Mosquito-borne West Nile virus (WNV) surveillance in the Upper Rhine Valley, Germany

Abstract

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 cO 2 -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. Journal of Vector Ecology 35 (1): 140-143. 2010.

Monitoring of West Nile Virus Infections in Germany

“…No WNV‐infected mosquitoes were detected in Germany to date. Timmermann and Becker (2010) tested 11 073 host‐seeking adult female mosquitoes (of 13 species) collected in the Upper Rhine Valley in 2007 and 2008 for WNV. However, USUV was detected in Culex pipiens pipiens mosquitoes in south‐west Germany most recently (Jöst et al., 2011).…”

“…Until lately, only few data were available on WNV epidemiology in Germany. In two previous studies, antibodies to WNV were found in several migratory and resident bird species (Linke et al, 2007;Seidowski et al, 2010), but WNV-specific RNA has so far never been detected in any of these studies (Schirrmeier et al, 2004;Hlinak et al, 2006;Linke et al, 2007;Seidowski et al, 2010;Ziegler et al, 2010), indicating no evidence for indigenous WNV infections in the past, even though potential vector mosquitoes are present in Germany (Timmermann and Becker, 2010). In August 2010, Usutu virus (USUV), a closely related virus to WNV, was isolated from a pool of Culex pipiens pipiens mosquitoes, trapped in south-west Germany, yet there was no reported increase in the mortality of wild and captive bird species in 2009 and 2010 (Jöst et al, 2011).…”

Rapid assessment of West Nile virus circulation in a German zoo based on honey-baited FTA cards in combination with box gravid traps

“…WNV circulates in an enzootic cycle with birds as amplifying host and mosquitoes as vectors [ 2 ]. The major vector species in Germany belong to the genus Culex , with Culex pipiens biotype pipiens , Culex pipiens biotype molestus , and Culex torrentium proven susceptible [ 3 , 4 ].…”

Surveillance of maternal antibodies against West Nile virus in chicken eggs in South‐West Germany

“…), a total of 1990 eggs were collected in 35 different sampling sites in the south‐west of Germany and transported to the laboratory (Figure ). The study area is characterised by a diverse and abundant mosquito fauna, including potential WNV vector species such as members of the widely distributed Culex pipiens complex or the species Aedes vexans , which shows very high densities during the summer floods in the Upper Rhine Valley . All hens were free ranged, which increases the chance of WNV infection.…”