High prevalence of Sarcocystis calchasi in racing pigeon flocks in Germany

The apicomplexan parasite Sarcocystis calchasi (Coccidia: Eimeriorina: Sarcocystidae) is the causative agent of Pigeon Protozoal Encephalitis (PPE) and infects birds of the orders Columbiformes, Piciformes and Psittaciformes. Accipiter hawks (Aves: Accipitriformes) are the definitive hosts of this parasite. Infections of S. calchasi have been detected in Germany, the United States and Japan. However, the prevalence of the parasite in racing pigeon flocks has not yet been determined. Here, the first cross-sectional prevalence study to investigate S. calchasi in pigeon racing flocks was accomplished including 245 pigeon flocks across Germany. A total of 1,225 muscle biopsies, were taken between 2012 and 2016 and examined by semi-nested PCR for S. calchasi DNA targeting the ITS gene. Additionally, a questionnaire on construction of the aviary as well as management and health status of the flock was conducted. In 27.8% (95% C.I. = 22.3–33.8%) of the flocks, S. calchasi DNA was detected in at least one pigeon. Positive flocks were located in 15 out of 16 federal states. A significant increase of infected racing pigeons was seen in spring. Half-covered or open aviary constructions showed a trend of increase of the prevalence rate, while anti-coccidian treatment and acidified drinking water had no effects. The high prevalence and the geographical distribution of S. calchasi suggest a long-standing occurrence of the parasite in the German racing pigeon population. For pigeons presented with neurological signs or other symptoms possibly related to PPE, S. calchasi should be considered as a potential cause throughout Germany

Accipiter hawks and Common Woodpigeon in Germany

The apicomplexan parasite Sarcocystis calchasi (S. calchasi) triggers pigeon protozoal encephalitis, a neurologic disease in columbids. Accipiter hawks have been identified as the final host, and Columbidae and Psittaciformes as intermediate hosts. In this study, 368 free-ranging Accipiter hawks and 647 free-ranging common woodpigeons were sampled in a country-wide study in order to identify the prevalence of S. calchasi in these populations. A semi-nested PCR specific for S. calchasi tested positive in 7.3% (4.9–10.5) of submitted samples from Accipiter hawks. Juvenile Accipiter hawks (13.7%; 7.7–22.0) had a significantly higher infection rate with S. calchasi than adult Accipiter hawks (5.8%; 2.7–9.3). The prevalence of S. calchasi in common woodpigeons was 3.3% (5.4–9.7). Positive pigeons were identified in 14/16 federal states, and a region-dependency was detected, with higher rates of infection in the eastern parts of Germany. The results of this study suggest that the common woodpigeon is a natural reservoir for S. calchasi. In a study of one region for four consecutive years, an increase in prevalence was not detected. Findings indicate that the parasite is not newly introduced to Germany, but rather long established. The prevalence suggests that there is a substantial risk of S. calchasi infections in other free-ranging as well as captive host species

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Encephalitis Associated with Sarcocystis halieti Infection in a Free-Ranging Little Owl (Athene noctua).

A juvenile Little Owl (Athene noctua) was diagnosed with granulomatous encephalitis and muscular sarcocysts. Sarcocystis halieti was identified in the brain and muscle tissue by PCR and subsequent sequencing. This is the first report of S. halieti as a potential encephalitis-causing pathogen in birds

Prevalence of Sarcocystis calchasi in free-ranging host species: Accipiter hawks and Common Woodpigeon in Germany

Abstract The apicomplexan parasite Sarcocystis calchasi (S. calchasi) triggers pigeon protozoal encephalitis, a neurologic disease in columbids. Accipiter hawks have been identified as the final host, and Columbidae and Psittaciformes as intermediate hosts. In this study, 368 free-ranging Accipiter hawks and 647 free-ranging common woodpigeons were sampled in a country-wide study in order to identify the prevalence of S. calchasi in these populations. A semi-nested PCR specific for S. calchasi tested positive in 7.3% (4.9–10.5) of submitted samples from Accipiter hawks. Juvenile Accipiter hawks (13.7%; 7.7–22.0) had a significantly higher infection rate with S. calchasi than adult Accipiter hawks (5.8%; 2.7–9.3). The prevalence of S. calchasi in common woodpigeons was 3.3% (5.4–9.7). Positive pigeons were identified in 14/16 federal states, and a region-dependency was detected, with higher rates of infection in the eastern parts of Germany. The results of this study suggest that the common woodpigeon is a natural reservoir for S. calchasi. In a study of one region for four consecutive years, an increase in prevalence was not detected. Findings indicate that the parasite is not newly introduced to Germany, but rather long established. The prevalence suggests that there is a substantial risk of S. calchasi infections in other free-ranging as well as captive host species

