Kevin Messacar

A novel outbreak enterovirus D68 strain associated with acute flaccid myelitis cases in the USA (2012–14): a retrospective cohort study

BACKGROUND Enterovirus D68 was implicated in a widespread outbreak of severe respiratory illness across the USA in 2014 and has also been reported sporadically in patients with acute flaccid myelitis. We aimed to investigate the association between enterovirus D68 infection and acute flaccid myelitis during the 2014 enterovirus D68 respiratory outbreak in the USA. METHODS Patients with acute flaccid myelitis who presented to two hospitals in Colorado and California, USA, between Nov 24, 2013, and Oct 11, 2014, were included in the study. Additional cases identified from Jan 1, 2012, to Oct 4, 2014, via statewide surveillance were provided by the California Department of Public Health. We investigated the cause of these cases by metagenomic next-generation sequencing, viral genome recovery, and enterovirus D68 phylogenetic analysis. We compared patients with acute flaccid myelitis who were positive for enterovirus D68 with those with acute flaccid myelitis but negative for enterovirus D68 using the two-tailed Fishers exact test, two-sample unpaired t test, and Mann-Whitney U test. FINDINGS 48 patients were included: 25 with acute flaccid myelitis, two with enterovirus-associated encephalitis, five with enterovirus-D68-associated upper respiratory illness, and 16 with aseptic meningitis or encephalitis who tested positive for enterovirus. Enterovirus D68 was detected in respiratory secretions from seven (64%) of 11 patients comprising two temporally and geographically linked acute flaccid myelitis clusters at the height of the 2014 outbreak, and from 12 (48%) of 25 patients with acute flaccid myelitis overall. Phylogenetic analysis revealed that all enterovirus D68 sequences associated with acute flaccid myelitis grouped into a clade B1 strain that emerged in 2010. Of six coding polymorphisms in the clade B1 enterovirus D68 polyprotein, five were present in neuropathogenic poliovirus or enterovirus D70, or both. One child with acute flaccid myelitis and a sibling with only upper respiratory illness were both infected by identical enterovirus D68 strains. Enterovirus D68 viraemia was identified in a child experiencing acute neurological progression of his paralytic illness. Deep metagenomic sequencing of cerebrospinal fluid from 14 patients with acute flaccid myelitis did not reveal evidence of an alternative infectious cause to enterovirus D68. INTERPRETATION These findings strengthen the putative association between enterovirus D68 and acute flaccid myelitis and the contention that acute flaccid myelitis is a rare yet severe clinical manifestation of enterovirus D68 infection in susceptible hosts. FUNDING National Institutes of Health, University of California, Abbott Laboratories, and the Centers for Disease Control and Prevention.

A cluster of acute flaccid paralysis and cranial nerve dysfunction temporally associated with an outbreak of enterovirus D68 in children in Colorado, USA

BACKGROUND Clusters of acute flaccid paralysis or cranial nerve dysfunction in children are uncommon. We aimed to assess a cluster of children with acute flaccid paralysis and cranial nerve dysfunction geographically and temporally associated with an outbreak of enterovirus-D68 respiratory disease. METHODS We defined a case of neurological disease as any child admitted to Childrens Hospital Colorado (Aurora, CO, USA) with acute flaccid paralysis with spinal-cord lesions involving mainly grey matter on imaging, or acute cranial nerve dysfunction with brainstem lesions on imaging, who had onset of neurological symptoms between Aug 1, 2014, and Oct 31, 2014. We used Poisson regression to assess whether the numbers of cases during the outbreak period were significantly greater than baseline case numbers from a historical control period (July 31, 2010, to July 31, 2014). FINDINGS 12 children met the case definition (median age 11·5 years [IQR 6·75-15]). All had a prodromal febrile illness preceding neurological symptoms by a median of 7 days (IQR 5·75-8). Neurological deficits included flaccid limb weakness (n=10; asymmetric n=7), bulbar weakness (n=6), and cranial nerve VI (n=3) and VII (n=2) dysfunction. Ten (83%) children had confluent, longitudinally extensive spinal-cord lesions of the central grey matter, with predominant anterior horn-cell involvement, and nine (75%) children had brainstem lesions. Ten (91%) of 11 children had cerebrospinal fluid pleocytosis. Nasopharyngeal specimens from eight (73%) of 11 children were positive for rhinovirus or enterovirus. Viruses from five (45%) of 11 children were typed as enterovirus D68. Enterovirus PCR of cerebrospinal fluid, blood, and rectal swabs, and tests for other causes, were negative. Improvement of cranial nerve dysfunction has been noted in three (30%) of ten children. All ten children with limb weakness have residual deficits. INTERPRETATION We report the first geographically and temporally defined cluster of acute flaccid paralysis and cranial nerve dysfunction in children associated with an outbreak of enterovirus-D68 respiratory illness. Our findings suggest the possibility of an association between enterovirus D68 and neurological disease in children. If enterovirus-D68 infections continue to happen in an endemic or epidemic pattern, development of effective antiviral or immunomodulatory therapies and vaccines should become scientific priorities. FUNDING National Center for Advancing Translational Sciences, National Institutes of Health.

