Background. Human parechoviruses (HPeVs), along with human enteroviruses (HEVs), are associated with neonatal sepsis and meningitis. We determined the relative importance of these viruses and the ...specific HPeV types involved in the development of central nervous system–associated disease. Methods. A total of 1575 cerebrospinal fluid (CSF) samples obtained during 2006–2008 were screened for HPeV by means of nested polymerase chain reaction. All samples for which results were positive were typed by sequencing of viral protein (VP) 3/VP1. Screening for HEV was performed in parallel, as was detection of HPeV in respiratory and fecal surveillance samples, to identify virus types circulating in the general population. Results. HPeV was detected in 14 CSF samples obtained exclusively from young infants (age, <3 months) with sepsis or pyrexia. The frequency of detection of HPeVs varied greatly by year, with the highest frequency (7.2%) noted in 2008 exceeding that of HEVs. Direct typing of CSF samples revealed that all infections were caused by HPeV type 3, a finding that is in contrast to the predominant circulation of HPeV1 in contemporary respiratory and fecal surveillance samples. Conclusion. HPeV was a significant cause of severe sepsis and fever with central nervous system involvement in young infants, rivaling enteroviruses. The specific targeting of young infants by HPeV type 3 may reflect a difference in tissue tropism between virus types or a lack of protection of young infants by maternal antibody consequent to the recent emergence of HPeV.
Rhinovirus infections are the most common cause of viral illness in humans, and there is increasing evidence of their etiological role in severe acute respiratory tract infections (ARTIs). Human ...rhinoviruses (HRVs) are classified into two species, species A and B, which contain over 100 serotypes, and a recently discovered genetically heterogeneous third species (HRV species C). To investigate their diversity and population turnover, screening for the detection and the genetic characterization of HRV variants in diagnostic respiratory samples was performed by using nested primers for the efficient amplification of the VP4-VP2 region of HRV (and enterovirus) species and serotype identification. HRV species A, B, and C variants were detected in 14%, 1.8%, and 6.8%, respectively, of 456 diagnostic respiratory samples from 345 subjects (6 samples also contained enteroviruses), predominantly among children under age 10 years. HRV species A and B variants were remarkably heterogeneous, with 22 and 6 different serotypes, respectively, detected among 73 positive samples. Similarly, by using a pairwise distance threshold of 0.1, species C variants occurring worldwide were provisionally assigned to 47 different types, of which 15 were present among samples from Edinburgh, United Kingdom. There was a rapid turnover of variants, with only 5 of 43 serotypes detected during both sampling periods. By using divergence thresholds and phylogenetic analysis, several species A and C variants could provisionally be assigned to new types. An initial investigation of the clinical differences between rhinovirus species found HRV species C to be nearly twice as frequently associated with ARTIs than other rhinovirus species, which matches the frequencies of detection of respiratory syncytial virus. The study demonstrates the extraordinary genetic diversity of HRVs, their rapid population turnover, and their extensive involvement in childhood respiratory disease.
Enterovirus 71 (EV71) is responsible for frequent large-scale outbreaks of hand, foot, and mouth disease worldwide and represent a major etiological agent of severe, sometimes fatal neurological ...disease. EV71 variants have been classified into three genogroups (GgA, GgB, and GgC), and the latter two are further subdivided into subgenogroups B1 to B5 and C1 to C5. To investigate the dual roles of recombination and evolution in the epidemiology and transmission of EV71 worldwide, we performed a large-scale genetic analysis of isolates (n = 308) collected from 19 countries worldwide over a 40-year period. A series of recombination events occurred over this period, which have been identified through incongruities in sequence grouping between the VP1 and 3Dpol regions. Eleven 3Dpol clades were identified, each specific to EV71 and associated with specific subgenogroups but interspersed phylogenetically with clades of coxsackievirus A16 and other EV species A serotypes. The likelihood of recombination increased with VP1 sequence divergence; mean half-lives for EV71 recombinant forms (RFs) of 6 and 9 years for GgB and GgC overlapped with those observed for the EV-B serotypes, echovirus 9 (E9), E30, and E11, respectively (1.3 to 9.8 years). Furthermore, within genogroups, sporadic recombination events occurred, such as the linkage of two B4 variants to RF-W instead of RF-A and of two C4 variants to RF-H. Intriguingly, recombination events occurred as a founding event of most subgenogroups immediately preceding their lineage expansion and global emergence. The possibility that recombination contributed to their subsequent spread through improved fitness requires further biological and immunological characterization.
