Author Correction: Forearc carbon sink reduces long-term volatile recycling into the mantle.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Author Correction: Forearc carbon sink reduces long-term volatile recycling into the mantle.

Change history: In this Article, the original affiliation 2 was not applicable and has been removed. In addition, in the Acknowledgements there was a statement missing and an error in a name. These errors have been corrected online.

Case-case analyses of cryptosporidiosis and giardiasis using routine national surveillance data in the United States - 2005-2015.

Understanding endemic infectious disease risk factors through traditional epidemiological tools is challenging. Population-based case-control studies are costly and time-consuming. A case-case analyses using surveillance data addresses these limitations by using resources more efficiently. We conducted a case-case analyses using routine surveillance data reported by 16 U.S. states (2005-2015), wherein reported cases of salmonellosis were used as a comparison group to identify exposure associations with reported cases of cryptosporidiosis and giardiasis. Odds ratios adjusted for age and reporting state (aOR) and 95% confidence intervals (95% CI) were calculated. A total of 10 704 cryptosporidiosis cases, 17 544 giardiasis cases, and 106 351 salmonellosis cases were included in this analyses. When compared with cases of salmonellosis, exposure to treated recreational water (aOR 4.7, 95% CI 4.3-5.0) and livestock (aOR: 3.2; 95% CI: 2.9-3.5) were significantly associated with cryptosporidiosis and exposure to untreated drinking (aOR 4.1, 95% CI 3.6-4.7) and recreational water (aOR 4.1, 95% CI 3.7-4.5) were associated with giardiasis. Our analyses shows that routine surveillance data with standardised exposure information can be used to identify associations of interest for cryptosporidiosis and giardiasis.

Forearc carbon sink reduces long-term volatile recycling into the mantle.

Carbon and other volatiles in the form of gases, fluids or mineral phases are transported from Earth's surface into the mantle at convergent margins, where the oceanic crust subducts beneath the continental crust. The efficiency of this transfer has profound implications for the nature and scale of geochemical heterogeneities in Earth's deep mantle and shallow crustal reservoirs, as well as Earth's oxidation state. However, the proportions of volatiles released from the forearc and backarc are not well constrained compared to fluxes from the volcanic arc front. Here we use helium and carbon isotope data from deeply sourced springs along two cross-arc transects to show that about 91 per cent of carbon released from the slab and mantle beneath the Costa Rican forearc is sequestered within the crust by calcite deposition. Around an additional three per cent is incorporated into the biomass through microbial chemolithoautotrophy, whereby microbes assimilate inorganic carbon into biomass. We estimate that between 1.2 × 108 and 1.3 × 1010 moles of carbon dioxide per year are released from the slab beneath the forearc, and thus up to about 19 per cent less carbon is being transferred into Earth's deep mantle than previously estimated.

Risk factors for sporadic Giardia infection in the USA: a case-control study in Colorado and Minnesota.

Giardia duodenalis is the most common intestinal parasite of humans in the USA, but the risk factors for sporadic (non-outbreak) giardiasis are not well described. The Centers for Disease Control and Prevention and the Colorado and Minnesota public health departments conducted a case-control study to assess risk factors for sporadic giardiasis in the USA. Cases (N = 199) were patients with non-outbreak-associated laboratory-confirmed Giardia infection in Colorado and Minnesota, and controls (N = 381) were matched by age and site. Identified risk factors included international travel (aOR = 13.9; 95% CI 4.9-39.8), drinking water from a river, lake, stream, or spring (aOR = 6.5; 95% CI 2.0-20.6), swimming in a natural body of water (aOR = 3.3; 95% CI 1.5-7.0), male-male sexual behaviour (aOR = 45.7; 95% CI 5.8-362.0), having contact with children in diapers (aOR = 1.6; 95% CI 1.01-2.6), taking antibiotics (aOR = 2.5; 95% CI 1.2-5.0) and having a chronic gastrointestinal condition (aOR = 1.8; 95% CI 1.1-3.0). Eating raw produce was inversely associated with infection (aOR = 0.2; 95% CI 0.1-0.7). Our results highlight the diversity of risk factors for sporadic giardiasis and the importance of non-international-travel-associated risk factors, particularly those involving person-to-person transmission. Prevention measures should focus on reducing risks associated with diaper handling, sexual contact, swimming in untreated water, and drinking untreated water.

Prevalence and direct costs of emergency department visits and hospitalizations for selected diseases that can be transmitted by water, United States.

