Evidence for microbial Fe(III) reduction in anoxic, mining-impacted lake sediments (Lake Coeur d'Alene, Idaho). (1/120)

Mining-impacted sediments of Lake Coeur d'Alene, Idaho, contain more than 10% metals on a dry weight basis, approximately 80% of which is iron. Since iron (hydr)oxides adsorb toxic, ore-associated elements, such as arsenic, iron (hydr)oxide reduction may in part control the mobility and bioavailability of these elements. Geochemical and microbiological data were collected to examine the ecological role of dissimilatory Fe(III)-reducing bacteria in this habitat. The concentration of mild-acid-extractable Fe(II) increased with sediment depth up to 50 g kg(-1), suggesting that iron reduction has occurred recently. The maximum concentrations of dissolved Fe(II) in interstitial water (41 mg liter(-1)) occurred 10 to 15 cm beneath the sediment-water interface, suggesting that sulfidogenesis may not be the predominant terminal electron-accepting process in this environment and that dissolved Fe(II) arises from biological reductive dissolution of iron (hydr)oxides. The concentration of sedimentary magnetite (Fe(3)O(4)), a common product of bacterial Fe(III) hydroxide reduction, was as much as 15.5 g kg(-1). Most-probable-number enrichment cultures revealed that the mean density of Fe(III)-reducing bacteria was 8.3 x 10(5) cells g (dry weight) of sediment(-1). Two new strains of dissimilatory Fe(III)-reducing bacteria were isolated from surface sediments. Collectively, the results of this study support the hypothesis that dissimilatory reduction of iron has been and continues to be an important biogeochemical process in the environment examined.  (+info)

Occurrence of Klebisiella pneumoniae in surface waters. (2/120)

The occurrence of Klebsiella pneumoniae in surface waters was not found to be ubiquitous. When it was isolated, Escherichia coli could also be found. The fecal coliform to fecal streptococci ratio suggest that its origin could be human, animal, or mixed sources.  (+info)

Genetic analyses reveal unusually high diversity of infectious haematopoietic necrosis virus in rainbow trout aquaculture. (3/120)

Infectious haematopoietic necrosis virus (IHNV) is the most significant virus pathogen of salmon and trout in North America. Previous studies have shown relatively low genetic diversity of IHNV within large geographical regions. In this study, the genetic heterogeneity of 84 IHNV isolates sampled from rainbow trout (Oncorhynchus mykiss) over a 20 year period at four aquaculture facilities within a 12 mile stretch of the Snake River in Idaho, USA was investigated. The virus isolates were characterized using an RNase protection assay (RPA) and nucleotide sequence analyses. Among the 84 isolates analysed, 46 RPA haplotypes were found and analyses revealed a high level of genetic heterogeneity relative to that detected in other regions. Sequence analyses revealed up to 7.6% nucleotide divergence, which is the highest level of diversity reported for IHNV to date. Phylogenetic analyses identified four distinct monophyletic clades representing four virus lineages. These lineages were distributed across facilities, and individual facilities contained multiple lineages. These results suggest that co-circulating IHNV lineages of relatively high genetic diversity are present in the IHNV populations in this rainbow trout culture study site. Three of the four lineages exhibited temporal trends consistent with rapid evolution.  (+info)

Genetic and phenotypic parameters for dietary selection of mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana. (4/120)

The heritability of diet selection for mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana [Rydb] Beetle) by grazing sheep was estimated from fecal samples collected from 549 Rambouillet ewes. Fecal samples were collected in September and October during 1996 and 1997 from free-grazing ewes on intermountain sagebrush-bunchgrass rangelands at the U.S. Sheep Experiment Station in Idaho. The total number of fecal samples was 1,949. Fecal samples were evaluated for composition of big sagebrush by near-infrared spectroscopy. Percentage of sagebrush in the diet was less in September than in October (21.6 vs 31.7%, respectively). Single-trait and bivariate derivative-free REML analyses were performed to genetically compare percentage of sagebrush in the diet in September and October. Heritability estimates were similar between September and October measurements (0.25 and 0.28, respectively). The genetic correlation between September and October percentages of sagebrush in the diet was high (0.91), implying that there is strong genetic similarity between September and October measurements and that an annual measurement may be sufficient for selection. These results contribute to a greater understanding of dietary preferences in freely grazing sheep, and suggest opportunities to improve production efficiency and forage management through selection for dietary preferences.  (+info)

