A point-of-care diagnostic for differentiating Ebola from endemic febrile diseases.

Hemorrhagic fever outbreaks such as Ebola are difficult to detect and control because of the lack of low-cost, easily deployable diagnostics and because initial clinical symptoms mimic other endemic diseases such as malaria. Current molecular diagnostic methods such as polymerase chain reaction require trained personnel and laboratory infrastructure, hindering diagnostics at the point of need. Although rapid tests such as lateral flow can be broadly deployed, they are typically not well-suited for differentiating among multiple diseases presenting with similar symptoms. Early detection and control of Ebola outbreaks require simple, easy-to-use assays that can detect and differentiate infection with Ebola virus from other more common febrile diseases. Here, we developed and tested an immunoassay technology that uses surface-enhanced Raman scattering (SERS) tags to simultaneously detect antigens from Ebola, Lassa, and malaria within a single blood sample. Results are provided in <30 min for individual or batched samples. Using 190 clinical samples collected from the 2014 West African Ebola outbreak, along with 163 malaria positives and 233 negative controls, we demonstrated Ebola detection with 90.0% sensitivity and 97.9% specificity and malaria detection with 100.0% sensitivity and 99.6% specificity. These results, along with corresponding live virus and nonhuman primate testing of an Ebola, Lassa, and malaria 3-plex assay, indicate the potential of the SERS technology as an important tool for outbreak detection and clinical triage in low-resource settings.

Zika virus induced cellular remodelling.

Zika virus (ZIKV) has been associated with morbidities such as Guillain-Barré, infant microcephaly, and ocular disease. The spread of this positive-sense, single-stranded RNA virus and its growing public health threat underscore gaps in our understanding of basic ZIKV virology. To advance knowledge of the virus replication cycle within mammalian cells, we use serial section 3-dimensional electron tomography to demonstrate the widespread remodelling of intracellular membranes upon infection with ZIKV. We report extensive structural rearrangements of the endoplasmic reticulum and reveal stages of the ZIKV viral replication cycle. Structures associated with RNA genome replication and virus assembly are observed integrated within the endoplasmic reticulum, and we show viruses in transit through the Golgi apparatus for viral maturation, and subsequent cellular egress. This study characterises in detail the 3-dimensional ultrastructural organisation of the ZIKV replication cycle stages. Our results show close adherence of the ZIKV replication cycle to the existing flavivirus replication paradigm.

PERP, a host tetraspanning membrane protein, is required for Salmonella-induced inflammation.

Salmonella enterica Typhimurium induces intestinal inflammation through the activity of type III secreted effector (T3SE) proteins. Our prior results indicate that the secretion of the T3SE SipA and the ability of SipA to induce epithelial cell responses that lead to induction of polymorphonuclear transepithelial migration are not coupled to its direct delivery into epithelial cells from Salmonella. We therefore tested the hypothesis that SipA interacts with a membrane protein located at the apical surface of intestinal epithelial cells. Employing a split ubiquitin yeast-two-hybrid screen, we identified the tetraspanning membrane protein, p53 effector related to PMP-22 (PERP), as a SipA binding partner. SipA and PERP appear to have intersecting activities as we found PERP to be involved in proinflammatory pathways shown to be regulated by SipA. In sum, our studies reveal a critical role for PERP in the pathogenesis of S. Typhimurium, and for the first time demonstrate that SipA, a T3SE protein, can engage a host protein at the epithelial surface.

Remote monitoring of the progression of primary pneumonic plague in Brown Norway rats in high-capacity, high-containment housing.

Development of new vaccines, diagnostics, and therapeutics for biodefense or other relatively rare infectious diseases is hindered by the lack of naturally occurring human disease on which to conduct clinical trials of efficacy. To overcome this experimental gap, the U.S. Food and Drug Administration established the Animal Rule, in which efficacy testing in two well-characterized animal models that closely resemble human disease may be accepted in lieu of large-scale clinical trials for diseases with limited natural human incidence. In this report, we evaluated the Brown Norway rat as a model for pneumonic plague and describe the natural history of clinical disease following inhalation exposure to Yersinia pestis. In high-capacity, high-containment housing, we monitored temperature, activity, heart rate, and rhythm by capturing electronic impulses transmitted from abdominal telemeter implants. Using this system, we show that reduced activity and development of fever are sensitive indications of disease progression. Furthermore, we identified heart arrhythmias as contributing factors to the rapid progression to lethality following the fever response. Together, these data validate the Brown Norway rat as an experimental model for human pneumonic plague and provide new insight that may ultimately lead to novel approaches in postexposure treatment of this devastating infection.