National emergency department (ED) visit prevalence and costs for selected diseases that can be transmitted by water were estimated using large healthcare databases (acute otitis externa, campylobacteriosis, cryptosporidiosis, Escherichia coli infection, free-living ameba infection, giardiasis, hepatitis A virus (HAV) infection, Legionnaires' disease, nontuberculous mycobacterial (NTM) infection, Pseudomonas-related pneumonia or septicemia, salmonellosis, shigellosis, and vibriosis or cholera). An estimated 477,000 annual ED visits (95% CI: 459,000-494,000) were documented, with 21% (n = 101,000, 95% CI: 97,000-105,000) resulting in immediate hospital admission. The remaining 376,000 annual treat-and-release ED visits (95% CI: 361,000-390,000) resulted in $194 million in annual direct costs. Most treat-and-release ED visits (97%) and costs ($178 million/year) were associated with acute otitis externa. HAV ($5.5 million), NTM ($2.3 million), and salmonellosis ($2.2 million) were associated with next highest total costs. Cryptosporidiosis ($2,035), campylobacteriosis ($1,783), and NTM ($1,709) had the highest mean costs per treat-and-release ED visit. Overall, the annual hospitalization and treat-and-release ED visit costs associated with the selected diseases totaled $3.8 billion. As most of these diseases are not solely transmitted by water, an attribution process is needed as a next step to determine the proportion of these visits and costs attributable to waterborne transmission.

Mortality from selected diseases that can be transmitted by water - United States, 2003-2009.

Diseases spread by water are caused by fecal-oral, contact, inhalation, or other routes, resulting in illnesses affecting multiple body systems. We selected 13 pathogens or syndromes implicated in waterborne disease outbreaks or other well-documented waterborne transmission (acute otitis externa, Campylobacter, Cryptosporidium, Escherichia coli (E. coli), free-living ameba, Giardia, Hepatitis A virus, Legionella (Legionnaires' disease), nontuberculous mycobacteria (NTM), Pseudomonas-related pneumonia or septicemia, Salmonella, Shigella, and Vibrio). We documented annual numbers of deaths in the United States associated with these infections using a combination of death certificate data, nationally representative hospital discharge data, and disease-specific surveillance systems (2003-2009). We documented 6,939 annual total deaths associated with the 13 infections; of these, 493 (7%) were caused by seven pathogens transmitted by the fecal-oral route. A total of 6,301 deaths (91%) were associated with infections from Pseudomonas, NTM, and Legionella, environmental pathogens that grow in water system biofilms. Biofilm-associated pathogens can cause illness following inhalation of aerosols or contact with contaminated water. These findings suggest that most mortality from these 13 selected infections in the United States does not result from classical fecal-oral transmission but rather from other transmission routes.

Evaluation of a structured expert elicitation estimating the proportion of illness acquired by foodborne transmission for nine enteric pathogens in Australia.

Estimates of the proportion of illness transmitted by food for different enteric pathogens are essential for foodborne burden-of-disease studies. Owing to insufficient scientific data, a formal synthesis of expert opinion, an expert elicitation, is commonly used to produce such estimates. Eleven experts participated in an elicitation to estimate the proportion of illnesses due to food in Australia for nine pathogens over three rounds: first, based on their own knowledge alone; second, after being provided with systematic reviews of the literature and Australian data; and finally, at a workshop where experts reflected on the evidence. Estimates changed significantly across the three rounds (P = 0·002) as measured by analysis of variance. Following the workshop in round 3, estimates showed smoother distributions with significantly less variation for several pathogens. When estimates were combined to provide combined distributions for each pathogen, the width of these combined distributions reflected experts' perceptions of the availability of evidence, with narrower intervals for pathogens for which evidence was judged to be strongest. Our findings show that the choice of expert elicitation process can significantly influence final estimates. Our structured process - and the workshop in particular - produced robust estimates and distributions appropriate for inclusion in burden-of-disease studies.

Attributing sporadic and outbreak-associated infections to sources: blending epidemiological data.

Common sources of shiga toxin-producing Escherichia coli (STEC) O157 infection have been identified by investigating outbreaks and by case-control studies of sporadic infections. We conducted an analysis to attribute STEC O157 infections ascertained in 1996 and 1999 by the Foodborne Diseases Active Surveillance Network (FoodNet) to sources. Multivariable models from two case-control studies conducted in FoodNet and outbreak investigations that occurred during the study years were used to calculate the annual number of infections attributable to six sources. Using the results of the outbreak investigations alone, 27% and 15% of infections were attributed to a source in 1996 and 1999, respectively. Combining information from both data sources, 65% of infections in 1996 and 34% of infections in 1999 were attributed. The results suggest that methods to incorporate data from multiple surveillance systems and over several years are needed to improve estimation of the number of illnesses attributable to exposure sources.