Erratum to: Clinical metagenomic identification of Balamuthia mandrillaris encephalitis and assembly of the draft genome: the continuing case for reference genome sequencing

Author details Department of Laboratory Medicine, University of California, 185 Berry Street, San Francisco 94107 CA, USA. UCSF-Abbott Viral Diagnostics and Discovery Center, San Francisco 91407 CA, USA. Children’s Hospital Colorado and University of Colorado School of Medicine, Aurora, CO, USA. California Department of Public Health, Richmond, CA, USA. Kaiser Permanente Hospital, Oakland, CA, USA. John Muir Hospital, Walnut Creek, CA, USA. Department of Medicine, Division of Infectious Diseases, University of California, San Francisco 94107 CA, USA.

Acute flaccid myelitis: A clinical review of US cases 2012–2015

This review highlights clinical features of the increasing cases of acute flaccid paralysis associated with anterior myelitis noted in the United States from 2012 to 2015. Acute flaccid myelitis refers to acute flaccid limb weakness with spinal cord gray matter lesions on imaging or evidence of spinal cord motor neuron injury on electrodiagnostic testing. Although some individuals demonstrated improvement in motor weakness and functional deficits, most have residual weakness a year or more after onset. Epidemiological evidence and biological plausibility support an association between enterovirus D68 and the recent increase in acute flaccid myelitis cases in the United States. Ann Neurol 2016;80:326–338

Neuroinvasive Arboviral Disease in the United States: 2003 to 2012

OBJECTIVE: To describe the epidemiologic and clinical syndromes associated with pediatric neuroinvasive arboviral infections among children in the United States from 2003 through 2012. METHODS: We reviewed data reported by state health departments to ArboNET, the national arboviral surveillance system, for 2003 through 2012. Children (<18 years) with neuroinvasive arboviral infections (eg, meningitis, encephalitis, or acute flaccid paralysis) were included. Demographic, clinical syndrome, outcome, geographic, and temporal data were analyzed for all cases. RESULTS: During the study period, 1217 cases and 22 deaths due to pediatric neuroinvasive arboviral infection were reported from the 48 contiguous states. La Crosse virus (665 cases; 55%) and West Nile virus (505 cases; 41%) were the most common etiologies identified. Although less common, Eastern equine encephalitis virus (30 cases; 2%) resulted in 10 pediatric deaths. La Crosse virus primarily affected younger children, whereas West Nile virus was more common in older children and adolescents. West Nile virus disease cases occurred throughout the country, whereas La Crosse and the other arboviruses were more focally distributed. CONCLUSIONS: Neuroinvasive arboviral infections were an important cause of pediatric disease from 2003 through 2012. Differences in the epidemiology and clinical disease result from complex interactions among virus, vector, host, and the environment. Decreasing the morbidity and mortality from these agents depends on vector control, personal protection to reduce mosquito and tick bites, and blood donor screening. Effective surveillance is critical to inform clinicians and public health officials about the epidemiologic features of these diseases and to direct prevention efforts.

Implementation of Rapid Molecular Infectious Disease Diagnostics: the Role of Diagnostic and Antimicrobial Stewardship

ABSTRACT New rapid molecular diagnostic technologies for infectious diseases enable expedited accurate microbiological diagnoses. However, diagnostic stewardship and antimicrobial stewardship are necessary to ensure that these technologies conserve, rather than consume, additional health care resources and optimally affect patient care. Diagnostic stewardship is needed to implement appropriate tests for the clinical setting and to direct testing toward appropriate patients. Antimicrobial stewardship is needed to ensure prompt appropriate clinical action to translate faster diagnostic test results in the laboratory into improved outcomes at the bedside. This minireview outlines the roles of diagnostic stewardship and antimicrobial stewardship in the implementation of rapid molecular infectious disease diagnostics.

