Genomics reveals historic and contemporary transmission dynamics of a bacterial disease among wildlife and livestock

Whole-genome sequencing has provided fundamental insights into infectious disease epidemiology, but has rarely been used for examining transmission dynamics of a bacterial pathogen in wildlife. In the Greater Yellowstone Ecosystem (GYE), outbreaks of brucellosis have increased in cattle along with rising seroprevalence in elk. Here we use a genomic approach to examine Brucella abortus evolution, cross-species transmission and spatial spread in the GYE. We find that brucellosis was introduced into wildlife in this region at least five times. The diffusion rate varies among Brucella lineages (∼3 to 8 km per year) and over time. We also estimate 12 host transitions from bison to elk, and 5 from elk to bison. Our results support the notion that free-ranging elk are currently a self-sustaining brucellosis reservoir and the source of livestock infections, and that control measures in bison are unlikely to affect the dynamics of unrelated strains circulating in nearby elk populations

Migratory and winter activity of bats in Yellowstone National Park

A substantial body of work exists describing timing of migration and hibernation among bats in eastern North America, but less is known about these events among bats inhabiting the Rocky Mountain region. Yellowstone National Park is a geothermally influenced landscape comprised of diverse habitats, creating the opportunity for unique behaviors to develop among local bat populations. We identified the timing of migration for the local bat community and determined if bats overwinter in Yellowstone. To accomplish this, we radiotracked 7 little brown myotis (Myotis lucifugus), 5 western long-eared myotis (M. evotis), 4 big brown bats (Eptesicus fuscus), 4 silver-haired bats (Lasionycteris noctivagans), and 1 western small-footed myotis (M. ciliolabrum) from August to September 2010 and September to October 2011. We also used acoustic detectors to record bat activity from November through April 2011–2014 and sampled abundance of nocturnal insects using black-light traps from 2011 to 2012. Although availability of insects declined rapidly during August and afterward, several bat species remained active throughout autumn and winter. Bat activity was recorded during all months, even during periods of extreme cold. Radiotagged big brown bats, little brown myotis, and western small-footed myotis remained active in the study area throughout October, after the 1st snowfall of the season. While data for activity patterns in late autumn and winter prevented an estimation of the onset of hibernation, spring emergence occurred in April despite persistence of winter conditions. These data provide insights into the migration and hibernation strategies of bat populations in the Rocky Mountains and highlight gaps in our understanding of seasonal changes in these species

Safety, efficacy, and immunogenicity of an inactivated influenza vaccine in healthy adults: a randomized, placebo-controlled trial over two influenza seasons

<p>Abstract</p> <p>Background</p> <p>Seasonal influenza imposes a substantial personal morbidity and societal cost burden. Vaccination is the major strategy for influenza prevention; however, because antigenically drifted influenza A and B viruses circulate annually, influenza vaccines must be updated to provide protection against the predicted prevalent strains for the next influenza season. The aim of this study was to assess the efficacy, safety, reactogenicity, and immunogenicity of a trivalent inactivated split virion influenza vaccine (TIV) in healthy adults over two influenza seasons in the US.</p> <p>Methods</p> <p>The primary endpoint of this double-blind, randomized study was the average efficacy of TIV versus placebo for the prevention of vaccine-matched, culture-confirmed influenza (VMCCI) across the 2005-2006 and 2006-2007 influenza seasons. Secondary endpoints included the prevention of laboratory-confirmed (defined by culture and/or serology) influenza, as well as safety, reactogenicity, immunogenicity, and consistency between three consecutive vaccine lots. Participants were assessed actively during both influenza seasons, and nasopharyngeal swabs were collected for viral culture from individuals with influenza-like illness. Blood specimens were obtained for serology one month after vaccination and at the end of each influenza season's surveillance period.</p> <p>Results</p> <p>Although the point estimate for efficacy in the prevention of all laboratory-confirmed influenza was 63.2% (97.5% confidence interval [CI] lower bound of 48.2%), the point estimate for the primary endpoint, efficacy of TIV against VMCCI across both influenza seasons, was 46.3% with a 97.5% CI lower bound of 9.8%. This did not satisfy the pre-specified success criterion of a one-sided 97.5% CI lower bound of >35% for vaccine efficacy. The VMCCI attack rates were very low overall at 0.6% and 1.2% in the TIV and placebo groups, respectively. Apart from a mismatch for influenza B virus lineage in 2005-2006, there was a good match between TIV and the circulating strains. TIV was highly immunogenic, and immune responses were consistent between three different TIV lots. The most common reactogenicity events and spontaneous adverse events were associated with the injection site, and were mild in severity.</p> <p>Conclusions</p> <p>Despite a good immune response, and an average efficacy over two influenza seasons against laboratory-confirmed influenza of 63.2%, the pre-specified target (lower one-sided 97.5% confidence bound for efficacy > 35%) for the primary efficacy endpoint, the prevention of VMCCI, was not met. However, the results should be interpreted with caution in view of the very low attack rates we observed at the study sites in the 2005-2006 and 2006-2007, which corresponded to relatively mild influenza seasons in the US. Overall, the results showed that TIV has an acceptable safety profile and offered clinical benefit that exceeded risk.</p> <p>Trial registration</p> <p>NCT00216242</p

Cross-Reactive Neuraminidase Antibodies Afford Partial Protection against H5N1 in Mice and Are Present in Unexposed Humans

