Phormia''
**''Calliphora spp.''

*Secondary flies cannot initiate a strike. Larvae attack an area already struck or damaged, extending it
**''Calliphora spp.''
**''Chrysomya spp.'' (in warmer climates)

*Tertiary flies attack lesions on carcasses which have become dry
**''Musca''
**''Sarcophaga spp.''


Predisposing factors to flystrike
*Temperature
**Temperature in the spring will determine when the overwintering larvae hatch
**High temperature and humidity will create a microclimate in the fleece, attracting adult flies to lay eggs

*Rainfall
**Persistent rainfall will make the fleece microclimate attractive to adult flies. Females lay eggs after the rain ceases
**Breeds with long, fine wool are the most susceptible

*Host susceptibility
**This is increased when putrefactive odours develop on the fleece due to bacterial decomposition of organic matter following soiling with urine or faeces
**Merino sheep have a narrow breech area with excessive wrinkling making them more susceptible to soiling
**A narrow opening of the penile sheath in rams and wethers may result in accumulation of urine and increase blowfly strike in this area
**Cuts during shearing, fighting and barbed wire will also increase the incidence of blowfly strike


Blowfly season
*Temperate regions in '''June to September'''
**Mostly in unshorn sheep in June
**Lambs from July to September

*Warmer regions have a more prolonged season due to greater number of blowfly generations


'''Pathogenesis'''
*Severe skin damage
**Larvae lacerate skin with oral hooks and liquefy host tissue by secreting proteolytic enzymes

*Skin lesions are extended and deepened
**Secondary blowfly attack
**Flies attracted to odour of decomposing tissue

*Secondary bacterial infection

*Production losses
**Irritation and distress associated with skin lesions
**Poor weight gain (often the first clinical sign)

*Risk of strike is highest in warm, moist weather


'''Clinical signs'''
*Anorexia
*Listlessness
*Animals standing apart from flock

*Fleece may appear darker, be damp and have a foul smell


'''Control'''
*Prophylactic [[Ectoparasiticides|insecticide]] treatment
**Must kill larvae and remain in fleece to prevent flies from laying eggs
**Applied by spraying, dipping, spray race or jetting

*Insect growth regulators
**Pour-on
**2-4 month protection depending upon the product used

*Effective worm control
**To minimise diarrhoea and therefore soiled fleece

*Crutching to prevent soiling

*'Mule's operation'
**Surgical removal of breech skin in Merino breeds

*Tail docking of lambs

*Proper carcass disposal
**Eliminates fly breeding sites

*Vaccination
**Experimental use against ''Luculia cuprina'' in Australia[[Category:Parasites]][[Category:Flies]][[Category:Myiasis_Producing_Flies]]
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