Impact of the Hunga Tonga volcanic eruption on stratospheric composition.

The explosive eruption of the Hunga Tonga-Hunga Ha'apai (HTHH) volcano on 15 January 2022 injected more water vapor into the stratosphere and to higher altitudes than ever observed in the satellite era. Here, the evolution of the stratospherically injected water vapor is examined as a function of latitude, altitude, and time in the year following the eruption (February to December 2022), and perturbations to stratospheric chemical composition resulting from the increased sulfate aerosols and water vapor are identified and analyzed. The average calculated mass distribution of elevated water vapor between hemispheres is approximately 78% Southern Hemisphere (SH) and 22% Northern Hemisphere in 2022. Significant changes in stratospheric composition following the HTHH eruption are identified using observations from the Aura Microwave Limb Sounder satellite instrument. The dominant features in the monthly mean vertical profiles averaged over 15° latitude ranges are decreases in O3 (-14%) and HCl (-22%) at SH midlatitudes and increases in ClO (>100%) and HNO3 (43%) in the tropics, with peak pressure-level perturbations listed. Anomalies in column ozone from 1.2-100 hPa due to the HTHH eruption include widespread O3 reductions in SH midlatitudes and O3 increases in the tropics, with peak anomalies in 15° latitude-binned, monthly averages of approximately -7% and +5%, respectively, occurring in austral spring. Using a 3-dimensional chemistry-climate-aerosol model and observational tracer correlations, changes in stratospheric composition are found to be due to both dynamical and chemical factors.

Fully synthetic platform to rapidly generate tetravalent bispecific nanobody-based immunoglobulins.

Nanobodies bind a target antigen with a kinetic profile similar to a conventional antibody, but exist as a single heavy chain domain that can be readily multimerized to engage antigen via multiple interactions. Presently, most nanobodies are produced by immunizing camelids; however, platforms for animal-free production are growing in popularity. Here, we describe the development of a fully synthetic nanobody library based on an engineered human VH3-23 variable gene and a multispecific antibody-like format designed for biparatopic target engagement. To validate our library, we selected nanobodies against the SARS-CoV-2 receptor-binding domain and employed an on-yeast epitope binning strategy to rapidly map the specificities of the selected nanobodies. We then generated antibody-like molecules by replacing the VH and VL domains of a conventional antibody with two different nanobodies, designed as a molecular clamp to engage the receptor-binding domain biparatopically. The resulting bispecific tetra-nanobody immunoglobulins neutralized diverse SARS-CoV-2 variants with potencies similar to antibodies isolated from convalescent donors. Subsequent biochemical analyses confirmed the accuracy of the on-yeast epitope binning and structures of both individual nanobodies, and a tetra-nanobody immunoglobulin revealed that the intended mode of interaction had been achieved. This overall workflow is applicable to nearly any protein target and provides a blueprint for a modular workflow for the development of multispecific molecules.

Nipah virus-associated neuropathology in African green monkeys during acute disease and convalescence.

BACKGROUND: Nipah virus is an emerging zoonotic virus that causes severe respiratory disease and meningoencephalitis. The pathophysiology of Nipah virus meningoencephalitis is poorly understood. METHODS: We have collected the brains of African green monkeys during multiple Nipah virus, Bangladesh studies, resulting in 14 brains with Nipah virus-associated lesions. RESULTS: The lesions seen in the brain of African green monkeys infected with Nipah virus, Bangladesh were very similar to those observed in humans with Nipah virus, Malaysia infection. We observed viral RNA and antigen within neurons and endothelial cells, within encephalitis foci and in uninflamed portions of the CNS. CD8+ T cells had a consistently high prevalence in CNS lesions. We developed a UNet model for quantifying and visualizing inflammation in the brain in a high-throughput and unbiased manner. While CD8+ T cells had a consistently high prevalence in CNS lesions, the model revealed that CD68+ cells were numerically the immune cell with the highest prevalence in the CNS of NiV-infected animals. CONCLUSION: Our study provides an in-depth analysis on Nipah virus infection in the brains of primates, and similarities between lesions in patients and the animals in our study validate this model.

Insulin receptor signalling in PDGFRß-expressing cells influences systemic metabolism and negatively impacts lipid storage.

