Acute Flaccid Myelitis: Current Status and Diagnostic Challenges

Pan-Enterovirus Characterization Reveals Cryptic Circulation of Clinically Relevant Subtypes in Arizona Wastewater

Background

Most seasonally circulating enteroviruses result in asymptomatic or mildly symptomatic infections. In rare cases, however, infection with some subtypes can result in paralysis or death. Of the 300 subtypes known, only poliovirus is reportable, limiting our understanding of the distribution of other enteroviruses that can cause clinical disease.

Objective

The overarching objectives of this study were to: 1) describe the distribution of enteroviruses in Arizona during the late summer and fall of 2022, the time of year when they are thought to be most abundant, and 2) demonstrate the utility of viral pan-assay approaches for semi-agnostic discovery that can be followed up by more targeted assays and phylogenomics.

Methods

This study utilizes pooled nasal samples collected from school-aged children and long-term care facility residents, and wastewater from multiple locations in Arizona during July-October of 2022. We used PCR to amplify and sequence a region common to all enteroviruses, followed by species-level bioinformatic characterization using the QIIME 2 platform. For Enterovirus-D68 (EV-D68), detection was carried out using RT-qPCR, followed by confirmation using near-complete whole EV-D68 genome sequencing using a newly designed tiled amplicon approach.

Results

In the late summer and early fall of 2022, multiple enterovirus species were identified in Arizona wastewater, with Coxsackievirus A6, EV-D68, and Coxsackievirus A19 composing 86% of the characterized reads sequenced. While EV-D68 was not identified in pooled human nasal samples, and the only reported acute flaccid myelitis case in Arizona did not test positive for the virus, an in-depth analysis of EV-D68 in wastewater revealed that the virus was circulating from August through mid-October. A phylogenetic analysis on this relatively limited dataset revealed just a few importations into the state, with a single clade indicating local circulation.

Significance

This study further supports the utility of wastewater-based epidemiology to identify potential public health threats. Our further investigations into EV-D68 shows how these data might help inform healthcare diagnoses for children presenting with concerning neurological symptoms.

Wastewater Surveillance in Europe for Non-Polio Enteroviruses and Beyond

Wastewater surveillance (WWS) was developed in the early 1960s for the detection of poliovirus (PV) circulation in the population. It has been used to monitor several pathogens, including non-polio enteroviruses (NPEVs), which are increasingly recognised as causes of morbidity in children. However, when applying WWS to a new pathogen, it is important to consider the purpose of such a study as well as the suitability of the chosen methodology. With this purpose, the European Non-Polio Enterovirus Network (ENPEN) organised an expert webinar to discuss its history, methods, and applications; its evolution from a culture-based method to molecular detection; and future implementation of next generation sequencing (NGS). The first simulation experiments with PV calculated that a 400 mL sewage sample is sufficient for the detection of viral particles if 1:10,000 people excrete poliovirus in a population of 700,000 people. If the method is applied correctly, several NPEV types are detected. Despite culture-based methods remaining the gold standard for WWS, direct methods followed by molecular-based and sequence-based assays have been developed, not only for enterovirus but for several pathogens. Along with case-based sentinel and/or syndromic surveillance, WWS for NPEV and other pathogens represents an inexpensive, flexible, anonymised, reliable, population-based tool for monitoring outbreaks and the (re)emergence of these virus types/strains within the general population.

Emerging trends and insights in acute flaccid myelitis: a comprehensive review of neurologic manifestations

Acute Flaccid Myelitis (AFM) is a neurological condition in the anterior portion of the spinal cord and can be characterised as paraplegia (paralysis of the lower limbs), and cranial nerve dysfunction. These lesions are caused by the infection due to Enterovirus 68 (EV-D68); a member of the Enterovirus (EV) family belongs to the Enterovirus species within the Picornavirus family and a Polio-like virus. In many cases, the facial, axial, bulbar, respiratory, and extraocular muscles were affected, hence reducing the overall quality of the patient's life. Moreover, severe pathological conditions demand hospitalisation and can cause mortality in a few cases. The data from previous case studies and literature suggest that the prevalence is high in paediatric patients, but careful clinical assessment and management can decrease the risk of mortality and paraplegia. Moreover, the clinical and laboratory diagnosis can be performed by Magnetic resonance imaging (MRI) of the spinal cord followed by Reverse transcription polymerase chain reaction (rRT-PCR) and VP1 seminested PCR assay of the cerebrospinal fluid (CSF), stool, and serum samples can reveal the disease condition to an extent. The primary measure to control the outbreak is social distancing as advised by public health administrations, but more effective ways are yet to discover. Nonetheless, vaccines in the form of the whole virus, live attenuated, sub-viral particles, and DNA vaccines can be an excellent choice to treat these conditions. The review discusses a variety of topics, such as epidemiology, pathophysiology, diagnosis/clinical features, hospitalisation/mortality, management/treatment, and potential future developments.

