Nephroblastoma in a Common Mudpuppy Necturus maculosus simultaneously Present with a Mollicute Bacterium of the Genus Acholeplasma.

In March 2017, a wild-caught female common mudpuppy Necturus maculosus from Iowa, USA, with an enlarged posterior abdomen was submitted for diagnostic assessment. The cause of the abdominal distension was a large fluid-filled abdominal mass, diagnosed as a nephroblastoma. Parasites and numerous bacteria were isolated and identified from the mudpuppy but were determined to be incidental. Samples of the neoplasm inoculated onto an American toad Anaxyrus americanus cell line (BufoTad) yielded cytopathic effect during several passages. However, standard molecular testing of the cell culture supernatant failed to identify any viruses. Next-generation sequencing identified the replicating agent as a bacterium of the genus Acholeplasma. Immunohistochemistry confirmed the presence of Acholeplasma within the nephroblastoma, including within tumor cells. This is the first report of nephroblastoma and the second report of neoplasia in this species. The results also suggest that certain bacteria of the genus Acholeplasma might be oncogenic.

Vagococcus salmoninarum II-qPCR, tropism and egg-associated transmission.

Vagococcus salmoninarum was identified as the causative agent of a chronic epizootic in broodstock "coaster" brook trout (Salvelinus fontinalis) at the Iron River National Fish Hatchery. The epizootic spanned more than a year, was unresponsive to multiple florfenicol treatments, and resulted in >50% mortality of the affected fish. The decision was made to cull the remaining fish during spawning, which presented an opportunity to more thoroughly examine V. salmoninarum sampling methods, organ tropism and vertical transmission. A newly developed qPCR targeting the pheS gene was used in concert with bacterial culture to show that V. salmoninarum indeed disproportionately affects females and has a tropism for female reproductive tissues. The study demonstrates that some female reproductive tissues (e.g. ovarian fluid, unfertilized eggs) are also an effective option for non-lethal detection. Despite the widespread presence of V. salmoninarum in ovarian fluid and on egg surfaces, we found no evidence of intra-ova transmission.

Vagococcus salmoninarum I-A chronic coldwater streptococcosis in broodstock brook trout (Salvelinus fontinalis) in Wisconsin, USA.

In 2018, Vagococcus salmoninarum was isolated from two lots of broodstock "coaster" brook trout (Salvelinus fontinalis) containing ~1,500 fish at the Iron River National Fish Hatchery, at which time it was identified as the causative agent of a chronic coldwater streptococcosis epizootic. Clinical signs included exophthalmia, lethargy, erratic swimming and loss of equilibrium. Female fish experienced disproportionately higher morbidity and mortality than male co-inhabitants, and routinely retained eggs following spawning. The most consistent gross clinical sign was heart pallor and turbid pericardial effusion. An attempted treatment using florfenicol was ineffective at halting the epizootic, which spanned more than a year and resulted in >50% mortality before remaining fish were culled. As there is no previous documentation of V. salmoninarum at this hatchery or in this species, it is still unclear what circumstances led to this epizootic. The inability to treat this chronic disease led to the loss of valuable broodstock, hampering ongoing fishery conservation efforts in the Great Lakes Basin.

Plasmodium falciparum subtilisin-like ookinete protein SOPT plays an important and conserved role during ookinete infection of the Anopheles stephensi midgut.

Transmission of the malaria parasite Plasmodium falciparum involves infection of Anopheles mosquitoes. Here we characterize SOPT, a protein expressed in P. falciparum ookinetes that facilitates infection of the mosquito midgut. SOPT was identified on the basis that it contains a signal peptide, a PEXEL-like sequence and is expressed in asexual, ookinete and sporozoite stages, suggesting it is involved in infecting the human or mosquito host. SOPT is predicted to contain a subtilisin-like fold with a non-canonical catalytic triad and is orthologous to P. berghei PIMMS2. Localization studies reveal that SOPT is not exported to the erythrocyte but is expressed in ookinetes at the parasite periphery. SOPT-deficient parasites develop normally through the asexual and sexual stages and produce equivalent numbers of ookinetes to NF54 controls, however, they form fewer oocysts and sporozoites in mosquitoes. SOPT-deficient parasites were also unable to activate the immune-responsive midgut invasion marker SRPN6 after mosquito ingestion, suggesting they are defective for entry into the midgut. Disruption of SOPT in P. berghei (PIMMS2) did not affect other lifecycle stages or ookinete development but again resulted in fewer oocysts and sporozoites in mosquitoes. Collectively, this study shows that SOPT/PIMMS2 plays a conserved role in ookinetes of different Plasmodium species.