Macrophages clean up: efferocytosis and microbial control.

Phagocytic leukocytes, predominantly macrophages, not only ingest and destroy invading pathogens, but are charged with clearing dead and dying host cells. The process of engulfing apoptotic cells is called efferocytosis and has long been appreciated for its role in the resolution of inflammation. New evidence is emerging that efferocytosis represents a double-edged sword in microbial immunity. Although efferocytosis of influenza and Mycobacterium tuberculosis-infected cells results in pathogen destruction, efferocytosis of Leishmania-infected neutrophils may promote infection. Understanding how macrophages, dendritic cells (DC) and neutrophils process pathogens encased within a dying cell could lead to the development of novel therapeutics that simultaneously suppress inflammation and promote pathogen clearance.

Breastfeeding and trajectories of children's cognitive development.

The aim of this study was to examine the association of breastfeeding practices with the growth trajectories of children's cognitive development. We used data from the Child Development Supplement (CDS) of the Panel Study of Income Dynamics (PSID) with variables on presence and duration of breastfeeding and standardized test scores obtained during three different panel waves (N = 2681). After adjusting for covariates we found that breastfed children had higher test scores but that breastfed and non-breastfed children had similar growth trajectories in test scores over time. The results indicate that breastfeeding has an important association with test scores, and that subsequent schooling and other experiences during adolescence do not eliminate the breastfeeding gap that appears in very early childhood.

Does breastfeeding contribute to the racial gap in reading and math test scores?

PURPOSE: The aim of this study was to examine the impact of divergent breastfeeding practices between Caucasian and African American mothers on the lingering achievement test gap between Caucasian and African American children. METHODS: The Child Development Supplement of the Panel Study of Income Dynamics, beginning in 1997, followed a cohort of 3563 children aged 0-12 years. Reading and math test scores from 2002 for 1928 children were linked with breastfeeding history. Regression analysis was used to examine associations between ever having been breastfed and duration of breastfeeding and test scores, controlling for characteristics of child, mother, and household. RESULTS: African American students scored significantly lower than Caucasian children by 10.6 and 10.9 points on reading and math tests, respectively. After accounting for the impact of having been breastfed during infancy, the racial test gap decreased by 17% for reading scores and 9% for math scores. CONCLUSIONS: Study findings indicate that breastfeeding explains 17% and 9% of the observed gaps in reading and math scores, respectively, between African Americans and Caucasians, an effect larger than most recent educational policy interventions. Renewed efforts around policies and clinical practices that promote and remove barriers for African American mothers to breastfeed should be implemented.

Early apoptosis of macrophages modulated by injection of Yersinia pestis YopK promotes progression of primary pneumonic plague.

Yersinia pestis causes pneumonic plague, a disease characterized by inflammation, necrosis and rapid bacterial growth which together cause acute lung congestion and lethality. The bacterial type III secretion system (T3SS) injects 7 effector proteins into host cells and their combined activities are necessary to establish infection. Y. pestis infection of the lungs proceeds as a biphasic inflammatory response believed to be regulated through the control of apoptosis and pyroptosis by a single, well-conserved T3SS effector protein YopJ. Recently, YopJ-mediated pyroptosis, which proceeds via the NLRP3-inflammasome, was shown to be regulated by a second T3SS effector protein YopK in the related strain Y. pseudotuberculosis. In this work, we show that for Y. pestis, YopK appears to regulate YopJ-mediated apoptosis, rather than pyroptosis, of macrophages. Inhibition of caspase-8 blocked YopK-dependent apoptosis, suggesting the involvement of the extrinsic pathway, and appeared cell-type specific. However, in contrast to yopJ, deletion of yopK caused a large decrease in virulence in a mouse pneumonic plague model. YopK-dependent modulation of macrophage apoptosis was observed at 6 and 24 hours post-infection (HPI). When YopK was absent, decreased populations of macrophages and dendritic cells were seen in the lungs at 24 HPI and correlated with resolution rather than progression of inflammation. Together the data suggest that Y. pestis YopK may coordinate the inflammatory response during pneumonic plague through the regulation of apoptosis of immune cells.

