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Timmermann U.,German Mosquito Control Association GMCA KABS | Becker N.,German Mosquito Control Association GMCA KABS | Becker N.,University of Heidelberg
Journal of Vector Ecology | Year: 2010

West Nile virus (WNV) could be introduced into Germany via migratory birds originating from Africa or southern Europe and subsequently transmitted to indigenous birds, humans, or horses by mosquitoes. Neither the virus itself nor antibodies against WNV have yet to be found in mosquitoes and horses, whereas antibodies have been detected in migrating birds and in humans that were in close contact with birds. At present, the West Nile virus itself has yet to be detected in Germany. This investigation was conducted primarily in major bird breeding, resting, and roosting habitats (hotspots) in the Upper Rhine Valley. Adult mosquitoes were trapped using CO2-baited Encephalitis Vector Surveillance (EVS)-traps and were tested for WNV by the VecTest WNV Antigen Assay. In 2007 and 2008, a total of 11,073 host-seeking adult female mosquitoes (13 species) were tested, and all tests were negative for WNV. Statistical calculations could be performed only where sufficient numbers of mosquitoes were trapped. For these sites, WNV infection among mosquitoes could be ruled out with 80% certainty. For the evaluation of the WNV situation in Germany, the results of this investigation are a further indication that the virus has not yet arrived.

Weitzel T.,German Mosquito Control Association GMCA KABS | Gauch C.,German Mosquito Control Association GMCA KABS | Becker N.,German Mosquito Control Association GMCA KABS
Parasitology Research | Year: 2012

Until the middle of the twentieth century, malaria was frequently endemic in parts of Germany; Anopheles maculipennis complex species were considered the primary vectors. Three species of this complex have been identified in Germany: A. maculipennis s.s., Anopheles messeae and Anopheles atroparvus; the last predominantly from the coastal regions of Northern Germany. Anopheles daciae is a recently described member of the A. maculipennis complex and resembles the well-characterised species A. messeae, although the two species can be distinguished through their egg morphology and sequencing of the internal transcribed spacer 2 (ITS2) region of their nuclear rDNA. In this study, we harvested larval and adult mosquito samples from five breeding sites and ten CO2 trap collection sites in the Upper Rhine Valley of Southwestern Germany to analyse the complement of anopheline species present. Mosquito ITS2 DNA was extracted and polymerase chain reaction (PCR)-amplified using established protocols. Genomic analysis was performed by a species-diagnostic restriction fragment length polymorphism assay as well as by sequencing of PCR products; the data obtained were aligned against nucleic acid sequences from English mosquitoes retrieved from GenBank. Additionally, the larval breeding sites of A. messeae were characterised through water quality measurement. Forty-seven samples were successfully processed, of which 6 were identified as A. daciae and 41 as A. messeae. All samples of A. daciae, which has not previously been found in Central Europe, originated from one CO2 trap collection site in Dettenheim, close to Karlsruhe, Southwestern Germany. The identification of this malarial vector in a novel area may have implications for the re-emergence of disease subsequent to climatic changes. © Springer-Verlag 2012.

Weitzel T.,German Mosquito Control Association GMCA KABS | Jawien P.,Wroclaw University | Rydzanicz K.,Wroclaw University | Lonc E.,German Mosquito Control Association GMCA KABS | Becker N.,German Mosquito Control Association GMCA KABS
Parasitology Research | Year: 2015

Both ornithophilic mosquito species, Culex pipiens s.l. (L.) and Culex torrentium (Martini, 1925), occur sympatric in temperate Europe. They are presumed to be primary vectors of West Nile and Sindbis viruses. Differentiation of these morphologically similar Culex species is essential for evaluation of different vector roles, for mosquito surveillance and integrated control strategies. Cx. torrentium has been neglected or erroneously determined as Cx. pipiens s.l. in some previous studies, because only males of both species can be diagnosed reliably by morphology. Thus, knowledge about species abundance, geographical distribution, breeding site preferences and the zoonotic risk assessment is incomplete also in Poland. In Wrocław area (Silesian Lowland), besides typical urban breeding sites, huge sewage irrigation fields provide suitable breeding conditions for Culex species. They are also inhabited by 180 resident and migratory bird species serving as potential virus reservoirs. In this study, morphology of larvae and males as well as species diagnostic enzyme markers, namely adenylate kinase (AK) and 2-hydroxybutyrate dehydrogenase (HBDH), were used to discriminate Cx. pipiens s.l. and Cx. torrentium. In a total of 650 Culex larvae from 24 natural and artificial breeding sites, Cx. pipiens s.l. had a proportion of 94.0 % and Cx. torrentium only 6.0 %. It could be shown that both species are well adapted to various breeding site types like ditches, catch basins, flower pots and buckets with diverse water quality. Cx. torrentium preferred more artificial water containers in urban surrounding (12 % species proportion), whereas in semi-natural breeding sites, Cx. torrentium was rare (3 %). In 12 of 24 breeding sites, larvae of both species have been found associated. © 2014, Springer-Verlag Berlin Heidelberg.

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