| Line 4: |
Line 4: |
| | *The ''Calliphoridae'' family are '''facultative''' parasites | | *The ''Calliphoridae'' family are '''facultative''' parasites |
| | | | |
| − | *Cause '''blowfly strike''' | + | *Cause <big>[[Blowfly Strike|'''blowfly strike''']] |
| | | | |
| | *If the fly lays eggs on an animal, the animal is said to be '''blown''' | | *If the fly lays eggs on an animal, the animal is said to be '''blown''' |
| Line 77: |
Line 77: |
| | | | |
| | | | |
| − | '''Epidemiology'''
| + | [[Category:Parasites]][[Category:Flies]][[Category:Myiasis_Producing_Flies]] |
| − | <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]]
| |