88 research outputs found

    Outcome of Diagnostic Tests Using Samples from Patients with Culture-Proven Human Monocytic Ehrlichiosis: Implications for Surveillance

    Get PDF
    We describe the concordance among results from various laboratory tests using samples derived from nine culture-proven cases of human monocytic ehrlichiosis (HME) caused by Ehrlichia chaffeensis. A class-specific indirect immunofluorescence assay for immunoglobulin M (IgM) and IgG, using E. chaffeensis antigen, identified 44 and 33% of the isolation-confirmed HME patients on the basis of samples obtained at initial clinical presentation, respectively; detection of morulae in blood smears was similarly insensitive (22% positive). PCR amplifications of ehrlichial DNA targeting the 16S rRNA gene, the variable-length PCR target gene, and the groESL operon were positive for whole blood specimens obtained from all patients at initial presentation. As most case definitions of HME require a serologic response with compatible illness for a categorization of even probable disease, PCR would have been required to confirm the diagnosis of HME in all nine of these patients without the submission of a convalescent-phase serum sample. These data suggest that many, if not most, cases of HME in patients who present early in the course of the disease may be missed and underscore the limitations of serologically based surveillance systems

    Analysis of Risk Factors for Fatal Rocky Mountain Spotted Fever: Evidence for Superiority of Tetracyclines for Therapy

    Get PDF
    Epidemiologic and clinical characteristics of fatal and nonfatal cases of Rocky Mountain spotted fever (RMSF) were compared to identify risk factors for death caused by this disease. Confirmed and probable RMSF cases reported through US national surveillance for 1981- 1998 were analyzed. Among 6388 RMSF patients, 213 died (annual case-fatality rate, 3M; range, 4.9 % in 1982 to 1.1 % in 1996). Use of tetracycline-class antibiotics for treatment of RMSF increased significantly in the 1990s, compared with use in the 1980s. Older patients, patients treated with chloramphenicol only, patients for whom tetracycline antibiotics were not the primary therapy, and patients for whom treatment was delayed ≥5 days after the onset of symptoms were at higher risk for death. Although the case-fatality rate was lower in the 1990s than in the 1980s, risk factors for fatal RMSF were similar. Despite the availability of effective antibiotics, RMSF-related deaths continue to occur because of delayed diagnosis and failure to use appropriate therapy

    Analysis of Risk Factors for Fatal Rocky Mountain Spotted Fever: Evidence for Superiority of Tetracyclines for Therapy

    Get PDF
    Epidemiologic and clinical characteristics of fatal and nonfatal cases of Rocky Mountain spotted fever (RMSF) were compared to identify risk factors for death caused by this disease. Confirmed and probable RMSF cases reported through US national surveillance for 1981- 1998 were analyzed. Among 6388 RMSF patients, 213 died (annual case-fatality rate, 3M; range, 4.9 % in 1982 to 1.1 % in 1996). Use of tetracycline-class antibiotics for treatment of RMSF increased significantly in the 1990s, compared with use in the 1980s. Older patients, patients treated with chloramphenicol only, patients for whom tetracycline antibiotics were not the primary therapy, and patients for whom treatment was delayed ≥5 days after the onset of symptoms were at higher risk for death. Although the case-fatality rate was lower in the 1990s than in the 1980s, risk factors for fatal RMSF were similar. Despite the availability of effective antibiotics, RMSF-related deaths continue to occur because of delayed diagnosis and failure to use appropriate therapy

    Methods for Extremely Sparse-Angle Proton Tomography

    Full text link
    Proton radiography is a widely-fielded diagnostic used to measure magnetic structures in plasma. The deflection of protons with multi-MeV kinetic energy by the magnetic fields is used to infer their path-integrated field strength. Here, the use of tomographic methods is proposed for the first time to lift the degeneracy inherent in these path-integrated measurements, allowing full reconstruction of spatially resolved magnetic field structures in three dimensions. Two techniques are proposed which improve the performance of tomographic reconstruction algorithms in cases with severely limited numbers of available probe beams, as is the case in laser-plasma interaction experiments where the probes are created by short, high-power laser pulse irradiation of secondary foil targets. The methods are equally applicable to optical probes such as shadowgraphy and interferometry [M. Kasim et al. Phys. Rev. E 95, 023306 (2017)], thereby providing a disruptive new approach to three dimensional imaging across the physical sciences and engineering disciplines.Comment: 11 pages, 6 figures, companion article to arXiv:2103.1126

    The Eco-Epidemiology of Pacific Coast Tick Fever in California

    Get PDF
    Rickettsia philipii (type strain “Rickettsia 364D”), the etiologic agent of Pacific Coast tick fever (PCTF), is transmitted to people by the Pacific Coast tick, Dermacentor occidentalis. Following the first confirmed human case of PCTF in 2008, 13 additional human cases have been reported in California, more than half of which were pediatric cases. The most common features of PCTF are the presence of at least one necrotic lesion known as an eschar (100%), fever (85%), and headache (79%); four case-patients required hospitalization and four had multiple eschars. Findings presented here implicate the nymphal or larval stages of D. occidentalis as the primary vectors of R. philipii to people. Peak transmission risk from ticks to people occurs in late summer. Rickettsia philipii DNA was detected in D. occidentalis ticks from 15 of 37 California counties. Similarly, non-pathogenic Rickettsia rhipicephali DNA was detected in D. occidentalis in 29 of 38 counties with an average prevalence of 12.0% in adult ticks. In total, 5,601 ticks tested from 2009 through 2015 yielded an overall R. philipii infection prevalence of 2.1% in adults, 0.9% in nymphs and a minimum infection prevalence of 0.4% in larval pools. Although most human cases of PCTF have been reported from northern California, acarological surveillance suggests that R. philipii may occur throughout the distribution range of D. occidentalis

    Energy gain of wetted-foam implosions with auxiliary heating for inertial fusion studies

    Get PDF
    Low convergence ratio implosions (where wetted-foam layers are used to limit capsule convergence, achieving improved robustness to instability growth) and auxiliary heating (where electron beams are used to provide collisionless heating of a hotspot) are two promising techniques that are being explored for inertial fusion energy applications. In this paper, a new analytic study is presented to understand and predict the performance of these implosions. Firstly, conventional gain models are adapted to produce gain curves for fixed convergence ratios, which are shown to well-describe previously simulated results. Secondly, auxiliary heating is demonstrated to be well understood and interpreted through the burn-up fraction of the deuterium-tritium fuel, with the gradient of burn-up with respect to burn-averaged temperature shown to provide good qualitative predictions of the effectiveness of this technique for a given implosion. Simulations of auxiliary heating for a range of implosions are presented in support of this and demonstrate that this heating can have significant benefit for high gain implosions, being most effective when the burn-averaged temperature is between 5 and 20 keV

    Making America A Better Place for All: Sustainable Development Recommendations for the Biden Administration

    Get PDF
    In 2015, the United Nations Member States, including the United States, unanimously approved 17 Sustainable Development Goals (SDGs) to be achieved by 2030. The SDGs are nonbinding; each nation is to implement them based on its own priorities and circumstances. This Article argues that the SDGs are a critical normative framework the United States should use to improve human quality of life, freedom, and opportunity by integrating economic and social development with environmental protection. It collects the recommendations of 22 experts on steps that the Biden-Harris Administration should take now to advance each of the SDGs. It is part of a book project that will recommend not only federal actions, but also actions by state and local governments, the private sector, and civil society. In the face of multiple challenges and opportunities, this Article is intended to contribute to a robust public discussion about how to accelerate the transition to a sustainable society and make America a better place for all
    corecore