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16 result(s) for "Lachmann, Lars"
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West Nile Virus Epidemic in Germany Triggered by Epizootic Emergence, 2019
One year after the first autochthonous transmission of West Nile virus (WNV) to birds and horses in Germany, an epizootic emergence of WNV was again observed in 2019. The number of infected birds and horses was considerably higher compared to 2018 (12 birds, two horses), resulting in the observation of the first WNV epidemy in Germany: 76 cases in birds, 36 in horses and five confirmed mosquito-borne, autochthonous human cases. We demonstrated that Germany experienced several WNV introduction events and that strains of a distinct group (Eastern German WNV clade), which was introduced to Germany as a single introduction event, dominated mosquito, birds, horse and human-related virus variants in 2018 and 2019. Virus strains in this clade are characterized by a specific-Lys2114Arg mutation, which might lead to an increase in viral fitness. Extraordinary high temperatures in 2018/2019 allowed a low extrinsic incubation period (EIP), which drove the epizootic emergence and, in the end, most likely triggered the 2019 epidemic. Spatiotemporal EIP values correlated with the geographical WNV incidence. This study highlights the risk of a further spread in Germany in the next years with additional human WNV infections. Thus, surveillance of birds is essential to provide an early epidemic warning and thus, initiate targeted control measures.
Improving Aquatic Warbler Population Assessments by Accounting for Imperfect Detection
Monitoring programs designed to assess changes in population size over time need to account for imperfect detection and provide estimates of precision around annual abundance estimates. Especially for species dependent on conservation management, robust monitoring is essential to evaluate the effectiveness of management. Many bird species of temperate grasslands depend on specific conservation management to maintain suitable breeding habitat. One such species is the Aquatic Warbler (Acrocephalus paludicola), which breeds in open fen mires in Central Europe. Aquatic Warbler populations have so far been assessed using a complete survey that aims to enumerate all singing males over a large area. Because this approach provides no estimate of precision and does not account for observation error, detecting moderate population changes is challenging. From 2011 to 2013 we trialled a new line transect sampling monitoring design in the Biebrza valley, Poland, to estimate abundance of singing male Aquatic Warblers. We surveyed Aquatic Warblers repeatedly along 50 randomly placed 1-km transects, and used binomial mixture models to estimate abundances per transect. The repeated line transect sampling required 150 observer days, and thus less effort than the traditional 'full count' approach (175 observer days). Aquatic Warbler abundance was highest at intermediate water levels, and detection probability varied between years and was influenced by vegetation height. A power analysis indicated that our line transect sampling design had a power of 68% to detect a 20% population change over 10 years, whereas raw count data had a 9% power to detect the same trend. Thus, by accounting for imperfect detection we increased the power to detect population changes. We recommend to adopt the repeated line transect sampling approach for monitoring Aquatic Warblers in Poland and in other important breeding areas to monitor changes in population size and the effects of habitat management.
Waterbird population estimates for a key staging site in Kazakhstan: a contribution to wetland conservation on the Central Asian flyway
Realistic population size estimates for waterbirds are crucial for the application of wetland conservation strategies, since the identification of internationally important wetlands is based on local numbers relative to the population size of the respective species. Central Asia is a poorly surveyed region that is situated at the intersection of migration routes that lead waterbirds from Western Siberia to the south-west (South-West Asia, East Africa) and to the south-east (South Asia, India). We calculated waterbird population estimates for the Tengiz–Korgalzhyn region, a large wetland complex in the steppe zone of Central Kazakhstan, based on waterbird surveys conducted between 1999 and 2004. For 20 of 43 species analysed the region supported more than 5% of the relevant flyway populations. Five species occurred with more than 40% of the flyway totals, including the Endangered White-headed Duck Oxyura leucocephala and the Vulnerable Dalmatian Pelican Pelecanus crispus. Peak numbers were recorded in summer and autumn and for most species numbers were more than an order of magnitude lower on spring migration compared with autumn migration. We identified 72 individual sites that held more than 20,000 waterbirds or more than 1% of a particular flyway population at least once. These sites are likely to constitute priorities for conservation. The general conservation status of the region is favourable, since many of the important sites are located within a strict nature reserve. However, outside the reserve hunting, fishing and powerline casualties represent conservation issues that should be monitored more carefully in the future.
