Difference between revisions of "Ceratopogonidae"

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{{OpenPagesTop}}
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==Introduction==
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{{Taxobox
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|kingdom            =
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{| cellpadding="10" cellspacing="0" border="1"
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|sub-kingdom        =
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| Also known as:
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|phylum            =[[:Category:Arthropods|Arthropoda]]
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| '''Midges
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|super-class        =
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|-
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|class              =[[:Category:Insecta|Insecta]]
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| The most important veterinary species
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|sub-class          =
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|'''''Culicoides'''''  
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|super-order        =
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|-
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|order              =
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|}
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|sub-order          =
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|super-family      =
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|family            =Ceratopogonidae
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*Found worldwide
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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==
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*Attacks a wide variety of animals and also attacks humans
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'''Recognition'''
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*Small flies 2-5mm long
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*Dark colouring
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*Arched thorax giving a 'hump-backed' appearance
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*Mottled wings
  
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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]].
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'''Life cycle'''
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*Eggs laid on plants near water
  
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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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*Larvae fall into water and pupate
  
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==Identification==
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*Life cycle takes '''6-12 months''' to complete in temperate climates
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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.
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**Takes only '''1 month''' in tropical climates
  
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==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.
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'''Pathogenesis'''
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*Most active in late afternoon and early evening
  
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==Distribution==
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*Painful irritating bites
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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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**Only females suck blood
  
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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.
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*Causes [[Skin Immunologic - Pathology#Culicoides hypersensitivity|'Sweet itch']], a culicoides hypersensitivity reaction
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**Seasonally occurring allergic dermatitis of horses
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**Affects the base of the tail and the withers
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**Intermediate-type hypersensitivity reaction to the midge saliva
  
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Classically, the major vector for [[Bluetongue Virus|BTV]] is ''Culicoides imicola''. This midge is found throughout Africa, the
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*Vectors for viruses
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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.
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**[[Bluetongue Virus|Bluetongue]] and [[African Horse Sickness|African horse sickness]]
  
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{{Learning
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*Vectors for parasites
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|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]
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**''Onchocerca spp.'' in cattle and horses
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}}
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**[[Parasitic skin infections - Pathology#Protozoa|Protozoal skin infections]]
  
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==References==
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*Causes [[Parasitic skin infections - Pathology#Flies|skin infections]]
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**[[Parasitic skin infections - Pathology#Onchocerciasis|Onchocerciasis]]
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**Involved in [[Parasitic skin infections - Pathology#Cutaneous habronemiasis|cutaneous habronemiasis]]
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**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'''
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This is difficult due to the extensive breeding sites
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*Drainage of breeding sites
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*Stable horses at peak midge activity times e.g. from late afternoon to early morning
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*Insecticide fly strips in stable
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*Topical fly repellent
  
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{{review}}
 
  
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{{OpenPages}}
 
 
[[Category:Biting_Flies]]
 
[[Category:Biting_Flies]]
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[[Category:To_Do_-_Parasites]]
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[[Category:Expert_Review]]
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[[Category:To_Do_-_Workshop]]

Revision as of 10:00, 30 June 2010

Introduction

Also known as: Midges
The most important veterinary species Culicoides


  • Found worldwide
  • Attacks a wide variety of animals and also attacks humans


Recognition

  • Small flies 2-5mm long
  • Dark colouring
  • Arched thorax giving a 'hump-backed' appearance
  • Mottled wings


Life cycle

  • Eggs laid on plants near water
  • Larvae fall into water and pupate
  • Life cycle takes 6-12 months to complete in temperate climates
    • Takes only 1 month in tropical climates


Pathogenesis

  • Most active in late afternoon and early evening
  • Painful irritating bites
    • Only females suck blood
  • 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


Control This is difficult due to the extensive breeding sites

  • Drainage of breeding sites
  • Stable horses at peak midge activity times e.g. from late afternoon to early morning
  • Insecticide fly strips in stable
  • Topical fly repellent
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