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Competing Interests: All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Stephen L. Guthery reports institutional grant funding from the National Institute for Digestive Diseases and Kidney Diseases (NIDDK) and institutional funding from NIDDK to the Childhood Liver Disease Research Network. No other potential conflicts of interest were disclosed.

Background: Inpatient quality deficits have important implications for the health and well-being of patients. They also have important financial implications for payers and hospitals by leading to longer lengths of stay and higher intensity of treatment. Many of these costly quality deficits are particularly sensitive to nursing care., Objective: To assess the effect of nurse staffing on quality of care and inpatient care costs., Design: Longitudinal analysis using hospital nurse staffing data and the Healthcare Cost and Utilization Project State Inpatient Databases from 2008 through 2011., Subjects: Hospital discharges from California, Nevada, and Maryland (n=18,474,860)., Methods: A longitudinal, hospital-fixed effect model was estimated to assess the effect of nurse staffing levels and skill mix on patient care costs, length of stay, and adverse events, adjusting for patient clinical and demographic characteristics., Results: Increases in nurse staffing levels were associated with reductions in nursing-sensitive adverse events and length of stay, but did not lead to increases in patient care costs. Changing skill mix by increasing the number of registered nurses, as a proportion of licensed nursing staff, led to reductions in costs., Conclusions: The study findings provide support for the value of inpatient nurse staffing as it contributes to improvements in inpatient care; increases in staff number and skill mix can lead to improved quality and reduced length of stay at no additional cost.

Purpose: The purpose of this qualitative study was to explore nutritional behaviors and attitudes among Latino women with type 2 diabetes., Methods: Women over 18 years old and previously diagnosed with type 2 diabetes were recruited to participate in semi-structured qualitative interviews in their homes in Los Angeles, California, and Las Vegas, Nevada. Recruitment was conducted through flyers posted in local businesses. Interviews were conducted in Spanish or English. Data were transcribed and analyzed using an iterative process that involves reading interview transcripts and designating themes that arise from the data., Results: Acquisition of nutritional knowledge and behavioral capability were positively associated with observational learning, formal nutritional education, and culturally competent meal planners. The use of traditional remedies and the consultation of naturistas reveal a tendency toward medical pluralism. In the home environment, husbands had the greatest influence on Latina women's attitudes and perceived choices., Conclusions: The social environment, including support and reinforcement, is critical for Latinas' nutritional success. Observational learning is critical for Latinas' behavioral capability.

Millions of people are exposed to arsenic in drinking water, which at high concentrations is known to cause lung cancer in humans. At lower concentrations, the risks are unknown. We enrolled 196 lung cancer cases and 359 controls matched on age and gender from western Nevada and Kings County, California in 2002-2005. After adjusting for age, sex, education, smoking and occupational exposures, odds ratios for arsenic concentrations ≥85 µg/L (median = 110 µg/L, mean = 173 µg/L, maximum = 1,460 µg/L) more than 40 years before enrollment were 1.39 (95% CI = 0.55-3.53) in all subjects and 1.61 (95% CI = 0.59-4.38) in smokers. Although odds ratios were greater than 1.0, these increases may have been due to chance given the small number of subjects exposed more than 40 years before enrollment. This study, designed before research in Chile suggested arsenic-related cancer latencies of 40 years or more, illustrates the enormous sample sizes needed to identify arsenic-related health effects in low-exposure countries with mobile populations like the U.S. Nonetheless, our findings suggest that concentrations near 100 µg/L are not associated with markedly high relative risks.

Background: Fifty-four outbreaks of domestically acquired typhoid fever were reported between 1960 and 1999. In 2010, the Southern Nevada Health District detected an outbreak of typhoid fever among persons who had not recently travelled abroad., Methods: We conducted a case-control study to examine the relationship between illness and exposures. A case was defined as illness with the outbreak strain of Salmonella serotype Typhi, as determined by pulsed-field gel electrophoresis (PFGE), with onset during 2010. Controls were matched by neighborhood, age, and sex. Bivariate and multivariate statistical analyses were completed using logistic regression. Traceback investigation was completed., Results: We identified 12 cases in 3 states with onset from 15 April 2010 to 4 September 2010. The median age of case patients was 18 years (range, 4-48 years), 8 (67%) were female, and 11 (92%) were Hispanic. Nine (82%) were hospitalized; none died. Consumption of frozen mamey pulp in a fruit shake was reported by 6 of 8 case patients (75%) and none of the 33 controls (matched odds ratio, 33.9; 95% confidence interval, 4.9). Traceback investigations implicated 2 brands of frozen mamey pulp from a single manufacturer in Guatemala, which was also implicated in a 1998-1999 outbreak of typhoid fever in Florida., Conclusions: Reporting of individual cases of typhoid fever and subtyping of isolates by PFGE resulted in rapid detection of an outbreak associated with a ready-to-eat frozen food imported from a typhoid-endemic region. Improvements in food manufacturing practices and monitoring will prevent additional outbreaks.