Seroprevalence of avian influenza in Baltic common eiders (Somateria mollissima) and pink-footed geese (Anser brachyrhynchus)

Influenza viruses are negative-sense single-stranded RNA viruses within the family of Orthomyxoviridae (Alexander, 2008). It holds Influenza A, B, C and D. Influenza A, B and C cause disease in humans, while only Influenza A viruses infect birds including waterfowl (Giwa et al., 2020, Lycett et al., 2019). The classification of Influenza A is based on profiling of surface proteins hemagglutinin (HA) and neuraminidase (NA), which divide the viruses into 18 and 11 subtypes, respectively (Giwa et al., 2020, Lycett et al., 2019). Waterfowl are considered a main reservoir of Avian Influenza (AI) A viruses with both low (LPAI) and high (HPAI) pathogenic subgroups; the latter causing disease outbreaks in both domestic and wild birds (Su et al., 2017, Beerens et al., 2020). So far, only H7 and H5 have been associated with HPAI, but they are not always pathogenic or cause clinical disease (Alexander, 2007). HPAI occurrence has far exceeded LPAI in flocks of wild birds although relative frequencies vary on a regional scale (Alexander, 2007, Pohlmann et al., 2019). AI appears to have the ability to infect most bird species, with the highest isolation rates found in waterfowl and birds from the Anatidae family which are more frequent hosts than any other family of birds (Stallknecht and Shane 1988). Pink-footed geese and common eiders are long-distance migratory bird species that carry AI and thus represent a potential for spreading the virus over wide geographical ranges (Harris et al., 2010, Hoye et al., 2011, Pasick et al., 2007). Moreover, the finding of influenza A in seals shows the virus’ potential to cross wide species barriers (Bodewes et al., 2013, Krog et al., 2015). Eiders occurring in Denmark are part of the Baltic/Wadden Sea flyway population, and has declined by 36% over the past decades (Christensen et al., 2013; HELCOM, 2013, Waltho and Coulson, 2015). In addition, pink-footed geese, likely due to environmental and climatic changes, have developed novel flyways into the Russian Arctic through Finland. Therefore, these two species are particularly appropriate for the monitoring of AI in wild Anatidae in the Baltic. The aim of the present study was therefore to investigate AI seroprevalence including occurrence of subtypes H5 and H7 in Baltic common eiders and pink-footed geese. These two species enable a broad coverage of Baltic terrestrial, brackish and marine ecosystems spanning from the Western to the Eastern and Northern parts of the area. Samples from three Danish eider colonies and migrating pink-footed geese were selected for study. The geese were sampled when they arrived from Denmark at their spring roost in Central Norway (Svalbard breeding population) and at their new flyway in the Finnish Baltic Sea (Russian breeding population). This is the basis for assessing environmental AI exposure in two Baltic key-species

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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Measurements of ttˉt\bar{t} differential cross-sections of highly boosted top quarks decaying to all-hadronic final states in pppp collisions at s=13 \sqrt{s}=13\, TeV using the ATLAS detector

Measurements are made of differential cross-sections of highly boosted pair-produced top quarks as a function of top-quark and $t\bar{t}$ system kinematic observables using proton--proton collisions at a center-of-mass energy of $\sqrt{s} = 13$ TeV. The data set corresponds to an integrated luminosity of $36.1$ fb$^{-1}$, recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. Events with two large-radius jets in the final state, one with transverse momentum $p_{\rm T} > 500$ GeV and a second with $p_{\rm T}>350$ GeV, are used for the measurement. The top-quark candidates are separated from the multijet background using jet substructure information and association with a $b$-tagged jet. The measured spectra are corrected for detector effects to a particle-level fiducial phase space and a parton-level limited phase space, and are compared to several Monte Carlo simulations by means of calculated $\chi^2$ values. The cross-section for $t\bar{t}$ production in the fiducial phase-space region is $292 \pm 7 \ \rm{(stat)} \pm 76 \rm{(syst)}$ fb, to be compared to the theoretical prediction of $384 \pm 36$ fb