Rapid diagnostic PCR assays for members of the Culicoides obsoletus and Culicoides pulicaris species complexes, implicated vectors of bluetongue virus in Europe

Damien V. Nolan, Simon Carpenter, James Barber, Philip S. Mellor, John F. Dallas, A. Jennifer (Luntz) Mordue*, Stuart B. Piertney

*Corresponding author for this work

Research output: Contribution to journalArticle

107 Citations (Scopus)

Abstract

Biting midges of the Culicoides obsoletus Meigen and Culicoides pulicari L. species complexes (Diptera: Ceratopogonidae) are increasingly implicated as vectors of bluetongue virus in Palearctic regions. However, predicting epidemiological risk and the spread of disease is hampered because whilst vector competence of Culicoides is expressed only in adult females, morphological identification of constituent species is only readily applicable to adult males and some species distinguishing traits have overlapping character states. Furthermore, adult males are typically rare in field collections, making characterisation of Culicoides communities impossible. Here we highlight the utility of mitochondrial cytochrome oxidase subunit I (COI) DNA sequences for taxonomic resolution and species identification of all species within C. obsoletus and C pulicarus complexes. Culicoides were collected from 18 sites in the UK and Continental Europe, and identified to species level, or species complex level, based on morphological characters. The sample comprised four species from the C obsoletus complex (n = 88) and five species from the C. pulicaris complex (n = 39). The DNA sequence of the 5' end of the COI gene was obtained from all individuals. Each member species formed a well-supported reciprocally monophyletic clade in a maximum likelihood phylogeny. Levels of DNA sequence divergence were sufficiently high between species to allow the design of species-specific PCR primers that can be used in PCR for identification of members of the C. pulicaris complex or in a multiplex PCR to identify members of the C. obsoletus complex. This approach provides a valuable diagnostic tool for monitoring species composition in mixed field collections of Culicoides. (c) 2007 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)82-94
Number of pages13
JournalVeterinary Microbiology
Volume124
Issue number1-2
Early online date27 Mar 2007
DOIs
Publication statusPublished - 20 Sep 2007

Keywords

  • COI
  • culicoides
  • mtDNA
  • C. obsoletus complex
  • C. pulicaris complex
  • species-specific PCR
  • African horse sickness
  • ribosomal dna-sequences
  • oxidase subunit-I
  • spatial-distribution
  • ceratopogonidae
  • diptera
  • imicola
  • midges
  • differentiation
  • identification

Cite this

Rapid diagnostic PCR assays for members of the Culicoides obsoletus and Culicoides pulicaris species complexes, implicated vectors of bluetongue virus in Europe. / Nolan, Damien V.; Carpenter, Simon; Barber, James; Mellor, Philip S.; Dallas, John F.; Mordue, A. Jennifer (Luntz); Piertney, Stuart B.

In: Veterinary Microbiology, Vol. 124, No. 1-2, 20.09.2007, p. 82-94.

Research output: Contribution to journalArticle

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abstract = "Biting midges of the Culicoides obsoletus Meigen and Culicoides pulicari L. species complexes (Diptera: Ceratopogonidae) are increasingly implicated as vectors of bluetongue virus in Palearctic regions. However, predicting epidemiological risk and the spread of disease is hampered because whilst vector competence of Culicoides is expressed only in adult females, morphological identification of constituent species is only readily applicable to adult males and some species distinguishing traits have overlapping character states. Furthermore, adult males are typically rare in field collections, making characterisation of Culicoides communities impossible. Here we highlight the utility of mitochondrial cytochrome oxidase subunit I (COI) DNA sequences for taxonomic resolution and species identification of all species within C. obsoletus and C pulicarus complexes. Culicoides were collected from 18 sites in the UK and Continental Europe, and identified to species level, or species complex level, based on morphological characters. The sample comprised four species from the C obsoletus complex (n = 88) and five species from the C. pulicaris complex (n = 39). The DNA sequence of the 5' end of the COI gene was obtained from all individuals. Each member species formed a well-supported reciprocally monophyletic clade in a maximum likelihood phylogeny. Levels of DNA sequence divergence were sufficiently high between species to allow the design of species-specific PCR primers that can be used in PCR for identification of members of the C. pulicaris complex or in a multiplex PCR to identify members of the C. obsoletus complex. This approach provides a valuable diagnostic tool for monitoring species composition in mixed field collections of Culicoides. (c) 2007 Elsevier B.V. All rights reserved.",
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AU - Barber, James

AU - Mellor, Philip S.

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AU - Mordue, A. Jennifer (Luntz)

AU - Piertney, Stuart B.

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AB - Biting midges of the Culicoides obsoletus Meigen and Culicoides pulicari L. species complexes (Diptera: Ceratopogonidae) are increasingly implicated as vectors of bluetongue virus in Palearctic regions. However, predicting epidemiological risk and the spread of disease is hampered because whilst vector competence of Culicoides is expressed only in adult females, morphological identification of constituent species is only readily applicable to adult males and some species distinguishing traits have overlapping character states. Furthermore, adult males are typically rare in field collections, making characterisation of Culicoides communities impossible. Here we highlight the utility of mitochondrial cytochrome oxidase subunit I (COI) DNA sequences for taxonomic resolution and species identification of all species within C. obsoletus and C pulicarus complexes. Culicoides were collected from 18 sites in the UK and Continental Europe, and identified to species level, or species complex level, based on morphological characters. The sample comprised four species from the C obsoletus complex (n = 88) and five species from the C. pulicaris complex (n = 39). The DNA sequence of the 5' end of the COI gene was obtained from all individuals. Each member species formed a well-supported reciprocally monophyletic clade in a maximum likelihood phylogeny. Levels of DNA sequence divergence were sufficiently high between species to allow the design of species-specific PCR primers that can be used in PCR for identification of members of the C. pulicaris complex or in a multiplex PCR to identify members of the C. obsoletus complex. This approach provides a valuable diagnostic tool for monitoring species composition in mixed field collections of Culicoides. (c) 2007 Elsevier B.V. All rights reserved.

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DO - 10.1016/j.vetmic.2007.03.019

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ER -