Bi-allelic SNAPC4 variants dysregulate global alternative splicing and lead to neuroregression and progressive spastic paraparesis.

The vast majority of human genes encode multiple isoforms through alternative splicing, and the temporal and spatial regulation of those isoforms is critical for organismal development and function. The spliceosome, which regulates and executes splicing reactions, is primarily composed of small nuclear ribonucleoproteins (snRNPs) that consist of small nuclear RNAs (snRNAs) and protein subunits. snRNA gene transcription is initiated by the snRNA-activating protein complex (SNAPc). Here, we report ten individuals, from eight families, with bi-allelic, deleterious SNAPC4 variants. SNAPC4 encoded one of the five SNAPc subunits that is critical for DNA binding. Most affected individuals presented with delayed motor development and developmental regression after the first year of life, followed by progressive spasticity that led to gait alterations, paraparesis, and oromotor dysfunction. Most individuals had cerebral, cerebellar, or basal ganglia volume loss by brain MRI. In the available cells from affected individuals, SNAPC4 abundance was decreased compared to unaffected controls, suggesting that the bi-allelic variants affect SNAPC4 accumulation. The depletion of SNAPC4 levels in HeLa cell lines via genomic editing led to decreased snRNA expression and global dysregulation of alternative splicing. Analysis of available fibroblasts from affected individuals showed decreased snRNA expression and global dysregulation of alternative splicing compared to unaffected cells. Altogether, these data suggest that these bi-allelic SNAPC4 variants result in loss of function and underlie the neuroregression and progressive spasticity in these affected individuals.

The Use of Opioids in the Management of Chronic Pain: Synopsis of the 2022 Updated U.S. Department of Veterans Affairs and U.S. Department of Defense Clinical Practice Guideline.

DESCRIPTION: In May 2022, leadership within the U.S. Department of Veterans Affairs (VA) and U.S. Department of Defense (DoD) approved a joint clinical practice guideline for the use of opioids when managing chronic pain. This synopsis summarizes the recommendations that the authors believe are the most important to highlight. METHODS: In December 2020, the VA/DoD Evidence-Based Practice Work Group assembled a team to update the 2017 VA/DoD Clinical Practice Guideline for Opioid Therapy for Chronic Pain. The guideline development team included clinical stakeholders and conformed to the National Academy of Medicine's tenets for trustworthy clinical practice guidelines. The guideline team developed key questions to guide a systematic evidence review that was done by an independent third party and distilled 20 recommendations for care using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. The guideline team also created 3 one-page algorithms to help guide clinical decision making. This synopsis presents the recommendations and highlights selected recommendations on the basis of clinical relevance. RECOMMENDATIONS: This guideline is intended for clinicians who may be considering opioid therapy to manage patients with chronic pain. This synopsis reviews updated recommendations for the initiation and continuation of opioid therapy; dose, duration, and taper of opioids; screening, assessment, and evaluation; and risk mitigation. New additions are highlighted, including recommendations about the use of buprenorphine instead of full agonist opioids; assessing for behavioral health conditions and factors associated with higher risk for harm, such as pain catastrophizing; and the use of pain and opioid education to reduce the risk for prolonged opioid use for postsurgical pain.

Diagnosis and management of glycogen storage disease type IV, including adult polyglucosan body disease: A clinical practice resource.

Glycogen storage disease type IV (GSD IV) is an ultra-rare autosomal recessive disorder caused by pathogenic variants in GBE1 which results in reduced or deficient glycogen branching enzyme activity. Consequently, glycogen synthesis is impaired and leads to accumulation of poorly branched glycogen known as polyglucosan. GSD IV is characterized by a remarkable degree of phenotypic heterogeneity with presentations in utero, during infancy, early childhood, adolescence, or middle to late adulthood. The clinical continuum encompasses hepatic, cardiac, muscular, and neurologic manifestations that range in severity. The adult-onset form of GSD IV, referred to as adult polyglucosan body disease (APBD), is a neurodegenerative disease characterized by neurogenic bladder, spastic paraparesis, and peripheral neuropathy. There are currently no consensus guidelines for the diagnosis and management of these patients, resulting in high rates of misdiagnosis, delayed diagnosis, and lack of standardized clinical care. To address this, a group of experts from the United States developed a set of recommendations for the diagnosis and management of all clinical phenotypes of GSD IV, including APBD, to support clinicians and caregivers who provide long-term care for individuals with GSD IV. The educational resource includes practical steps to confirm a GSD IV diagnosis and best practices for medical management, including (a) imaging of the liver, heart, skeletal muscle, brain, and spine, (b) functional and neuromusculoskeletal assessments, (c) laboratory investigations, (d) liver and heart transplantation, and (e) long-term follow-up care. Remaining knowledge gaps are detailed to emphasize areas for improvement and future research.