Bluegill Picornavirus isolated from a mortality event involving Bluegill (Lepomis macrochirus) in the upper Mississippi River.

A mortality event involving an estimated 1,000 adult bluegills (Lepomis macrochirus) was observed in an ice-covered backwater lake of the upper Mississippi River near Alma, Wisconsin, in December of 2017. Macroscopic signs of disease included abdominal distension due to fluid accumulation within the internal organs as well as external and internal haemorrhaging. Histological evaluation revealed chronic peritonitis with peritoneal adhesions in all fish examined. Kidney, spleen and ascites fluid samples were collected from diseased bluegills and examined for the presence of pathogens. Bluegill picornavirus (BGPV) was isolated using tissue cell culture methods utilizing a recently developed, uncharacterized bluegill fry cell line (BF-4), and the presence of this virus was confirmed through molecular identification. The current geographic range, known susceptible hosts as well as historical epizootics associated with BPGV is discussed. The ability of BGPV to cause significant mortality in wild fish further emphasizes the importance of monitoring both wild and hatchery populations for this pathogen.

Yersinia ruckeri Isolated from Common Mudpuppy Necturus maculosus.

During a routine health inspection of apparently healthy wild-caught common mudpuppies Necturus maculosus, the bacteria Yersinia ruckeri was isolated and the identity confirmed using biochemical and molecular methods. This represents the first isolation of Y. ruckeri from an amphibian. This finding increases the known host range capable of harboring this important fish pathogen and could have serious management implications for aquaculture. Furthermore, addressing wild amphibians in fish hatchery biosecurity plans is discussed.

AMA1 and MAEBL are important for Plasmodium falciparum sporozoite infection of the liver.

The malaria sporozoite injected by a mosquito migrates to the liver by traversing host cells. The sporozoite also traverses hepatocytes before invading a terminal hepatocyte and developing into exoerythrocytic forms. Hepatocyte infection is critical for parasite development into merozoites that infect erythrocytes, and the sporozoite is thus an important target for antimalarial intervention. Here, we investigated two abundant sporozoite proteins of the most virulent malaria parasite Plasmodium falciparum and show that they play important roles during cell traversal and invasion of human hepatocytes. Incubation of P. falciparum sporozoites with R1 peptide, an inhibitor of apical merozoite antigen 1 (AMA1) that blocks merozoite invasion of erythrocytes, strongly reduced cell traversal activity. Consistent with its inhibitory effect on merozoites, R1 peptide also reduced sporozoite entry into human hepatocytes. The strong but incomplete inhibition prompted us to study the AMA-like protein, merozoite apical erythrocyte-binding ligand (MAEBL). MAEBL-deficient P. falciparum sporozoites were severely attenuated for cell traversal activity and hepatocyte entry in vitro and for liver infection in humanized chimeric liver mice. This study shows that AMA1 and MAEBL are important for P. falciparum sporozoites to perform typical functions necessary for infection of human hepatocytes. These two proteins therefore have important roles during infection at distinct points in the life cycle, including the blood, mosquito, and liver stages.

Optimizing, validating, and field testing a multiplex qPCR for the detection of amphibian pathogens.

Amphibian populations worldwide are facing numerous threats, including the emergence and spread of infectious diseases. In the past 2 decades, Batrachochytrium dendrobatidis (Bd), a parasitic fungus, and a group of viruses comprising the genus Ranavirus have become widespread and resulted in mass mortality events and extirpations worldwide. In 2013, another novel fungus, B. salamandrivorans (Bsal), was attributed to dramatic declines in populations of fire salamander Salamandra salamandra in the Netherlands. Experimental infections demonstrated that Bsal is highly pathogenic to numerous salamander genera. In an effort to prevent the introduction of Bsal to North America, the US Fish and Wildlife Service (USFWS) listed 201 salamander species as injurious wildlife under the Lacey Act. To determine infection status and accurately assess amphibian health, the development of a sensitive and specific diagnostic assay was needed. We describe the optimization and validation of a multiplex quantitative polymerase chain reaction (qPCR) protocol for the simultaneous detection of Bd, Bsal, and frog virus 3-like ranaviruses. A synthetic genome template (gBlock®) containing the target genes from all 3 pathogens served as the positive control and allowed accurate quantification of pathogen genes. The assay was validated in the field using an established non-lethal swabbing technique to survey local amphibian populations throughout a range of habitats. This multiplex qPCR demonstrates high reproducibility, sensitivity, and was capable of detecting both Bd and ranavirus in numerous locations, species, and life stages. Bsal was not detected at any point during these sampling efforts.

