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| Myiasis is the parasitism of living animals by dipteran larvae. Myiasis can be obligatory or facultative (optional) and is described as cutaneous, nasal or somatic. | | Myiasis is the parasitism of living animals by dipteran larvae. Myiasis can be obligatory or facultative (optional) and is described as cutaneous, nasal or somatic. |
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| ==Oestridae== | | ==Oestridae== |
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| *The larvae of ''Oestridae spp.'' are '''obligatory''' parasites | | *The larvae of ''Oestridae spp.'' are '''obligatory''' parasites |
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− | *The three important species of veterinary interest are ''Hypoderma'', ''Oestrus'' and ''Gasterophilus'' | + | *The three important species of veterinary interest |
| + | **''Hypoderma'' |
| + | **''Oestrus'' |
| + | **''Gasterophilus'' |
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− | ===''Hypoderma'' spp.=== | + | |
| + | ===''Hypoderma spp.''=== |
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| *Also known as warble flies | | *Also known as warble flies |
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| **Also parasitise horses, small ruminants and sometimes humans | | **Also parasitise horses, small ruminants and sometimes humans |
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− | *The two main species in cattle are ''H. bovis'' and ''H. lineatum'' | + | *The two main species in cattle are |
| + | **''H. bovis'' |
| + | **''H. lineatum'' |
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| *''H. diana'' parasitises deer | | *''H. diana'' parasitises deer |
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| *Infestation is largely confined to the Northern Hemisphere | | *Infestation is largely confined to the Northern Hemisphere |
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| '''Recognition''' | | '''Recognition''' |
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| *Similar to bumble bees in appearance | | *Similar to bumble bees in appearance |
| **Yellow abdomen | | **Yellow abdomen |
− | *Band of black hairs | + | **Band of black hairs |
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| + | *1 pair of wings |
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− | *One pair of wings
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− | '''Life Cycle''' | + | '''Life cycle''' |
− | *Adult flies emerge on warm, sunny days between June and August | + | *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 | | *White eggs are laid around the belly and legs of the animal |
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| *Larvae migrate through the subcutaneous tissue towards the diaphragm | | *Larvae migrate through the subcutaneous tissue towards the diaphragm |
− | **Enzymatic secretions and mouth hooks aids larval migration | + | **Enzymatic secretions and mouth hooks aid larval migration |
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− | *After 3 months larvae reach '''winter resting sites''' where they remain from November to February/March whilst moulting to the L2 stage | + | *After 3 months larvae reach '''winter resting sites''' where they remain from November to February/March whilst moulting to the L2 stage. These sites are different between the 2 species |
| **Epidural fat in the spinal canal for ''H. bovis'' | | **Epidural fat in the spinal canal for ''H. bovis'' |
| **Wall of the [[Oesophagus - Anatomy & Physiology|oesophagus]] for ''H. lineatum'' | | **Wall of the [[Oesophagus - Anatomy & Physiology|oesophagus]] for ''H. lineatum'' |
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| *L3 larvae emerge after 4-10 weeks where they fall to the ground and pupate under loose vegetation | | *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 | + | *Adult flies emerge from the pupa after 1 month where they copulate, lay eggs and die within 2 weeks |
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| *''H. lineatum'' are on the wing 6-8 weeks before ''H. bovis'' | | *''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 | + | *There is only '''1 generation''' of warble flies per year |
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| '''Pathogenesis''' | | '''Pathogenesis''' |
− | *Causes[[Muscles Inflammatory - Pathology#Arthropods| myositis]] | + | *Causes[[Muscles Inflammatory - Pathology#Arthropods|myositis]] |
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| *Production losses | | *Production losses |
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| ***'Butcher's Jelly' around warbles which is green due to mass [[Eosinophils - WikiBlood|eosinophil]] attraction | | ***'Butcher's Jelly' around warbles which is green due to mass [[Eosinophils - WikiBlood|eosinophil]] attraction |
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− | *Paraplegia resulting from: | + | *Paraplegia resulting from |
| **Toxin release | | **Toxin release |
| **Pressure on the spinal cord (''H. bovis'') | | **Pressure on the spinal cord (''H. bovis'') |
| **Bloat from pressure on the [[Oesophagus - Anatomy & Physiology|oesophageal wall]] (''H. lineatum'') | | **Bloat from pressure on the [[Oesophagus - Anatomy & Physiology|oesophageal wall]] (''H. lineatum'') |
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| '''Control''' | | '''Control''' |
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| *Old methods include popping out warbles | | *Old methods include popping out warbles |
− | **But could lead to anaphylactic shock | + | **But this could lead to anaphylactic shock |
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| *[[Ectoparasiticides]] | | *[[Ectoparasiticides]] |
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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 | | **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 |
| **Ivermectin can be given at any time without risking host infection as larval antigen is released much slower | | **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''' | | '''Legislation in the UK''' |
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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] | | *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''=== | | ===''Oestrus ovis''=== |
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| *Found in most sheep rearing areas of the world | | *Found in most sheep rearing areas of the world |
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| '''Recognition''' | | '''Recognition''' |
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| *Larvae have distinct black bands on each body segment | | *Larvae have distinct black bands on each body segment |
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− | '''Life Cycle'''
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− | *Larvae are squirted into the nostrils of sheep in a jet of liquid
