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Wernike K.,Institute of Diagnostic Virology | Jost H.,Bernhard Nocht Institute for Tropical Medicine | Jost H.,German Center for Infection Research | Becker N.,German Mosquito Control Association KABS | And 3 more authors.
Parasites and Vectors | Year: 2014

Background: In 2011, a novel orthobunyavirus of the Simbu serogroup was discovered near the German-Dutch border and named Schmallenberg virus (SBV). So far, SBV genome has been detected in various field-collected Culicoides species; however, other members of the Simbu serogroup are also transmitted by mosquitoes. Findings. In the present study, approximately 50,000 mosquitoes of various species were collected during summer and early autumn 2011 in Germany. None of them tested positive in an SBV-specific real-time PCR. Conclusions: The absence of SBV in mosquitoes caught in 2011 in Germany suggests that they play no or only a negligible role in the spread of the disease. © 2014 Wernike et al.; licensee BioMed Central Ltd. Source


Nartey R.,Kwame Nkrumah University Of Science And Technology | Owusu-Dabo E.,Kwame Nkrumah University Of Science And Technology | Kruppa T.,Bernhard Nocht Institute for Tropical Medicine | Baffour-Awuah S.,Kwame Nkrumah University Of Science And Technology | And 4 more authors.
Parasites and Vectors | Year: 2013

Background: Integrated Vector Control (IVC) remains the approach for managing the malaria-causing vector. The study investigated the contribution of Bacillus thuringiensis israelensis (Bti) in the control of malaria by targeting the larvae and also mapped and documented major breeding sites in the Kumasi metropolis, Ghana. Methods. Using a hand held GPS receiver unit, major breeding sites within the metropolis were mapped out during the larval survey. Mosquito larvae were then collected from the breeding sites and reared in an insectary to obtain an F1 generation for laboratory bioassays. The minimum effective dosage of Bti Water Dispersible Granular (WDG) formulation was determined by a series of bioassays. Based on the results obtained in the laboratory, the optimum effective dosage of Bti formulations against naturally occurring larvae of the indigenous mosquito species was determined through open field trials. Results: A total of 33 breeding sites were identified and geo-referenced during the larval surveys with the majority of the breeding sites located in the Asokwa sub-metropolis, Kumasi, Ghana. A Bti (3,000 International Toxic Unit (ITU)/mg) concentration of 0.026 mg/l resulted in 50% mortality whilst a concentration of 0.136 mg/l resulted in 95% mortality. Results from the open field trials with Bti showed that a dosage of 0.2 kg/ha is as effective as 0.4 kg/ha in suppressing late instars and resulting pupae. Conclusion: This study reveals that Bti at a very low dosage of 0.2 kg/ha is highly effective against Anopheles larvae and therefore offers viable options for the management of vector mosquitoes. Further research is needed to extend this to the field in order to determine its ability to reduce malaria incidence. © 2013 Nartey et al.; licensee BioMed Central Ltd. Source


Becker N.,German Mosquito Control Association KABS | Becker N.,University of Heidelberg | Jost A.,German Mosquito Control Association KABS | Weitzel T.,German Mosquito Control Association KABS
Journal of the American Mosquito Control Association | Year: 2012