Is it beneficial to increase the provision of thrombolysis?-- a discrete-event simulation model.

BACKGROUND: Although Thrombolysis has been licensed in the UK since 2003, it is still administered only to a small percentage of eligible patients. AIM: We consider the impact of investing the impact of thrombolysis on important acute stroke services, and the effect on quality of life. The concept is illustrated using data from the Northern Ireland Stroke Service. DESIGN: Retrospective study. METHODS: We first present results of survival analysis utilizing length of stay (LOS) for discharge destinations, based on data from the Belfast City Hospital (BCH). None of these patients actually received thrombolysis but from those who would have been eligible, we created two initial groups, the first representing a scenario where they received thrombolysis and the second comprising those who do not receive thrombolysis. On the basis of the survival analysis, we created several subgroups based on discharge destination. We then developed a discrete event simulation (DES) model, where each group is a patient pathway within the simulation. Coxian phase type distributions were used to model the group LOS. Various scenarios were explored focusing on cost-effectiveness across hospital, community and social services had thrombolysis been administered to these patients, and the possible improvement in quality of life, should the proportion of patients who are administered thrombolysis be increased. Our aim in simulating various scenarios for this historical group of patients is to assess what the cost-effectiveness of thrombolysis would have been under different scenarios; from this we can infer the likely cost-effectiveness of future policies. RESULTS: The cost of thrombolysis is offset by reduction in hospital, community rehabilitation and institutional care costs, with a corresponding improvement in quality of life. CONCLUSION: Our model suggests that provision of thrombolysis would produce moderate overall improvement to the service assuming current levels of funding.

Re-assessment of risk factors for sporadic Salmonella serotype Enteritidis infections: a case-control study in five FoodNet Sites, 2002-2003.

Active surveillance for laboratory-confirmed Salmonella serotype Enteritidis (SE) infection revealed a decline in incidence in the 1990s, followed by an increase starting in 2000. We sought to determine if the fluctuation in SE incidence could be explained by changes in foodborne sources of infection. We conducted a population-based case-control study of sporadic SE infection in five of the Foodborne Diseases Active Surveillance Network (FoodNet) sites during a 12-month period in 2002-2003. A total of 218 cases and 742 controls were enrolled. Sixty-seven (31%) of the 218 case-patients and six (1%) of the 742 controls reported travel outside the United States during the 5 days before the case's illness onset (OR 53, 95% CI 23-125). Eighty-one percent of cases with SE phage type 4 travelled internationally. Among persons who did not travel internationally, eating chicken prepared outside the home and undercooked eggs inside the home were associated with SE infections. Contact with birds and reptiles was also associated with SE infections. This study supports the findings of previous case-control studies and identifies risk factors associated with specific phage types and molecular subtypes.

Widespread distribution of urinary tract infections caused by a multidrug-resistant Escherichia coli clonal group.

BACKGROUND: The management of urinary tract infections is complicated by the increasing prevalence of antibiotic-resistant strains of Escherichia coli. We studied the clonal composition of E. coli isolates that were resistant to trimethoprim-sulfamethoxazole from women with community-acquired urinary tract infections. METHODS: Prospectively collected E. coli isolates from women with urinary tract infections in a university community in California were evaluated for antibiotic susceptibility, O:H serotype, DNA fingerprinting, pulsed-field gel electrophoretic pattern, and virulence factors. The prevalence and characteristics of an antibiotic-resistant clone were evaluated in this group of isolates and in those from comparison cohorts in Michigan and Minnesota. RESULTS: Fifty-five of the 255 E. coli isolates (22 percent) from the California cohort were resistant to trimethoprim-sulfamethoxazole as well as other antibiotics. There was a common pattern of DNA fingerprinting, suggesting that the isolates belonged to the same clonal group (clonal group A), in 28 of 55 isolates with trimethoprim-sulfamethoxazole resistance (51 percent) and in 2 of 50 randomly selected isolates that were susceptible to trimethoprim-sulfamethoxazole (4 percent, P<0.001). In addition, 11 of 29 resistant isolates (38 percent) from the Michigan cohort and 7 of 18 (39 percent) from the Minnesota cohort belonged to clonal group A. Most of the clonal group A isolates were serotype O11:H(nt) or O77:H(nt), with similar patterns of virulence factors, antibiotic susceptibility, and electrophoretic features. CONCLUSIONS: In three geographically diverse communities, a single clonal group accounted for nearly half of community-acquired urinary tract infections in women that were caused by E. coli strains with resistance to trimethoprim-sulfamethoxazole. The widespread distribution and high prevalence of E. coli clonal group A has major public health implications.

