Investigation of Acute Flaccid Paralysis Reported with La Crosse Virus Infection, Ohio, USA, 2008-2014

A Scoping Review on the Epidemiology of Orthobunyaviruses in Canada, in the Context of Human, Wildlife, and Domestic Animal Host Species

Background: Mosquito-borne orthobunyaviruses in Canada are a growing public health concern. Orthobunyaviral diseases are commonly underdiagnosed and in Canada, likely underreported as surveillance is passive. No vaccines or specific treatments exist for these disease agents. Further, climate change is facilitating habitat expansion for relevant reservoirs and vectors, and it is likely that the majority of the Canadian population is susceptible to these viruses. Methods: A scoping review was conducted to describe the current state of knowledge on orthobunyavirus epidemiology in Canada. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guideline was used. Literature searches were conducted in six databases and in gray literature. The epidemiology of orthobunyaviruses was characterized for studies focusing on host species, including spatiotemporal patterns, risk factors, and climate change impact. Results: A total of 172 relevant studies were identified from 1734 citations from which 95 addressed host species, including humans, wildlife, and domestic animals including livestock. The orthobunyaviruses-Cache Valley virus (CVV), Jamestown Canyon virus (JCV), Snowshoe Hare virus (SHV), and La Crosse virus (LACV)-were identified, and prevalence was widespread across vertebrate species. CVV, JCV, and SHV were detected across Canada and the United States. LACV was reported only in the United States, predominantly the Mid-Atlantic and Appalachian regions. Disease varied by orthobunyavirus and was associated with age, environment, preexisting compromised immune systems, or livestock breeding schedule. Conclusion: Knowledge gaps included seroprevalence data in Canada, risk factor analyses, particularly for livestock, and disease projections in the context of climate change. Additional surveillance and mitigation strategies, especially accounting for climate change, are needed to guide future public health efforts to prevent orthobunyavirus exposure and disease.

Comparison of children with acute flaccid myeltis before and after 2014

Objective

To observe whether cases of acute flaccid myelitis (AFM) before and since August 1, 2014, had important differences and to further characterize patients with AFM regarding clinical, laboratory, imaging, and treatment findings.

Methods

All pediatric patients with AFM at our institution were reviewed. Demographic, clinical, and diagnostic data were collected through medical record review. Patients with onset before August 1, 2014, and after that date were compared and when applicable compared with Centers for Disease Control and Prevention data.

Results

Sixteen patients were included, 6 in the pre-2014 and 10 in the post-2014 group. The mean age in the pre-2014 group was 7.4 years and in the post-2014 group was 6.4 years. Initial symptoms were similar in both groups, as were functional and motor abilities at disease nadir and the most recent follow-up. Post-2014 patients had a higher mean CSF white blood cell count (57) and neutrophil count (30%) compared with pre-2014 patients (3.2 and 0.5%, respectively). Eighty percent of post-2014 patients had positive enterovirus/rhinovirus testing, with 57% of specimens positive for enterovirus D68 (EV-D68). On acute imaging, a triad of brainstem, cervical cord gray matter involvement, and ventral nerve root/cauda equina (CE) thickening/enhancement was found in 5 patients.

Conclusion

The groups had more similarities than differences but with a more inflammatory picture in the post-2014 patients. The constellation of cervical cord gray matter, brainstem, and nerve root/CE thickening should raise suspicion for AFM in the appropriate clinical setting. Most post-2014 patients had associated enterovirus infections, and over half tested for EV-D68 were positive. There was minimal clinical improvement in both groups despite various immunotherapies.

Comparative quantitative clinical, neuroimaging, and functional profiles in children with acute flaccid myelitis at acute and convalescent stages of disease

AIM

To quantify characteristics in acute flaccid myelitis (AFM) at acute and convalescent stages.

METHOD

This was a retrospective case series of children with AFM evaluated at a single institution in the USA (2014-2017). Acute inflammatory/ischemic myelopathies were excluded. Neurological assessments and segmental quantitative analysis of signal abnormalities on magnetic resonance imaging (MRI) of the brain and spinal cord were performed.

RESULTS

Sixteen patients (11 males, five females) were evaluated. Median age at onset was 4 years (interquartile range [IQR] 3-6y). All had parainfectious acute-onset limb weakness, lower motor neuron examination, and spinal fluid pleocytosis. On acute spinal cord MRI, longitudinally extensive T2 hyperintensities were identified throughout the spinal cord mostly within grey matter; five out of 12 patients had dorsal brainstem T2 hyperintensities. At a median of 2 months follow-up (IQR 2-3mo), spinal cord MRI improved in seven out of nine patients although focal T2 hyperintensities persisted in cervical and lumbar grey matter. At a median follow-up of 4 months (IQR 2-6mo), Medical Research Council sum score rose from a median of 29 to 32; distal muscle groups improved more than proximal ones; four out of 16 patients were ventilator-dependent; and two out of 16 patients were quadriplegic.

INTERPRETATION

While patients may show marked improvement on neuroimaging from acute to convalescent stages, the majority of children with AFM have limited motor recovery and continued disability. Clinicians should consider the timing of clinical and neuroimaging exams when assessing diagnosis and prognosis.

WHAT THIS PAPER ADDS

During the 2014 to 2017 acute flaccid myelitis outbreak in the USA, clinical recovery was better in distal than proximal muscle groups. Lumbar spinal cord showed more residual abnormalities at convalescence.