Geographic distribution of livestock-associated Staphylococcus aureus in the United States

Sampling for livestock-associated Staphylococcus aureus (LA-SA) in the United States is haphazard. The diversity of LA-S. aureus in the U.S. appears to be greater than in other countries. We review the epidemiology of LA-S. aureus in U.S. pigs, occupationally-exposed individuals, and environmental samples to assess the diversity and abundance of U.S. LA-S. aureus.     

Geographic Analysis of Urologist Density and Prostate Cancer Mortality in the United States

Context

Financial and demographic pressures in US require an understanding of the most efficient distribution of physicians to maximize population-level health benefits. Prior work has assumed a constant negative relationship between physician supply and mortality outcomes throughout the US and has not addressed regional variation.

Methods

In this ecological analysis, geographically weighted regression was used to identify spatially varying relationships between local urologist density and prostate cancer mortality at the county level. Data from 1,492 counties in 30 eastern and southern states from 2006–2010 were analyzed.

Findings

The ordinary least squares (OLS) regression found that, on average, increasing urologist density by 1 urologist per 100,000 people resulted in an expected decrease in prostate cancer mortality of -0.499 deaths per 100,000 men (95% CI -0.709 to -0.289, p-value < 0.001), or a 1.5% decrease. Geographic weighted regression demonstrated that the addition of one urologist per 100,000 people in counties in the southern Mississippi River states of Arkansas, Mississippi, and Louisiana, as well as parts of Illinois, Indiana, and Wisconsin is associated with decrease of 0.411 to 0.916 in prostate cancer mortality per 100,000 men (1.6–3.6%). In contrast, the urologist density was not significantly associated with the prostate state mortality in the new England region.

Conclusions

The strength of association between urologist density and prostate cancer mortality varied regionally. Those areas with the highest potential for effects could be targeted for increasing the supply of urologists, as it associated with the largest predicted improvement in prostate cancer mortality.     

北京野生水鸟迁徙规律及其监测策略初探

2005年全球暴发的禽流感疫情备受世界关注,候鸟带毒且野生水鸟是禽流感病毒的天然储库已被世界公认,我国野生动物疫源疫病监测工作已被提到重要议事日程.通过对2006～2008年监测数据的分析,发现北京市野生水鸟春季迁徙从2月下旬开始,4月初达到迁徙高峰;9月下旬开始秋季南迁,11月下旬达到迁徙高峰.并分别对北京地区雁鸭类、鹬鸻类、鹭类的迁徙规律进行了分析;根据北京的气候特点分析了野生水鸟的分布和迁徙特点;根据禽流感病毒与温度的关系,提出了北京的重点监测时期及物种.     

Patterns of success in game bird introductions in the United States

Better predictions of the success of species’ introductions require careful evaluation of the relative importance of at least three kinds of factors: species characteristics, characteristics of the site of introduction, and event-level factors such as the numbers of individuals released. (Henceforth, we call this propagule pressure.) The 1644 introductions of 17 Phasianid species released in various US states during the Foreign Game Investigation Program provides a particularly rich source of data to test these ideas. An examination of these records indicates that 13 of these 17 species always failed, despite generally numerous individual releases and large numbers of individuals in each release. Moreover, ten of these species have been successfully introduced elsewhere. Only four of the 17 species were successful in at least one state. Some 20 sets of releases of three of these four species always failed in some states, again given generally numerous individual releases of large numbers of individuals in each release. Simply, the combination of site and species factors explain the lack of successes. This leaves a combination of 18 states where one or more of the four species succeeded. For these, there are significant differences in the numbers of birds introduced from state to state. But only for two species Alectoris chukar and; Tetraogallus himalayensis are there significant differences that show a greater chance of success when more individuals are introduced. These results support the conclusion that the number of individuals released, meaning propagule pressure, is not as important as characteristics of the species and the location to where its introduction occurred.     