Pericytes are vascular mural cells that support the microvasculature; their dysfunction contributes to diabetic retinopathy and has been linked to obesity in humans. To explore the role of pericyte insulin signalling on systemic metabolism we utilised male mice from our previously described PIR-/- (PIRKO) mouse line which has insulin receptor (Insr) knockout in PDGFRß-expressing cells. These animals exhibit systemic insulin resistance from as early as 8-weeks of age, despite no change in body weight or activity level, and show altered body composition and hepatosteatosis. When challenged with high fat diet, PIR-/- remain insulin resistant but are protected from weight gain with reduced adipose tissue expansion across all depots and altered adipose morphology. Exhibiting parallels with the metabolically-obese-normal-weight (MONW) human phenotype, the PIR-/- line underlines the importance of pericyte biology in the development of both diabetes and obesity and establishes the angiopoietin (Ang)/Tie signalling pathway as a focus for future research.

Reconstructing curcumin biosynthesis in yeast reveals the implication of caffeoyl-shikimate esterase in phenylpropanoid metabolic flux.

Curcumin is a polyphenolic natural product from the roots of turmeric (Curcuma longa). It has been a popular coloring and flavoring agent in food industries with known health benefits. The conventional phenylpropanoid pathway is known to proceed from phenylalanine via p-coumaroyl-CoA intermediate. Although hydroxycinnamoyl-CoA: shikimate hydroxycinnamoyl transferase (HCT) plays a key catalysis in the biosynthesis of phenylpropanoid products at the downstream of p-coumaric acid, a recent discovery of caffeoyl-shikimate esterase (CSE) showed that an alternative pathway exists. Here, the biosynthetic efficiency of the conventional and the alternative pathway in producing feruloyl-CoA was examined using curcumin production in yeast. A novel modular multiplex genome-edit (MMG)-CRISPR platform was developed to facilitate rapid integrations of up to eight genes into the yeast genome in two steps. Using this MMG-CRISPR platform and metabolic engineering strategies, the alternative CSE phenylpropanoid pathway consistently showed higher titers (2-19 folds) of curcumin production than the conventional pathway in engineered yeast strains. In shake flask cultures using a synthetic minimal medium without phenylalanine, the curcumin production titer reached up to 1.5 mg/L, which is three orders of magnitude (∼4800-fold) improvement over non-engineered base strain. This is the first demonstration of de novo curcumin biosynthesis in yeast. Our work shows the critical role of CSE in improving the metabolic flux in yeast towards the phenylpropanoid biosynthetic pathway. In addition, we showcased the convenience and reliability of modular multiplex CRISPR/Cas9 genome editing in constructing complex synthetic pathways in yeast.

Update on ischemic hepatitis.

PURPOSE OF REVIEW: Ischemic hepatitis (IH) refers to diffuse liver injury secondary to hypoperfusion. The condition is usually seen in the critical care setting and is associated with significant mortality. IH typically occurs in the setting of systemic hypotension superimposed on some form of underlying cardiac dysfunction. This review aims to report what is known and what is new about the etiology, pathophysiology, and clinical features associated with IH. RECENT FINDINGS: In recent years, studies on IH have largely confirmed earlier reports regarding etiologies, comorbid conditions, and associated mortality. Recent study has also shed light on the potential treatment of IH with N -acetyl-cysteine (NAC). SUMMARY: IH is typically associated with underlying cardiac disease, and patients with IH have a very high mortality rate. Treatment remains largely supportive, although the utility of agents such as NAC are being explored.

Two Outbreaks of Legionnaires Disease Associated with Outdoor Hot Tubs for Private Use - Two Cruise Ships, November 2022-July 2024.

Legionnaires disease is a serious pneumonia caused by Legionella bacteria. During November 2022-June 2024, CDC was notified of 12 cases of Legionnaires disease among travelers on two cruise ships; eight on cruise ship A and four on cruise ship B. CDC, in collaboration with the cruise lines, initiated investigations to ascertain the potential sources of on-board exposure after notification of the second potentially associated case for each ship. Epidemiologic data collected from patient interviews and environmental assessment and sampling results identified private hot tubs on selected cabin balconies as the most likely exposure source. To minimize Legionella growth, both cruise lines modified the operation and maintenance of these devices by removing the heating elements, draining water between uses, and increasing the frequency of hyperchlorination and cleaning. Hot tubs offer favorable conditions for Legionella growth and transmission when maintained and operated inadequately, regardless of location. Private hot tubs on cruise ships are not subject to the same maintenance requirements as are public hot tubs in common areas. Given the range of hot tub-type devices offered as amenities across the cruise industry, to reduce risk for Legionella growth and transmission, it is important for cruise ship water management program staff members to inventory and assess private balcony hot tubs and adapt public hot tub maintenance and operations protocols for use on private outdoor hot tubs.