Effect of mowing on productivity in the endangered Aquatic Warbler Acrocephalus paludicola
The Aquatic Warbler Acrocephalus paludicola is a globally threatened habitat specialist that breeds in open fens in Central and Eastern Europe. Because bush and reed encroachment threaten many suitable breeding areas, habitat management is necessary to maintain the open wetlands that Aquatic Warblers require for nesting. The effectiveness of mowing as habitat management has so far only been assessed by counting the number of singing males. To assess whether mowing also affected vital reproduction parameters, we analysed Aquatic Warbler productivity in the Biebrza National Park, Poland, on plots in four different successional stages after mowing. Our study showed that productivity was lowest in the first year after mowing, but increased to the highest levels in the second year after mowing. The productivity differences between areas at different stages after mowing resulted from differences in nest density, since we found little evidence for an effect of mowing on nest survival or the number of fledglings produced per successful nest. Nest survival was highly variable between years and varied mostly with nest age and nest initiation date. The density of singing males was positively correlated with both the nest density and the number of fledglings produced in an area, suggesting that this simple indicator could be used to rank the quality of Aquatic Warbler habitats. We recommend that in mesotrophic fen mires, such as the Biebrza valley, mowing as habitat management is applied less frequently than every second year.
Improving Aquatic Warbler Population Assessments by Accounting for Imperfect Detection: e94406
Monitoring programs designed to assess changes in population size over time need to account for imperfect detection and provide estimates of precision around annual abundance estimates. Especially for species dependent on conservation management, robust monitoring is essential to evaluate the effectiveness of management. Many bird species of temperate grasslands depend on specific conservation management to maintain suitable breeding habitat. One such species is the Aquatic Warbler (Acrocephalus paludicola), which breeds in open fen mires in Central Europe. Aquatic Warbler populations have so far been assessed using a complete survey that aims to enumerate all singing males over a large area. Because this approach provides no estimate of precision and does not account for observation error, detecting moderate population changes is challenging. From 2011 to 2013 we trialled a new line transect sampling monitoring design in the Biebrza valley, Poland, to estimate abundance of singing male Aquatic Warblers. We surveyed Aquatic Warblers repeatedly along 50 randomly placed 1-km transects, and used binomial mixture models to estimate abundances per transect. The repeated line transect sampling required 150 observer days, and thus less effort than the traditional 'full count' approach (175 observer days). Aquatic Warbler abundance was highest at intermediate water levels, and detection probability varied between years and was influenced by vegetation height. A power analysis indicated that our line transect sampling design had a power of 68% to detect a 20% population change over 10 years, whereas raw count data had a 9% power to detect the same trend. Thus, by accounting for imperfect detection we increased the power to detect population changes. We recommend to adopt the repeated line transect sampling approach for monitoring Aquatic Warblers in Poland and in other important breeding areas to monitor changes in population size and the effects of habitat management.
High variation reduces the value of feather stable isotope ratios in identifying new wintering areas for aquatic warblers Acrocephalus paludicola in West Africa
Stable isotope analysis of feathers can be useful in the study of seasonal interactions and migratory connectivity in birds. For the Palaearctic–African migration system, however, the lack of isotope data from feathers of known origin in Africa renders the geographic assignment of birds captured on European breeding grounds to potential wintering areas problematic. Rectrices of the threatened aquatic warbler Acrocephalus paludicola grown in Africa were sampled across six European countries to assess whether birds in different breeding populations shared similar isotopic signatures and so were likely to have wintered in the same region in Africa. Freshly grown feathers of aquatic warblers collected at the only known wintering site in Senegal showed high variation in carbon, nitrogen, and hydrogen isotope ratios. Due to similarly high variation in isotope ratios of African‐grown feathers within all breeding populations, it was not possible to determine whether different populations wintered in different regions. However, isotope signatures of 20% of birds captured on European breeding grounds fell outside the range of those captured in Senegal, suggesting a wider wintering distribution than is currently known. We therefore assessed whether the origin of these feathers could be estimated by trying to establish isotopic gradients across sub‐Saharan West Africa. Feathers of three ecologically similar surrogate species were sampled from wetlands across a 3000 km east‐west and a 2000 km north–south transect. Within‐site variation in feather isotope ratios was frequently larger than the difference predicted by gradients across West Africa. Thus, predicting the origin of individual feathers using single‐isotope gradients was not reliable. The large within‐site variability of feather isotope ratios of a habitat specialist species like the aquatic warbler indicates that using feather isotope ratios will require large sample sizes from many locations, and may thus not be an efficient tool in identifying wintering areas of Palaearctic–African migrants.