Necrotizing fasciitis associated with injection drug use.

We studied cases of necrotizing fasciitis among injection drug users (IDUs) and non-IDUs who presented at the University of California Davis Medical Center from 1984 through 1999. Of 107 patients, 59 (55%) were IDUs and 48 (45%) non-IDUs. Among IDUs, 32 (54%) recently injected at the site of infection, and 17 patients (29%) presented with an abscess. Among non-IDUs, 17 (35%) reported a recent insect bite and 9 (19%) reported a wound or abrasion at the site of infection. Overall, seventy cases (65%) had > or = 3 debridements, and 31 patients (29%) had > 5% of their total body surface area debrided. Of all patients with necrotizing fasciitis, 16 (15%) did not survive. Among the 59 IDUs, 6 (10%) did not survive, while among non-IDUs, 10 (21%) did not survive. Our results indicate the need for a high index of suspicion for necrotizing fasciitis among patients presenting with cellulitis, a recent insect bite, wound, or recent injection drug use. Preventive interventions for necrotizing fasciitis among IDUs should include street-based education and treatment for abscesses and cellulitis.

Correctable visual impairment in stroke rehabilitation patients.

BACKGROUND: after stroke, visual impairment may exacerbate the impact of other impairments on overall disability and negatively influence rehabilitation. OBJECTIVE: to examine the visual status of patients after stroke and determine whether this can be improved by simple interventions. DESIGN: prospective study. SETTINGS: stroke rehabilitation unit in a Belfast teaching hospital. SUBJECTS: 77 consecutive patients admitted for rehabilitation after acute stroke. METHODS: full optometric and ophthalmic assessment within 2 weeks of admission. RESULTS: of 70 patients with glasses, 19 did not have their glasses in hospital before prompting and 18 had glasses in unacceptable condition. Twenty patients had impaired visual acuity (6/12 or worse) with existing glasses (if helpful); 11 of these improved to better than 6/12 with refractive correction. CONCLUSIONS: stroke professionals need to enquire about patients' spectacles and assess their condition. Patients with reduced visual acuity in the absence of significant non-refractive disease should be referred to an optometrist: in this series 14% of patients had visual impairment which benefited from refractive correction.

The winter bed crisis--quantifying seasonal effects on hospital bed usage.

Winter bed crises are a common feature in NHS hospitals, and have given rise to great concern. We set out to determine the relative contribution of seasonal effects and other factors to bed occupancy in a large teaching hospital over one year. There were 190,804 occupied bed-days, which we analysed by specialty groupings. There was considerable variability in bed occupancy in each specialty. A significant winter peak occurred for general medicine and orthopaedics together with a significant increase on 'take-in' days. Virtually all specialties showed a significant variation in occupancy between weekdays. Geriatric Medicine had a high and fairly constant occupancy, with some seasonal effect. We conclude that seasonal trends in bed occupancy occur in 'front door' specialties and are predictable. In these specialties, admission policies also make a contribution to bed usage and are amenable to modification. There is no surge in occupancy in the immediate post-Christmas period, except that attributable to the seasonal trend. In the 'elective' specialties, bed occupancy fluctuates widely, with reduced occupancy at weekends and at Christmas. These differences are entirely amenable to modification. More effective bed management would make a very significant contribution to avoiding winter bed crises.

Fluid balance in elderly patients following acute stroke.

We studied the relationship between plasma osmolality, arginine vasopressin (AVP), and fluid input in patients during the acute phase of a first stroke. Fifteen consecutive patients were studied (median age 79) and their blood sampled on days 0, 1, 2, 3, 7 and 14. Plasma osmolality was related to fluid input over days 0-3 (p = 0.0013) and AVP over 14 days (p less than 0.001). Patients with a poor outcome had higher AVP concentrations (p = 0.02). Those on intravenous fluids received a higher volume (p less than 0.01) and had a lower plasma osmolality (p = 0.04). The results of this preliminary study indicate that a standard regime for fluid input is inappropriate.