Disaster Mental Health and Community-Based Psychological First Aid: Concepts and Education/Training.

Any community can experience a disaster, and many traumatic events occur without warning. Psychologists can be an important resource assisting in psychological support for individuals and communities, in preparation for and in response to traumatic events. Disaster mental health and the community-based model of psychological first aid are described. The National Preparedness and Response Science Board has recommended that all mental health professionals be trained in disaster mental health, and that first responders, civic officials, emergency managers, and the general public be trained in community-based psychological first aid. Education and training resources in these two fields are described to assist psychologists and others in preparing themselves to assist their communities in difficult times and to help their communities learn to support one another.

Helping the Helpers: Assisting Staff and Volunteer Workers Before, During, and After Disaster Relief Operations.

Self-care strategies and system supports employed in preparation for, during, and after disaster relief operations (DROs) are crucial to relief worker well-being and the overall effectiveness of relief efforts. Relief organizations and management must structure DROs in a manner that promotes self-care and workers must implement proper self-care strategies. Proper self-care before, during, and after a DRO can reduce negative reactions to stressful emergency work and promote growth, mastery, and self-efficacy after the experience. Therefore, the purpose of this article is to discuss the importance of organizational supports and self-care strategies in disaster relief settings. This article emphasizes the role of both individual and management participation and commitment to relief worker support and positive experience in DROs and provides suggestions for doing so. These suggestions are derived from the empirical and experiential literature and extensions from the theoretical background, and from our experience as managers in DROs.

Vaccination against Rabbit Hemorrhagic Disease Virus 2 (RHDV2) Using a Baculovirus Recombinant Vaccine Provides Durable Immunity in Rabbits.

Rabbit hemorrhagic disease virus 2 (RHDV2) emerged in the United States in 2018 and has spread in both domestic and wild rabbits nationwide. The virus has a high mortality rate and can spread rapidly once introduced in a rabbit population. Vaccination against RHDV2 provides the best protection against disease and should be considered by all rabbit owners. Here, we investigate the duration of immunity provided by vaccination with the Medgene Platform conditionally licensed commercial vaccine 6 months following the initial series. Rabbits received either the vaccination or a placebo and were challenged with RHDV2 6 months later. All vaccinated rabbits survived challenge whereas 18/19 non-vaccinated controls succumbed to infection within 10 or fewer days post-challenge. These results demonstrate lasting immunity following vaccination with the Medgene RHDV2 vaccine.

Trends in the incidence of noncardiogenic acute respiratory failure: the role of race.

OBJECTIVE: We sought to examine trends in the race-specific incidence of acute respiratory failure in the United States. DESIGN: Retrospective cohort study. SETTING: We used the National Hospital Discharge Survey database (1992-2007), an annual survey of approximately 500 hospitals weighted to provide national hospitalization estimates. PATIENTS: All incident cases of noncardiogenic acute respiratory failure hospitalized in the United States. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We identified noncardiogenic acute respiratory failure by the presence of International Classification of Diseases, Ninth Revision, codes for respiratory failure or pulmonary edema (518.4, 518.5, 518.81, and 518.82) and mechanical ventilation (96.7×), excluding congestive heart failure. Incidence rates were calculated using yearly census estimates standardized to the age and sex distribution of the 2000 census population. Annual cases of noncardiogenic acute respiratory failure increased from 86,755 in 1992 to 323,474 in 2007. Noncardiogenic acute respiratory failure among black Americans increased from 56.4 (95% confidence interval 39.7-73.1) to 143.8 (95% confidence interval 123.8-163.8) cases per 100,000 in 1992 and 2007, respectively. Among white Americans, the incidence of noncardiogenic acute respiratory failure increased from 31.2 (95% confidence interval 26.2-36.5) to 94.0 (95% confidence interval 86.7-101.2) cases per 100,000 in 1992 and 2007, respectively. The average annual incidence of noncardiogenic acute respiratory failure over the entire study period was 95.1 (95% confidence interval 93.9-96.4) cases per 100,000 for black Americans compared to 66.5 (95% confidence interval 65.8-67.2) cases per 100,000 for white Americans (rate ratio 1.43, 95% confidence interval 1.42-1.44). Overall in-hospital mortality was greater for other-race Americans, but only among patients with two or more organ failures (57% [95% confidence interval 56%-59%] for other race, 51% [95% confidence interval 50%-52%] for white, 50% [95% confidence interval 49%-51%] for black). CONCLUSIONS: The incidence of noncardiogenic acute respiratory failure in the United States increased between 1992 and 2007. Black and other-race Americans are at greater risk of developing noncardiogenic acute respiratory failure compared to white Americans.