Pre-implementation formative evaluation of cooperative pain education and self-management expanding treatment for real-world access: A pragmatic pain trial.

OBJECTIVE: Cognitive behavioral therapy for chronic pain (CBT-CP) is an evidence-based treatment for improving functioning and pain intensity for people with chronic pain with extensive evidence of effectiveness. However, there has been relatively little investigation of the factors associated with successful implementation and uptake of CBT-CP, particularly clinician and system level factors. This formative evaluation examined barriers and facilitators to the successful implementation and uptake of CBT-CP from the perspective of CBT-CP clinicians and referring primary care clinicians. METHODS: Qualitative interviews guided by the Consolidated Framework for Implementation Research were conducted at nine geographically diverse Veterans Affairs sites as part of a pragmatic clinical trial comparing synchronous, clinician-delivered CBT-CP and remotely delivered, technology-assisted CBT-CP. Analysis was informed by a grounded theory approach. RESULTS: Twenty-six clinicians (CBT-CP clinicians = 17, primary care clinicians = 9) from nine VA medical centers participated in individual qualitative interviews conducted by telephone from April 2019 to August 2020. Four themes emerged in the qualitative interviews: (1) the complexity and variability of referral pathways across sites, (2) referring clinician's lack of knowledge about CBT-CP, (3) referring clinician's difficulty identifying suitable candidates for CBT-CP, and (4) preference for interventions that can be completed from home. CONCLUSIONS: This formative evaluation identified clinician and system barriers to widespread implementation of CBT-CP and allowed for refinement of the subsequent implementation of two forms of CBT-CP in an ongoing pragmatic trial. Identification of relative difference in barriers and facilitators in the two forms of CBT-CP may emerge more clearly in a pragmatic trial that evaluates how treatments perform in real-world settings and may provide important information to guide future system-wide implementation efforts.

Psychometric Evaluation of the Comfort from Companion Animals Scale in a Sexual and Gender Minority Sample.

Human-animal interaction research is growing in popularity and methodological rigor; however, there remains a need for psychometrically validated measures and inclusion of broader populations. This study addressed these gaps by reporting on the psychometric properties of the Comfort from Companion Animals Scale (CCAS) in a sample of sexual and gender minority emerging adults. Participants included 138 emerging adults between the ages of 18-21 years (M = 19.33 years, SD = 1.11; 38.4% racial/ethnic minority) who identified as a gender (48.6%) and/or sexual minority (98.6%) and who reported living with a companion animal in the past year. We utilized the following analytic methods: (a) confirmatory factor analyses to compare the unidimensional structure of the CCAS with the two alternative models, (b) multiple group analyses to test measurement invariance across demographic groups, and (c) structural equation models to evaluate construct validity. Preliminary analysis found that the majority of participants did not endorse the two lowest response options. To conduct invariance testing, we eliminated items 3, 5, and 8 from the CCAS and collapsed the lowest response options. The results of the confirmatory factor analysis supported the use of this revised unidimensional model. We found evidence of measurement invariance across gender identity, sexual orientation, and race/ethnicity groups. Construct validity was supported by comparing the CCAS with factors on the Pet Attachment and Life Impact Scale; the positive association between the CCAS and anxiety are discussed in the context of prior research. Overall, our findings highlight the importance of validating human-animal interaction measures across samples from diverse backgrounds. We recommend that future studies continue to test the CCAS and other measures of human-animal attachment among diverse samples to delineate which aspects of human-animal interaction may be most beneficial in promoting mental health in vulnerable populations.

Functional analysis of a de novo variant in the neurodevelopment and generalized epilepsy disease gene NBEA.

Neurobeachin (NBEA) was initially identified as a candidate gene for autism. Recently, variants in NBEA have been associated with neurodevelopmental delay and childhood epilepsy. Here, we report on a novel NBEA missense variant (c.5899G > A, p.Gly1967Arg) in the Domain of Unknown Function 1088 (DUF1088) identified in a child enrolled in the Undiagnosed Diseases Network (UDN), who presented with neurodevelopmental delay and seizures. Modeling of this variant in the Caenorhabditis elegans NBEA ortholog, sel-2, indicated that the variant was damaging to in vivo function as evidenced by altered cell fate determination and trafficking of potassium channels in neurons. The variant effect was indistinguishable from that of the reference null mutation suggesting that the variant is a strong hypomorph or a complete loss-of-function. Our experimental data provide strong support for the molecular diagnosis and pathogenicity of the NBEA p.Gly1967Arg variant and the importance of the DUF1088 for NBEA function.

