We propose 'the moving target hypothesis' to describe the aetiology of a contemporary coral disease that differs from that of its historical disease state. Hitting the target with coral disease ...aetiology is a complex pursuit that requires understanding of host and environment, and may lack a single pathogen solution. White pox disease (WPX) affects the Caribbean coral Acropora palmata. Acroporid serratiosis is a form of WPX for which the bacterial pathogen (Serratia marcescens) has been established. We used long-term (1994–2014) photographic monitoring to evaluate historical and contemporary epizootiology and aetiology of WPX affecting A. palmata at eight reefs in the Florida Keys. Ranges of WPX prevalence over time (0–71.4%) were comparable for the duration of the 20-year study. Whole colony mortality and disease severity were high in historical (1994–2004), and low in contemporary (2008–2014), outbreaks of WPX. Acroporid serratiosis was diagnosed for some historical (1999, 2003) and contemporary (2012, 2013) outbreaks, but this form of WPX was not confirmed for all WPX cases. Our results serve as a context for considering aetiology as a moving target for WPX and other coral diseases for which pathogens are established and/or candidate pathogens are identified. Coral aetiology investigations completed to date suggest that changes in pathogen, host and/or environment alter the disease state and complicate diagnosis.
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The thermal dissociation of N2O in argon was investigated by monitoring the formation of O(3P) atoms in the reflected shock regime using atomic resonance absorption spectrophotometry (ARAS). The ...total density and N2O ranges were, (2.6 × 1018)−(5.4 × 1018) molecules cm-3 and (3.3 × 1012)−(7.9 × 1015) molecules cm-3, respectively. Values for the bimolecular rate constant (131 points), derived under low-pressure limit conditions are given by the Arrhenius expression: k 1(T) = (1.18 ± 0.16) × 10-9 exp(−57820 ± 460 cal mol-1)/RT cm3 molecule-1 s-1 for the temperature range, 1195 ≤ T ≤ 2384 K. These results extend the low-temperature range of ARAS measurements of k 1 by about 200 °C which is very significant in 1/T; and the value of the rate constant was extended by more than an order of magnitude. The present data were combined with previously published ARAS data to form a composite data set with a total of 278 points. Although systematic differences between the data of the various groups were discernible, all the data are well represented by the following Arrhenius equation: k 1(T) = (9.52 ± 1.07) × 10-10 exp(−57570 ± 390 cal mol-1)/RT cm3 molecule-1 s-1 for the temperature range, 1195 ≤ T ≤ 2494 K). Uncertainties in the Arrhenius expression are given at the one standard deviation level and the mean deviation of the experimental data from that predicted by the expression is ±26%. These results are compared to those from previous experimental studies. The rate of the reaction of O(3P) with N2O was investigated experimentally and by kinetic modeling, but only over a limited temperature range, 1200 ≤ T ≤ 1400 K. Upper limit values of the overall rate constant for the O(3P) + N2O reaction were estimated by a statistical technique. These values were about a factor of 10 lower (with an overall uncertainty of about a factor of three) than those calculated from the recommended Arrhenius expressions of Baulch et al. (1973), Hanson and Salimian (1984), and Tsang and Herron (1991).
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Echocardiography has evolved to be an important tool in the assessment of patients with hypertrophic and restrictive cardiomyopathy. In this article, the authors review the use of echocardiography in ...diagnosis, differentiation from disease mimics, assessment of prognosis, and the assistance of specific therapies. A pathophysiologic understanding of restrictive cardiomyopathy and constrictive pericarditis will be reviewed along with echocardiographic and Doppler features that help to distinguish these two entities.
A randomized, double-blind, placebo-controlled, parallel-group study was conducted to evaluate the efficacy and safety of gabapentin in relieving the symptoms of social phobia. Sixty-nine patients ...were randomly assigned to receive double-blind treatment with either gabapentin (dosed flexibly between 900 and 3,600 mg daily in three divided doses) or placebo for 14 weeks. A significant reduction (p < 0.05) in the symptoms of social phobia was observed among patients on gabapentin compared with those on placebo as evaluated by clinician- and patient-rated scales. Results were similar for the intent-to-treat and week-2 completer populations. Adverse events were consistent with the known side effect profile of gabapentin. Dizziness (p = 0.05), dry mouth (p = 0.05), somnolence, nausea, flatulence, and decreased libido occurred at a higher frequency among patients receiving gabapentin than among those receiving placebo. No serious adverse events or deaths were reported. On the basis of these limited data, it seems that gabapentin offers a favorable risk-benefit ratio for the treatment of patients with social phobia. Further studies are required to confirm this effect and to determine whether a dose-response relationship exists.
