Risk for Infection in Humans after Exposure to Birds Infected with Highly Pathogenic Avian Influenza A(H5N1) Virus, United States, 2022.

During February 7─September 3, 2022, a total of 39 US states experienced outbreaks of highly pathogenic avian influenza A(H5N1) virus in birds from commercial poultry farms and backyard flocks. Among persons exposed to infected birds, highly pathogenic avian influenza A(H5) viral RNA was detected in 1 respiratory specimen from 1 person.

Multistate Mumps Outbreak Originating from Asymptomatic Transmission at a Nebraska Wedding - Six States, August-October 2019.

In August 2019, 30 attendees at a Nebraska wedding developed mumps after being exposed to one asymptomatic index patient who was fully vaccinated according to Advisory Committee on Immunization Practices (ACIP) recommendations (1), resulting in a multistate outbreak. A public health investigation and response revealed epidemiologic links that extended from the index patient through secondary, tertiary, and quaternary patients and culminated in a measles-mumps-rubella (MMR) booster vaccination campaign in the local community where approximately half of the patients resided.

TREM2-activating antibodies abrogate the negative pleiotropic effects of the Alzheimer's disease variant Trem2R47H on murine myeloid cell function.

Triggering receptor expressed on myeloid cells 2 (TREM2) is an orphan immune receptor expressed on cells of myeloid lineage such as macrophages and microglia. The rare variant R47H TREM2 is associated with an increased risk for Alzheimer's disease, supporting the hypothesis that TREM2 loss of function may exacerbate disease progression. However, a complete knockout of the TREM2 gene in different genetic models of neurodegenerative diseases has been reported to result in both protective and deleterious effects on disease-related end points and myeloid cell function. Here, we describe a Trem2R47H transgenic mouse model and report that even in the absence of additional genetic perturbations, this variant clearly confers a loss of function on myeloid cells. The Trem2R47H variant-containing myeloid cells exhibited subtle defects in survival and migration and displayed an unexpected dysregulation of cytokine responses in a lipopolysaccharide challenge environment. These subtle phenotypic defects with a gradation in severity across genotypes were confirmed in whole-genome RNA-Seq analyses of WT, Trem2-/-, and Trem2R47H myeloid cells under challenge conditions. Of note, TREM2-activating antibodies that boost proximal signaling abrogated survival defects conferred by the variant and also modulated migration and cytokine responses in an antibody-, ligand-, and challenge-dependent manner. In some instances, these antibodies also boosted WT myeloid cell function. Our studies provide a first glimpse into the boost in myeloid cell function that can be achieved by pharmacological modulation of TREM2 activity that can potentially be ameliorative in neurodegenerative diseases such as Alzheimer's disease.

Campylobacteriosis Outbreak Associated with Contaminated Municipal Water Supply - Nebraska, 2017.

In March 2017, the Nebraska Department of Health and Human Services (NDHHS) and the Southwest Nebraska Public Health Department were notified of an apparent cluster of Campylobacter jejuni infections in city A and initiated an investigation. Overall, 39 cases were investigated, including six confirmed and 33 probable. Untreated, unboiled city A tap water (i.e., well water) was the only exposure significantly associated with illness (odds ratio [OR] = 7.84; 95% confidence interval [CI] = 1.69-36.36). City A is served by four untreated wells and an interconnected distribution system. Onsite investigations identified that a center pivot irrigation system intended to pump livestock wastewater from a nearby concentrated animal feeding operation onto adjacent farmland had malfunctioned, allowing excessive runoff to collect in a road ditch near two wells that supplied water to the city. These wells were promptly removed from service, after which no subsequent cases occurred. This coordinated response rapidly identified an important risk to city A's municipal water supply and provided the evidence needed to decommission the affected wells, with plans to build a new well to safely serve this community.

Successive Norovirus Outbreaks at an Event Center - Nebraska, October-November, 2017.