Geographic diversity and temporal trends of antimicrobial resistance in Streptococcus pneumoniae in the United States

Resistance of Streptococcus pneumoniae to antibiotics is increasing throughout the United States, with substantial variation among geographic regions. We show that patterns of geographic variation are best explained by the intensity of selection for resistance, which is reflected by differences between the proportions of resistance within individual serotypes, rather than by differences between the frequencies of particular serotypes. Using a mathematical transmission model, we analyzed temporal trends in the proportions of singly and dually resistant organisms and found that pneumococcal strains resistant to both penicillin and erythromycin are increasing faster than strains singly resistant to either. Using the model, we predict that by 1 July 2004, in the absence of a vaccine, 41% of pneumococci at the Centers for Disease Control and Prevention (CDC)'s Active Bacterial Core surveillance (ABCs) sites, taken together, will be dually resistant, with 5% resistant to penicillin only and 5% to erythromycin only.     

Temporal Relationship between Vitamin D Status and Parathyroid Hormone in the United States

Background

Interpretation of parathyroid hormone (iPTH) requires knowledge of vitamin D status that is influenced by season.

Objective

Characterize the temporal relationship between 25-hydroxyvitamin D₃ levels [25(OH)D₃] and intact iPTH for several seasons, by gender and latitude in the U.S. and relate 25-hydrovitamin D₂ [25(OH)D₂] levels with PTH levels and total 25(OH)D levels.

Method

We retrospectively determined population weekly-mean concentrations of unpaired [25(OH)D₂ and 25(OH)D₃] and iPTH using 3.8 million laboratory results of adults. The 25(OH)D₃ and iPTH distributions were normalized and the means fit with a sinusoidal function for both gender and latitudes: North >40, Central 32–40 and South <32 degrees. We analyzed PTH and total 25(OH)D separately in samples with detectable 25(OH)D₂ (≥4 ng/mL).

Findings

Seasonal variation was observed for all genders and latitudes. 25(OH)D₃ peaks occurred in September and troughs in March. iPTH levels showed an inverted pattern of peaks and troughs relative to 25(OH)D₃, with a delay of 4 weeks. Vitamin D deficiency and insufficiency was common (33% <20 ng/mL; 60% <30 ng/mL) as was elevated iPTH levels (33%>65 pg/mL). The percentage of patients deficient in 25(OH)D₃ seasonally varied from 21% to 48% and the percentage with elevated iPTH reciprocally varied from 28% to 38%. Patients with detectable 25(OH)D₂ had higher PTH levels and 57% of the samples with a total 25(OH)D > 50 ng/mL had detectable 25(OH)D₂.

Interpretation

25(OH)D₃ and iPTH levels vary in a sinusoidal pattern throughout the year, even in vitamin D₂ treated patients; 25(OH)D₃, being higher in the summer and lower in the winter months, with iPTH showing the reverse pattern. A large percentage of the tested population showed vitamin D deficiency and secondary hyperparathyroidism. These observations held across three latitudinal regions, both genders, multiple-years, and in the presence or absence of detectable 25(OH)D₂, and thus are applicable for patient care.     

Geographic Variation of Intrahepatic Cholangiocarcinoma,Extrahepatic Cholangiocarcinoma,and Hepatocellular Carcinoma in the United States

Background

Intrahepatic (ICC) and extrahepatic cholangiocarcinomas (ECC) are tumors that arise from cholangiocytes in the bile duct, but ICCs are coded as primary liver cancers while ECCs are coded as biliary tract cancers. The etiology of these tumors is not well understood. It has been suggested that the etiology of ICC is more similar to that of another type of liver cancer, hepatocellular carcinoma (HCC), than to the etiology of ECC. If this is true, geographic incidence patterns and trends in ICC incidence should be more similar to that of HCC than ECC.

Methods

To examine this hypothesis, data from the North American Association of Central Cancer Registries Cancer in North America data file were analyzed. Incidence rates and joinpoint trends were calculated by demographic subgroup. County-level incidence rates were mapped.