Removal and Inactivation of an Enveloped Virus Surrogate by Iron Conventional Coagulation and Electrocoagulation.

It is imperative to understand the behavior of enveloped viruses during water treatment to better protect public health, especially in the light of evidence of detection of coronaviruses in wastewater. We report bench-scale experiments evaluating the extent and mechanisms of removal and/or inactivation of a coronavirus surrogate (ϕ6 bacteriophage) in water by conventional FeCl3 coagulation and Fe(0) electrocoagulation. Both coagulation methods achieved ∼5-log removal/inactivation of ϕ6 in 20 min. Enhanced removal was attributed to the high hydrophobicity of ϕ6 imparted by its characteristic phospholipid envelope. ϕ6 adhesion to freshly precipitated iron (hydr)oxide also led to envelope damage causing inactivation in both coagulation techniques. Fourier transform infrared spectroscopy revealed oxidative damages to ϕ6 lipids only for electrocoagulation consistent with electro-Fenton reactions. Monitoring ϕ6 dsRNA by a novel reverse transcription quantitative polymerase chain reaction (RT-qPCR) method quantified significantly lower viral removal/inactivation in water compared with the plaque assay demonstrating that relying solely on RT-qPCR assays may overstate human health risks arising from viruses. Transmission electron microscopy and computationally generated electron density maps of ϕ6 showed severe morphological damages to virus' envelope and loss of capsid volume accompanying coagulation. Both conventional and electro- coagulation appear to be highly effective in controlling enveloped viruses during surface water treatment.

The Resurrection of Interdisciplinary Pain Rehabilitation: Outcomes Across a Veterans Affairs Collaborative.

OBJECTIVE: Despite empirical support for interdisciplinary pain rehabilitation programs improving functioning and quality of life, access to this treatment approach has decreased dramatically over the last 20 years within the United States but has grown significantly in the Department of Veterans Affairs (VA). Between 2009 and 2019, VA pain rehabilitation programs accredited by the Commission on Accreditation of Rehabilitation Facilities increased 10-fold in the VA, expanding from two to 20. The aim of this collaborative observational evaluation was to examine patient outcomes across a subset of six programs at five sites. METHODS: Outcomes were assessed using agreed-upon measures of patient-reported pain intensity, pain interference across various domains, pain catastrophizing, and sleep. RESULTS: A total of 931 patients enrolled in the selected VA interdisciplinary pain programs, with 84.1% of participants completing the full course of treatment. Overall, all programs showed significant improvements from pretreatment to posttreatment in nearly all patient-reported outcomes. The effect sizes ranged from medium to large. Notably, the results demonstrate that positive outcomes were typical despite differences in structure and resources across programs. CONCLUSIONS: The adverse impacts of opioid use have highlighted the importance of chronic pain treatment approaches that emphasize team-based care focused on functional improvements. This study represents the first and largest analysis of outcomes across chronic pain rehabilitation programs and demonstrates the need for increased access to similar comprehensive approaches to pain management across the health care system. Further, it suggests that a variety of structures may be effective, encouraging flexibility in adopting this interdisciplinary approach.

A National Survey of Patient Completion of Cognitive Behavioral Therapy for Chronic Pain: The Role of Therapist Characteristics, Attempt Rates, and Modification.

The implementation of evidence-based psychotherapies, including patient-level measures such as penetration and rates of successfully completing a course of therapy, has received increasing attention. While much attention has been paid to the effect of patient-level factors on implementation, relatively little attention has been paid to therapist factors (e.g., professional training, experience). OBJECTIVE: The current study explores therapists' decisions to offer a particular evidence-based psychotherapy (cognitive behavioral therapy for chronic pain; CBT-CP), whether and how they modify CBT-CP, and the relationship between these decisions and patient completion rates. METHODS: The study utilized survey responses from 141 Veterans Affairs therapists certified in CBT-CP. RESULTS: Therapists reported attempting CBT-CP with a little less than one half of their patients with chronic pain (mean = 48.8%, s.d.=35.7). Therapist were generally split between reporting modifying CBT-CP for either very few or most of their patients. After controlling for therapist characteristics and modification, therapist-reported percentage of patients with attempted CBT-CP was positively associated with completion rates, t (111) = 4.57, p<.001. CONCLUSIONS: Therapists who attempt CBT-CP more frequently may experience better completion rates, perhaps due to practice effects or contextual factors that support both attempts and completion. Future research should examine this relationship using objective measures of attempt rates and completion.