In October 2017, the Nebraska Department of Health and Human Services (NDHHS) was notified by a local health department of a gastrointestinal illness outbreak among attendees of a wedding reception at facility A, an event center. Shortly thereafter, state and local public health officials began receiving reports of similar gastrointestinal illness among attendees of subsequent facility A events. An investigation was initiated to identify cases, establish the cause, assess possible transmission routes, and provide control recommendations. Overall, 159 cases consistent with norovirus infection (three confirmed and 156 probable) were identified among employees of facility A and attendees of nine facility A events during October 27-November 18, 2017. The investigation revealed a public vomiting episode at the facility on October 27 and at least one employee involved with preparing and serving food who returned to work <24 hours after symptom resolution, suggesting that a combination of contaminated environmental surfaces and infected food handlers likely sustained the outbreak. Recommendations regarding sanitation and excluding ill employees were communicated to facility A management. However, facility A performed minimal environmental cleaning and did not exclude ill employees. Consequently, transmission continued. To prevent persistent norovirus outbreaks in similar settings, public health officials should ensure that involved facilities implement a comprehensive prevention strategy as early as possible that includes extensive sanitation and strict exclusion of ill food handlers for at least 48 hours after symptom resolution (1).

A TRPC5-regulated calcium signaling pathway controls dendrite patterning in the mammalian brain.

Transient receptor potential (TRP) channels have been implicated as sensors of diverse stimuli in mature neurons. However, developmental roles for TRP channels in the establishment of neuronal connectivity remain largely unexplored. Here, we identify an essential function for TRPC5, a member of the canonical TRP subfamily, in the regulation of dendrite patterning in the mammalian brain. Strikingly, TRPC5 knockout mice harbor long, highly branched granule neuron dendrites with impaired dendritic claw differentiation in the cerebellar cortex. In vivo RNAi analyses suggest that TRPC5 regulates dendrite morphogenesis in the cerebellar cortex in a cell-autonomous manner. Correlating with impaired dendrite patterning in the cerebellar cortex, behavioral analyses reveal that TRPC5 knockout mice have deficits in gait and motor coordination. Finally, we uncover the molecular basis of TRPC5's function in dendrite patterning. We identify the major protein kinase calcium/calmodulin-dependent kinase II ß (CaMKIIß) as a critical effector of TRPC5 function in neurons. Remarkably, TRPC5 forms a complex specifically with CaMKIIß, but not the closely related kinase CaMKIIα, and thereby induces the CaMKIIß-dependent phosphorylation of the ubiquitin ligase Cdc20-APC at the centrosome. Accordingly, centrosomal CaMKIIß signaling mediates the ability of TRPC5 to regulate dendrite morphogenesis in neurons. Our findings define a novel function for TRPC5 that couples calcium signaling to a ubiquitin ligase pathway at the centrosome and thereby orchestrates dendrite patterning and connectivity in the brain.

Notes from the Field: Acute Mercury Poisoning After Home Gold and Silver Smelting--Iowa, 2014.

In March 2014, a man, aged 59 years, who lived alone and had been using different smelting techniques viewed on the Internet to recover gold and silver from computer components, was evaluated at a local emergency department for shortness of breath, tremors, anorexia, and generalized weakness. During the smelting processes, he had used hydrogen peroxide, nitric acid, muriatic acid, and sulfuric acid purchased from local stores or Internet retailers. For protection, he wore a military gas mask of unknown type. The mask was used with filter cartridges, but their effectiveness against chemical fumes was not known.

Elucidation of the GSK3α Structure Informs the Design of Novel, Paralog-Selective Inhibitors.

Glycogen synthase kinase 3 (GSK3) remains a therapeutic target of interest for diverse clinical indications. However, one hurdle in the development of small molecule GSK3 inhibitors has been safety concerns related to pan-inhibition of both GSK3 paralogs, leading to activation of the Wnt/ß-catenin pathway and potential for aberrant cell proliferation. Development of GSK3α or GSK3ß paralog-selective inhibitors that could offer an improved safety profile has been reported but further advancement has been hampered by the lack of structural information for GSK3α. Here we report for the first time the crystal structure for GSK3α, both in apo form and bound to a paralog-selective inhibitor. Taking advantage of this new structural information, we describe the design and in vitro testing of novel compounds with up to ∼37-fold selectivity for GSK3α over GSK3ß with favorable drug-like properties. Furthermore, using chemoproteomics, we confirm that acute inhibition of GSK3α can lower tau phosphorylation at disease-relevant sites in vivo, with a high degree of selectivity over GSK3ß and other kinases. Altogether, our studies advance prior efforts to develop GSK3 inhibitors by describing GSK3α structure and novel GSK3α inhibitors with improved selectivity, potency, and activity in disease-relevant systems.

