Defining Critical Genes During Spherule Remodeling and Endospore Development in the Fungal Pathogen, Coccidioides posadasii.

Coccidioides immitis and C. posadasii are soil dwelling dimorphic fungi found in North and South America. Inhalation of aerosolized asexual conidia can result in asymptomatic, acute, or chronic respiratory infection. In the United States there are approximately 350,000 new infections per year. The Coccidioides genus is the only known fungal pathogen to make specialized parasitic spherules, which contain endospores that are released into the host upon spherule rupture. The molecular determinants involved in this key step of infection remain largely elusive as 49% of genes are hypothetical with unknown function. An attenuated mutant strain C. posadasii Δcts2/Δard1/Δcts3 in which chitinase genes 2 and 3 were deleted was previously created for vaccine development. This strain does not complete endospore development, which prevents completion of the parasitic lifecycle. We sought to identify pathways active in the wild-type strain during spherule remodeling and endospore formation that have been affected by gene deletion in the mutant. We compared the transcriptome and volatile metabolome of the mutant Δcts2/Δard1/Δcts3 to the wild-type C735. First, the global transcriptome was compared for both isolates using RNA sequencing. The raw reads were aligned to the reference genome using TOPHAT2 and analyzed using the Cufflinks package. Genes of interest were screened in an in vivo model using NanoString technology. Using solid phase microextraction (SPME) and comprehensive two-dimensional gas chromatography - time-of-flight mass spectrometry (GC × GC-TOFMS) volatile organic compounds (VOCs) were collected and analyzed. Our RNA-Seq analyses reveal approximately 280 significantly differentially regulated transcripts that are either absent or show opposite expression patterns in the mutant compared to the parent strain. This suggests that these genes are tied to networks impacted by deletion and may be critical for endospore development and/or spherule rupture in the wild-type strain. Of these genes, 14 were specific to the Coccidioides genus. We also found that the wild-type and mutant strains differed significantly in their production versus consumption of metabolites, with the mutant displaying increased nutrient scavenging. Overall, our results provide the first targeted list of key genes that are active during endospore formation and demonstrate that this approach can define targets for functional assays in future studies.

Coinfections identified from metagenomic analysis of cervical lymph nodes from tularemia patients.

BACKGROUND: Underlying coinfections may complicate infectious disease states but commonly go unnoticed because an a priori clinical suspicion is usually required so they can be detected via targeted diagnostic tools. Shotgun metagenomics is a broad diagnostic tool that can be useful for identifying multiple microbes simultaneously especially if coupled with lymph node aspirates, a clinical matrix known to house disparate pathogens. The objective of this study was to analyze the utility of this unconventional diagnostic approach (shotgun metagenomics) using clinical samples from human tularemia cases as a test model. Tularemia, caused by the bacterium Francisella tularensis, is an emerging infectious disease in Turkey. This disease commonly manifests as swelling of the lymph nodes nearest to the entry of infection. Because swollen cervical nodes are observed from many different types of human infections we used these clinical sample types to analyze the utility of shotgun metagenomics. METHODS: We conducted an unbiased molecular survey using shotgun metagenomics sequencing of DNA extracts from fine-needle aspirates of neck lymph nodes from eight tularemia patients who displayed protracted symptoms. The resulting metagenomics data were searched for microbial sequences (bacterial and viral). RESULTS: F. tularensis sequences were detected in all samples. In addition, we detected DNA of other known pathogens in three patients. Both Hepatitis B virus (HBV) and Human Parvovirus B-19 were detected in one individual and Human Parvovirus B-19 alone was detected in two other individuals. Subsequent PCR coupled with Sanger sequencing verified the metagenomics results. The HBV status was independently confirmed via serological diagnostics, despite evading notice during the initial assessment. CONCLUSION: Our data highlight that shotgun metagenomics of fine-needle lymph node aspirates is a promising clinical diagnostic strategy to identify coinfections. Given the feasibility of the diagnostic approach demonstrated here, further steps to promote integration of this type of diagnostic capability into mainstream clinical practice are warranted.

Unexpected Relations of Historical Anthrax Strain.

