Horse-, Bird-, and Human-Seeking Behavior and Seasonal Abundance of Mosquitoes in a West Nile Virus Focus of Southern France

Unité Biomathématiques et epidémiologie, Ecole Nationale Vétérinaire de Lyon, 1 avenue Bourgelat, 69280 Marcy l'Etoile, France.
Journal of Medical Entomology (Impact Factor: 1.95). 10/2006; 43(5):936-46. DOI: 10.1603/0022-2585(2006)43[936:HBAHBA]2.0.CO;2
Source: PubMed


After 35 yr of disease absence, West Nile virus (family Flaviviridae, genus Flavivirus, WNV) circulation has been regularly detected in the Camargue region (southern France) since 2000. WNV was isolated from Culex modestus Ficalbi, which was considered the main vector in southern France after horse outbreaks in the 1960s. Recent WNV transmissions outside of the Cx. modestus distribution suggested the existence of other vectors. To study potential WNV vectors, horse- and bird-baited traps and human landing collections of mosquitoes were carried out weekly from May to October 2004 at two Camargue sites: one site in a wet area and the other site in a dry area, both chosen for their past history of WNV transmission. At the wet site, the most abundant species in bird-baited traps were Culex pipiens L. and Cx. modestus; both species also were found in lower proportions on horses and humans. The most abundant species in horse-baited traps and human landing collections were Aedes caspius (Pallas), Aedes vexans (Meigen), and Anopheles hyrcanus (Pallas) sensu lato; some of these species were occasionally collected with avian blood at the end of the summer. Anopheles maculipennis Meigen sensu lato was an abundant horse feeder, but it was rarely collected landing on human bait and never contained avian blood. At the dry site, Cx. pipiens was the most abundant species in bird- and horse-baited traps. The seasonal and circadian dynamics of these species are analyzed, and their potential in WNV transmission in Camargue discussed.