Longitudinal EEG model detects antisense oligonucleotide treatment effect and increased UBE3A in Angelman syndrome.

Angelman syndrome is a neurodevelopmental disorder caused by deficiency of the maternally inherited UBE3A gene in neurons. Antisense oligonucleotide therapies are under development to reinstate UBE3A protein production. Non-invasive biomarkers to detect target engagement and treatment response are needed to support clinical trials. Delta power measured in the scalp EEG is a reliable biomarker for Angelman syndrome but varies widely across individuals and throughout development, making detection of a treatment effect using single measurements challenging. We utilized a longitudinal dataset of 204 EEG recordings from 56 subjects with Angelman syndrome to develop a natural history model of delta (2-4 Hz) power, with predictors of age, elapsed time, and relative delta power at an initial recording. Using this model, we computed the sample and effect sizes needed to detect a treatment effect in a human clinical trial with 80% power. We applied the same model structure to a mouse model of Angelman syndrome (n = 41) to detect antisense oligonucleotide-mediated treatment effects on absolute delta activity and Ube3a expression. In humans, delta power at a second time point can be reliably predicted using the natural history model. In mice, a treatment effect can be detected after antisense oligonucleotide treatment targeting the Ube3a-antisense transcript through at least 8 weeks post-treatment (P < 1e-15). Deviations in delta power from the expected natural history correlated with Ube3a expression in the mouse model (P < 0.001). Deviations in delta power from a human natural history model in Angelman syndrome can detect antisense oligonucleotide-mediated improvement in Ube3a expression in Angelman syndrome mice and may be relevant for human clinical trials.

Aedes aegypti Identified in York, Nebraska, Through Routine Arboviral Surveillance-August-October 2019.

On August 27, 2019, Aedes aegypti mosquitoes were identified in a neighborhood located in York, NE, through routine arboviral surveillance. Expanded surveillance using traps and morphologic identification revealed 118 adult Ae. aegypti throughout the adjacent neighborhood, including identification from larval sampling. Our findings describe the first recorded Ae. aegypti introduction in Nebraska and provide evidence of a breeding mosquito population, which suggests suitable habitat and the risk of potential establishment, raising concerns about prevention of arboviral diseases in Nebraska.

GPR56-regulated granule cell adhesion is essential for rostral cerebellar development.

Mutations in GPR56, an orphan G-protein-coupled receptor (GPCR), cause bilateral frontoparietal polymicrogyria (BFPP), a disorder characterized by mental retardation, seizures, motor developmental delay, and ataxia. BFPP patients have structural abnormalities of the cerebral cortex, cerebellum, and pons. To shed light on the function of GPR56 and the anatomical and behavioral defects underlying BFPP, we analyzed the cerebellum of mice lacking this GPCR. Gpr56(-/-) mice display a severe malformation of the rostral cerebellum that develops perinatally. Defects involve fusion of adjacent lobules, disrupted layering of neurons and glia, and fragmentation of the pial basement membrane. At the age of defect onset, GPR56 expression is restricted specifically to developing granule cells in the rostral cerebellum, suggesting that GPR56 regulates properties of these cells. Indeed, granule cells from the rostral region of perinatal Gpr56(-/-) cerebella show loss of adhesion to extracellular matrix molecules of the pial basement membrane. Interference RNA-mediated knockdown of GPR56 recapitulates the loss of adhesion seen in knock-outs, and reexpression of GPR56 rescues the adhesion defect in knock-out granule cells. Loss of GPR56 does not affect cell proliferation, migration, or neurite outgrowth. These studies establish a novel role for GPR56 in the adhesion of developing neurons to basal lamina molecules and suggest that this adhesion is critical for maintenance of the pia and proper cerebellar morphogenesis.