Implementing and Optimizing Biosimilar Use at Mayo Clinic.

OBJECTIVE: To determine whether the formation of a multidisciplinary team, pharmacist-led therapeutic interchange, and streamlined electronic health record optimization improved biosimilar adoption throughout Mayo Clinic. PATIENTS AND METHODS: The project focused on the use of reference products and biosimilars for 5 biologics-bevacizumab, epoetin alfa, filgrastim, rituximab, and trastuzumab-at all Mayo Clinic locations. Pharmaceutical wholesale purchase histories of those reference products and biosimilars were assessed from September 1, 2020, through August 31, 2021, and compared with data from September 1, 2019, through August 31, 2020. Formulary decisions were implemented across 5 biologics for most ordering pathways on September 1, 2020. Pharmaceutical purchased drug units and expenditures were tracked at 3-month intervals for conversion to formulary-preferred contracted biosimilars. RESULTS: In the final postimplementation period, the absolute percentage increase of formulary-preferred biosimilars was 69% for bevacizumab, 63% for epoetin alfa, 80% for filgrastim, 79% for rituximab, and 72% for trastuzumab. Pharmaceutical line item savings in the 12-month postimplementation period totaled $23.1 million across all 5 biologics. CONCLUSION: Creation of a multidisciplinary team to implement formulary-preferred contracted biosimilars led to the adoption of biosimilars throughout Mayo Clinic with considerable pharmaceutical line item savings.

The effect of race and ethnicity on outcomes among patients in the intensive care unit: a comprehensive study involving socioeconomic status and resuscitation preferences.

OBJECTIVE: We sought to determine whether race or ethnicity is independently associated with mortality or intensive care unit length of stay among critically ill patients after accounting for patients' clinical and demographic characteristics including socioeconomic status and resuscitation preferences. DESIGN: Historical cohort study of patients hospitalized in intensive care units. SETTING: Adult intensive care units in 35 California hospitals during the years 2001-2004. PATIENTS: A total of 9,518 intensive care unit patients (6,334 white, 655 black, 1,917 Hispanic, and 612 Asian/Pacific Islander patients). MEASUREMENTS AND MAIN RESULTS: The primary outcome was risk-adjusted mortality and a secondary outcome was risk-adjusted intensive care unit length of stay. Crude hospital mortality was 15.9% among the entire cohort. Asian patients had the highest crude hospital mortality at 18.6% and black patients had the lowest at 15.0%. After adjusting for age and gender, Hispanic and Asian patients had a higher risk of death compared to white patients, but these differences were not significant after additional adjustment for severity of illness. Black patients had more acute physiologic derangements at intensive care unit admission and longer unadjusted intensive care unit lengths of stay. Intensive care unit length of stay was not significantly different among racial/ethnic groups after adjustment for demographic, clinical, and socioeconomic factors and do-not-resuscitate status. In an analysis restricted only to those who died, decedent black patients averaged 1.1 additional days in the intensive care unit (95% confidence interval, 0.26-2.6) compared to white patients who died, although this was not statistically significant. CONCLUSIONS: Hospital mortality and intensive care unit length of stay did not differ by race or ethnicity among this diverse cohort of critically ill patients after adjustment for severity of illness, resuscitation status, socioeconomic status, insurance status, and admission type. Black patients had more acute physiologic derangements at intensive care unit admission and were less likely to have a do-not-resuscitate order. These results suggest that among intensive care unit patients, there are no racial or ethnic differences in mortality within individual hospitals. If disparities in intensive care unit care exist, they may be explained by differences in the quality of care provided by hospitals that serve high proportions of minority patients.

Clinical and pharmacy utilization outcomes with brand to generic antiepileptic switches in patients with epilepsy.