Despite increasing concerns about the vulnerability of species' populations to climate change, there has been little overall synthesis of how individual population responses to variation in climate ...differ between taxa, with trophic level or geographically. To address this, we extracted data from 132 long-term (greater than or equal to 20 years) studies of population responses to temperature and precipitation covering 236 animal and plant species across terrestrial and freshwater habitats. Our results identify likely geographical differences in the effects of climate change on populations and communities in line with macroecological theory. Temperature tended to have a greater overall impact on populations than precipitation, although the effects of increased precipitation varied strongly with latitude, being most positive at low latitudes. Population responses to increased temperature were generally positive, but did not vary significantly with latitude. Studies reporting significant climatic trends through time tended to show more negative effects of temperature and more positive effects of precipitation upon populations than other studies, indicating climate change has already impacted many populations. Most studies of climate change impacts on biodiversity have focused on temperature and are from middle to high northern latitudes. Our results suggest their findings may be less applicable to low latitudes.
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Background Mosquito-borne Rift Valley fever virus (RVFV) causes acute, often severe, disease in livestock and humans. To determine the exposure factors and range of symptoms associated with human ...RVF, we performed a population-based cross-sectional survey in six villages across a 40 km transect in northeastern Kenya. Methodology/Principal Findings: A systematic survey of the total populations of six Northeastern Kenyan villages was performed. Among 1082 residents tested via anti-RVFV IgG ELISA, seroprevalence was 15% (CI95%, 13-17%). Prevalence did not vary significantly among villages. Subject age was a significant factor, with 31% (154/498) of adults seropositive vs. only 2% of children ≤15 years (12/583). Seroprevalence was higher among men (18%) than women (13%). Factors associated with seropositivity included a history of animal exposure, non-focal fever symptoms, symptoms related to meningoencephalitis, and eye symptoms. Using cluster analysis in RVFV positive participants, a more severe symptom phenotype was empirically defined as having somatic symptoms of acute fever plus eye symptoms, and possibly one or more meningoencephalitic or hemorrhagic symptoms. Associated with this more severe disease phenotype were older age, village, recent illness, and loss of a family member during the last outbreak. In multivariate analysis, sheltering livestock (aOR = 3.5 CI95% 0.93-13.61, P = 0.065), disposing of livestock abortus (aOR = 4.11, CI95% 0.63-26.79, P = 0.14), and village location (P = 0.009) were independently associated with the severe disease phenotype. Conclusions/Significance Our results demonstrate that a significant proportion of the population in northeastern Kenya has been infected with RVFV. Village and certain animal husbandry activities were associated with more severe disease. Older age, male gender, herder occupation, killing and butchering livestock, and poor visual acuity were useful markers for increased RVFV infection. Formal vision testing may therefore prove to be a helpful, low-technology tool for RVF screening during epidemics in high-risk rural settings.
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Background Multiple recent outbreaks of Rift Valley Fever (RVF) in Africa, Madagascar, and the Arabian Peninsula have resulted in significant morbidity, mortality, and financial loss due to related ...livestock epizootics. Presentation of human RVF varies from mild febrile illness to meningoencephalitis, hemorrhagic diathesis, and/or ophthalmitis with residual retinal scarring, but the determinants for severe disease are not understood. The aim of the present study was to identify human genes associated with RVF clinical disease in a high-risk population in Northeastern Province, Kenya. Methodology/Principal Findings We conducted a cross-sectional survey among residents (N = 1,080; 1-85 yrs) in 6 villages in the Sangailu Division of Ijara District. Participants completed questionnaires on past symptoms and exposures, physical exam, vision testing, and blood collection. Single nucleotide polymorphism (SNP) genotyping was performed on a subset of individuals who reported past clinical symptoms consistent with RVF and unrelated subjects. Four symptom clusters were defined: meningoencephalitis, hemorrhagic fever, eye disease, and RVF-not otherwise specified. SNPs in 46 viral sensing and response genes were investigated. Association was analyzed between SNP genotype, serology and RVF symptom clusters. The meningoencephalitis symptom phenotype cluster among seropositive patients was associated with polymorphisms in DDX58/RIG-I and TLR8. Having three or more RVF-related symptoms was significantly associated with polymorphisms in TICAM1/TRIF, MAVS, IFNAR1 and DDX58/RIG-I. SNPs significantly associated with eye disease included three different polymorphisms TLR8 and hemorrhagic fever symptoms associated with TLR3, TLR7, TLR8 and MyD88. Conclusions/Significance Of the 46 SNPs tested, TLR3, TLR7, TLR8, MyD88, TRIF, MAVS, and RIG-I were repeatedly associated with severe symptomatology, suggesting that these genes may have a robust association with RVFV-associated clinical outcomes. Studies of these and related genetic polymorphisms are warranted to advance understanding of RVF pathogenesis.
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