In 1998, it was claimed that an 80-year-old glass tube intentionally filled with Bacillus anthracis and embedded in a sugar lump as a WWI biological weapon still contained viable spores. Today, genome sequencing of three colonies isolated in 1998 and subjected to phylogenetic analysis surprisingly identified a well-known B. anthracis reference strain isolated in the United States in 1981, pointing to accidental laboratory contamination.IMPORTANCE Next-generation sequencing and subsequent phylogenetic analyses are useful and reliable tools for the classification of recent and historical samples. The reliability of sequences obtained and bioinformatic algorithms has increased in recent years, and research has uncovered the identity of a presumed bioweapon agent as a contaminant.

ELF magnetic fields in electric and gasoline-powered vehicles.

We conducted a pilot study to assess magnetic field levels in electric compared to gasoline-powered vehicles, and established a methodology that would provide valid data for further assessments. The sample consisted of 14 vehicles, all manufactured between January 2000 and April 2009; 6 were gasoline-powered vehicles and 8 were electric vehicles of various types. Of the eight models available, three were represented by a gasoline-powered vehicle and at least one electric vehicle, enabling intra-model comparisons. Vehicles were driven over a 16.3 km test route. Each vehicle was equipped with six EMDEX Lite broadband meters with a 40-1,000 Hz bandwidth programmed to sample every 4 s. Standard statistical testing was based on the fact that the autocorrelation statistic damped quickly with time. For seven electric cars, the geometric mean (GM) of all measurements (N = 18,318) was 0.095 µT with a geometric standard deviation (GSD) of 2.66, compared to 0.051 µT (N = 9,301; GSD = 2.11) for four gasoline-powered cars (P < 0.0001). Using the data from a previous exposure assessment of residential exposure in eight geographic regions in the United States as a basis for comparison (N = 218), the broadband magnetic fields in electric vehicles covered the same range as personal exposure levels recorded in that study. All fields measured in all vehicles were much less than the exposure limits published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Institute of Electrical and Electronics Engineers (IEEE). Future studies should include larger sample sizes representative of a greater cross-section of electric-type vehicles.

Radiofrequency fields associated with the Itron smart meter.

This study examined radiofrequency (RF) emissions from smart electric power meters deployed in two service territories in California for the purpose of evaluating potential human exposure. These meters included transmitters operating in a local area mesh network (RF LAN, ∼250 mW); a cell relay, which uses a wireless wide area network (WWAN, ∼1 W); and a transmitter serving a home area network (HAN, ∼70 mW). In all instances, RF fields were found to comply by a wide margin with the RF exposure limits established by the US Federal Communications Commission. The study included specialised measurement techniques and reported the spatial distribution of the fields near the meters and their duty cycles (typically <1 %) whose value is crucial to assessing time-averaged exposure levels. This study is the first to characterise smart meters as deployed. However, the results are restricted to a single manufacturer's emitters.

Comparative analyses of the studies of magnetic fields and cancer in electric utility workers: studies from France, Canada, and the United States.

OBJECTIVES: To summarise and to facilitate comparison of three major studies of electric utility workers that examined the relation between quantitative measurements of occupational exposure to magnetic fields and risk of brain cancer and leukaemia. These studies have been interpreted as providing conflicting evidence. METHODS: A common analytical approach was applied to data from the five cohorts included in the three studies based on original data from four of the cohorts, and published data from one additional cohort. A nested case-control design with conditional logistic regression was used to estimate the relative risk/10 microtesla-years (microT-years) for each of the contributing cohorts and for the combined data. The homogeneity of these estimates among the studies was also evaluated. RESULTS: Apparent inconsistencies in the findings of these studies can be explained by statistical variation. Overall, the studies suggest a small increase in risk of both brain cancer and leukaemia. Different methodological choices had little impact on the results. Based on a combined analysis of data from all five studies, the relative risk/10 microT-years was 1.12 (95% confidence interval (95% CI) 0.98 to 1.28) for brain cancer, and 1.09 (95% CI 0.98 to 1.21) for leukaemia. CONCLUSIONS: The combined estimates seem to provide the best summary measures of the data from all studies. However, fluctuations in risks among studies may reflect real differences, and the exposure measurements in different studies may not be entirely comparable.

Projecting corporate health plan utilization and charges from annual ICD-9-CM diagnostic rates: a value-added opportunity for pathologists.