PURPOSE: To determine if switching from select branded to generic equivalent antiepileptic drugs (AEDs) in patients with epilepsy is associated with adverse outcomes. METHODS: A retrospective cohort study using a large health insurance plan claims database comparing patients with epilepsy who switched from brand to generic equivalent phenytoin, lamotrigine, or divalproex after 6 months (switch cohorts) to matched patients who remained on the brand (nonswitch cohorts). Primary outcomes measured include the incidence rate ratio (IRR) of discontinuation of the index AED; change in dose of index AED or addition of another AED; and the event rate ratio (ERR) of the composite of all-cause emergency department (ED) visits or hospitalizations. KEY FINDINGS: Lamotrigine and divalproex showed no differences in AED utilization changes between the switchers and nonswitchers [IRR for lamotrigine 1.00, 95% confidence interval (CI) 0.84-1.19; IRR for divalproex 1.02, 95% CI, 0.88-1.42]. Compared with nonswitchers, the phenytoin switch cohort had greater incidence of AED utilization changes (IRR 1.85, 95% CI 1.50-2.29). The switch versus nonswitch cohorts did not demonstrate differences in ED visits or hospitalizations for the studied AEDs (ERR for phenytoin 0.96, 95% CI 0.80-1.16; ERR for lamotrigine 0.97, 95% CI 0.80-1.17; ERR for divalproex 0.83, 95% CI 0.66-1.06). SIGNIFICANCE: Brand to generic switching of phenytoin was not associated with more clinical events but was associated with increased index drug discontinuations, dose changes, or therapy augmentations. Lamotrigine or divalproex brand to generic switching was not associated with increased incidence of events or utilization changes compared with patients remaining on the branded product. Changes in AED utilization may be more sensitive than ED visits and hospitalizations for detecting adverse outcomes.

Role of CD4+ and CD8+ T cells in clearance of primary pulmonary infection with Coxiella burnetii.

The mechanisms of the primary adaptive immune response to Coxiella burnetii are not well known. Following inoculation of the lungs with C. burnetii Nine Mile phase I (NMI), SCID mice developed pneumonia and splenomegaly and succumbed to infection, whereas wild-type mice cleared the infection by 24 days. SCID mice reconstituted with either CD4+ T cells or CD8+ T cells alone were able to control the infection, indicating that the presence of either type of T cells was sufficient to control infection, and B cells were not necessary for primary immunity. Similarly, wild-type mice depleted of either CD4+ T cells or CD8+ T cells controlled infections in their lungs, but these mice were highly susceptible if they were depleted of both types of T cells. However, compared to CD4+ T-cell-dependent protection, CD8+ T-cell-dependent protection resulted in less inflammation in the lungs and less growth of bacteria in the spleens.

Age-, sex-, and race-based differences among patients enrolled versus not enrolled in acute lung injury clinical trials.

OBJECTIVE: Little is known about the participation of racial/ethnic minorities, women, and the elderly into critical care clinical trials. We sought to characterize the representation of racial and ethnic minorities, women, and older patients in clinical trials of patients with acute lung injury and to determine the reasons for nonenrollment. DESIGN, SETTING, AND PATIENTS: We performed a cross-sectional analysis of pooled screening logs from 44 academic hospitals participating in three multicentered, randomized, controlled trials conducted by the Acute Respiratory Distress Syndrome Network from 1996 to 2005. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We calculated odds ratios of enrollment for age, sex, racial groups, and the odds ratio for the presence of each exclusion criterion by age, sex, and race adjusted for demographics, acute lung injury risk factor, study, and study center. A total of 10.4% of 17,459 screened patients with acute lung injury were enrolled. The median (range) enrollment by center was 15% (2% to 88%). Older patients of both sexes were less likely to be enrolled, but older women were more likely to be enrolled than older men. The adjusted odds ratio (95% confidence interval) for enrollment among men > or =75 yrs of age was 0.59 (0.45 to 0.77) and for women > or =75 yrs of age was 0.45 (0.32 to 0.62) compared with men <35 yrs of age. There were no differences in the likelihood of enrollment among all racial/ethnic groups. Older patients and men were less likely to be enrolled because of medical comorbidity. Among all patients who were not enrolled, black patients and their families refused participation more often than white patients. CONCLUSIONS: Older patients are less likely to be enrolled in acute lung injury clinical trials. There is no evidence that women or racial/ethnic minorities are underrepresented in acute lung injury clinical trials.