The sensitivity of real-time PCR amplification targeting invasive Salmonella serovars in biological specimens.

BACKGROUND: PCR amplification for the detection of pathogens in biological material is generally considered a rapid and informative diagnostic technique. Invasive Salmonella serovars, which cause enteric fever, can be commonly cultured from the blood of infected patients. Yet, the isolation of invasive Salmonella serovars from blood is protracted and potentially insensitive. METHODS: We developed and optimised a novel multiplex three colour real-time PCR assay to detect specific target sequences in the genomes of Salmonella serovars Typhi and Paratyphi A. We performed the assay on DNA extracted from blood and bone marrow samples from culture positive and negative enteric fever patients. RESULTS: The assay was validated and demonstrated a high level of specificity and reproducibility under experimental conditions. All bone marrow samples tested positive for Salmonella, however, the sensitivity on blood samples was limited. The assay demonstrated an overall specificity of 100% (75/75) and sensitivity of 53.9% (69/128) on all biological samples. We then tested the PCR detection limit by performing bacterial counts after inoculation into blood culture bottles. CONCLUSIONS: Our findings corroborate previous clinical findings, whereby the bacterial load of S. Typhi in peripheral blood is low, often below detection by culture and, consequently, below detection by PCR. Whilst the assay may be utilised for environmental sampling or on differing biological samples, our data suggest that PCR performed directly on blood samples may be an unsuitable methodology and a potentially unachievable target for the routine diagnosis of enteric fever.

GPR56 regulates pial basement membrane integrity and cortical lamination.

GPR56 is a member of the family of adhesion G-protein-coupled receptors that have a large extracellular region containing a GPS (G-protein proteolytic site) domain. Loss-of-function mutations in the GPR56 gene cause a specific human brain malformation called bilateral frontoparietal polymicrogyria (BFPP). BFPP is a radiological diagnosis and its histopathology remains unclear. This study demonstrates that loss of the mouse Gpr56 gene leads to neuronal ectopia in the cerebral cortex, a cobblestone-like cortical malformation. There are four crucial events in the development of cobblestone cortex, namely defective pial basement membrane (BM), abnormal anchorage of radial glial endfeet, mislocalized Cajal-Retzius cells, and neuronal overmigration. By detailed time course analysis, we reveal that the leading causal events are likely the breaches in the pial BM. We show further that GPR56 is present in abundance in radial glial endfeet. Furthermore, a putative ligand of GPR56 is localized in the marginal zone or overlying extracellular matrix. These observations provide compelling evidence that GPR56 functions in regulating pial BM integrity during cortical development.

REDCap for Biocontainment Worker Symptom Monitoring.

The Ebola epidemic of 2014 demonstrated that outbreaks of high-consequence infectious diseases, even in remote parts of the world, can affect communities anywhere in the developed world and that every healthcare facility must be prepared to identify, isolate, and provide care for infected patients. The Nebraska Biocontainment Unit (NBU), located at Nebraska Medicine in Omaha, Nebraska, cared for 3 American citizens exposed in West Africa and confirmed with Ebola virus disease (EVD). Symptom monitoring of healthcare workers caring for these patients was implemented, which included twice daily contact to document the absence or presence of signs of fever or illness. This article describes the symptom monitoring experience of the NBU and local and state public health agencies. Based on lessons learned from that experience, we sought a more efficient solution to meet the needs of both the healthcare facility and public health authorities. REDCap, an open-source application used commonly by academic health centers, was used to develop an inexpensive symptom monitoring application that could reduce the burden of managing these activities, thus freeing up valuable time. Our pilot activities demonstrated that this novel use of REDCap holds promise for minimizing costs and resource demands associated with symptom monitoring while offering a more user-friendly experience for people being monitored and the officials managing the response.