Wader, gull and tern population estimates for a key breeding and stopover site in Central Kazakhstan
Population size estimates of waders, gulls and terns passing through or breeding in Central Asia are very scarce, although highly important for global flyway population estimates as well as for targeting local conservation efforts. The Tengiz-Korgalzhyn region is one of the largest wetland complexes in Central Asia. We conducted surveys in this region between 1999 and 2008 and present estimates of population size as well as information on phenology and age structure for 50 species of Charadriiformes. The Tengiz-Korgalzhyn wetlands are especially important for Red-necked Phalaropes Phalaropus lobatus and Ruffs Philomachus pugnax with, respectively, 41% and 13% of their flyway populations using the area during spring migration. The region is also an important post-breeding moulting site for Pied Avocets Recurvirostra avosetta and Black-tailed Godwits Limosa limosa used by, respectively, 5% and 4% of their flyway populations. Besides its key importance as a migratory stopover site, the study area is a key breeding site for the Critically Endangered Sociable Lapwing Vanellus gregarius, the Near Threatened Black-winged Pratincole Glareola nordmanni and for Pallas’s Gull Larus ichthyaetus with 16%, 6% and 5% of their world populations, respectively. We identified 29 individual sites that held more than 1% of the relevant flyway populations of at least one species of Charadriiformes. Including data on other species of waterbirds (mainly waterfowl), there were 93 sites that qualify for Important Bird Areas (IBA). About half of them are protected in a state nature reserve, while an additional 20% are recognised as IBAs. Nevertheless, 28 important sites are currently not recognised as IBAs nor are they protected by other conservation means. These sites require conservation attention.
Viral modulation of type II interferon increases T cell adhesion and virus spread
During primary varicella zoster virus (VZV) infection, infected lymphocytes drive primary viremia, causing systemic dissemination throughout the host, including the skin. This results in cytokine expression, including interferons (IFNs), which partly limit infection. VZV also spreads from skin keratinocytes to lymphocytes prior to secondary viremia. It is not clear how VZV achieves this while evading the cytokine response. Here, we show that VZV glycoprotein C (gC) binds IFN-γ and modifies its activity, increasing the expression of a subset of IFN-stimulated genes (ISGs), including intercellular adhesion molecule 1 ( ICAM1 ), chemokines and immunomodulatory genes. The higher ICAM1 protein level at the plasma membrane of keratinocytes facilitates lymphocyte function-associated antigen 1-dependent T cell adhesion and expression of gC during infection increases VZV spread to peripheral blood mononuclear cells. This constitutes the discovery of a strategy to modulate IFN-γ activity, upregulating a subset of ISGs, promoting enhanced lymphocyte adhesion and virus spread. Here, Jacobsen et al show that Varicella zoster virus glycoprotein C binds interferon gamma and induces biased signalling through its receptor, leading to higher expression of adhesion molecules, more T cell adhesion and viral spread from epithelial cells.
Vascular Tissue Specific miRNA Profiles Reveal Novel Correlations with Risk Factors in Coronary Artery Disease
Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide. Non-coding RNAs have already been linked to CVD development and progression. While microRNAs (miRs) have been well studied in blood samples, there is little data on tissue-specific miRs in cardiovascular relevant tissues and their relation to cardiovascular risk factors. Tissue-specific miRs derived from Arteria mammaria interna (IMA) from 192 coronary artery disease (CAD) patients undergoing coronary artery bypass grafting (CABG) were analyzed. The aims of the study were 1) to establish a reference atlas which can be utilized for identification of novel diagnostic biomarkers and potential therapeutic targets, and 2) to relate these miRs to cardiovascular risk factors. Overall, 393 individual miRs showed sufficient expression levels and passed quality control for further analysis. We identified 17 miRs–miR-10b-3p, miR-10-5p, miR-17-3p, miR-21-5p, miR-151a-5p, miR-181a-5p, miR-185-5p, miR-194-5p, miR-199a-3p, miR-199b-3p, miR-212-3p, miR-363-3p, miR-548d-5p, miR-744-5p, miR-3117-3p, miR-5683 and miR-5701–significantly correlated with cardiovascular risk factors (correlation coefficient >0.2 in both directions, p-value (p < 0.006, false discovery rate (FDR) <0.05). Of particular interest, miR-5701 was positively correlated with hypertension, hypercholesterolemia, and diabetes. In addition, we found that miR-629-5p and miR-98-5p were significantly correlated with acute myocardial infarction. We provide a first atlas of miR profiles in IMA samples from CAD patients. In perspective, these miRs might play an important role in improved risk assessment, mechanistic disease understanding and local therapy of CAD.
Effectiveness of vaccines in preventing hospitalization due to COVID-19: A multicenter hospital-based case-control study, Germany, June 2021 to January 2022
•This study assesses detailed first-hand data and therefore provides a very high data quality.•Detailed interviews, abstraction of medical records and laboratory analyses were combined to obtain comprehensive data sets.•More than half of the cases (58 %) were not vaccinated at all, compared to 11 % of the controls.•The vaccine effictiveness to prevent severe disease in the Delta wave was 89 % overall for two doses and 98 % for three doses. We included 852 patients in a prospectively recruiting multicenter matched case-control study in Germany to assess vaccine effectiveness (VE) in preventing COVID-19-associated hospitalization during the Delta-variant dominance. The two-dose VE was 89 % (95 % CI 84–93 %) overall, 79 % in patients with more than two comorbidities and 77 % in adults aged 60–75 years. A third dose increased the VE to more than 93 % in all patient-subgroups.