Results

Overall incidence rates, racial distribution, male:female ratio, and peak ages were more similar between ICC and ECC than with HCC. During 2000–2009, average annual incidence rates of ECC increased. During 2005–2009, average annual ICC incidence rates also increased. High rates for all three cancer sites were found in the Pacific region, particularly Hawaii and Alaska. Rates of ICC and ECC were also high in the Northeast and the upper Midwest, while rates of HCC were high in the South.

Conclusions

Demographic patterns and geographical variation were more closely related between ICC and ECC than HCC, suggesting that the etiology of ICC and ECC may be similar. Increasing rates of both tumors suggest that further etiology studies are warranted.     

Patterns of plant species richness in pasture lands of the northeast United States

Pasture lands are an important facet of land use in the northeast United States, yet little is known about their recent diversity. To answer some fundamental questions about the diversity of these pasture lands, we designed a broad survey to document plant species richness using an intensive, multi scale sampling method. We also wanted to learn whether environmental (soils or climate) or land management variables could help explain patterns of species richness. A total of 17 farms, encompassing 37 pastures, were sampled in New York, Pennsylvania, Vermont, Maryland, Massachusetts and Connecticut during July and August 1998. We positively identified a total of 161 different plant species across the study region. Species richness averaged 31.7±1.1 on pastures. Infrequent, transient species that were mostly perennial and annual forbs accounted for 90% of the species richness. Except for a subjective rating of grazing intensity, land management methods were not good predictors of species richness. Over time, it appears that grazing neither reduces nor increases species richness in pastures. Of the environmental variables measured, only soil P explained a significant amount of the variation in species richness. Soil P was inversely related to species richness at the 1m² scale. Percent SOM was positively associated with species richness at this scale, although weakly. At larger spatial scales, we suggest that patterns of species richness are best explained by the species diversity of soil seed banks, or seed rain, and stochastic recruitment of these species into existing vegetation.     

National Patterns in Environmental Injustice and Inequality: Outdoor NO2 Air Pollution in the United States

We describe spatial patterns in environmental injustice and inequality for residential outdoor nitrogen dioxide (NO₂) concentrations in the contiguous United States. Our approach employs Census demographic data and a recently published high-resolution dataset of outdoor NO₂ concentrations. Nationally, population-weighted mean NO₂ concentrations are 4.6 ppb (38%, p<0.01) higher for nonwhites than for whites. The environmental health implications of that concentration disparity are compelling. For example, we estimate that reducing nonwhites’ NO₂ concentrations to levels experienced by whites would reduce Ischemic Heart Disease (IHD) mortality by ∼7,000 deaths per year, which is equivalent to 16 million people increasing their physical activity level from inactive (0 hours/week of physical activity) to sufficiently active (>2.5 hours/week of physical activity). Inequality for NO₂ concentration is greater than inequality for income (Atkinson Index: 0.11 versus 0.08). Low-income nonwhite young children and elderly people are disproportionately exposed to residential outdoor NO₂. Our findings establish a national context for previous work that has documented air pollution environmental injustice and inequality within individual US metropolitan areas and regions. Results given here can aid policy-makers in identifying locations with high environmental injustice and inequality. For example, states with both high injustice and high inequality (top quintile) for outdoor residential NO₂ include New York, Michigan, and Wisconsin.     

Temporal Patterns of Ascospore Release in Leptosphaeria maculans Vary Depending on Geographic Region and Time of Observation

Diurnal patterns of spore release have been observed in a number of fungal pathogens that undergo wind-assisted dispersal. The mechanisms that drive these patterns, while not well understood, are thought to relate to the ability of dispersing spores to survive their journey and infect new hosts. In this paper, we characterise the diurnal pattern of ascospore release by a Western Australian population of Leptosphaeria maculans. Although L. maculans has been previously shown to exhibit diurnal patterns of ascospore release, these patterns appear to vary from region to region. In order to characterise the pattern of release in the Mediterranean climate of Western Australia, we analysed historical data describing the bi-hourly count of airborne ascospores at Mt Barker, Western Australia. Results of this analysis showed diurnal patterns that differ from those previously observed in other countries, with ascospore release in our study most likely to occur in the afternoon. Furthermore, we found that the time of peak release can shift from month to month within any one season, and from year to year. In explaining the hourly pattern of spore release over an entire season, time since rainfall, time since last release, temperature, hour and month were all shown to be significant variables.     