Host stress and immune responses during aerosol challenge of Brown Norway rats with Yersinia pestis.

Inhalation exposure models are becoming the preferred method for the comparative study of respiratory infectious diseases due to their resemblance to the natural route of infection. To enable precise delivery of pathogen to the lower respiratory tract in a manner that imposes minimal biosafety risk, nose-only exposure systems have been developed. Early inhalation exposure technology for infectious disease research grew out of technology used in asthma research where predominantly the Collison nebulizer is used to generate an aerosol by beating a liquid sample against glass. Although infectious aerosol droplets of 1-5 µm in size can be generated, the Collison often causes loss of viability. In this work, we evaluate a gentler method for aerosolization of living cells and describe the use of the Sparging Liquid Aerosol Generator (SLAG) in a rat pneumonic plague model. The SLAG creates aerosols by continuous dripping of liquid sample on a porous metal disc. We show the generation of 0.5-1 µm Yersinia pestis aerosol particles using the SLAG with spray factors typically ranging from 10(-7) to 10(-8) with no detectable loss of bacterial viability. Delivery of these infectious particles via nose-only exposure led to the rapid development of lethal pneumonic plague. Further, we evaluated the effect of restraint-stress imposed by the nose-only exposure chamber on early inflammatory responses and bacterial deposition. Elevated serum corticosterone which peaked at 2 h post-procedure indicated the animals experienced stress as a result of restraint in the nose-only chamber. However, we observed no correlation between elevated corticosterone and the amount of bacterial deposition or inflammation in the lungs. Together these data demonstrate the utility of the SLAG and the nose-only chamber for aerosol challenge of rodents by Y. pestis.

Who are truant youth? Examining distinctive profiles of truant youth using latent profile analysis.

The present study explored the heterogeneity of truant youth to provide a more nuanced examination of the nature of adolescent truancy and examine distinct profiles of truant youth as they relate to externalizing behaviors. Latent profile analysis was employed to examine the heterogeneity of truant youth by using a nationally representative sample of 1,646 truant adolescents (49.8 % female) from the 2010 National Survey on Drug Use and Health. Five key indicator variables were utilized to identify latent classes: school engagement, participation in school-based activities, grades, parental academic involvement, and number of school days skipped. Additionally, multinomial regression was employed to examine the relationship between latent truant youth classes and externalizing behaviors. Four classes of truant youth were identified: achievers (28.55 %), moderate students (24.30 %), academically disengaged (40.89 %), and chronic skippers (6.26 %). Additionally, group membership was found to be associated differentially with marijuana use, fighting, theft and selling drugs. Results from the present study suggest that truant youth are not a homogenous group, but rather present with different risk profiles as they relate to key indicators, demographic characteristics and externalizing behaviors. Implications for practice, policy and future research are discussed.

Comparison of two creativity style measures.

The purpose of this study was to examine the relation between two measures of creativity style for a sample of beginning teachers. 116 student teachers enrolled in an undergraduate teacher-education program in a medium-sized, metropolitan university completed the Kirton Adaption-Innovation Inventory and Basadur Creative Problem Solving Profile measures. A preference for an Innovator style (higher scores on Kirton's inventory) was correlated with the Generator profile on the Basadur profile (r=.36, p<.01). The KAI Efficiency scores, suggesting a preference for broad, global ideas as opposed to narrow, specific ones, was correlated with the Basadur Conceptualizer scores (r=.26, p<.01). Implications are discussed for teachers who must adapt to newer instructional and assessment methods designed to foster students' higher-level thinking skills.