Interests and Barriers to Medical Students Participation in a Dedicated Global Surgery Curriculum.

INTRODUCTION: Despite many institutions establishing global surgery (GS) programs to support clinical care and education in resource-limited settings, few have established a specific curriculum in GS. This study's objective was to assess medical student interest in such a curriculum and prospects for future careers in GS/global health (GH), and to define the barriers to pursuing an international rotation. METHODS: We conducted an anonymous online survey of all 495 medical students at a major academic medical center in the mid-South that collected demographic data, country of origin, interest in a GS/GH elective, and barriers to pursuing a GS/GH rotation abroad. The data were analyzed using SPSS software. RESULTS: Prior international experience increased the likelihood of a student's involvement in GS/GH and more preclinical (years 1 & 2) students (90%) than clinical students. (years 3 & 4) (70%) felt strongly about the value of a GS/GH experience. Of the 163 students who completed the survey, 80% expressed interest in a GS/GH elective, with preclinical students expressing more interest (90%) than clinical students (71%). This interest strongly correlated with an interest in pursuing a career in GH (94%) and/or GS (100%). Identified barriers to engagement in a GS/GH experience abroad included financing (74%), scheduling (58%), family obligations (23%), and personal safety (19%). CONCLUSIONS: The students we surveyed were very interested in a GS/GH curriculum that included a rotation abroad, especially if they were to receive financial support. Preclinical students expressed more willingness to self-fund such experiences. The findings of this survey further strengthen the need to incorporate GS/GH in medical school curricula.

Consumption responses to sweetened beverage taxes by household income in four U.S. cities.

Taxes on sweetened beverages have become an important policy response to growing obesity rates and the prevalence of type 2 diabetes in the U.S. and other nations. Since 2015, eight U.S. cities have implemented these taxes, but so far direct evidence of their impacts on household purchasing behavior is scarce. Of particular interest to many researchers and policy makers is the response of lower-income consumers to these taxes, both because they have higher sweetened beverage consumption on average and because of concerns that sweetened beverage taxes are regressive. This project investigates the income-stratified household response to SSB taxes using a data set containing the purchasing behavior of approximately 400 households in the cities of Seattle, San Francisco, Oakland, and Philadelphia, all of which have recently introduced beverage taxes. Using doubly-robust estimation of dynamic and heterogeneous treatment effects relative to a propensity-matched set of households in three comparison cities, we find that households in taxed cities experience increased prices and reduce their purchases of those beverages, with no evidence of cross-border shopping. We further find differential tax impacts by income level, with lower-income households (households with income <200% of the federal poverty line for their size) reducing their purchases of taxed beverages by nearly 50% - more than double the 18% reduction found in higher-income households (households with income >400% of the federal poverty line for their size). Our finding that lower-income households decrease their consumption more than twice as much as higher-income households suggests that these taxes may reduce health disparities and promote population health.

Mast cell distribution and prevalence in the murine urinary bladder.

BACKGROUND: Mast cells have been implicated in the pathology of various urinary bladder disorders. However, the distribution of mast cells throughout urinary bladder tissue remains uncertain despite mast cell prevalence being relatively well-defined. Using a mouse tissue model, this study aims to characterise the prevalence and distribution of mast cells throughout the urinary bladder. METHODS: Bladder tissues were collected from six C57BL/6J female mice. Mast cell prevalence was quantified by flow cytometry, based on the expression of the following characteristic markers: CD45, CD117 and FcɛRIα. The toluidine blue stain assessed mast cell distribution, size, and proximity to vasculature. A repeated measures one-way ANOVA was used to evaluate the density of mast cells between the discrete layers of the urinary bladder, and an ordinary one-way ANOVA was used to assess potential differences between mast cell size across the urinary bladder wall. RESULTS: It was determined that mast cells compose less than 4% of all live leukocytes in the urinary bladder. They were also found to be more prominent in the lamina propria and detrusor muscle layers, compared to the urothelium and adventitia. In addition, 20.89% of mast cells were located near vasculature, which may be an important factor in consideration of their function and potential to contribute to various bladder pathologies, such as cystitis or overactive bladder. CONCLUSION: These findings provide a baseline understanding of mast cell prevalence and distribution throughout the urinary bladder.

Method for the production of a compact source of atomic line spectra in the vacuum ultraviolet.