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− | *The larvae crawl caudally into the [[Nasal cavity - Anatomy & Physiology|nasal cavity]] and feed on the nasal mucosa and mature before returning to the nostrils | + | '''Life cycle''' |
| + | *Larvae are squirted into the nostrils of sheep in a jet of liquid by the adult fly |
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| + | *The larvae crawl caudally into the nasal cavity and feed on the nasal mucosa and mature before returning to the nostrils |
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− | *Larval development takes up to two months | + | *Larval development takes up to 2 months |
− | **Larvae can overwinter in the [[Nasal cavity - Anatomy & Physiology|nasal cavity]] if deposited late in the summer | + | **Larvae can overwinter in the nasal cavity if deposited late in the summer |
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| *Once the larvae have developed they are sneezed out and pupate on the ground | | *Once the larvae have developed they are sneezed out and pupate on the ground |
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− | *The adult fly emerges one months later | + | *The adult fly emerges 1 months later |
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| *Adult flies only live for 2-3 weeks | | *Adult flies only live for 2-3 weeks |
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| '''Pathogenesis''' | | '''Pathogenesis''' |
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| *[[Respiratory Parasitic Infections - Pathology#Oestrus ovis|Pathology in the nasal cavity]] | | *[[Respiratory Parasitic Infections - Pathology#Oestrus ovis|Pathology in the nasal cavity]] |
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| '''Control''' | | '''Control''' |
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| *In warmer countries, strategic prophylactic treatment can be used | | *In warmer countries, strategic prophylactic treatment can be used |
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− | ===''Gasterophilus'' spp.=== | + | |
| + | ===''Gasterophilus spp.''=== |
| [[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 |
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| *Obligate parasites of equids | | *Obligate parasites of equids |
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− | *Spend most of life cycle in equine stomach | + | *Spend most of life cycle in the equine stomach |
| **Of little pathogenic significance | | **Of little pathogenic significance |
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| **''G. haemorrhoidalis'' which is rare | | **''G. haemorrhoidalis'' which is rare |
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− | *Two other important veterinary species | + | *Two other important veterinary species |
| **''G. nigricornis'' | | **''G. nigricornis'' |
| **''G. inermis'' | | **''G. inermis'' |
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| '''Recognition''' | | '''Recognition''' |
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| *Clear wings with brown patches | | *Clear wings with brown patches |
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− | '''Life Cycle'''
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− | *Adults are most active in late summer
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− | *Eggs hatch spontaneously or are stimulated to hatch through an increase in warmth and moisture from the animal self-grooming | + | '''Life cycle''' |
− | **''G. intestinalis'' | + | *Adults are most active in '''late summer''' |
− | ***Creamy-white eggs
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− | ***1-2mm in length
| + | *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 |
− | ***Eggs laid in the hair of the shoulders and fore legs
| + | **''G. intestinalis'' eggs are laid in the hair of the shoulders and fore legs |
− | **''G. nasalis'' | + | **''G. nasalis'' eggs are laid in the intermandibular area |
− | ***Eggs laid in the intermandibular area
| + | **''G. haemorrhoidalis'' eggs are laid around the lips |
− | **''G. haemorrhoidalis'' | + | |
− | ***Eggs laid around the [[Lips - Anatomy & Physiology|lips]] | + | *Creamy-white eggs |
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| + | *1-2mm in length |
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| *Larvae crawl into the mouth and penetrate the tissues of the tongue and buccal mucosa | | *Larvae crawl into the mouth and penetrate the tissues of the tongue and buccal mucosa |
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| **''G. nasalis'' attaches to the pylorus | | **''G. nasalis'' attaches to the pylorus |
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− | *After 10-12 months in the [[Forestomach - Anatomy & Physiology|stomach]], the larvae detach and are passed out in the faeces | + | *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 | | **''G. haemorrhoidalis'' attaches to the rectal mucosa before being passed out |
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| *Larvae pupate on the ground | | *Larvae pupate on the ground |
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− | *Adults hatch after 1-2 months and survive from a few days to two weeks | + | *Adults hatch after 1-2 months and survive from a few days to 2 weeks |
| **Adults have non-functional mouthparts so cannot feed | | **Adults have non-functional mouthparts so cannot feed |
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− | *There is only one generation per year in temperate regions of the world | + | *There is only '''1 generation per year''' in temperate regions of the world |
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| '''Pathogenesis''' | | '''Pathogenesis''' |
− | *Adult cause annoyance when egg laying | + | *Adults cause annoyance when egg laying |
| **Disturbance and panic can ensue | | **Disturbance and panic can ensue |
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| *''G. haemorrhoidalis'' can cause mild irritation to the rectal wall | | *''G. haemorrhoidalis'' can cause mild irritation to the rectal wall |
− | **Host reaction to larvae in the mouth is minimal
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| + | *Host reaction to larvae in the mouth is minimal |
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| '''Control''' | | '''Control''' |
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| **Stimulates hatching | | **Stimulates hatching |
| **Kills larvae | | **Kills larvae |
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| ===''Dermatobia hominis''=== | | ===''Dermatobia hominis''=== |
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| *Specifically found in South America | | *Specifically found in South America |
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− | '''Recongition''' | + | |
| + | '''Recognition''' |
| *Adult can grow up to 25mm in length | | *Adult can grow up to 25mm in length |
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