Acute flaccid myelitis a review of the literature

Acute flaccid myelitis (AFM) is a rare neurological disorder that first rose to national attention in 2014. This neurological disorder has a biennial presentation with every other even year being a peak year. Most patients present in childhood 5 days after a prodromal infection. Patients usually present with muscle weakness and hypo or areflexia in the summer or fall months. Clinical outcomes are variable however most patients do not improve. Currently there are no definitive prognostic factors or etiologies found. However, it is thought that enterovirus-D68 (EV-D68) could be a potential component in the pathobiology of AFM. Treatment options are limited with variable options and no consensus. Supportive therapy has been shown to be the most effective thus far. With our review of the literature, we highlight the recent growing evidence of a possible relationship between EV-D68 and AFM. Additionally, we identify the knowledge gaps in AFM with treatment and prognostic factors.

Acute flaccid paralysis incidence rate and epidemiology in children in Lebanon: a rise in numbers in the post-vaccination and refugee crisis era

Background

Acute flaccid paralysis (AFP) is a clinical syndrome characterized by the acute onset of weakness and paralysis with reduced muscle tone. This study explored the incidence and different aspects of AFP in Lebanese children between 2009 and 2019.

Methods

AFP data were collected from the Lebanese Ministry of Public Health. Incidence rate according to year, age groups, clinical data, follow-up, diagnosis, and vaccination status was analyzed in the 11-years period.

Results

AFP incidence rates increased importantly from 0.63 per 100,000 in 2009 till 4.96 per 100,000 in 2019. Most of the patients were children under ten years of age, 40.6% of all cases were under five years old, and 37.9% were between 5 and 9 years old. Follow-up revealed that approximately two out of five patients experienced residual weakness. As for the final diagnosis, around 30% of cases were diagnosed as Guillain-Barre Syndrome (GBS). Most cases were children having received between 3 and 5 doses of polio vaccine.

Conclusions

The rise in cases coincided with the Syrian refugee crisis in Lebanon and the progressively deteriorating economy in the country; yet, incidence rates were in the lower margin compared with other countries.

Clinical profile and predictors for outcome in children presenting with Guillain-Barré syndrome

Introduction:

Acute Flaccid Paralysis (AFP) is a group of diverse clinical conditions with Guillain–Barré syndrome (GBS) as one of the most common cause. The aim of this study was to study the clinical features and predictors for the requirement of ventilation in children with GBS.

Materials and Methods:

This is a prospective observational study done at a tertiary care hospital where all consecutive children less than 15 years who presented with AFP were enrolled. Demographic characteristics, symptomatology, and physical findings of those patients who were diagnosed with GBS were recorded using a pre-defined questionnaire. Univariate analysis was done to identify clinical variables associated with a higher requirement of ventilation.

Results:

Of a total of 53 children with AFP enrolled in the study, a total of 30 patients were diagnosed with GBS. A total of 12 (40%) patients required ventilation, while five of these patients eventually died. The following variants of GBS were identified: AIDP (13/30), AMAN (12/30), and ASMAN (2/30). Lower limbs were affected in 97% of the patients, whereas upper limbs were affected in 83% of the patients. Deep tendon reflexes of the upper limb and lower limb were preserved in 56% and 7% of the patients, respectively. Presence of antecedent URTI was associated with a lower requirement of ventilation. Presence of bulbar palsy, lower upper limb power on presentation, and absence of deep tendon reflex in upper limbs were associated with a higher requirement of ventilation.

Conclusion:

GBS is an important cause of AFP in India with no significant difference between the variants in terms of frequency and prognosis. Simple physical findings can be used by primary care physicians to predict the requirement of higher levels of care.