uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Geographic distribution and relative abundance of the sibling vector species Culex torrentium and Culex pipiens in Sweden
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
2011 (English)In: Vector Borne and Zoonotic Diseases, ISSN 1530-3667, E-ISSN 1557-7759, Vol. 11, no 10, 1383-1389 p.Article in journal (Refereed) Published
Abstract [en]

Culex torrentium and Culex pipiens are sibling species and potential viral vectors that coexist in Europe. Larvae and females of the two species are morphologically almost identical, and reliable identification can only be done on males. To investigate the distribution and relative abundance of the two species in Sweden, we collected Culex larvae from sites spread over the country, identified them as Culex pipiens/torrentium based on morphology, and identified them to species using a recently developed restriction enzyme method. Cx. torrentium was the dominant species (89%, n = 1012) and it occurred in 48 of the 49 sites investigated, and also dominated in most of the study sites. The proportion of Cx. pipiens larvae in relation to Cx. torrentium collected at each site decreased with both increasing latitude and altitude, and the presence of Cx. pipiens decreased with latitude. In addition, Cx. pipiens/torrentium females were sampled with Centres for Disease Control light traps baited with carbon dioxide. The overall country mean was 4.0 Cx. pipiens/torrentium caught per trap night, with decreasing numbers of Cx. pipiens/torrentium caught per trap night with increasing latitude. Thus, the abundance of Cx. pipiens/torrentium decreased, but the proportion Cx. torrentium increased, with increasing latitude. This is the first study that shows the vast dominance of Cx. torrentium over Cx. pipiens in Sweden. The unexpected dominance of Cx. torrentium highlights the importance of distinguishing between the two species in studies of Culex-borne arboviruses in Europe.

Place, publisher, year, edition, pages
2011. Vol. 11, no 10, 1383-1389 p.
Keyword [en]
Abundance, Culex pipiens, Culex torrentium, Distribution, Sindbis virus, Sweden, VectorsWest Nile virus
National Category
Biological Sciences
Identifiers
URN: urn:nbn:se:uu:diva-160728DOI: 10.1089/vbz.2011.0630ISI: 000295870800012OAI: oai:DiVA.org:uu-160728DiVA: diva2:453093
Available from: 2011-11-01 Created: 2011-10-31 Last updated: 2017-12-08
In thesis
1. Clearing up Culex Confusion: A Basis for Virus Vector Discrimination in Europe
Open this publication in new window or tab >>Clearing up Culex Confusion: A Basis for Virus Vector Discrimination in Europe
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Mosquito species of the Culex genus are the enzootic vectors for several bird-associated viruses that cause disease in humans. In Europe, these viruses include Sindbis (SINV), West Nile and Usutu viruses. The morphologically similar females of Cx. torrentium and Cx. pipiens are potential vectors of these viruses, but difficulties in correctly identifying the mosquito species have caused confusion regarding their respective distribution, abundance, ecology, and consequently their importance as vectors. Species-specific knowledge from correctly identified field material is however of crucial importance since previous research shows that the relatively unknown Cx. torrentium is a far more efficient SINV vector than the widely recognized Cx. pipiens. The latter is involved in the transmission of several other viruses, but its potential importance for SINV transmission is debated.

In this thesis I describe the development of a molecular method for species identification, based on reliably identified males of Cx. torrentium and Cx. pipiens. This identification method was then used in consecutive studies on the distribution and relative abundance of the two species in Sweden and 12 other European countries, SINV field infection rates in mosquitoes identified to species level, and evaluation of potential trap bias associated with common sampling techniques.

The results showed that Cx. torrentium is a far more common species in Europe than previously assumed. In Sweden and Finland, it is the dominant species, accounting for 89% of the sampled Culex population. In central Europe, it is equally common to Cx. pipiens, while Cx. pipiens dominates south of the Alps Mountain range. Larvae of both species are often found together in both artificial containers (e.g. car tires) and natural sites. Also, a trapping bias against Cx. torrentium was revealed for CDC-traps. For the first time, SINV was isolated from species-identified Cx. torrentium and Cx. pipiens mosquitoes caught in the field, with Cx. torrentium being superior in infection rates (36/1,000 vs. 8.2/1,000). Future studies on SINV, as well as other mosquito-borne bird viruses in Europe, can hopefully gain from the baseline information provided here, and from principles of vector discrimination discussed in the thesis.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2014. 56 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1185
Keyword
Culex torrentium, Culex pipiens, mosquitoes, vector, ornithophilic, Sindbis virus, West Nile virus
National Category
Biological Sciences
Research subject
Population Biology
Identifiers
urn:nbn:se:uu:diva-232726 (URN)978-91-554-9044-7 (ISBN)
Public defence
2014-11-07, Zootissalen, Villavägen 9, 2 tr, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2014-10-17 Created: 2014-09-23 Last updated: 2015-01-23

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Hesson, Jenny C.Östman, ÖrjanSchäfer, MartinaLundström, Jan O.

Search in DiVA

By author/editor
Hesson, Jenny C.Östman, ÖrjanSchäfer, MartinaLundström, Jan O.
By organisation
Population and Conservation Biology
In the same journal
Vector Borne and Zoonotic Diseases
Biological Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 678 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf