|West Nile virus vector Culex modestus established in southern England.|
|Jump to Full Text|
|PMID: 22316288 Owner: NLM Status: Publisher|
|ABSTRACT: BACKGROUND: The risk posed to the United Kingdom by West Nile virus (WNV) has previously been considered low, due to the absence or scarcity of the main Culex sp. bridge vectors. The mosquito Culex modestus is widespread in southern Europe, where it acts as the principle bridge vector of WNV. This species was not previously thought to be present in the United Kingdom. FINDINGS: Mosquito larval surveys carried out in 2010 identified substantial populations of Cx. modestus at two sites in marshland in southeast England. Host-seeking-adult traps placed at a third site indicate that the relative seasonal abundance of Cx. modestus peaks in early August. DNA barcoding of these specimens from the United Kingdom and material from southern France confirmed the morphological identification. CONCLUSIONS: Cx. modestus appears to be established in the North Kent Marshes, possibly as the result of a recent introduction. The addition of this species to the United Kingdom's mosquito fauna may increase the risk posed to the United Kingom by WNV.|
|Nick Golding; Miles A Nunn; Jolyon M Medlock; Bethan V Purse; Alexander G C Vaux; Stefanie M Schafer|
Related Documents :
|16793058 - Horizontal and vertical transmission of viruses in the honey bee, apis mellifera.
22382168 - Dengue virus-like particles: construction and application.
22897918 - Entomological profile of yellow fever epidemics in the central african republic, 2006-2...
16494238 - Effects of atrazine and iridovirus infection on survival and life-history traits of the...
70508 - Activation of an endogenous c-type rna virus in rat embryo cells after transformation b...
24158348 - Cloning, expression and purification of duck hepatitis b virus (dhbv) core protein and ...
|Type: JOURNAL ARTICLE Date: 2012-2-9|
|Title: Parasites & vectors Volume: 5 ISSN: 1756-3305 ISO Abbreviation: - Publication Date: 2012 Feb|
|Created Date: 2012-2-9 Completed Date: - Revised Date: -|
Medline Journal Info:
|Nlm Unique ID: 101462774 Medline TA: Parasit Vectors Country: -|
|Languages: ENG Pagination: 32 Citation Subset: -|
|APA/MLA Format Download EndNote Download BibTex|
Journal ID (nlm-ta): Parasit Vectors
Publisher: BioMed Central
Copyright ©2012 Golding et al; licensee BioMed Central Ltd.
Received Day: 10 Month: 11 Year: 2011
Accepted Day: 9 Month: 2 Year: 2012
collection publication date: Year: 2012
Electronic publication date: Day: 9 Month: 2 Year: 2012
Volume: 5First Page: 32 Last Page: 32
Publisher Id: 1756-3305-5-32
PubMed Id: 22316288
|West Nile virus vector Culex modestus established in southern England|
|Nick Golding12||Email: email@example.com|
|Miles A Nunn2||Email: firstname.lastname@example.org|
|Jolyon M Medlock3||Email: email@example.com|
|Bethan V Purse4||Email: firstname.lastname@example.org|
|Alexander GC Vaux3||Email: email@example.com|
|Stefanie M Schäfer2||Email: firstname.lastname@example.org|
1Spatial Ecology and Epidemiology Group, Tinbergen Building, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
2Centre for Ecology & Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford OX10 8BB, UK
3Medical Entomology & Zoonoses Ecology group, Microbial Risk Assessment, Emergency Response Department, Health Protection Agency, Porton Down, Salisbury, Wiltshire SP4 0JG, UK
4Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK
Culex modestus is a competent laboratory vector of West Nile virus (WNV, ) and regularly bites birds, humans and horses in continental Europe . This mosquito is considered the principle bridge vector of WNV between birds and humans in the Camargue wetland, southern France and is thought to have played a role in the transmission of WNV in the Danube delta, Caspian and Asov sea deltas, and the Volga region in Russia . It has also been implicated in Tahyna and Lednice virus transmission in France and Slovakia respectively .