Atomic emission spectra provide a means to identify and to gain insight into the electronic structure of emitting or absorbing matter. Detailed procedures are provided for the construction of low-pressure electrodeless discharge lamps that yield targeted emission in the vacuum ultraviolet for the spectroscopic study of water vapor and halogen species aboard an array of airborne observation platforms in the upper atmosphere, as well as in laboratory environments. While specific to the production of Lyman-alpha, atomic chlorine, and atomic bromine emissions in this study, the configuration of the lamps and their interchangeability with respect to operation lend these procedures to constructing sources engaging a wide selection of atomic and molecular spectra with straightforward modifications. The features and limitations of each type of lamp are discussed, as well as methods to improve spectral purity and factors affecting operational lifetime.

COVID-19 Pandemic Increases in Nursing-Sensitive Quality Indicators.

BACKGROUND: The pandemic profoundly stressed practicing nurses and could have thereby affected trends in nursing-sensitive quality indicators (NSIs), measures that detect changes in patient health status directly affected by nursing care. OBJECTIVES: The aim of the study was to determine if NSIs have worsened in response to the pandemic and then returned to prepandemic levels using data from 2019 through 2022. METHODS: We conducted a cross-sectional descriptive study of annual trends, examining unit data from the National Database of Nursing Quality Indicators (NDNQI) from 2019 through 2022 for five indicators: rates of falls, central line-associated bloodstream infections (CLABSI), catheter-associated urinary tract infections (CAUTI), hospital-acquired pressure injuries (HAPI), and ventilator-associated events (VAE). The NDNQI is the largest repository of nursing quality indicators, which are derived from patient-level events, reported at the nursing unit level, and submitted quarterly by over 2,000 member hospitals. Adult medical-surgical or critical care inpatient nursing units with complete data for the 4 years were included, with samples ranging from 456 to 5,818 nursing units in 2,346 hospitals. Analysis of variance was conducted by comparing the 2019 rates to each subsequent year. RESULTS: In decreasing order of prevalence, the mean prepandemic rates were 6.58 VAE per 1,000 ventilator days (critical care only), 2.41 HAPI per 1,000 device days, 2.20 falls per 1,000 patient days, 0.96 CAUTI per 1,000 catheter days, and 0.68 CLABSI per 1,000 central line days for medical-surgical and critical care units combined. The rates for all five nurse-sensitive indicators increased significantly beginning in 2020 and have begun to decline but have not returned to baseline by 2022. The maximum rate was observed in 2020 for falls and 2021 for the remaining indicators. These increases to the maximum ranged from a 12% increase in CAUTI to 49% for CLABSI. DISCUSSION: NSIs increased during the pandemic and are now returning to baseline. The pandemic underscored the importance of nursing practice. The pandemic's enduring negative effects on the nursing workforce must be addressed to preserve patient safety.

Pseudoendocrine sarcoma: a rare new entity with unique radiologic and pathologic/molecular characteristics.

Pseudoendocrine sarcoma is a rare, recently described intermediate grade sarcoma of uncertain phenotype that most commonly affects the paraspinal location in older patients with a distinctive endocrine/paraganglioma-like morphology and unique CTNNB1 point mutation. While these tumors appear as epithelial or even benign endocrine tumors, these lack markers for such and are highlighted by nuclear expression of beta-catenin. This case is the first among the previously reported only twenty-five cases of this entity, including one original series and a few case reports, to correlate the radiologic imaging with the pathologic features. Furthermore, this case illustrates the oldest-to-date patient with this unique location as a palpable painful chest wall/paraspinal location, with new morphologic observations and, finally, this is only the second case to have this specific CTNNB1 hotspot point mutation for this rare entity.

Associations between hospital organizational features, person-centred care and nurse-sensitive outcomes for persons with dementia in acute care: A systematic literature review.