The effects of changes in the gut environment upon the human colonic microbiota are poorly understood. The response of human fecal microbial communities from two donors to alterations in pH (5.5 or ...6.5) and peptides (0.6 or 0.1%) was studied here in anaerobic continuous cultures supplied with a mixed carbohydrate source. Final butyrate concentrations were markedly higher at pH 5.5 (0.6% peptide mean, 24.9 mM; 0.1% peptide mean, 13.8 mM) than at pH 6.5 (0.6% peptide mean, 5.3 mM; 0.1% peptide mean, 7.6 mM). At pH 5.5 and 0.6% peptide input, a high butyrate production coincided with decreasing acetate concentrations. The highest propionate concentrations (mean, 20.6 mM) occurred at pH 6.5 and 0.6% peptide input. In parallel, major bacterial groups were monitored by using fluorescence in situ hybridization with a panel of specific 16S rRNA probes. Bacteroides levels increased from ca. 20 to 75% of total eubacteria after a shift from pH 5.5 to 6.5, at 0.6% peptide, coinciding with high propionate formation. Conversely, populations of the butyrate-producing Roseburia group were highest (11 to 19%) at pH 5.5 but fell at pH 6.5, a finding that correlates with butyrate formation. When tested in batch culture, three Bacteroides species grew well at pH 6.7 but poorly at pH 5.5, which is consistent with the behavior observed for the mixed community. Two Roseburia isolates grew equally well at pH 6.7 and 5.5. These findings suggest that a lowering of pH resulting from substrate fermentation in the colon may boost butyrate production and populations of butyrate-producing bacteria, while at the same time curtailing the growth of Bacteroides spp.
To estimate the frequency, molecular epidemiological and clinical associations of infection with the newly described species C variants of human rhinoviruses (HRV), 3243 diagnostic respiratory ...samples referred for diagnostic testing in Edinburgh were screened using a VP4-encoding region-based selective polymerase chain reaction (PCR) for HRV-C along with parallel PCR testing for 13 other respiratory viruses. HRV-C was the third most frequently detected behind respiratory syncytial virus (RSV) and adenovirus, with 141 infection episodes detected among 1885 subjects over 13 months (7.5%). Infections predominantly targeted the very young (median age 6-12 months; 80% of infections in those <2 years), occurred throughout the year but with peak incidence in early winter months. HRV-C was detected significantly more frequently among subjects with lower (LRT) and upper respiratory tract (URT) disease than controls without respiratory symptoms; HRV-C mono-infections were the second most frequently detected virus (behind RSV) in both disease presentations (6.9% and 7.8% of all cases respectively). HRV variants were classified by VP4/VP2 sequencing into 39 genotypically defined types, increasing the current total worldwide to 60. Through sequence comparisons of the 5'untranslated region (5'UTR), the majority grouped with species A (n = 96; 68%, described as HRV-Ca), the remainder forming a phylogenetically distinct 5'UTR group (HRV-Cc). Multiple and bidirectional recombination events between HRV-Ca and HRV-Cc variants and with HRV species A represents the most parsimonious explanation for their interspersed phylogeny relationships in the VP4/VP2-encoding region. No difference in age distribution, seasonality or disease associations was identified between HRV-Ca and HRV-Cc variants. HRV-C-infected subjects showed markedly reduced detection frequencies of RSV and other respiratory viruses, providing evidence for a major interfering effect of HRV-C on susceptibility to other respiratory virus infections. HRV-C's disease associations, its prevalence and evidence for interfering effects on other respiratory viruses mandates incorporation of rhinoviruses into future diagnostic virology screening.
The 10 Meter South Pole Telescope Carlstrom, J. E.; Ade, P. A. R.; Aird, K. A. ...
Publications of the Astronomical Society of the Pacific,
05/2011, Letnik:
123, Številka:
903
Journal Article
Recenzirano
Odprti dostop
The South Pole Telescope (SPT) is a 10 m diameter, wide-field, offset Gregorian telescope with a 966 pixel, multicolor, millimeter-wave, bolometer camera. It is located at the Amundsen-Scott South ...Pole station in Antarctica. The design of the SPT emphasizes careful control of spillover and scattering, to minimize noise and false signals due to ground pickup. The key initial project is a large-area survey at wavelengths of 3, 2, and 1.3 mm, to detect clusters of galaxies via the Sunyaev-Zel’dovich effect and to measure the small-scale angular power spectrum of the cosmic microwave background (CMB). The data will be used to characterize the primordial matter power spectrum and to place constraints on the equation of state of dark energy. A second-generation camera will measure the polarization of the CMB, potentially leading to constraints on the neutrino mass and the energy scale of inflation.