Correction: KAT6A Syndrome: genotype-phenotype correlation in 76 patients with pathogenic KAT6A variants.

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

Knowledge and Practices Regarding Safe Household Cleaning and Disinfection for COVID-19 Prevention - United States, May 2020.

A recent report described a sharp increase in calls to poison centers related to exposures to cleaners and disinfectants since the onset of the coronavirus disease 2019 (COVID-19) pandemic (1). However, data describing cleaning and disinfection practices within household settings in the United States are limited, particularly concerning those practices intended to prevent transmission of SARS-CoV-2, the virus that causes COVID-19. To provide contextual and behavioral insight into the reported increase in poison center calls and to inform timely and relevant prevention strategies, an opt-in Internet panel survey of 502 U.S. adults was conducted in May 2020 to characterize knowledge and practices regarding household cleaning and disinfection during the COVID-19 pandemic. Knowledge gaps were identified in several areas, including safe preparation of cleaning and disinfectant solutions, use of recommended personal protective equipment when using cleaners and disinfectants, and safe storage of hand sanitizers, cleaners, and disinfectants. Thirty-nine percent of respondents reported engaging in nonrecommended high-risk practices with the intent of preventing SARS-CoV-2 transmission, such as washing food products with bleach, applying household cleaning or disinfectant products to bare skin, and intentionally inhaling or ingesting these products. Respondents who engaged in high-risk practices more frequently reported an adverse health effect that they believed was a result of using cleaners or disinfectants than did those who did not report engaging in these practices. Public messaging should continue to emphasize evidence-based, safe practices such as hand hygiene and recommended cleaning and disinfection of high-touch surfaces to prevent transmission of SARS-CoV-2 in household settings (2). Messaging should also emphasize avoidance of high-risk practices such as unsafe preparation of cleaning and disinfectant solutions, use of bleach on food products, application of household cleaning and disinfectant products to skin, and inhalation or ingestion of cleaners and disinfectants.

Co-Operative Pain Education and Self-management (COPES) Expanding Treatment for Real-World Access (ExTRA): Pragmatic Trial Protocol.

BACKGROUND: Given access barriers to cognitive behavioral therapy for chronic pain (CBT-CP), this pragmatic superiority trial will determine whether a remotely delivered CBT-CP intervention that addresses these barriers outperforms in-person and other synchronous forms of CBT-CP for veterans with musculoskeletal pain. DESIGN: This pragmatic trial compares an asynchronous form of CBT-CP that uses interactive voice response (IVR) to allow patients to participate from their home (IVR CBT-CP) with synchronous CBT-CP delivered by a Department of Veterans Affairs (VA) clinician. Veterans (n=764; 50% male) with chronic musculoskeletal pain throughout nine VA medical centers will participate. The primary outcome is pain interference after treatment (4 months). Secondary outcomes, including pain intensity, depression symptom severity, sleep, self-efficacy, and global impression of change, are also measured after treatment. Where possible, outcomes are collected via electronic health record extraction, with remaining measures collected via IVR calls to maintain blinding. Quantitative and qualitative process evaluation metrics will be collected to evaluate factors related to implementation. A budget impact analysis will be performed. SUMMARY: This pragmatic trial compares the outcomes, cost, and implementation of two forms of CBT-CP as delivered in the real-world setting. Findings from the trial can be used to guide future policy and implementation efforts related to these interventions and their use in the health system. If one of the interventions emerges as superior, resources can be directed to this modality. If both treatments are effective, patient preferences and health care system factors will take precedence when making referrals. Implications of COVID-19 on treatment provision and trial outcomes are discussed.

Whole Health Options and Pain Education (wHOPE): A Pragmatic Trial Comparing Whole Health Team vs Primary Care Group Education to Promote Nonpharmacological Strategies to Improve Pain, Functioning, and Quality of Life in Veterans-Rationale, Methods, and Implementation.