AIM(S): The aim of this systematic literature review was to determine the extent and quality of quantitative evidence regarding associations between hospital organizational features, person-centred care (PCC) and nursing-sensitive outcomes among persons with dementia in the acute care setting. DESIGN: Systematic review. METHODS: Key terms were utilized to guide searches in four databases. The two reviewers deduplicated articles and came to a consensus for the final sample using inclusion and exclusion criteria. DATA SOURCES: MEDLINE/OVID, CINHAL, COCHRANE and WEB OF SCIENCE. RESULTS: There were 10 studies included. PCC was associated with better outcomes for persons with dementia (i.e. decreased restraint use, decreased length of stay, increased involvement with families and the patient, and increased nurse confidence and competence in caring for this population). Of the studies, none explicitly identified an association between nursing-sensitive outcomes, PCC and hospital organizational features in the acute care setting among persons with dementia. CONCLUSION: This review highlights a clinically significant gap in knowledge regarding associations between hospital organizational features, PCC and nursing sensitive outcomes. The impact of face-to-face dementia competency training as a standard practice among acute care facilities, the importance of leadership engagement, support and involvement to improve nurse confidence and competence in caring for persons with dementia needs to be explored. IMPACT STATEMENT: These findings support future research to understand the relationship between organization features and patient-centred care and how these collectively impact nursing-sensitive outcomes, specifically in persons with dementia in acute care settings.

"They're scared that somebody's gonna judge them": Female African American youth in foster care's perspectives on sexual and reproductive health communication with caregivers.

BACKGROUND: Obtaining accurate information is critical for youth's sexual and reproductive health (SRH). Youth not in foster care often learn about SRH from their biological parents. Separated from their biological parents, youth in care depend on healthcare providers and caregivers for SRH information. However, they often receive insufficient information and feel unsupported in meeting their needs for SRH information. PURPOSE: This study explored female African American adolescents in foster care's perspectives on effective SRH communication with caregivers to help them avoid sexual risks. METHODS: A qualitative study was conducted using semi-structured interviews. We used purposive sampling to recruit 16 adolescents aged 18 to 20 years old with a history of foster care placement. The transcribed interviews underwent inductive thematic analysis. The Positive Youth Development theory underpinned this research. RESULTS: Two prominent themes emerged: establishing a relationship and preferred communication approach. Youth reported that for caregivers to engage in effective SRH communication, they must first establish a relationship by being aware of the youth's childhood trauma, building trust, having patience, and being vulnerable. Youth also appreciated caregivers who ensured comfortability and were honest and straightforward. DISCUSSION: Caregivers should be trained on adverse childhood experiences, trauma-informed approaches, SRH knowledge, and communication. IMPLICATIONS TO PRACTICE: Healthcare providers should make use of the time spent with youth and discuss SRH topics during clinical encounters. This time spent with youth may be their only chance to obtain accurate SRH information. Youth's perspectives regarding communication about SRH should be implemented in future SRH communication interventions.

Nurses' moral distress and leadership communication in hospitals serving Black patients during COVID-19.

BACKGROUND: Poorer leadership communication during COVID-19 may have contributed to the moral distress of nurses in hospitals where Black patients predominantly access their care (BSH). PURPOSE: To compare nurse moral distress and leadership communication during the COVID-19 pandemic in hospitals that serve disproportionately many or few patients of Black race. METHODS: In a national hospital sample (n = 90), nurse survey data were collected (March 2021). Nurse moral distress was analyzed in linear regression models. The key covariates were BSH category (Medicare Black patient percentage) and leadership communication. DISCUSSION: Nurses in high-BSH had significantly greater moral distress and more difficulty accessing personal protective equipment than nurses in low-BSH. The percentage of nurses in high-BSHs with high moral distress was double that of nurses in low-BSHs. Poorer leadership communication in BSHs accounted for the nurses' greater moral distress. CONCLUSION: Policies should improve leadership communication, mitigate distress, and support nurses in under-resourced settings.

A philosophical exploration of rural health and nursing based on an undergraduate United States-Australian collaboration through the lens of 'positionality'.

Growing nursing workforce maldistributions impede rural healthcare access globally. In-depth exploration of underlying philosophical ideas about rural health in nursing curricular could support recruitment and retention of nurses who are well positioned to support and advocated for health care and services relevant to their communities. Through a lens of positionality, the purpose of this paper is to explore rural health and nursing within the United States and Australia from the perspective of undergraduate students. Recognizing that both countries have 'first world' health services, issues of access to services associated with systemic and structural biases were significant features identified by participants. Their perceptions were supported by discussion with attendees of the 26th International Nursing Philosophy Conference from several countries, during a presentation titled 'What is different about rural health nursing: A philosophical exploration.' This international consistency suggests that systemic and structural biases are global phenomena. While exposure to rural health and rural nursing may be beneficial for recruitment, preparing nurses for rural practice requires more than educating students to complete clinical tasks. Uncovering collaboration, advocacy and policy development opportunities for nurses in rural communities could move the dial from recruiting rural nurses to fulfill immediate needs to retention of well-educated and highly skilled nurses. Building a stronger philosophical base for rural healthcare inclusive of all people, honouring their distinguishing characteristics such as age, gender, ethnicity, is long overdue. Positionality can inform how nurses across the globe relate to other countries' governments, cultures, norms, values, expectations, etc., which can influence the advancement of the profession and address social inequities among rural populations.