Public health providers are increasingly called on to do more with fewer resources. Aiming to help HIV clinical training providers in 15 local sites to better target their efforts, the Pacific AIDS Education and Training Center (PAETC) implemented a method for integrating disparate information, such as program-level evaluation and publicly available health services data, into one combined and useful format. The resulting local area profiles were distributed to each training site and were updated annually for 2 years. As a result, local training teams adopted data-based approaches to doing their work. Training managers and faculty reported that data presented in spatial formats (i.e., maps) were most helpful for targeting their outreach and training. In addition to achieving the aim of supporting better programs, the project increased capacity for using data to support all aspects of training and education, from grant writing to strategic planning.

Tickborne relapsing fever (TBRF) is a bacterial illness caused by certain species of Borrelia and transmitted through brief and painless bites from Ornithodoros ticks. Illness usually is characterized by intermittent periods of fever, fatigue, and muscle aches. In April 2005, CDC received reports of two cases of severe TBRF associated with acute respiratory distress syndrome (ARDS) in residents of California and Nevada. After a report describing these cases was posted on CDC's Epidemic Information Exchange (Epi-X), health officials in Washington reported a third severe case associated with ARDS. This report summarizes these three cases and the results of the subsequent epidemiologic investigations. The findings indicate that ARDS might occur more frequently in patients with TBRF than previously recognized. Optimal management of TBRF requires both prompt diagnosis and careful observation during the initial phases of treatment.

We investigated a multistate outbreak of Escherichia coli O157:H7 infections. Isolates from 13 case patients from California, Nevada, and Arizona were matched by pulsed-field gel electrophoresis subtyping. Five case patients (38%) were hospitalized, and 3 (23%) developed hemolytic uremic syndrome; none died. The median age was 12 years (range, 2-75 years), and 10 (77%) were female. Case-control studies found an association between illness and eating beef tacos at a national Mexican-style fast-food restaurant chain (88% of cases versus 38% of controls; matched OR, undefined; 95% confidence interval, 1.49 to infinity; P=.009). A trace-back investigation implicated an upstream supplier of beef, but a farm investigation was not possible. This outbreak illustrates the value of employing hospital laboratory-based surveillance to detect local clusters of infections and the effectiveness of using molecular subtyping to identify geographically dispersed outbreaks. The outbreak investigation also highlights the need for a more efficient tracking system for food products.

Numerous epidemiologic investigations have identified links between high concentrations of arsenic in drinking water and cancer, although the risks at lower exposures are largely unknown. This paper presents the results of a case-control study of arsenic ingestion and bladder cancer in seven counties in the western United States. These counties contain the largest populations historically exposed to drinking water arsenic at concentrations near 100 microg/liter. All incident cases diagnosed from 1994 to 2000 were recruited. Individual data on water sources, water consumption patterns, smoking, and other factors were collected for 181 cases and 328 controls. Overall, no increased risks were identified for arsenic intakes greater than 80 microg/day (odds ratio=0.94, 95% confidence interval: 0.56, 1.57; linear trend, p=0.48). These risks are below predictions based on high dose studies from Taiwan. When the analysis was focused on exposures 40 or more years ago, an odds ratio of 3.67 (95% confidence interval: 1.43, 9.42; linear trend, p<0.01) was identified for intakes greater than 80 microg/day (median intake, 177 microg/day) in smokers. These data provide some evidence that smokers who ingest arsenic at concentrations near 200 microg/day may be at increased risk of bladder cancer.