Cx. modestus is widely distributed in the Palaearctic region, the larvae inhabit fresh to slightly saline water in irrigation channels, marshes and rice fields . Prior to this report, the only record of this species in the United Kingdom totalled three adults and ten larvae found in and around Portsmouth in southern England in 1944-45 .
Mosquito surveys were carried out during 2010 in the North Kent Marshes, south-east England (Figure 1). Larval surveys were undertaken at two sites - Cliffe marshes (Cliffe; 51°28'58"N 0°28'45"E) and Elmley National Nature Reserve (Elmley; 51°23'03"N 0°47'19"E) - in June, July and August. At each visit larvae were sampled twice using a 1 litre dipper at randomly located points along the edges of drainage ditches, reed beds and pools. A total of 230 points were sampled, across an area of 3.83 km2. The relative seasonal abundance of host-seeking female mosquitoes was measured at Northward Hill bird reserve (51°27'45"N 0°33'2"E) using a Mosquito Magnet trap (Liberty plus model, American Biophysics, Rhode Island, USA). This site is 5 km from Cliffe and 18 km from Elmley (Figure 1A). The trap ran for four nights on alternate weeks between April and October.
Larval and adult mosquitoes were identified morphologically using a range of keys [5,7-9]. To confirm the morphological identification DNA barcodes of a subset of Cx. modestus specimens from the North Kent Marshes (7 larvae, 10 adults) and the Camargue (3 adults) were generated. A 709 bp fragment of the cytochrome c oxidase subunit I (COI) was amplified by PCR  and sequenced. Cx. modestus COI barcodes were compared to those obtained from Cx. pipiens specimens from the North Kent Marshes (n = 3) and Somerset (n = 6) as well as 35 COI sequences downloaded from GenBank. Phylogenetic analyses were carried out using MEGA5 software .
In larval surveys 850 Cx. modestus of all stages were collected, along with Anopheles maculipennis s.l., Cx. pipiens s.l. and Culiseta annulata. At both sites Cx. modestus was the second most abundant species after Cx. pipiens s.l., making up 44% and 23% of the overall larval population sampled at Cliffe and Elmley respectively (Table 1).
A total of 649 adult female Cx. modestus were captured at Northward Hill between 12 July and 10 September, with a peak of 325 adults in the second week of August (Table 2). Overall, Cx. modestus comprised 75% of the mosquitoes collected at Northward Hill. Morphological identification of Cx. modestus was confirmed by DNA barcoding and phylogenetic analyses. All the COI sequences from Cx. modestus specimens form a discrete clade with high bootstrap support (Figure 2).
Established populations of Cx. modestus have been reported from the Camargue and Dombes wetlands in southern and central France [3,12] as well as in wetlands in the Czech Republic  but the species is believed to be more widely distributed than this in Europe. Its previous known northerly limit in Europe was in northern France (see Figure 1A, Francis Schaffner, personal communication) and Oostvardersplassen, the Netherlands . However these records comprise only a few specimens and it is unclear whether there are established populations at these sites. The species was not detected during a recent and intensive survey of the mosquito fauna of Belgium . Our finding demonstrates that established populations of Cx. modestus are present in the United Kingdom and provides further support for the existence of northern populations of the species.
It seems unlikely that Cx. modestus could have been present in the North Kent Marshes for a long time without being detected. The mosquito fauna of the North Kent Marshes are among the most well sampled in the United Kingdom, both by amateur entomologists and by professionals engaged in mosquito control .
An extensive larval survey was carried out at Elmley in 2003 . This survey identified 95 sites containing An. maculipennis s.l. but did not detect Cx. modestus. In the present larval survey Cx. modestus were found to be strongly associated with An. maculipennis s.l.; being present in 73% of sites containing An. maculipennis s.l. larvae. This suggests Cx. modestus was absent from this site in 2003. However the 2003 survey did not record any Cx. pipiens s.l. in An. maculipennis s.l. positive sites, whilst they were present in 20% of such sites in the present study; suggesting that the sampling strategy employed in 2003 may not have been sensitive to Culicines.
If these Cx. modestus populations were established recently, international shipping may well have been the route of introduction. International shipping has previously been implicated in the introduction of mosquito species; including Cx. modestus to China  and there are a high number of shipping terminals in the area of the North Kent Marshes (see Figure 1B).
A number of vectors and vector-borne diseases have undergone changes in their geographic ranges in recent years, in response to varied biotic and abiotic environmental factors . There is some evidence that Cx. modestus is extending its distribution in Europe, with speculation that this may be driven by weather events or changes to wetlands [12,13]. Without detailed information on the previous and current distribution of this species, however, it is unclear what role these factors might play.
A recent review of the potential vectors of WNV  concluded that the risk of human cases in the United Kingdom is low due to limited human exposure to potential bridge vectors. However, the risk of transmission of WNV in this part of Kent may be higher than previously supposed, as we have shown that Cx. modestus populations exist alongside the potential WNV maintenance vector Cx. pipiens s.l. at sites hosting many migratory and resident birds. Since human population numbers in the North Kent Marshes are relatively low and little is known of the dispersal range or host preferences of Cx. modestus in the United Kingdom, it is difficult to quantify the significance of any change in risk to humans. It does seem likely, however, that the risk posed to horses, which are often grazed in the North Kent Marshes, will have increased. In light of this, and until the national distribution of Cx. modestus is established, surveillance for WNV in the United Kingdom should now focus on this part of Kent.
In summary, the discovery of populations of Cx. modestus in southern England suggests a recent introduction of this species and provides further evidence for expansion of its geographic range. There is an associated increased risk posed to the United Kingdom by WNV and other pathogens transmitted by Cx. modestus.
The authors declare that they have no competing interests.
NG designed and carried out the larval surveys, identified the larvae and drafted the manuscript. SMS initially identified the larvae as Cx. modestus, carried out the phylogenetic analysis and contributed to revision of the manuscript. JMM and AGCV designed and carried out the adult trapping, identified the adults and contributed to revision of the manuscript. MAN and BVP contributed to the design of the larval survey, interpretation of the results and revision of the manuscript. All authors read and approved the final manuscript.
We thank Steve Gordon and Andy Daw for their cooperation and help with fieldwork, Stephen Larcombe for providing Cx. modestus from the Camargue, and the Port of London Authority for providing shipping data. NG, SS, MN, and BVP acknowledge funding from the NERC Centre for Ecology & Hydrology (CEH Environmental Change Integrating Fund programme). JM and AV are funded by HPA Government Grant-in-Aid, and an HPA fund for nationwide mosquito surveillance.
|Balenghien T,Vazeille M,Grandadam M,Schaffner F,Zeller H,Reiter P,Sabatier P,Fouque F,Bicout DJ,Vector competence of some French Culex and Aedes mosquitoes for West Nile virusVector-Borne Zoonot DisYear: 200885899510.1089/vbz.2007.0266|
|Balenghien T,Fouque F,Sabatier P,Bicout DJ,Horse-, Bird-, and Human-Seeking Behaviour and Seasonal Abundance of Mosquitoes in a West Nile Virus Focus of Southern FranceJ Med EntomolYear: 20064393694610.1603/0022-2585(2006)43[936:HBAHBA]2.0.CO;217017231|
|Ponçon N,Balenghien T,Toty C,Baptiste Ferré J,Thomas C,Dervieux A,L'ambert G,Schaffner F,Bardin O,Fontenille D,Effects of Local Anthropogenic Changes on Potential Malaria Vector Anopheles hyrcanus and West Nile Virus Vector Culex modestus, Camargue, FranceEmerg Infect DisYear: 2007131810518258028|
|Lundström JO,Vector competence of Western European mosquitoes for arboviruses: A review of field and experimental studiesBull Soc Vector EcolYear: 1994192336|
|Becker N,Petric D,Zgomba M,Boase C,Madon M,Dahl C,Kaiser A,Mosquitoes and their controlYear: 2010Second. Berlin: Springer Verlag|
|Marshall JF,Records of Culex (Barraudius) modestus Ficalbi (Diptera, Culicidæ) obtained in the South of EnglandNatureYear: 194515617217310.1038/156172a0|
|Snow KR,Mosquitoes (Naturalists' Handbooks 14)Year: 1990Richmond Publishing|
|Cranston PS,Ramsdale CD,Snow KR,White GB,Adults, Larvae, and Pupae of British Mosquitoes (Culicidae) A KeyYear: 1987Freshwater Biological Association|
|Lechthaler W,Culicidae 05 - Key to Larvae, Pupae and Males from Central and Western Europe. (CD-edition). EutaxaYear: 2005|
|Folmer O,Black M,Hoeh W,Lutz R,Vrijenhoek R,DNA primers for amplification of mitochondrial cytochrome c oxidase subunit I from diverse metazoan invertebratesMol Mar Biol BiotechYear: 199432949|
|Tamura K,Peterson D,Peterson N,Stecher G,Nei M,Kumar S,MEGA5: molecular evolutionary genetics analysis using maximum likelihood, evolutionary distance, and maximum parsimony methodsMol Biol EvolYear: 2011282731273910.1093/molbev/msr12121546353|
|Pradel JA,Martin T,Rey D,Foussadier R,Bicout DJ,Is Culex modestus (Diptera: Culicidae), Vector of West Nile Virus, Spreading in the Dombes Area, France?J Med EntomolYear: 2009461269128110.1603/033.046.060419960670|
|Votýpka J,Šeblová V,Rádrová J,Spread of the West Nile virus vector Culex modestus and the potential malaria vector Anopheles hyrcanus in central EuropeJ Vector EcolYear: 20083326927710.3376/1081-1710-33.2.26919263846|
|Reusken C,De Vries A,Den Hartog W,Braks M,Scholte E-J,A study of the circulation of West Nile virus in mosquitoes in a potential high-risk area for arbovirus circulation in the Netherlands,"De Oostvaardersplassen"Europ Mosq BullYear: 2010286983|
|Van Bortel W,Grootaert P,Hance T,Hendrickx G,Takken W,Mosquito Vectors of Disease: Spatial Biodiversity, Drivers of Change and Risk "MODIRISK" Final Report Phase 1Year: 2009Brussels: Belgian Science Policy|
|Ramsdale C,Snow KR,Mosquito control in BritainYear: 1995London: University of East London Press|
|Hutchinson RA,Mosquito Borne Diseases in England: past, present and future risks, with special reference to malaria in the Kent MarshesPhD ThesisYear: 2004University of Durham, Department of Biological & Biomedical Sciences|
|Nie W-Z,Li J-C,Li D-X,Wang R-J,Gratz N,Mosquitoes found aboard ships arriving at Qinhuangdao Port, P. R. ChinaMed Entomol ZoolYear: 200455333335|
|Randolph SE,Rogers DJ,The arrival, establishment and spread of exotic diseases: patterns and predictionsNat Rev MicrobiolYear: 201083617110.1038/nrmicro233620372156|
|Medlock J,Leach S,Snow KR,Potential transmission of West Nile virus in the British Isles: an ecological review of candidate mosquito bridge vectorsMed Vet EntomolYear: 20051922110.1111/j.0269-283X.2005.00547.x15752172|
Numbers and proportions (given as %) of larvae collected from Cliffe marshes and Elmley National Nature Reserve
|%||Culiseta annulata||%||Anopheles maculipennis s.l.||%|
Numbers and proportions (given as %) of adult female Cx. modestus collected at RSPB Northward Hill
|14-18 June||12-16 July||26-30 July||09-13 August||23-27 August||06-10 September||20-24 September|
Keywords: Anopheles, Arboviruses, Culex, Culicidae, Disease Vectors, DNA Barcoding, Taxonomic, Introduced Species, West Nile virus.
Previous Document: Does the X-ray Technologist or the Fluoroscopy Time Affect Treatment Success with Shockwave Lithotri...
Next Document: Novel insights in the role of peripheral corticotropin-releasing factor and mast cells in stress-ind...