The present study examines the mating and breeding behavior as well as the genetic differentiation of Culex pipiens biotype pipiens and Cx. pipiens biotype molestus. Firstly, the mating behavior of Cx. pipiens s.l. originating from larval populations of various epigeous and hypogeous breeding sites in Germany was examined. Autogeny was prevailing in underground populations, occasionally found in semi-open water reservoirs like drains, rarely in containers, but never in ponds and ditches. Secondly, in a multilocus enzyme electrophoretic study the gene flow among seven geographic populations of Cx. pipiens biotype pipiens and the biotype molestus from several European countries was quantified. For comparison, five populations of Cx. quinquefasciatus from Asia, Africa and North America, three populations of Cx. torrentium (Germany) and other outgroup species were also examined. Thirdly, the mitochondrial cytochrome c oxidase submit I gene of both biotypes from Germany was analysed by a polymerase chain reaction - restriction fragment length polymorphism assay and the ascertained DNA-sequences were aligned with genebank data of Russian populations. The population genetic analyses revealed much higher genetic distances between local populations of Cx. pipiens biotype pipiens and Cx. pipiens biotype molestus compared to the low differentiation between geographically remote populations within each taxon. The UPGMA (unweighted pair group method with arithmetic mean) analysis and F-statistics positioned the biotypes pipiens on one side and molestus on the other side in discrete monophyletic clusters. Gene flow between local populations of the biotypes pipiens and molestus could be shown to be lower than gene flow between geographically distant populations within each of the two groups, leading to the conclusion that Cx. pipiens biotype molestus could be a distinct taxon. Culex quinquefasciatus was genetically well-separated, in particular by the diagnostic enzyme marker malate dehydrogenase (nicotinamide adenine dinucleotide phosphate). The genetic markers adenylatekinase and hydrobutyrate dehydrogenase allowed to screen thousands of morphologically similar samples of either Cx. pipiens s.l. and Cx torrentium and it could be shown that Cx. torrentium is a very frequent species in central Europe. © 2012 by The American Mosquito Control Association, Inc. Source


Pfitzner W.P.,German Mosquito Control Association KABS | Beck M.,German Mosquito Control Association KABS | Weitzel T.,German Mosquito Control Association KABS | Becker N.,German Mosquito Control Association KABS | Becker N.,University of Heidelberg
Journal of the American Mosquito Control Association | Year: 2015

The flood plains of the Upper Rhine Valley provide excellent conditions for the proliferation of mosquitoes as well as for the development of dragon and damselflies. It could be assumed that mosquitoes belong to the diet of the Odonata and that the latter could be harmed by the reduction of the mosquito population with the purpose of diminishing the massive nuisance for the people living there. A total of 41 adult dragonflies and damselflies were examined by immunoblot for remnants of mosquitoes in their guts. A rabbit antiserum against Aedes vexans proteins was used for the immunoblot. Only 3 Aeshna cyanea and 1 Platycnemis pennipes could be shown to have fed on mosquitoes. In specimens of the genus Sympetrum no mosquitoes were detected. It seems very doubtful that mosquitoes are an essential part of the Odonata diet. © 2015 by The American Mosquito Control Association, Inc. Source


Becker N.,German Mosquito Control Association KABS | Becker N.,University of Heidelberg | Jost H.,German Mosquito Control Association KABS | Jost H.,University of Heidelberg | And 22 more authors.
PLoS ONE | Year: 2012

This study aimed to identify the causative agent of mass mortality in wild and captive birds in southwest Germany and to gather insights into the phylogenetic relationship and spatial distribution of the pathogen. Since June 2011, 223 dead birds were collected and tested for the presence of viral pathogens. Usutu virus (USUV) RNA was detected by real-time RT-PCR in 86 birds representing 6 species. The virus was isolated in cell culture from the heart of 18 Blackbirds (Turdus merula). USUV-specific antigen was demonstrated by immunohistochemistry in brain, heart, liver, and lung of infected Blackbirds. The complete polyprotein coding sequence was obtained by deep sequencing of liver and spleen samples of a dead Blackbird from Mannheim (BH65/11-02-03). Phylogenetic analysis of the German USUV strain BH65/11-02-03 revealed a close relationship with strain Vienna that caused mass mortality among birds in Austria in 2001. Wild birds from lowland river valleys in southwest Germany were mainly affected by USUV, but also birds kept in aviaries. Our data suggest that after the initial detection of USUV in German mosquitoes in 2010, the virus spread in 2011 and caused epizootics among wild and captive birds in southwest Germany. The data also indicate an increased risk of USUV infections in humans in Germany. © 2012 Becker et al. Source

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