Decreasing Multiple Sclerosis Treatment Expenditures and Improving Quality at the Health System Level.

OBJECTIVE: This study was undertaken to evaluate a multicomponent health system intervention designed to reduce escalating disease-modifying treatment (DMT) expenditures and improve multiple sclerosis (MS) outcomes by increasing use of preferred formulary and highly effective DMTs (HETs). METHODS: We conducted a trend study of treatment utilization and expenditure outcomes prior to (2009-2011) and during (2012-2018) MS Treatment Optimization Program (MSTOP) implementation in Kaiser Permanente Southern California (KPSC) compared to a Kaiser Permanente region of similar size. Annual relapse rates (ARRs) were obtained from KPSC's electronic health records. RESULTS: Adherence to preferred formulary DMTs increased from 25.4% in 2011 to 72.2% in 2017 following MSTOP implementation in KPSC and 22.1% to 43.8%, respectively, in the comparator. KPSC's annual DMT expenditures in 2018 were less than in 2011 despite an 11.3% increase in DMT-treated members. The decline in average per patient per year of treatment expenditures from a peak of $43.1 K in 2014 to $26.3 K in 2018 in KPSC was greater than the comparator, which peaked at $52.1 K and declined to $40.0 K in 2018. Over the 7 years following initiation of MSTOP, cumulative MS DMT expenditures were $161.6 million less than the comparator. HET use increased to 62.5% of per patient treatment-years versus 32.4% in the comparator. This corresponded to a 69% decline in adjusted ARR (95% confidence interval = 64.1-73.2%; p < 0.0001) among DMT-treated patients in KPSC. INTERPRETATION: A novel, expert-led health system intervention reduced MS DMT expenditures despite rising prices while simultaneously reducing MS relapse rates. Our focus on health system progress toward meaningful, measurable targets could serve as a model to improve quality and affordability of MS care in other settings. ANN NEUROL 2022;92:164-172.

Blood-brain barrier penetration of non-replicating SARS-CoV-2 and S1 variants of concern induce neuroinflammation which is accentuated in a mouse model of Alzheimer's disease.

COVID-19 and especially Long COVID are associated with severe CNS symptoms and may place persons at risk to develop long-term cognitive impairments. Here, we show that two non-infective models of SARS-CoV-2 can cross the blood-brain barrier (BBB) and induce neuroinflammation, a major mechanism underpinning CNS and cognitive impairments, even in the absence of productive infection. The viral models cross the BBB by the mechanism of adsorptive transcytosis with the sugar N-acetylglucosamine being key. The delta and omicron variants cross the BB B faster than the other variants of concern, with peripheral tissue uptake rates also differing for the variants. Neuroinflammation induced by icv injection of S1 protein was greatly enhanced in young and especially in aged SAMP8 mice, a model of Alzheimer's disease, whereas sex and obesity had little effect.

Large Community Outbreak of Legionnaires Disease Potentially Associated with a Cooling Tower - Napa County, California, 2022.

Legionnaires disease is a serious infection acquired by inhalation of water droplets from human-made building water systems that contain Legionella bacteria. On July 11 and 12, 2022, Napa County Public Health (NCPH) in California received reports of three positive urinary antigen tests for Legionella pneumophila serogroup 1 in the town of Napa. By July 21, six Legionnaires disease cases had been confirmed among Napa County residents, compared with a baseline of one or two cases per year. NCPH requested assistance from the California Department of Public Health (CDPH) and CDC to aid in the investigations. Close temporal and geospatial clustering permitted a focused environmental sampling strategy of high-risk facilities which, coupled with whole genome sequencing results from samples and investigation of water system maintenance, facilitated potential linking of the outbreak with an environmental source. NCPH, with technical support from CDC and CDPH, instructed and monitored remediation practices for all environmental locations that tested positive for Legionella. The investigation response to this community outbreak illustrates the importance of interdisciplinary collaboration by public health agencies, laboratory support, timely communication with the public, and cooperation of managers of potentially implicated water systems. Timely identification of possible sources, sampling, and remediation of any facility testing positive for Legionella is crucial to interrupting further transmission.