Data from naturally infected deer mice (Peromyscus maniculatus) were used to investigate vertical transmission of Sin Nombre virus (SNV) and SNV-specific antibody. The antibody prevalence in juvenile mice (14 g or less) was inversely proportional to the mass of the animal, with juvenile deer mice weighing less than 11 g most likely to be antibody positive (26.9%) and juvenile mice weighing between 13 and 14 g least likely to be antibody positive (12.9%). Although a significant sex bias in seropositivity was detected in adult deer mice, no significant sex bias in seropositivity was detected in juvenile animals. Ten juvenile deer mice were identified that had initially tested positive for SNV-specific immunoglobulin G (IgG) by enzyme-linked immunosorbent assay (ELISA) but had subsequently tested negative when recaptured as adults. SNV RNA was detected by reverse transcriptase PCR (RT-PCR) in the blood of ELISA-positive adult deer mice but not in the blood of ELISA-positive juveniles. One of the juvenile mice initially tested negative for SNV RNA but later tested positive when recaptured as an ELISA-positive adult. The RT-PCR results for that individual correlated with the disappearance and then reappearance of SNV-specific IgG, indicating that the presence of SNV RNA at later time points was due to infection with SNV via horizontal transmission. SNV-specific antibody present in both ELISA-positive juvenile and adult mice was capable of neutralizing SNV. Additionally, our data indicate that SNV is not transmitted vertically.

During the 1980s and 1990s, Salmonella serotype Enteritidis (SE) emerged as an important cause of human illness in the United States. The rate of SE isolates reported to CDC increased from 0.6 per 100,000 population in 1976 to 3.6 per 100,000 in 1996 (Figure 1). Case-control studies of sporadic infections and outbreak investigations found that this increase was associated with eating raw or undercooked shell eggs (1). From 1996 to 1998, the rate of culture-confirmed SE cases reported to CDC declined to 2.2 per 100,000; however, outbreaks of illness caused by SE continue to occur. This report describes four SE outbreaks during 1996-1998 associated with eating raw or undercooked shell eggs and discusses measures that may be contributing to the decline in culture-confirmed SE cases.

Perchlorate, known to inhibit the human thyroid at doses above 200 mg/day, was detected in the drinking-water supplies of seven counties in California and Nevada at levels of 4 to 16 micrograms/L in 1997. The data from the neonatal screening programs of the state health departments in these two states were analyzed for any increased incidence of congenital hypothyroidism in those counties. County-specific, ethnicity-specific data for Nevada and California were obtained for 1996 and 1997. Within these seven counties, nearly 700,000 newborns had been screened. In all, 249 cases were identified, where 243 were expected, for an overall risk ratio of 1.0 (95% confidence interval, 0.9 to 1.2). The risk ratios for the individual counties ranged between 0.6 and 1.1. These data in this ecological analysis do not indicate an increase in the incidence of congenital hypothyroidism with the reported perchlorate levels.

To study the ecologic correlates of hantavirus in deer mice (Peromyscus maniculatus), we sampled 114 sites in the Walker River Basin of Nevada and California in 1995-1996. Blood samples were tested for antibody to hantavirus, and a subset of samples was also tested for virus RNA by reverse transcription-polymerase chain reaction. Average prevalence of antibody-positive mice was 17%, with heavier males the most likely to be infected. Antibody prevalence varied within repeatedly sampled sites from 0% to 50% over the course of several months, suggesting possible infection cycles. Although there was no linear correlation between deer mouse density and antibody prevalence on sample sites, more complex relationships between density and prevalence appeared likely. Specifically, infections were less likely where rodent densities were lower than a critical threshold value. However, above this value, density had no effect on prevalence.

An outbreak of food intoxication involving over 265 cases in western United States occurred in October 1991. Staphylococcus intermedius was implicated as the aetiologic agent. Representative outbreak isolates (five clinical and ten from foods) produced type A enterotoxin. DNA fragments generated by four restriction endonucleases and analysed by pulsed-field gel electrophoresis (PFGE) provided definitive evidence that all isolates from nine different counties in California and Nevada were derived from a single strain. The PFGE pattern of these outbreak isolates was distinct from those of a heterogeneous collection of seven S. intermedius strains of veterinary origin and five unrelated S. aureus laboratory strains. The data show a significant PFGE pattern heterogeneity not only among members of different Staphylococcus species but also within members of the same species and even the same enterotoxin type. The results indicate that PFGE is a valuable strain-specific discriminator for the epidemiological characterization of S. intermedius. To our knowledge, this represents the first documented foodborne outbreak caused by S. intermedius. These findings suggest that the presence of S. intermedius and other species such as S. hyicus in food should be reason for concern.