BACKGROUND: The Whole Health model of the U.S. Department of Veterans Affairs (VA) emphasizes holistic self-care and multimodal approaches to improve pain, functioning, and quality of life. wHOPE (Whole Health Options and Pain Education) seeks to be the first multisite pragmatic trial to establish evidence for the VA Whole Health model for chronic pain care. DESIGN: wHOPE is a pragmatic randomized controlled trial comparing a Whole Health Team (WHT) approach to Primary Care Group Education (PC-GE); both will be compared to Usual VA Primary Care (UPC). The WHT consists of a medical provider, a complementary and integrative health (CIH) provider, and a Whole Health coach, who collaborate with VA patients to create a Personalized Health Plan emphasizing CIH approaches to chronic pain management. The active comparator, PC-GE, is adapted group cognitive behavioral therapy for chronic pain. The first aim is to test whether the WHT approach is superior to PC-GE and whether both are superior to UPC in decreasing pain interference in functioning in 750 veterans with moderate to severe chronic pain (primary outcome). Secondary outcomes include changes in pain severity, quality of life, mental health symptoms, and use of nonpharmacological and pharmacological therapies for pain. Outcomes will be collected from the VA electronic health record and patient-reported data over 12 months of follow-up. Aim 2 consists of an implementation-focused process evaluation and budget impact analysis. SUMMARY: This trial is part of the Pain Management Collaboratory, which seeks to create national-level infrastructure to support evidence-based nonpharmacological pain management approaches for veterans and military service personnel.

A case of primary amebic meningoencephalitis caused by Naegleria fowleri in Bangladesh.

We present the first recognized case of primary amebic meningoencephalitis (PAM) caused by Naegleria fowleri in a 15-year-old male from Bangladesh. He performed daily nasal rinsing with untreated ground water and bathed in untreated ground water or river water, which likely exposed him to N. fowleri.

KAT6A Syndrome: genotype-phenotype correlation in 76 patients with pathogenic KAT6A variants.

PURPOSE: Pathogenic variants in KAT6A have recently been identified as a cause of syndromic developmental delay. Within 2 years, the number of patients identified with pathogenic KAT6A variants has rapidly expanded and the full extent and variability of the clinical phenotype has not been reported. METHODS: We obtained data for patients with KAT6A pathogenic variants through three sources: treating clinicians, an online family survey distributed through social media, and a literature review. RESULTS: We identified 52 unreported cases, bringing the total number of published cases to 76. Our results expand the genotypic spectrum of pathogenic variants to include missense and splicing mutations. We functionally validated a pathogenic splice-site variant and identified a likely hotspot location for de novo missense variants. The majority of clinical features in KAT6A syndrome have highly variable penetrance. For core features such as intellectual disability, speech delay, microcephaly, cardiac anomalies, and gastrointestinal complications, genotype- phenotype correlations show that late-truncating pathogenic variants (exons 16-17) are significantly more prevalent. We highlight novel associations, including an increased risk of gastrointestinal obstruction. CONCLUSION: Our data expand the genotypic and phenotypic spectrum for individuals with genetic pathogenic variants in KAT6A and we outline appropriate clinical management.

The utility of whole exome sequencing in diagnosing neurological disorders in adults from a highly consanguineous population.

There is increasing evidence that whole exome sequencing (WES) has a high diagnostic yield and is cost-efficient for individuals with neurological phenotypes. However, there is limited data on the use of WES in non-Western populations, including populations with a high rate of consanguinity. Retrospective chart review was performed on 24 adults with undiagnosed neurological symptoms evaluated in genetics and neurology clinics in a tertiary care facility on the Arabian Peninsula, and had WES between 2014 and 2016. Definitive diagnoses were made in 13/24 (54%) of cases. Of these, 5/13 (38%) revealed novel pathogenic variants. Of the known 19/24 (79%) consanguineous cases, diagnostic rate was slightly higher, 11/19 (58%) as compared to 2/5 (40%) among non-consanguineous cases. Autosomal recessive disorders comprised 10/13 (77%) of molecular diagnoses, all found to be due to homozygous pathogenic variants among consanguineous cases. WES in this cohort of adults with neurological symptoms had a high diagnostic rate likely due to high consanguinity rates in this population, as evidenced by the high diagnostic rate of homozygous pathogenic variants.

Loss-of-function alanyl-tRNA synthetase mutations cause an autosomal-recessive early-onset epileptic encephalopathy with persistent myelination defect.