Centers for Disease Control and Prevention's Temporary Epidemiology Field Assignee program: Supporting state and local preparedness in the wake of Ebola.

OBJECTIVES: The Centers for Disease Control and Prevention launched the Temporary Epidemiology Field Assignee (TEFA) Program to help state and local jurisdictions respond to the risk of Ebola virus importation during the 2014-2016 Ebola Outbreak in West Africa. We describe steps taken to launch the 2-year program, its outcomes and lessons learned. METHODS: State and local health departments submitted proposals for a TEFA to strengthen local capacity in four key public health preparedness areas: 1) epidemiology and surveillance, 2) health systems preparedness, 3) health communications, and 4) incident management. TEFAs and jurisdictions were selected through a competitive process. Descriptions of TEFA activities in their quarterly reports were reviewed to select illustrative examples for each preparedness area. RESULTS: Eleven TEFAs began in the fall of 2015, assigned to 7 states, 2 cities, 1 county and the District of Columbia. TEFAs strengthened epidemiologic capacity, investigating routine and major outbreaks in addition to implementing event-based and syndromic surveillance systems. They supported improvements in health communications, strengthened healthcare coalitions, and enhanced collaboration between local epidemiology and emergency preparedness units. Several TEFAs deployed to United States territories for the 2016 Zika Outbreak response. CONCLUSION: TEFAs made important contributions to their jurisdictions' preparedness. We believe the TEFA model can be a significant component of a national strategy for surging state and local capacity in future high-consequence events.

Pruning an axon piece by piece: a new mode of synapse elimination.

The process by which excess axons are pruned during development has remained unclear. In this issue of Neuron, Bishop et al. use time-lapse imaging and serial electron microscopy of developing neuromuscular junctions to describe a novel cellular mechanism in which retracting axon branches shed fragments rich in normal synaptic organelles. These "axosomes" are engulfed by adjacent Schwann cells and may be assimilated into the glial cytoplasm. Shedding of axosomes and glial engulfment may represent a widespread mechanism of synapse elimination.

Glial cells maintain synaptic structure and function and promote development of the neuromuscular junction in vivo.

To investigate the in vivo role of glial cells in synaptic function, maintenance, and development, we have developed an approach to selectively ablate perisynaptic Schwann cells (PSCs), the glial cells at the neuromuscular junction (NMJ), en masse from live frog muscles. In adults, following acute PSC ablation, synaptic structure and function were not altered. However, 1 week after PSC ablation, presynaptic function decreased by approximately half, while postsynaptic function was unchanged. Retraction of nerve terminals increased over 10-fold at PSC-ablated NMJs. Furthermore, nerve-evoked muscle twitch tension was reduced. In tadpoles, repeated in vivo observations revealed that PSC processes lead nerve terminal growth. In the absence of PSCs, growth and addition of synapses was dramatically reduced, and existing synapses underwent widespread retraction. Our findings provide in vivo evidence that glial cells maintain presynaptic structure and function at adult synapses and are vital for the growth and stability of developing synapses.

Changing Antimicrobial Resistance Trends in Kathmandu, Nepal: A 23-Year Retrospective Analysis of Bacteraemia.

A comprehensive longitudinal understanding of the changing epidemiology of the agents causing bacteraemia and their AMR profiles in key locations is crucial for assessing the progression and magnitude of the global AMR crisis. We performed a retrospective analysis of routine microbiological data from April 1992 to December 2014, studying the time trends of non-Salmonella associated bacteraemia at a single Kathmandu healthcare facility. The distribution of aetiological agents, their antimicrobial susceptibility profiles, and the hospital ward of isolation were assessed. Two hundred twenty-four thousand seven hundred forty-one blood cultures were performed over the study period, of which, 30,353 (13.5%) exhibited growth for non-contaminant bacteria. We observed a significant increasing trend in the proportion of MDR non-Salmonella Enterobacteriaceae (p < 0.001), other Gram-negative organisms (p = 0.006), and Gram-positive organisms (p = 0.006) over time. Additionally, there was an annual increasing trend in the proportion of MDR organisms in bacteria-positive blood cultures originating from patients attending the emergency ward (p = 0.006) and the outpatient department (p = 0.006). This unique dataset demonstrates that community acquired non-Salmonella bacteraemia has become an increasingly important cause of hospital admission in Kathmandu. An increasing burden of bacteraemia associated with MDR organisms in the community underscores the need for preventing the circulation of MDR bacteria within the local population.