Outbreaks of illness variously identified by a number of terms, including epidemic neuromyasthenia, myalgic encephalomyelitis, Iceland disease, and atypical poliomyelitis, have been reported from many countries during the past 45 years. Since the first well-described outbreak occurring in 1934, > 60 outbreaks have been reported, but few of these have been described in considerable detail. These outbreaks are usually cited in historical reports of chronic fatigue syndrome (CFS) since each of these outbreaks appears to contain a number of cases meeting the current case definition of CFS. There has been inadequate attention given to the fact that epidemic neuromyasthenia and related clusters characterized by various complaints, including fatigue, do not have an accepted epidemiological or clinical definition, and only rarely have descriptions of these clusters included a specific case definition. When such case definitions have been applied, the occurrence of cases meeting the current case definition for CFS appears to be both variable and infrequent. This report utilizes examples of several well-documented outbreaks to emphasize specific aspects that should be considered in the investigation of future clusters.

Nearly 80,000 immature and adult mosquitoes in three genera were collected in high-elevation (> 1,000 m) areas of California (68,229), Nevada (3,721), Oregon (5,918), and Washington (1,629) during 1990-1992 and tested for virus as adult males or females in 1,799 pools. Collections comprised primarily alpine Aedes in the Aedes communis (De Geer) group of the subgenus Ochlerotatus. Thirteen strains of Jamestown Canyon (JC) virus were recovered by plaque assay in Vero cell culture from three members of the Ae. communis group: 10 from Aedes tahoensis Dyar, 2 from Aedes cataphylla Dyar, and 1 from Aedes hexodontus Dyar. All isolates came from collections made in Alpine, Sierra, Tulare, or Tuolumne counties in the Sierra Nevada of California. Vertical transmission of JC virus in all three mosquito species was demonstrated by the isolation of virus from adult males or females reared from field-collected larvae or pupae. The prevalence of infected Ae. tahoensis was significantly higher in field-collected adult females than in reared adult males and females in Alpine County, which indicated that JC virus was being amplified by horizontal transmission. This study further incriminated Ae. tahoensis, Ae. cataphylla, and Ae. hexodontus as natural vectors of JC virus in California and greatly extended the known geographical range of this virus in the Sierra Nevada.

Background: The purpose of this study is to provide a case definition of chronic fatigue syndrome in an outbreak occurring in the Nevada-California region to evaluate candidate etiologic agents and observe the natural history of the illness., Methods: Patients diagnosed as having chronic fatigue syndrome were studied by repeated interviews, questionnaires, and blood collection over a 3-year period. Serum samples were tested for antibodies to Epstein-Barr virus, human herpesvirus-6, and human T-lymphotropic viruses I and II. Leukocytes from typical cases were also assayed for human T-lymphotropic viruses I and II., Results: Cases were defined as persons who had: (1) severe persistent fatigue following an acute illness appearing in an individual with no previous physical or psychological symptoms; (2) presenting signs and symptoms of an acute infection; (3) severe and persistent headache and/or myalgias; and (4) abrupt change in cognitive function or the appearance of a new mood disorder. After 3 years of follow-up, almost all study subjects were able to return to pre-illness activity. None of the viruses evaluated--human T-lymphotropic viruses I and II, Epstein-Barr virus, or human herpesvirus-6--could be etiologically linked to these outbreaks., Conclusion: Clinical features of outbreaks of chronic fatigue syndrome differ sufficiently to suggest different etiologic agents. Giardiasis appears to have precipitated one of the four clusters in this study but the cause(s) of the other three outbreaks is as yet uncertain. The overall prognosis of chronic fatigue syndrome is usually favorable.

Elderly patients on chronic peritoneal dialysis (CPD) from two large chronic peritoneal dialysis programs were compared with younger patients in regard to peritonitis rates, catheter problems, hospital days, transfers to other forms of therapy, and mortality. Peritonitis rates and organisms were similar in younger and older patients. Catheter replacements were less common in the elderly. Differences in hospital days were attributable to hospitalization for vascular disease. The elderly were more likely to have the first episode of peritonitis, to die and to change dialysis modalities at all times after the first year of continuous ambulatory peritoneal dialysis (CAPD) treatment, although other than increased mortality, differences between the two groups were small. CPD appears to be an acceptable form of renal replacement therapy in the elderly.