Patterns and drivers for wetland connections in the Prairie Pothole Region,United States

Ecosystem function in rivers, lakes and coastal waters depends on the functioning of upstream aquatic ecosystems, necessitating an improved understanding of watershed-scale interactions including variable surface-water flows between wetlands and streams. As surface water in the Prairie Pothole Region expands in wet years, surface-water connections occur between many depressional wetlands and streams. Minimal research has explored the spatial patterns and drivers for the abundance of these connections, despite their potential to inform resource management and regulatory programs including the U.S. Clean Water Act. In this study, wetlands were identified that did not intersect the stream network, but were shown with Landsat images (1990–2011) to become merged with the stream network as surface water expanded. Wetlands were found to spill into or consolidate with other wetlands within both small (2–10 wetlands) and large (>100 wetlands) wetland clusters, eventually intersecting a stream channel, most often via a riparian wetland. These surface-water connections occurred over a wide range of wetland distances from streams (averaging 90–1400 m in different ecoregions). Differences in the spatial abundance of wetlands that show a variable surface-water connection to a stream were best explained by smaller wetland-to-wetland distances, greater wetland abundance, and maximum surface-water extent. This analysis demonstrated that wetland arrangement and surface water expansion are important mechanisms for depressional wetlands to connect to streams and provides a first step to understanding the frequency and abundance of these surface-water connections across the Prairie Pothole Region.     

Chinese chestnut production in the United States: Practice,problems, and possible solutions

There are fewer than 162 ha of commercial Chinese chestnut orchards in the United States, with approximately half of these in the Southeast. Large numbers of Chinese chestnut seedlings are planted annually in the United States for home and game food production; however, knowledge about chestnut propagation, fertilization, pests, harvest, storage and marketing is not adequate. There is little commercial marketing of U.S.-grown Chinese chestnuts through roadside markets and local farmers’ markets as the supply is low and unpredictable. However, we yearly import 4.5 mill kg of European chestnuts to satisfy the U.S. market. Successful chestnut orchards will require vegetatively propagated selections, intensive management, mechanical harvesting, and control of insect and disease pests.     

Monitoring HIV Testing in the United States: Consequences of Methodology Changes to National Surveys

Objective

In 2011, the National Health Interview Survey (NHIS), an in-person household interview, revised the human immunodeficiency virus (HIV) section of the survey and the Behavioral Risk Factor Surveillance System (BRFSS), a telephone-based survey, added cellphone numbers to its sampling frame. We sought to determine how these changes might affect assessment of HIV testing trends.

Methods

We used linear regression with pairwise contrasts with 2003-2013 data from NHIS and BRFSS to compare percentages of persons aged 18-64 years who reported HIV testing in landline versus cellphone-only households before and after 2011, when NHIS revised its in-person questionnaire and BRFSS added cellphone numbers to its telephone-based sample.

Results

In NHIS, the percentage of persons in cellphone-only households increased 13-fold from 2003 to 2013. The percentage ever tested for HIV was 6%–10% higher among persons in cellphone-only than landline households. The percentage ever tested for HIV increased significantly from 40.2% in 2003 to 45.0% in 2010, but was significantly lower in 2011 (40.6%) and 2012 (39.7%). In BRFSS, the percentage ever tested decreased significantly from 45.9% in 2003 to 40.2% in 2010, but increased to 42.9% in 2011 and 43.5% in 2013.

Conclusions

HIV testing estimates were lower after NHIS questionnaire changes but higher after BRFSS methodology changes. Data before and after 2011 are not comparable, complicating assessment of trends.     

The Practice of Cranial Neurosurgery and the Malpractice Liability Environment in the United States

Object

The potential imbalance between malpractice liability cost and quality of care has been an issue of debate. We investigated the association of malpractice liability with unfavorable outcomes and increased hospitalization charges in cranial neurosurgery.