BACKGROUND: A pandemic H5N1 influenza outbreak would be facilitated by an absence of immunity to the avian-derived virus in the human population. Although this condition is likely in regard to hemagglutinin-mediated immunity, the neuraminidase (NA) of H5N1 viruses (avN1) and of endemic human H1N1 viruses (huN1) are classified in the same serotype. We hypothesized that an immune response to huN1 could mediate cross-protection against H5N1 influenza virus infection. METHODS AND FINDINGS: Mice were immunized against the NA of a contemporary human H1N1 strain by DNA vaccination. They were challenged with recombinant A/Puerto Rico/8/34 (PR8) viruses bearing huN1 (PR8-huN1) or avN1 (PR8-avN1) or with H5N1 virus A/Vietnam/1203/04. Additional naïve mice were injected with sera from vaccinated mice prior to H5N1 challenge. Also, serum specimens from humans were analyzed for reactivity with avN1. Immunization elicited a serum IgG response to huN1 and robust protection against the homologous challenge virus. Immunized mice were partially protected from lethal challenge with H5N1 virus or recombinant PR8-avN1. Sera transferred from immunized mice to naïve animals conferred similar protection against H5N1 mortality. Analysis of human sera showed that antibodies able to inhibit the sialidase activity of avN1 exist in some individuals. CONCLUSIONS: These data reveal that humoral immunity elicited by huN1 can partially protect against H5N1 infection in a mammalian host. Our results suggest that a portion of the human population could have some degree of resistance to H5N1 influenza, with the possibility that this could be induced or enhanced through immunization with seasonal influenza vaccines

Genomics of Brucellosis in Wildlife and Livestock of the Greater Yellowstone Ecosystem

Brucellosis, a disease caused by the bacterium Brucella abortus, has recently been expanding its distribution in the Greater Yellowstone Ecosystem (GYE), with increased outbreaks in cattle and rising seroprevalence in elk (Cervus elaphus) over the past decade. Genetic studies suggest elk are a primary source of recent transmission to cattle. However, these studies are based on Variable Number Tandem Repeat (VNTR) data, which are limited in assessing and quantifying transmission among species. The goal of this study was to (i) investigate the introduction history of B. abortus in the GYE, (ii) identify B. abortus lineages associated with host species and/or geographic localities, and (iii) quantify transmission across wildlife and livestock host species and populations. We sequenced B. abortus whole genomes (n= 207) derived from isolates collected from three host species (bison, elk, cattle) over the past 30 years, throughout the GYE. We identified genetic variation among isolates, and applied a spatial diffusion phylogeographic modeling approach that incorporated temporal information from sampling. Based on these data, our results suggest four divergent Brucella lineages, with a time to most recent common ancestor of ~130 years ago, possibly representing a minimum of four brucellosis introductions into the GYE. Two Brucella lineages were generally clustered by geography. Evidence for cross-species transmission was detected among all species, though most events occur within species and herds. Understanding transmission dynamics is imperative for implementing effective control measures and may assist in identifying source populations responsible for past and future brucellosis infections in wildlife and outbreaks in livestock

Benzene adsorption on Rh(111) : a new perspective on intermolecular interactions and molecular ordering

The authors acknowledge financial support from the Scottish Funding Council (through EaStCHEM and SRD-Grant HR07003) and from EPSRC (PhD studentships for JAGT − EP/M506631/1, and MJT − EP/K503162/1).The adsorption of benzene on the Rh(111) substrate was investigated through scanning tunneling microscopy (STM) imaging and density functional theory (DFT) calculations. Experiments were carried out at various surface coverages, with the amount of benzene adsorbed determined to influence the molecular adsorption site, the intermolecular interactions, and the interaction between the molecule and the substrate. At a sub-monolayer coverage of the surface, the molecules are disordered and kept apart by a strong inter-adsorbate repulsion, with a preference for the molecule to adsorb on a three-fold hcp hollow site. At high coverage, the preferred adsorption site becomes the two-fold symmetric bridge site, whether as part of the two dense ordered structures that form at high coverage ((2√3×3)rect or (√19×√19)R23.4°) or as part of the disordered array of benzene molecules, which are arranged in formations which resemble the “building blocks” of the ordered overlayers. Despite the adsorption energy for benzene within both dense structures being similar, the (√19×√19)R23.4° overlayer is only observed if the substrate is annealed to 363 K during or after deposition, indicating that the formation of the (√19×√19)R23.4° ordering is inhibited by an activation barrier at lower temperatures and can only be overcome by increasing the temperature of the Rh(111) support.PostprintPeer reviewe

A Rapid Flp-In System for Expression of Secreted H5N1 Influenza Hemagglutinin Vaccine Immunogen in Mammalian Cells

Continuing transmissions of highly pathogenic H5N1 viruses in poultry and humans underscores the need for a rapid response to potential pandemic in the form of vaccine. Recombinant technologies for production of immunogenic hemagglutinin (HA) could provide an advantage over the traditional inactivated vaccine manufacturing process. Generation of stably transfected mammalian cells secreting properly folded HA proteins is important for scalable controlled manufacturing.We have developed a Flp-In based 293 stable cell lines through targeted site-specific recombination for expression of secreted hemagglutinin (HA) proteins and evaluated their immunogenicity. H5N1 globular domain HA1(1-330) and HA0(1-500) proteins were purified from the supernatants of 293 Flp-In stable cell lines. Both proteins were properly folded as confirmed by binding to H5N1-neutralizing conformation-dependent human monoclonal antibodies. The HA0 (with unmodified cleavage site) was monomeric, while the HA1 contained oligomeric forms. Upon rabbit immunization, both HA proteins elicited neutralizing antibodies against the homologous virus (A/Vietnam/1203/2004, clade 1) as well as cross-neutralizing antibodies against heterologous H5N1 clade 2 strains, including A/Indonesia/5/2005. These results exceeded the human antibody responses against the inactivated sub-virion H5N1 vaccine.Our data suggest that the 293 Flp-In system could serve as a platform for rapid expression of HA immunogens in mammalian cells from emerging influenza strains