Download full-text


Available from: Florence Fouque, Sep 30, 2015
35 Reads
  • Source
    • "An. maculipennis s.l. showed a peak from 2000 to 0000 hours in the CDC-CO 2 traps and a peak at 0400–0600 hours in the gravid traps (Fig. 5), overlapping perfectly with data reported in France using horse-baited traps (Balenghien et al. 2006). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The seasonal and daily activity of mosquito vectors of pathogens affecting animals and humans were studied in northeastern Italy at a site within the Po River Delta Park. A CDC-CO2 trap and a gravid trap were operated at 2-h intervals for 24 h every 15 d from May to October 2010. Overall, 5,788 mosquitoes comprising six species were collected, namely Culex pipiens L. (75.1% of total), Aedes caspius (Pallas) (15.2%), Aedes vexans (Meigen) (6.9%), Anopheles maculipennis s.l. Meigen (2.6%), Culiseta annulata (Schrank) (0.2%), and Culex modestus Ficalbi (<0.1%). The relative abundance of these species increased from May until the beginning of July and then decreased, disappearing at the beginning of October. The diel host-seeking patterns and oviposition site-seeking patterns were species specific and were differentially affected by the ecological variables recorded at the day and hour of mosquito collection or two weeks before collection. Knowledge of the seasonal and daily host-seeking patterns of mosquitoes highlights the time periods of the day and the seasons of potential exposure for animals and humans to mosquito-borne pathogens, therefore delineating the best time for the application of preventive measures. Furthermore, knowledge of the oviposition site-seeking activity of the mosquitoes optimizes the capture of gravid females, thereby enhancing the likelihood of detecting pathogens. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.For Permissions, please e-mail:
    Journal of Medical Entomology 01/2015; 52(1):56-62. DOI:10.1093/jme/tju002 · 1.95 Impact Factor
  • Source
    • "This discovery was the first time this vector had been found in natural habitats in GB since 1945 (Golding et al., 2012), and it has subsequently been found in several other locations in the south of England (Medlock and Vaux, 2012). Cx. modestus is of particular importance because it is one of the principal vectors for WNV in Western Europe (Pradier et al., 2012) and is an extremely efficient vector that can become infected when exposed to relatively low viraemia (Balenghien et al., 2006, 2007, 2008). Culex spp. "
    [Show abstract] [Hide abstract]
    ABSTRACT: West Nile virus (WNV) is a mosquito borne arbovirus that circulates within avian reservoirs. WNV can spill over into humans and Equidae that are dead-end hosts for WNV but suffer fever, acute morbidity and sometimes death. Outbreaks of WNV are common across Africa and Eastern Europe, and there have also been sporadic outbreaks in Spain and the Camargue Regional Park in France, but never in Great Britain (GB). These areas all fall along a major bird migration route. In this study, we analyse a scenario in which WNV is circulating in the Camargue or in other wetland areas in France and we estimate the risk of northward migrating passerine birds stopping in a WNV hotspot, becoming infected and carrying active infection to GB. If the disease were circulating in the Camargue during a single migratory season, the probability that one or more migrating birds becomes infected and lands in GB whilst still infected is 0.881 with 0.384 birds arriving in areas of suitable vector habitat. However, if WNV became established in the Grand Brière National Park or La Brenne Regional Park wetland areas further to the north, the model predicts that at least one infected bird will continue to GB. Thus, GB is at risk of WNV introduction from the Camargue, but the risk is considerably greater if WNV were to circulate further north than its previous focus in France, but this is highly sensitive to the force of infection in the infected area. However, the risk of establishment and infection of humans in GB is dependent upon a number of additional factors, in particular the vector and epidemiological situation in GB.
    Transboundary and Emerging Diseases 12/2014; DOI:10.1111/tbed.12310 · 2.94 Impact Factor
  • Source
    • "Along with Cx. pipiens, Culex modestus is widely accepted as a most effective vector of West Nile virus in Europe (Hannoun et al., 1964; Mouchet et al., 1970; Balenghien et al., 2006; Balenghien et al., 2007), due in no small part to its abundance and opportunistic feeding habits on both birds and mammals (Hubálek and Halouzka, 1999). Despite reports of the perceived spread of Cx. modestus in central Europe ( Vot´ypka et al., 2008) and its high density in the Czech Republic ( Vot´ypka et al., 2008), France (Balenghien et al., 2006) and in neighbouring Greece (Chaskopoulou et al., 2013), Cx. modestus seems quite rare in Turkey, with only one verified specimen collected in C ¸ ankiri, despite significant collection efforts spanning several years and many provinces. Thus, unless locally abundant in regions as yet unsampled, it seems highly unlikely that Cx. modestus will play a significant role in arbovirus transmission in Turkey. "
    [Show abstract] [Hide abstract]
    ABSTRACT: As a precursor to planned arboviral vector incrimination studies, an integrated systematics approach was adopted using morphology and DNA barcoding to examine the Culex fauna present in Turkey. The mitochondrial COI gene (658bp) were sequenced from 185 specimens collected across 11 Turkish provinces, as well as from colony material. Although by morphology only 9 species were recognised, DNA barcoding recovered 13 distinct species including: Cx. (Barraudius) modestus, Cx. (Culex) laticinctus, Cx. (Cux.) mimeticus, Cx. (Cux.) perexiguus, Cx. (Cux.) pipiens, Cx. (Cux.) pipiens form molestus, Cx. (Cux.) quinquefasciatus, Cx. (Cux.) theileri, Cx. (Cux.) torrentium, Cx. (Cux.) tritaeniorhynchus and Cx. (Maillotia) hortensis. The taxon formerly identified as Cx. (Neoculex) territans was shown to comprise two distinct species, neither of which correspond to Cx. territans s.s. These include Cx. (Neo.) impudicus and another uncertain species, which may be Cx. (Neo.) europaeus or Cx. (Neo.) martinii (herein=Cx. (Neo.) sp. 1). Detailed examination of the Pipiens Group revealed Cx. pipiens, Cx. pipiens f. molestus and the widespread presence of the highly efficient West Nile virus vector Cx. quinquefasciatus for the first time. Four new country records are reported, increasing the Culex of Turkey to 15 recognised species and Cx. pipiens f. molestus. A new taxonomic checklist is provided, annotated with respective vector competencies for transmission of arboviruses. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.
    Acta Tropica 10/2014; 143. DOI:10.1016/j.actatropica.2014.10.013 · 2.27 Impact Factor
Show more