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| − | {{OpenPagesTop}}
| + | ==Introduction== |
| − | {{Taxobox
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| − | |kingdom =
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| − | |sub-kingdom =
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| − | |phylum =[[:Category:Arthropods|Arthropoda]]
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| − | |super-class =
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| − | |class =[[:Category:Insecta|Insecta]]
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| − | |sub-class =
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| − | |super-order =
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| − | |order =
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| − | |sub-order =
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| − | |super-family =
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| − | |family =Ceratopogonidae
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| − | |sub-family =
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| − | |genus =Culicoides
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| − | |species =
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| − | }}
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| − | Also known as: '''''Midges'''''<br>
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| − | The most important veterinary species is '''''Culicoides''''' <br>
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| − | ==Introduction== | + | {| cellpadding="10" cellspacing="0" border="1" |
| | + | | Also known as: |
| | + | | '''Midges |
| | + | |- |
| | + | | The most important veterinary species |
| | + | |'''''Culicoides''''' |
| | + | |- |
| | + | |} |
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| − | This parasite is found worldwide and attacks humans and a wide variety of animals. The only genus of the family ''Ceratopogonidae'' of current veterinary significance is ''Culicoides''.
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| − | The midge is a vector for several viruses, including [[Bluetongue Virus|Bluetongue]] and [[African Horse Sickness|African horse sickness]].
| + | This parasite is found worldwide and attacks a wide variety of animals and also attacks humans. |
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| − | It causes allergic dermatitis of horses, primarily affecting the base of the tail and the withers, and induces an intermediate-type hypersensitivity reaction to the midge saliva, known as [[Culicoides Hypersensitivity|'Sweet itch']]
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| − | ==Identification==
| + | '''Recognition''' |
| − | Culicoides are small flies 2-5mm long with a dark colouring, more commonly known as '''biting midges'''. They have a characteristic arched thorax giving a 'hump-backed' appearance. The wings are mottled.
| + | Small flies 2-5mm long with a dark colouring. They have a characteristic arched thorax giving a 'hump-backed' appearance. The wings are mottled. |
| | | | |
| − | ==Life cycle==
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| − | Eggs are laid onto plants near water and the larvae fall into water and pupate. The life cycle takes '''6-12 months''' to complete in temperate climates, but can take only '''1 month''' in tropical climates. Females of most species are adapted to sucking blood from the host.
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| − | ''Culicoides'' take blood meals from vertebrate hosts and breed in damp, dung-enriched soil, and so are abundant in the vicinity of domestic livestock. Once eggs are laid in the soil, ''Culicoides'' larvae progress through four stages and pupate before becoming an adult midge. The lifecycle is greatly influenced by temperature: in temperate regions such as Britain, the adult midge population declines in October and is absent by December. The fourth larval stage overwinters, and adults re-appear the following April. The environmental conditions also affect the activity of midges in several ways. ''Culicoides'' survive around 10 days in warm weather but up to one month when conditions are cooler and are most active at night, from an hour before sunset to an hour after sunrise. Activity is decreased by windy conditions, and increased during the day when the weather is dull. | + | '''Life cycle''' |
| | + | Eggsare laid on to plants near water and the larvae fall into water and pupate. The life cycle takes '''6-12 months''' to complete in temperate climates but is only '''1 month''' in tropical climates. |
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| − | ==Distribution==
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| − | The ''Culicoides'' species found in the British Isles are ''C. pulicaris'' and ''C. obsoletus'', which are also common across central and northern Europe. Knowledge of the distribution of these species in the UK is incomplete but the insects tend to gather where breeding sites and hosts occur in tandem, with the highest midge concentrations in areas containing cattle, horses and pigs. Removal of livestock decreases populations of ''Culicoides'' by a factor of 10 to 20<sup>1</sup>, but some persist by feeding on wild animals and man. Hill sites have fewer midges as climatic conditions are less favourable, and the presence of sheep encourages the midge population less than that of cattle.
