Poliomyelitis

Enterovirus D68 capsid formation and stability requires acidic compartments

IMPORTANCE

The respiratory picornavirus enterovirus D68 is a causative agent of acute flaccid myelitis, a childhood paralysis disease identified in the last decade. Poliovirus, another picornavirus associated with paralytic disease, is a fecal-oral virus that survives acidic environments when passing from host to host. Here, we follow up on our previous work showing a requirement for acidic intracellular compartments for maturation cleavage of poliovirus particles. Enterovirus D68 requires acidic vesicles for an earlier step, assembly, and maintenance of viral particles themselves. These data have strong implications for the use of acidification blocking treatments to combat enterovirus diseases.

Enterovirus D68 capsid formation and stability requires acidic compartments

Enterovirus D68 (EV-D68), a picornavirus traditionally associated with respiratory infections, has recently been linked to a polio-like paralytic condition known as acute flaccid myelitis (AFM). EV-D68 is understudied, and much of the field's understanding of this virus is based on studies of poliovirus. For poliovirus, we previously showed that low pH promotes virus capsid maturation, but here we show that, for EV-D68, inhibition of compartment acidification during a specific window of infection causes a defect in capsid formation and maintenance. These phenotypes are accompanied by radical changes in the infected cell, with viral replication organelles clustering in a tight juxtanuclear grouping. Organelle acidification is critical during a narrow window from 3-4hpi, which we have termed the "transition point," separating translation and peak RNA replication from capsid formation, maturation and egress. Our findings highlight that acidification is crucial only when vesicles convert from RNA factories to virion crucibles.

[Infections of the spinal cord and adjacent structures]

Inflammation of the spinal cord and the adjacent structures can be caused by viruses, bacteria, fungi and parasites. Viruses predominantly infect the spinal cord and the nerve roots directly or trigger a secondary immune response, whereas bacteria, fungi and parasites tend to form abscesses, granulomas and cysts and can lead to a secondary compression of the spinal cord, similar to a destructive osteomyelitis. The etiological clarification of an acute or subacute spinal process is carried out based on the clinical presentation, the time course of the development of symptoms, the immune status, neuroimaging and microbial and/or molecular biological examinations of cerebrospinal fluid and serum. The tropism of individual pathogens to certain fiber structures and cellular clusters in the spinal cord in synopsis with the clinical presentation, neuroimaging and a history of exposure, can often quickly lead to a focused clarification and diagnosis. This article deals with important pathogens of spinal and paraspinal infections, the geographical distribution, the clinical and neuroimaging presentation with special consideration of the anatomical and topographical localization and recent epidemiological developments. Particular attention is paid to the outbreak of poliomyelitis due to circulating vaccine-derived poliovirus (cVDPV).

Spinal cord motor disorders

Spinal cord diseases are frequently devastating due to the precipitous and often permanently debilitating nature of the deficits. Spastic or flaccid paraparesis accompanied by dermatomal and myotomal signatures complementary to the incurred deficits facilitates localization of the insult within the cord. However, laboratory studies often employing disease-specific serology, neuroradiology, neurophysiology, and cerebrospinal fluid analysis aid in the etiologic diagnosis. While many spinal cord diseases are reversible and treatable, especially when recognized early, more than ever, neuroscientists are being called to investigate endogenous mechanisms of neural plasticity. This chapter is a review of the embryology, neuroanatomy, clinical localization, evaluation, and management of adult and childhood spinal cord motor disorders.

Facioscapulohumeral Muscular Dystrophy and Poliomyelitis followed by Multiple Sclerosis: A "triple trouble" case report and review of the literature on the association of MS and muscle disorders

We describe herein a "triple trouble" case of a patient affected by Facioscapulohumeral muscular dystrophy type 1 (FSHD1), with a previous history of poliomyelitis, who later developed multiple sclerosis (MS). Association of muscle disorders and MS is uncommon; in fact, there are only three case reports of this unusual co-occurrence. As regard as this combination, some hypotheses have been raised about the role of immunological factors. Genetic basis of FSHD1 is a deletion of a critical number of macrosatellite repeats (D4Z4) in the subtelomeric region of chromosome 4q35, resulting in transcriptional de-repression of a gene DUX4. This molecular change could induce an alteration of immune responses, likely conferring susceptibility to both diseases. In this case, poliomyelitis could have delayed the FSHD1 diagnosis and likely acted as a trigger for MS onset. Association of multiple neurological disorders has to be kept in mind to avoid misinterpretation of symptoms and diagnostic delays.

Infectious Myelopathies

In the setting of both globalization and increasing use of immunosuppressive therapy, infectious myelopathies are an important cause of morbidity worldwide. Clinical spinal cord syndromes related to infection are varied, including transverse myelitis, acute flaccid paralysis related to anterior horn cell involvement, spinal cord compression, chronic spastic paraparesis, and myeloradiculitis. Causative pathogens include viruses, parasites, pyogenic and atypical bacteria, and fungi. The epidemiology, clinical characteristics, diagnosis, and treatment of selected organisms will be discussed in this article.