OBJECTIVE: To develop an allocation method for corporate health plan resources and expenditures based on annual International Classification of Disease, 9th revision, Clinical Modification (ICD-9-CM) diagnostic rate stratification as a surrogate for disease incidence. DESIGN: A data-mining process was applied to a self-insured corporate health plan database. Annual membership rates of Current Procedural Terminology (CPT) procedure utilization and charges between 1990 and 1994 for a cohort of 7216 continuously employed plan members were stratified according to the annual rates of the 19 major ICD-9-CM diagnostic classifications. The stratified annual CPT utilization and charge rates were analyzed by correlation analysis and one-tailed t test. RESULTS: Laboratory and pathology procedure utilization and charge rates were highly correlated with specific rankings of ICD-9-CM diagnostic classifications. The health plan diagnostic rate, laboratory utilization rate, and all charge rates increased significantly during the 5 study years. CONCLUSION: Although all procedure utilization and charge rates in this health plan increased each year, their proportionality consistently was maintained among diagnostically related groups of patients. By restraining global expenditures, managed health plans conflict with historical utilization and charge patterns. Treating ICD-9-CM diagnostic groups as disease management services within a managed care plan allows procedures and expenses to be allocated according to medical necessity in the context of total membership benefits. For pathologists, who recently were mandated by the Health Care Financing Administration and the Office of Inspector General of the Department of Health and Human Services to become stewards of ICD-9-CM coding, this is a unique opportunity to lead an initiative to perfect managed care. The process will require permanent patient numbers, computerized longitudinal patient records, and standardized coded medical terminology.

Mortality among a cohort of electric utility workers, 1960-1991.

Overall mortality trends among an electric utility workforce are examined. The study cohort (n = 40,335) included all workers with at least 1 year of work experience from 1960-1991; 3,753 deaths were observed in this cohort. Standardized mortality ratios (SMRs) and internal cohort analyses were used to assess mortality trends for the entire cohort and for specific occupational groups. Most SMRs were < or = 1.0 and were generally lower for noncancer (cardiovascular, COPD, and injuries) than for cancer mortality. Compared to office staff, rate ratios (RR) were higher for respiratory cancers for field staff [(RR = 2.3, 95% CI, 1.0-5.0) linecrew (RR = 2.2 95% CI, 1.5-3.1), and power plant occupations (RR = 2.4, 95% CI, 1.6-3.6)]. Nonmanagement occupations had rate ratios for motor vehicle injuries and all types of injuries, within a range of 2.5-4.7, with all lower CIs > 1.0. The healthy worker effect is an important factor in explaining the difference between SMR and internal cohort analyses results. The SMR results indicate that this workforce has lower rates for overall mortality, cardiovascular disease, cancer and nonintentional injury. A consistent finding in the internal cohort analyses that merits further research was higher mortality rates for respiratory cancer and injuries among nonoffice staff.

Acute work injuries among electric utility meter readers.

This report provides estimates of incidence rates for acute work injuries for a well defined cohort of electric utility meter readers. Specifically, person-time rates by sex, age, and job experience are evaluated by part of body injured and type of injury. Meter readers experienced 731 acute lost time [11.1 per 100 person-work years; 95% confidence interval (CI) = 10.3-11.9] and 4,401 acute non-lost time (66.5 per 100 person-work years; 95% CI = 64.6-68.5) work injuries over the study period, 1980-1992. Women had nearly twice the lost time injury rate as men (17.5 vs 9.6 per 100 person-work years). There is an inverse relation between job experience and both lost time and non-lost time injuries. Although these data are limited to the electric utility industry, they may be relevant to occupations with similar tasks and environments, including residential gas and water supply industry meter readers and postal carriers.

Acute work injuries among electric utility linemen.

This analysis presents differences in acute work injury rates among electric utility linemen who perform different work tasks. Incidence-density rate ratios were the primary measure of association and are based on the work injury and person-time data for each job title. Logistic regression was used to model race, age, job experience, total inservice, prior injury, and time from prior injury. Transmission linemen had the lower acute injury rate with 18.9 per 100 person-work-years (95% CI 16-20), distribution linemen had 27.8 per 100 person-work-years (95% CI 27-28), and apprentice linemen had 43.3 per 100 person-work-years (95% CI 41-45). Injuries to the trunk and sprains and strains are the predominant injury categories. Having a prior lost time injury increases the risk for subsequent lost time injury for transmission linemen (OR = 1.6, 95% CI = 1.0-2.7) and for distribution linemen (OR = 1.5, 95% CI = 1.3-1.6).

Effects function analysis of ELF magnetic field exposure in the electric utility work environment.