Mutations in genes encoding aminoacyl-tRNA synthetases are known to cause leukodystrophies and genetic leukoencephalopathies-heritable disorders that result in white matter abnormalities in the central nervous system. Here we report three individuals (two siblings and an unrelated individual) with severe infantile epileptic encephalopathy, clubfoot, absent deep tendon reflexes, extrapyramidal symptoms, and persistently deficient myelination on MRI. Analysis by whole exome sequencing identified mutations in the nuclear-encoded alanyl-tRNA synthetase (AARS) in these two unrelated families: the two affected siblings are compound heterozygous for p.Lys81Thr and p.Arg751Gly AARS, and the single affected child is homozygous for p.Arg751Gly AARS. The two identified mutations were found to result in a significant reduction in function. Mutations in AARS were previously associated with an autosomal-dominant inherited form of axonal neuropathy, Charcot-Marie-Tooth disease type 2N (CMT2N). The autosomal-recessive AARS mutations identified in the individuals described here, however, cause a severe infantile epileptic encephalopathy with a central myelin defect and peripheral neuropathy, demonstrating that defects of alanyl-tRNA charging can result in a wide spectrum of disease manifestations.

Clinical Policy Recommendations from the VHA State-of-the-Art Conference on Non-Pharmacological Approaches to Chronic Musculoskeletal Pain.

As a large national healthcare system, Veterans Health Administration (VHA) is ideally suited to build on its work to date and develop a safe, evidence-based, and comprehensive approach to the care of chronic musculoskeletal pain conditions that de-emphasizes opioid use and emphasizes non-pharmacological strategies. The VHA Office of Health Services Research and Development (HSR&D) held a state-of-the-art (SOTA) conference titled "Non-pharmacological Approaches to Chronic Musculoskeletal Pain Management" in November 2016. Goals of the conference were (1) to establish consensus on the current state of evidence regarding non-pharmacological approaches to chronic musculoskeletal pain to inform VHA policy in this area and (2) to begin to identify priorities for the future VHA research agenda. Workgroups were established and asked to reach consensus recommendations on clinical and research priorities for the following treatment strategies: psychological/behavioral therapies, exercise/movement therapies, manual therapies, and models for delivering multimodal pain care. Participants in the SOTA identified nine non-pharmacological therapies with sufficient evidence to be implemented across the VHA system as part of pain care. Participants further recommended that effective integration of these non-pharmacological approaches across the VHA and especially into VHA primary care, pain care, and mental health settings should be a priority, and that these treatments should be offered early in the course of pain treatment and delivered in a team-based, multimodal treatment setting concurrently with active self-care and self-management approaches. In addition, we recommend that VHA leadership and policy makers systematically address the barriers to implementation of these approaches by expanding opportunities for clinician and veteran education on the effectiveness of these strategies; supporting and funding further research to determine optimal dosage, duration, sequencing, combination, and frequency of treatment; emphasizing multimodal care with rigorous evaluation grounded in team-based approaches to test integrated models of delivery and stepped-care approaches; and working to address socioeconomic and cultural barriers to veterans' access to non-pharmacological approaches.

Outbreaks Associated with Treated Recreational Water - United States, 2000-2014.

Outbreaks associated with exposure to treated recreational water can be caused by pathogens or chemicals in venues such as pools, hot tubs/spas, and interactive water play venues (i.e., water playgrounds). During 2000-2014, public health officials from 46 states and Puerto Rico reported 493 outbreaks associated with treated recreational water. These outbreaks resulted in at least 27,219 cases and eight deaths. Among the 363 outbreaks with a confirmed infectious etiology, 212 (58%) were caused by Cryptosporidium (which causes predominantly gastrointestinal illness), 57 (16%) by Legionella (which causes Legionnaires' disease, a severe pneumonia, and Pontiac fever, a milder illness with flu-like symptoms), and 47 (13%) by Pseudomonas (which causes folliculitis ["hot tub rash"] and otitis externa ["swimmers' ear"]). Investigations of the 363 outbreaks identified 24,453 cases; 21,766 (89%) were caused by Cryptosporidium, 920 (4%) by Pseudomonas, and 624 (3%) by Legionella. At least six of the eight reported deaths occurred in persons affected by outbreaks caused by Legionella. Hotels were the leading setting, associated with 157 (32%) of the 493 outbreaks. Overall, the outbreaks had a bimodal temporal distribution: 275 (56%) outbreaks started during June-August and 46 (9%) in March. Assessment of trends in the annual counts of outbreaks caused by Cryptosporidium, Legionella, or Pseudomonas indicate mixed progress in preventing transmission. Pathogens able to evade chlorine inactivation have become leading outbreak etiologies. The consequent outbreak and case counts and mortality underscore the utility of CDC's Model Aquatic Health Code (https://www.cdc.gov/mahc) to prevent outbreaks associated with treated recreational water.