We present results from an analysis of all data taken by the bicep2/Keck CMB polarization experiments up to and including the 2015 observing season. This includes the first Keck Array observations at ...220 GHz and additional observations at 95 and 150 GHz. The Q and U maps reach depths of 5.2, 2.9, and 26 μK_{CMB} arcmin at 95, 150, and 220 GHz, respectively, over an effective area of ≈400 square degrees. The 220 GHz maps achieve a signal to noise on polarized dust emission approximately equal to that of Planck at 353 GHz. We take auto and cross spectra between these maps and publicly available WMAP and Planck maps at frequencies from 23 to 353 GHz. We evaluate the joint likelihood of the spectra versus a multicomponent model of lensed-ΛCDM+r+dust+synchrotron+noise. The foreground model has seven parameters, and we impose priors on some of these using external information from Planck and WMAP derived from larger regions of sky. The model is shown to be an adequate description of the data at the current noise levels. The likelihood analysis yields the constraint r_{0.05}<0.07 at 95% confidence, which tightens to r_{0.05}<0.06 in conjunction with Planck temperature measurements and other data. The lensing signal is detected at 8.8σ significance. Running a maximum likelihood search on simulations we obtain unbiased results and find that σ(r)=0.020. These are the strongest constraints to date on primordial gravitational waves.
Infections with human parechoviruses (HPeVs) are prevalent in young children and have been associated with mild gastroenteritis and, less frequently, with meningitis and neonatal sepsis. To ...investigate the involvement of these viruses in respiratory disease, a highly sensitive nested PCR was used to screen a large archive of respiratory specimens, collected between January and December 2007. Respiratory samples had previously been tested for eight respiratory viruses, including respiratory syncytial virus and adenovirus, by PCR. HPeV was detected in 34 of 3,844 specimens, representing 27 of 2,220 study subjects (1.2%). HPeV types were identified by sequencing the VP3/VP1 junction amplified by PCR directly from clinical specimens. The assay could amplify all HPeV types examined with high sensitivity (types 1 and 3 to 6) and also identified HPeV types in all but one of the screen-positive study specimens (25 HPeV1 and eight HPeV6 specimens). Infections with both HPeV1 and HPeV6 were seasonal, with highest frequencies in July and August, and restricted to children aged between 6 months and 5 years. Other respiratory viruses were frequently codetected in HPeV-positive specimens, with significant overrepresentation of adenovirus coinfections (37%). Most HPeV-positive specimens were referred from emergency departments, although no association with specific respiratory symptoms or disease was found. In summary, the low frequency of detection and lack of clear disease associations indicate that HPeV1 and -6 are not major pathogens in individuals presenting with respiratory disease. However, the screening and typing methods developed will be of value in further HPeV testing, including testing for meningitis cases and other suspected HPeV-associated disease presentations.
We present results from an analysis of all data taken by the BICEP2 and Keck Array cosmic microwave background (CMB) polarization experiments up to and including the 2014 observing season. This ...includes the first Keck Array observations at 95 GHz. The maps reach a depth of 50 nK deg in Stokes Q and U in the 150 GHz band and 127 nK deg in the 95 GHz band. We take auto- and cross-spectra between these maps and publicly available maps from WMAP and Planck at frequencies from 23 to 353 GHz. An excess over lensed ΛCDM is detected at modest significance in the 95×150 BB spectrum, and is consistent with the dust contribution expected from our previous work. No significant evidence for synchrotron emission is found in spectra such as 23×95, or for correlation between the dust and synchrotron sky patterns in spectra such as 23×353. We take the likelihood of all the spectra for a multicomponent model including lensed ΛCDM, dust, synchrotron, and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r) using priors on the frequency spectral behaviors of dust and synchrotron emission from previous analyses of WMAP and Planck data in other regions of the sky. This analysis yields an upper limit r_{0.05}<0.09 at 95% confidence, which is robust to variations explored in analysis and priors. Combining these B-mode results with the (more model-dependent) constraints from Planck analysis of CMB temperature plus baryon acoustic oscillations and other data yields a combined limit r_{0.05}<0.07 at 95% confidence. These are the strongest constraints to date on inflationary gravitational waves.
PDF