The incomplete understanding of the relation between power-frequency fields and biological responses raises problems in defining an appropriate metric for exposure assessment and epidemiological studies. Based on evidence from biological experiments, one can define alternative metrics or effects functions that embody the relationship between field exposure patterns and hypothetical health effects. In this paper, we explore the application of the "effects function" approach to occupational exposure data. Our analysis provides examples of exposure assessments based on a range of plausible effects functions. An EMDEX time series data set of ELF frequency (40-800 Hz) magnetic field exposure measurements for electric utility workers was analyzed with several statistical measures and effects functions: average field strength, combination of threshold and exposure duration, and field strength changes. Results were compared for eight job categories: electrician, substation operator, machinist, welder, plant operator, lineman/splicer, meter reader, and clerical. Average field strength yields a different ranking for these job categories than the ranks obtained using other biologically plausible effects functions. Whereas the group of electricians has the highest exposure by average field strength, the group of substation operators has the highest ranking for most of the other effects functions. Plant operators rank highest in the total number of field strength changes greater than 1 microT per hour. The clerical group remains at the lowest end for all of these effects functions. Our analysis suggests that, although average field strength could be used as a surrogate of field exposure for simply classifying exposure into "low" and "high," this summary measure may be misleading in the relative ranking of job categories in which workers are in "high" fields. These results indicate the relevance of metrics other than average field strength in occupational exposure assessment and in the design and analysis of epidemiological studies.

An evaluation of precaution-based approaches as EMF policy tools in community environments.

This paper explores the use of precaution-based approaches as policy tools when responding to concerns about power-frequency electric and magnetic fields (EMF) in community environments. The combination of public concern and scientific uncertainty about potential health impacts from exposure to EMF challenges society to adopt EMF policies that balance the benefits of electric power against the possibility that some aspect of the use of electricity may be harmful. Inappropriate policy responses can undermine the economics of society's use of electricity and have other adverse consequences on public health. These adverse consequences result from the inappropriate diversion of scarce public and private resources. Precaution-based approaches are rooted in individual concepts of common sense and can be an effective component of a comprehensive set of EMF policy options. Precaution-based approaches do not replace science-based policy options and should only be used when the available science-based guidelines are not applicable. The application of these approaches should balance the real and expected costs and benefits of taking or not taking action. Given our current scientific knowledge, actions taken to reduce EMF exposure should necessarily be low cost because the expected benefits are uncertain. Society also needs to avoid adopting EMF policies that could incur high costs from distorting resources from other, more important, personal and public health priorities.

Sex differences in work-related injury rates among electric utility workers.

Few epidemiologic studies have evaluated sex differences in work-related injury rates. In this study, the authors examined injury trends by type of injury, severity of injury, and how the injury occurred among a cohort of 9,582 female and 26,898 male electric utility workers employed during 1980-1992 by the Southern California Edison Company. Sex-specific unadjusted injury rates were higher throughout the period for male workers. However, after adjustment for occupation, job experience, and age, elevated rate ratios indicate that female workers have higher injury rates. Mantel-Haenszel summary rate ratios and 95% confidence intervals were 1.49 (1.43-1.54) for all types of injuries, 1.27 (1.16-1.39) for head and neck injuries, 1.48 (1.38-1.58) for upper extremity injuries, 1.11 (1.01-1.21) for back injuries, and 2.11 (1.97-2.25) for lower extremity injuries. The rate ratios were slightly higher for more severe injuries, which suggests that potential reporting bias was not a likely explanation for these findings. The authors conclude that differences between male and female workers in training, physical capacity, task assignments, and other factors could explain these injury trends.

Viral contacts confound studies of childhood leukemia and high-voltage transmission lines.

Studies of childhood leukemia have reported a link with residential proximity to electric utility facilities. This paper elaborates on the hypothesis that residential proximity to electric utility transmission-systems is a surrogate for viral contacts, a potential confounder in these studies. While the causal implications of increased viral contacts is not established, the assumption made here is that a significant component of childhood leukemia has an infectious etiology. Increased viral contacts can result from residential mobility, being first born, or use of community childcare facilities. Re-analysis of existing studies should look specifically for the interaction between childhood leukemia, markers for viral contacts (e.g., residential mobility, birth order, use of outside childcare facilities), and residential proximity to high-voltage transmission lines. New study designs should include parameters to test directly for a virus-related infectious model for childhood leukemia.

Exposure to 60 Hz magnetic fields in the electric utility work environment.