Notch1 signaling regulates radial glia differentiation through multiple transcriptional mechanisms.

Signaling by the Notch1 receptor is critical for the formation of radial glia in the developing nervous system. We have shown previously that Notch1 regulates the molecular and morphological differentiation of radial glia through the transcriptional activation of at least two genes, brain lipid binding protein (BLBP) and the erbB2 receptor tyrosine kinase. However, the mechanisms by which this occurs remained undefined. Here we demonstrate that Notch1 effects on radial glia gene expression are mediated by two downstream mechanisms, one that the depends on Suppressor of Hairless [Su(H)] and the other on Deltex1 (DTX1). These two Notch1-binding proteins contribute to the regulation of BLBP and erbB2 expression, respectively. Importantly, our results suggest that, although these events can occur simultaneously, a hierarchical relationship might exist between DTX1 and Su(H), because overexpression of DTX1 or a dominant-negative form of this protein inhibits Su(H)-mediated events but not vice versa. In contrast to the effects of DTX1 overexpression, interference RNA-mediated knock-down of DTX1 blocks Notch1-induced erbB2 promoter activation and radial glia formation selectively, without affecting Su(H)-dependent pathways, indicating that loss of DTX1 expression and expression of dominant-negative DTX1 result in different alterations in cell differentiation and gene expression. Together, these results show that Notch1 regulates radial glia formation through two distinct transcriptional mechanisms and that the outcomes of Notch1 signaling may depend on the relative expression levels of its coregulators.

A 23-year retrospective investigation of Salmonella Typhi and Salmonella Paratyphi isolated in a tertiary Kathmandu hospital.

BACKGROUND: Salmonella serovars Typhi (S. Typhi) and Paratyphi A (S. Paratyphi A), the causative agents of enteric fever, have been routinely isolated organisms from the blood of febrile patients in the Kathmandu Valley since the early 1990s. Susceptibility against commonly used antimicrobials for treating enteric fever has gradually changed throughout South Asia since this time, posing serious treatment challenges. Here, we aimed to longitudinally describe trends in the isolation of Salmonella enterica and assess changes in their antimicrobial susceptibility in Kathmandu over a 23-year period. METHODS: We conducted a retrospective analysis of standardised microbiological data from April 1992 to December 2014 at a single healthcare facility in Kathmandu, examining time trends of Salmonella-associated bacteraemia and the corresponding antimicrobial susceptibility profiles of the isolated organisms. RESULTS: Over 23 years there were 30,353 positive blood cultures. Salmonella enterica accounted for 65.4% (19,857/30,353) of all the bacteria positive blood cultures. S. Typhi and S. Paratyphi A were the dominant serovars, constituting 68.5% (13,592/19,857) and 30.5% (6,057/19,857) of all isolated Salmonellae. We observed (i) a peak in the number of Salmonella-positive cultures in 2002, a year of heavy rainfall and flooding in the Kathmandu Valley, followed by a decline toward pre-flood baseline by 2014, (ii) an increase in the proportion of S. Paratyphi in all Salmonella-positive cultures between 1992 and 2014, (iii) a decrease in the prevalence of MDR for both S. Typhi and S. Paratyphi, and (iv) a recent increase in fluoroquinolone non-susceptibility in both S. Typhi and S. Paratyphi isolates. CONCLUSIONS: Our work describes significant changes in the epidemiology of Salmonella enterica in the Kathmandu Valley during the last quarter of a century. We highlight the need to examine current treatment protocols for enteric fever and suggest a change from fluoroquinolone monotherapy to combination therapies of macrolides or cephalosporins along with older first-line antimicrobials that have regained their efficacy.