Methods

We performed a retrospective cohort study involving patients who underwent cranial neurosurgical procedures from 2005-2010, and were registered in the National Inpatient Sample (NIS) database. We used data from the National Practitioner Data Bank (NPDB) from 2005 to 2010 to create measures of volume and size of malpractice claim payments. The association of the latter with the state-level mortality, length of stay (LOS), unfavorable discharge, and hospitalization charges for cranial neurosurgery was investigated.

Results

During the study period, there were 189,103 patients (mean age 46.4 years, with 48.3% females) who underwent cranial neurosurgical procedures, and were registered in NIS. In a multivariable regression, higher number of claims per physician in a state was associated with increased ln-transformed hospitalization charges (beta 0.18; 95% CI, 0.17 to 0.19). On the contrary, there was no association with mortality (OR 1.00; 95% CI, 0.94 to 1.06). We observed a small association with unfavorable discharge (OR 1.09; 95% CI, 1.06 to 1.13), and LOS (beta 0.01; 95% CI, 0.002 to 0.03). The size of the awarded claims demonstrated similar relationships. The average claims payment size (ln-transformed) (Pearson’s rho=0.435, P=0.01) demonstrated a positive correlation with the risk-adjusted hospitalization charges but did not demonstrate a correlation with mortality, unfavorable discharge, or LOS.

Conclusions

In the present national study, aggressive malpractice environment was not correlated with mortality but was associated with higher hospitalization charges after cranial neurosurgery. In view of the association of malpractice with the economics of healthcare, further research on its impact is necessary.     

Geographic distribution and genetics of killer phenotypes for the yeast Pichia kluyveri across the United States.

Representative strains (n = 61) of the yeast Pichia kluyveri from across the United States were studied for their ability to kill 71 other strains (representing 25 species) of yeast. This survey showed killing activity in 69% of the P. kluyveri strains tested. More extensive analysis of killer activity of 197 P. kluyveri strains against strains of five tester species showed comparable activity (67% of strains tested). This activity was shown to be equally variable within localities, within regions, and across the continent. The genetic basis of the variability was ascertained by tetrad analysis and is most likely due to alleles segregating at three epistatic loci. Evidence for the idea that killer toxins have a role in excluding other yeasts from particular habitats is discussed.     

Geographic distribution and genetics of killer phenotypes for the yeast Pichia kluyveri across the United States.

Representative strains (n = 61) of the yeast Pichia kluyveri from across the United States were studied for their ability to kill 71 other strains (representing 25 species) of yeast. This survey showed killing activity in 69% of the P. kluyveri strains tested. More extensive analysis of killer activity of 197 P. kluyveri strains against strains of five tester species showed comparable activity (67% of strains tested). This activity was shown to be equally variable within localities, within regions, and across the continent. The genetic basis of the variability was ascertained by tetrad analysis and is most likely due to alleles segregating at three epistatic loci. Evidence for the idea that killer toxins have a role in excluding other yeasts from particular habitats is discussed.     

Assessing the Impact of Advected African Dust on Air Quality and Health in the Eastern United States

Large quantities of African dust are carried into the southeastern United States each summer with concentrations typically in the range of 10 to 100?µg m^?3. Because approximately one-third to one-half of the dust mass is in the size range under 2.5?µm diameter, the advection of African dust has implications for the EPA's newly implemented standard for PM_2.5 particulate matter and for the assessment of human health effects. It will be difficult to assess the impact of African dust events on air quality because they occur during the summer (maximum in July) when photochemical pollution events are frequent and intense in the eastern United States. Indeed, the presence of dust could affect the evolution of photochemical dust events. In order to assess the role of African dust in air quality in the United States, it will be necessary to develop a set of diagnostic indicators; it appears that dust mineralogy and elemental composition might be useful for this purpose. Various satellite products can be used to characterize the spatial coverage of dust events and, when coupled with meteorological tools, to predict impact regions.