Research that has attempted to examine the relationship between work exposures to magnetic fields and health effects has suffered from limited exposure information. Power-frequency electric and magnetic (EM) field exposures vary substantially between industries, occupations, and individuals. In this study magnetic field data were collected for a variety of occupational categories within an electric utility. The sampling procedures emphasized craft occupations that were presumed to have higher exposures to magnetic fields. The objectives were to provide better exposure information for an ongoing cancer mortality study, examine the relationship between different summary measures of magnetic field exposure, and make available descriptive information useful for exposure reduction and worker education. Principal components analysis (PCA) and Varimax rotation were used to explore the relationships between the different summary measures among all utility workers and among the subset of electrical craft occupations. Discriminant analysis was used to assess summary measures of exposure that differentiated occupational groups. Measurements for 770 days generated a total of 42378 hours of magnetic field data. Eleven summary indices of exposure were calculated for specific occupational groups. These include arithmetic mean, geometric mean, median, 95th and 99th percentiles, and fraction of measurements exceeding .5, 1, 5, 10, and 100 microT. Electrical craft occupations had higher work exposures than non-craft occupations. Electricians and substation operators had the highest exposures among craft occupations. We identified subsets of summary measures that were intercorrelated. The first PCA axis included the geometric mean, median, and the fractions exceeding 0.5 and 1.0 microT. This set of measures also were best at discriminating occupational groups. The relevance of these findings may become more important if consistent associations are found between particular occupations and disease and particular occupations and magnetic field summary measures. Further research is needed to evaluate these exposure assessment findings.

Cohort and nested case-control studies of hematopoietic cancers and brain cancer among electric utility workers.

Recent studies have raised concern about the potential health effects of occupational exposures to power frequency electric and magnetic fields. We evaluated cancer mortality for leukemia, brain cancer, and lymphoma from 1960 to 1988 in a cohort of 36,221 electric utility workers using cohort analyses and three nested case-control studies. From a volunteer sample of the current workforce that represented a variety of different occupations and work locations, we collected 776 days of magnetic field measurements. We derived exposure information from company job history information and developed exposure scores by linking job history data to measured magnetic fields. In job title analyses, we compared "electrical workers" with other field and craft occupations, office, and technical support staff. Age-specific cancer rates for electrical and reference workers were similar. "Electrical workers" had rate ratios or odds ratios ranging from 0.7 to 1.4. Most ratios were close to 1.0. Lymphomas were slightly elevated compared with leukemias and brain cancers (ratios of 0.9-1.4 vs 0.7-1.2, respectively). Odds ratios for magnetic field exposure indices, based on scores for the mean, median, 99th percentile, and fractions exceeding 10 milligauss and 50 milligauss, were all close to or less than 1.0. The interval estimates indicate no strong association but are somewhat limited by imprecision.

Polychlorinated biphenyl concentrations in the blood plasma of a selected sample of non-occupationally exposed southern California working adults.

Blood samples from 738 employees of the Southern California Edison Company were analyzed for PCBs prior to their starting work, as part of a pre-employment medical examination. Blood PCB concentrations of the pre-employment sample had a median of 4 ppb and a mean of 5 +/- 4 ppb. These data are comparable to previously published values for blood PCB concentrations in people without occupational exposure. Plasma PCB concentrations are also sorted by demographic characteristics of the sample (age/race/sex/education). Since the demographic properties of the newly hired employees are reasonably similar to those of the Los Angeles-Long Beach work force, as determined in the 1980 census, we conclude that the low PCB concentrations present in the blood of a sample of new electric utility employees is representative of the regional work force and arise from exposures to PCBs present in the general environment.

Polychlorinated biphenyls in the blood of personnel from an electric utility.

Because polychlorinated biphenyls (PCBs) have been implicated as potentially toxic to humans and because the electric utility industry is thought to have significant opportunity for occupational exposure, a study was performed to identify electric utility personnel with the highest PCB exposure potential and to assess their current blood PCB concentrations. For currently employed personnel, a median PCB plasma value of 3 ppb with a mean of 4 +/- 3.65 ppb was found; for a preemployment sample the median was 4 ppb with a mean of 5 +/- 4.25 ppb. PCB concentrations in blood of these personnel are similar to concentrations reported for other populations without occupational exposure. No adverse health impacts would be expected to result from these blood concentrations. These data indicate that no significant occupational exposure has occurred in this utility. This study shows the importance of assessing exposure potential at specific worksites prior to making general exposure or hazard assessments.