Outbreaks of multidrug-resistant Salmonella typhimurium associated with veterinary facilities--Idaho, Minnesota, and Washington, 1999. (5/120)

CDC received reports in 1999 from three state health departments of outbreaks of multidrug-resistant Salmonella serotype Typhimurium infections in employees and clients of small animal veterinary clinics and an animal shelter. Salmonella infections usually are acquired by eating contaminated food; however, direct contact with infected animals, including dogs and cats, also can result in exposure and infection. This report summarizes clinical and epidemiologic data about these outbreaks and reviews methods of reducing the likelihood of Salmonella transmission in veterinary settings by avoiding fecal-oral contact.  (+info)

Effect of racial/ethnic misclassification of American Indians and Alaskan Natives on Washington State death certificates, 1989-1997. (6/120)

OBJECTIVES: This study examined effects of racial/ethnic misclassification of American Indians and Alaskan Natives on Washington State death certificates. METHODS: Probabilistic record linkage were used to match the 1989-1997 state death files to the Northwest Tribal Registry. RESULTS: We identified matches for 2819 decedents, including 414 (14.7%) who had been misclassified as non-American Indians and Alaskan Natives on the death certificates. The likelihood of being correctly classified increased 3-fold for each higher level of American Indian and Alaskan Native ancestry (odds ratio = 2.88; 95% confidence interval [CI] = 2.51, 3.30) and decreased by 6.9% per calendar year (95% CI = 2.0, 11.5). CONCLUSIONS: Systematic biases on death certificates in Washington State persist. Methods to reduce misclassification can improve data quality and enhance efforts to measure and reduce racial/ethnic health disparities.  (+info)

Effective size of fluctuating salmon populations. (7/120)

Pacific salmon are semelparous but have overlapping year classes, which presents special challenges for the application of standard population genetics theory to these species. This article examines the relationship between the effective number of breeders per year (N(b)) and single-generation and multigeneration effective population size (N(e)) in salmon populations that fluctuate in size. A simple analytical model is developed that allows calculation of N(e) on the basis of the number of spawners in individual years and their reproductive contribution (productivity) to the next generation. Application of the model to a 36-year time series of data for a threatened population of Snake River chinook salmon suggests that variation in population dynamic processes across years reduced the multigeneration N(e) by approximately 40-60%, and reductions may have been substantially greater within some generations. These reductions are comparable in magnitude to, and in addition to, reductions in N(b) within a year due to unequal sex ratio and nonrandom variation in reproductive success. Computer simulations suggest that the effects of variable population dynamics on N(e) observed in this dataset are not unexpected for species with a salmon life history, as random variation in productivity can lead to similar results.  (+info)

Coordinated response to reports of possible anthrax contamination, Idaho, 2001. (8/120)

In 2001, the intentional release of anthrax spores in the eastern United States increased concern about exposure to anthrax nationwide, and residents of Idaho sought assistance. Response from state and local agencies was required, increasing the strain on epidemiologists, laboratorians, and communications personnel. In late 2001, Idaho's public health communications system handled 133 calls about suspicious powders. For each call, a multiagency bridge call was established, and participants (public health officials, epidemiologists, police, Federal Bureau of Investigation personnel, hazardous materials officials, and others) determined which samples would be tested by the state public health laboratory. A triage system for calls helped relieve the burden on public safety and health systems.  (+info)

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