Acute flaccid myelitis: cause, diagnosis, and management

Acute flaccid myelitis (AFM) is a disabling, polio-like illness mainly affecting children. Outbreaks of AFM have occurred across multiple global regions since 2012, and the disease appears to be caused by non-polio enterovirus infection, posing a major public health challenge. The clinical presentation of flaccid and often profound muscle weakness (which can invoke respiratory failure and other critical complications) can mimic several other acute neurological illnesses. There is no single sensitive and specific test for AFM, and the diagnosis relies on identification of several important clinical, neuroimaging, and cerebrospinal fluid characteristics. Following the acute phase of AFM, patients typically have substantial residual disability and unique long-term rehabilitation needs. In this Review we describe the epidemiology, clinical features, course, and outcomes of AFM to help to guide diagnosis, management, and rehabilitation. Future research directions include further studies evaluating host and pathogen factors, including investigations into genetic, viral, and immunological features of affected patients, host-virus interactions, and investigations of targeted therapeutic approaches to improve the long-term outcomes in this population.

The experiences of using polio outbreak simulation exercises to strengthen national outbreaks preparedness and response plans in sub-Saharan Africa

Introduction

globally, by 2020 the paralytic poliomyelitis disease burden decreased to over 99% of the reported cases in 1988 when resolution 41.8 was endorsed by the World Health Assembly (WHA) for global polio eradication. It is clearly understood that, if there is Wild Poliovirus (WPV) and circulating Vaccines Derived Poliovirus (cVDPV) in the world, no country is safe from polio outbreaks. All countries remain at high risk of re-importation depending on the level of the containment of the types vaccine withdrawn, the laboratory poliovirus isolates, and the population immunity induced by the vaccination program. In this regard, countries to have polio outbreak preparedness and response plans, and conducting the polio outbreak simulation exercises for these plans remain important.

Methods

we conducted a cross-section qualitative study to review to 8 countries conducted polio outbreak simulation exercises in the East and Southern Africa from 2016 to 2018. The findings were categorized into 5 outbreak response thematic areas analyzed qualitatively and summarized them on their strengths and weaknesses.

Results

we found out that, most countries have the overall technical capacities and expertise to deal with outbreaks to a certain extent. Nevertheless, we noted that the national polio outbreak preparedness and response plans were not comprehensive enough to provide proper guidance in responding to outbreaks. The guidelines were inadequately aligned with the WHO POSOPs, and IHR 2005. Additionally, most participants who participated in the simulation exercises were less familiar with their preparedness and response plans, the WHO POSOPs, and therefore reported to be sensitized.

Conclusion

we also realized that, in all countries where the polio simulation exercise conducted, their national polio outbreak preparedness and response plan was revised to be improved in line with the WHO POSOPs and IHR 2005. we, therefore, recommend the polio outbreak simulation exercises to be done in every country with an interval of 3-5 years.

Is Intervention to Prevent Falls Necessary in Prior Polio Patients?

Objective

To investigate whether intervention to prevent falls is necessary in prior polio patients, by identifying the frequency, circumstances and consequences of falls among patients in Sweden with prior polio.

Subjects

Patients with prior polio diagnosis.

Methods

A falls history questionnaire was completed by patients with prior polio visiting the outpatient clinic at the Department of Rehabilitation Medicine, Danderyd University Hospital, Stock-holm, Sweden, or participating in group activities organized by the patient organization.

Results

A total of 80 patients answered the questionnaire; 32 men and 48 women. Eighty-one percent (n = 63/77) of respondents walked outdoors, but rarely more than 1 km, or only inside and near the house. Three-quarters of patients had fallen one or more times over the past year and one-quarter of patients had fallen 5 times or more. The falls often occurred during daytime in an environment known to the patient. Sixty-nine percent (n = 40/58) of respondents had been injured due to falling during the past year. The most common injuries were minor injuries.

Conclusion

Falls are common in patients in Sweden with prior polio. Interventions to prevent falls in people with prior polio are therefore clinically relevant.

Antiviral activity of flavonoids present in aerial parts of Marcetia taxifolia against Hepatitis B virus, Poliovirus, and Herpes Simplex Virus in vitro

Marcetia taxifolia is a neotropical plant present in South America and it has been evaluated in several biological models due to the presence of active metabolites. Nevertheless, there is a limited quantity of studies related to the antiviral activity of the compounds present in this genus. In our work, the antiviral effect of the compounds isolated from the aerial parts of Marcetia taxifolia was evaluated against Hepatitis B virus (HBV), Herpes Simplex Virus type 1 (HSV-1), and Poliovirus type 1 (PV-1). The cytopathic effect and viral quantification by qPCR were determined as indicative of antiviral activity. Our data show that myricetin rhamnoside (MyrG), myricetin-3-α-O-ramnosil (1→6)-α-galactoside (MyrGG), 5,3'-dihydroxy-3,6,7,8,4'-pentamethoxyflavone (PMF), 5-hydroxy-3,6,7,3',4'pentamethoxyflavone (PMF-OH) had antiviral activity without cytotoxic effects. The methoxyflavones PMF and PMF-OH were the most active compounds, showing an antiviral effect against all the evaluated viruses. Computational studies showed that these compounds could interact with the Reverse Transcriptase. Altogether, these results suggest that the flavonoids (related to myricetin and methoxyflavones) are the main antiviral compounds present in the aerial parts of Marcetia taxifolia. Furthermore, our results showed that the methoxyflavones have a broad antiviral activity, which represents an opportunity to evaluate these flavonoids as lead molecules to develop new antiviral compounds.