Targeting the Extrinsic Pathway of Hepatocyte Apoptosis Promotes Clearance of Plasmodium Liver Infection.

Plasmodium sporozoites infect the liver and develop into exoerythrocytic merozoites that initiate blood-stage disease. The hepatocyte molecular pathways that permit or abrogate parasite replication and merozoite formation have not been thoroughly explored, and a deeper understanding may identify therapeutic strategies to mitigate malaria. Cellular inhibitor of apoptosis (cIAP) proteins regulate cell survival and are co-opted by intracellular pathogens to support development. Here, we show that cIAP1 levels are upregulated during Plasmodium liver infection and that genetic or pharmacological targeting of cIAPs using clinical-stage antagonists preferentially kills infected hepatocytes and promotes immunity. Using gene-targeted mice, the mechanism was defined as TNF-TNFR1-mediated apoptosis via caspases 3 and 8 to clear parasites. This study reveals the importance of cIAPs to Plasmodium infection and demonstrates that host-directed antimalarial drugs can eliminate liver parasites and induce immunity while likely providing a high barrier to resistance in the parasite.

Racial and ethnic disparities in mortality from acute lung injury.

OBJECTIVE: Little is known about the influence of race and ethnicity on mortality from acute lung injury (ALI). We sought to determine whether black race or Hispanic ethnicity is independently associated with mortality among patients with ALI. DESIGN: Retrospective cohort study of patients enrolled in the Acute Respiratory Distress Syndrome Network randomized controlled trials. SETTING: Adult intensive care units participating in the Acute Respiratory Distress Syndrome Network trials. PATIENTS: A total of 2362 mechanically ventilated patients (1715 white, 449 black, and 198 Hispanic) with ALI. MEASUREMENTS AND MAIN RESULTS: The primary outcome was 60-day mortality. A secondary outcome was number of ventilator-free days. Crude mortality was 33% for both blacks and Hispanics compared with 27% for whites (p = 0.02). After adjusting for demographic and clinical covariates, the association between race/ethnicity and mortality persisted (odds ratio [OR] = 1.42; 95% confidence interval [CI] 1.10-1.84 for blacks; OR = 1.94; 95% CI, 1.36-2.77 for Hispanics; OR = 1.00 for whites). After adjustment for severity of illness (Acute Physiology Score), black race was no longer significantly associated with mortality (OR = 1.25; 95% CI, 0.95-1.66), whereas the association with Hispanic ethnicity persisted (OR = 2.00; 95% CI, 1.37-2.90). Hispanics had significantly fewer ventilator-free days compared with whites after adjustment for demographic and clinical covariates (mean difference in days = -2.3; 95% CI -3.90 to -0.70). CONCLUSIONS: Black and Hispanic patients with ALI have a significantly higher risk of death compared with white patients. This increased risk seemed to be mediated by increased severity of illness at presentation for blacks, but was unexplained among Hispanics.

Recent trends in acute lung injury mortality: 1996-2005.

OBJECTIVE: Studies from single centers have suggested that mortality from acute lung injury (ALI) has declined over time. However, recent trends in ALI mortality from centers across the United States are unknown. We sought to determine whether recent advances in the treatment of ALI and related critical illnesses have resulted in decreased mortality from ALI. DESIGN: Retrospective cohort study of patients enrolled in the Acute Respiratory Distress Syndrome (ARDS) Network randomized controlled trials. SETTING: Adult intensive care units participating in the ARDS Network trials. PATIENTS: 2,451 mechanically ventilated patients with ALI enrolled in the ARDS Network randomized controlled trials between 1996 and 2005. MEASUREMENTS AND MAIN RESULTS: Crude mortality was 35% in 1996-1997 and declined during each subsequent time period to a low of 26% in 2004-2005 (test for trend p < 0.0005). After adjusting for demographic and clinical covariates, including receipt of lower tidal volume ventilation and severity of illness, the temporal trend persisted (test for trend p = 0.002). When analyzed by individual causes of lung injury, there were not any statistically significant temporal trends in 60-day mortality for the most common causes of lung injury (pneumonia, sepsis, aspiration, and trauma). CONCLUSIONS: Over the past decade, there seems to be a clear temporal improvement in survival among patients with ALI treated at ARDS Network centers. Our findings strongly suggest that other advancements in critical care, aside from lower tidal volume ventilation, accounted for this improvement in mortality.