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| − | In Britain, studies are ongoing to determine midge distribution, seasonal incidence and the competency of the various ''Culicoides'' species to act as BTV vectors.
| + | '''Pathogenesis''' |
| | + | Culicoides is most active in late afternoon and early evening. Bites are painful and irritating. Only females suck blood. |
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| − | Classically, the major vector for [[Bluetongue Virus|BTV]] is ''Culicoides imicola''. This midge is found throughout Africa, the
| + | A bite causes [[Skin Immunologic - Pathology#Culicoides hypersensitivity|'Sweet itch']], a culicoides hypersensitivity reaction |
| − | Middle East, southern Asia, Portugal, Greece, Corsica, Sardinia, Sicily and areas of Italy<sup>1</sup>, and its distribution appears to be extending northwards. However, ''C. imicola'' has not yet been demonstrated in the United Kingdom.
| + | *Seasonally occurring allergic dermatitis of horses |
| | + | *Affects the base of the tail and the withers |
| | + | *Intermediate-type hypersensitivity reaction to the midge saliva |
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| − | {{Learning
| + | The midge is a vector for several viruses: |
| − | |literature search = [http://www.cabdirect.org/search.html?rowId=1&options1=AND&q1=%28%28%28od%3A%28Ceratopogonidae%29+OR+od%3A%28midges%29%29+AND+sc%3A%22ve%22%29%29+OR+%28%28%28title%3A%28Ceratopogonidae%29+OR+title%3A%28midges%29%29++AND+sc%3A%22ve%22%29%29&occuring1=freetext&rowId=2&options2=AND&q2=&occuring2=freetext&rowId=3&options3=AND&q3=&occuring3=freetext&publishedstart=2000&publishedend=yyyy&calendarInput=yyyy-mm-dd&la=any&it=any&show=all&x=52&y=12 Ceratopogonidae publications since 2000] | + | *[[Bluetongue Virus|Bluetongue]] |
| − | }}
| + | *[[African Horse Sickness|African horse sickness]] |
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| − | ==References==
| + | It is also a vector for several other parasites: |
| | + | *''Onchocerca spp.'' in cattle and horses |
| | + | *[[Parasitic skin infections - Pathology#Onchocerciasis|Onchocerciasis]] |
| | + | *Involved in [[Parasitic skin infections - Pathology#Cutaneous habronemiasis|cutaneous habronemiasis]] |
| | + | *Involved in [[Parasitic skin infections - Pathology#Stephanofilariasis|stephanofilariasis]] |
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| − | #DEFRA (2002) [http://www.defra.gov.uk/foodfarm/farmanimal/diseases/atoz/documents/bluetongue_technical.PDF Technical Review - Bluetongue : The Virus, Hosts and Vectors.]
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| | + | '''Control''' |
| | + | This is difficult due to the extensive breeding sites but can include drainage of breeding sites, stabling horses at peak midge activity times e.g. from late afternoon to early morning, the use of insecticide fly strips in stables and topical fly repellent. |
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| − | {{review}}
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| − | {{OpenPages}}
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| | [[Category:Biting_Flies]] | | [[Category:Biting_Flies]] |
| − | | + | [[Category:To_Do_-_Parasites]] |
| − | [[Category:Expert_Review]] | + | [[Category:To_Do_-_Workshop]] |
Introduction
| Also known as:
|
Midges
|
| The most important veterinary species
|
Culicoides
|
This parasite is found worldwide and attacks a wide variety of animals and also attacks humans.
Recognition
Small flies 2-5mm long with a dark colouring. They have a characteristic arched thorax giving a 'hump-backed' appearance. The wings are mottled.
Life cycle
Eggsare laid on to plants near water and the larvae fall into water and pupate. The life cycle takes 6-12 months to complete in temperate climates but is only 1 month in tropical climates.
Pathogenesis
Culicoides is most active in late afternoon and early evening. Bites are painful and irritating. Only females suck blood.
A bite causes 'Sweet itch', a culicoides hypersensitivity reaction
- Seasonally occurring allergic dermatitis of horses
- Affects the base of the tail and the withers
- Intermediate-type hypersensitivity reaction to the midge saliva
The midge is a vector for several viruses:
It is also a vector for several other parasites:
Control
This is difficult due to the extensive breeding sites but can include drainage of breeding sites, stabling horses at peak midge activity times e.g. from late afternoon to early morning, the use of insecticide fly strips in stables and topical fly repellent.