Surveillance for enterovirus D68 in colorado children reveals continued circulation

BACKGROUND The largest, most widespread outbreak of enterovirus D68 respiratory disease occurred from August to December of 2014 in the United States with 1153 confirmed infections in 49 states. The epidemiology of enterovirus D68 following the 2014 outbreak is unknown. OBJECTIVES This study seeks to describe the epidemiology of enterovirus D68 circulation amongst Colorado children from 2014 to 2016. STUDY DESIGN This is a prospective observational surveillance study of enterovirus D68 infection amongst children tested for respiratory pathogens from July-October 2014-2016 at Childrens Hospital Colorado (CHCO), a quaternary care childrens hospital in Aurora, CO. RESULTS Amongst rhinovirus/enterovirus positive respiratory specimens from intensive care unit patients, ninety-eight of 314 (31.2%) in 2014, none of 307 (0%) specimens in 2015, and 19 of 240 (7.9%) specimens in 2016 were identified as enterovirus D68. Amongst respiratory specimens from all patients during the prospective active surveillance period, none of 1469 (0%) in 2015 and 46 of 1403 (3.3%) were positive for enterovirus D68. CONCLUSIONS Surveillance for enterovirus D68 amongst respiratory specimens at a quaternary care childrens hospital revealed a seasonal pattern of circulation in the late summer to early fall of 2014 and 2016. Continued surveillance of respiratory specimens is necessary to define the circulation pattern and understand the epidemiology of this emerging pathogen.

A Handshake From Antimicrobial Stewardship Opens Doors for Infectious Disease Consultations

Implementation of a unique in-person pediatric antimicrobial stewardship program was associated with a significant increase in infectious disease consultations at a quaternary care childrens hospital. This study demonstrates that antimicrobial stewardship programs support, and do not compete with, infectious disease programs.

Enterovirus D68 and acute flaccid myelitis—evaluating the evidence for causality

Increased circulation of enterovirus D68 in 2014 and 2016 temporally and geographically coincided with increases in cases of acute flaccid myelitis, an uncommon condition of paralysis due to lesions in the anterior horn of the spinal cord. The identification of enterovirus D68 in respiratory specimens from cases of acute flaccid myelitis worldwide further supports an association, yet the absence of direct virus isolation from affected tissues, infrequent detection in cerebrospinal fluid, and the absence, until recently, of an animal model has left the causal nature of the relationship unproven. In this Personal View we evaluate epidemiological and biological evidence linking enterovirus D68 and acute flaccid myelitis. We applied the Bradford Hill criteria to investigate the evidence for a causal relationship and highlight the importance of comprehensive surveillance and research to further characterise the role of enterovirus D68 in acute flaccid myelitis and pursue effective therapies and prevention strategies.

Laboratory Validation of a Clinical Metagenomic Sequencing Assay for Pathogen Detection in Cerebrospinal Fluid

Metagenomic next-generation sequencing (mNGS) for pan-pathogen detection has been successfully tested in proof-of-concept case studies in patients with acute illness of unknown etiology, but to date has been largely confined to research settings. Here we developed and validated an mNGS assay for diagnosis of infectious causes of meningitis and encephalitis from cerebrospinal fluid (CSF) in a licensed clinical laboratory. A clinical bioinformatics pipeline, SURPI+, was developed to rapidly analyze mNGS data, automatically report detected pathogens, and provide a graphical user interface for evaluating and interpreting results. We established quality metrics, threshold values, and limits of detection of between 0.16 – 313 genomic copies or colony forming units per milliliter for each representative organism type. Gross hemolysis and excess host nucleic acid reduced assay sensitivity; however, a spiked phage used as an internal control was a reliable indicator of sensitivity loss. Diagnostic test accuracy was evaluated by blinded mNGS testing of 95 patient samples, revealing 73% sensitivity and 99% specificity compared to original clinical test results, with 81% positive percent agreement and 99% negative percent agreement after discrepancy analysis. Subsequent mNGS challenge testing of 20 positive CSF samples prospectively collected from a cohort of pediatric patients hospitalized with meningitis, myelitis, and/or encephalitis showed 92% sensitivity and 96% specificity relative to conventional microbiological testing of CSF in identifying the causative pathogen. These results demonstrate the analytic performance of a laboratory-validated mNGS assay for pan-pathogen detection, to be used clinically for diagnosis of neurological infections from CSF.