An Overview of Acute Flaccid Myelitis

Beyond Poliomyelitis: A 21-Year Study of Non-Polio Enterovirus Genotyping and Its Relevance in Acute Flaccid Paralysis in São Paulo, Brazil

In the context of the near-global eradication of wild poliovirus, the significance of non-polio enteroviruses (NPEVs) in causing acute flaccid paralysis (AFP) and their impact on public health has gained increased attention. This research, conducted from 2001 to 2021, examined stool samples from 1597 children under 15 years in São Paulo, Brazil, through the AFP/Poliomyelitis Surveillance Program, detecting NPEVs in 6.9% of cases. Among the 100 NPEV-positive strains analyzed, 90 were genotyped through genomic sequencing of the partial VP1 region, revealing a predominance of EV-B species (58.9%), followed by EV-A (27.8%) and EV-C (13.3%). This study identified 31 unique NPEV types, including EV-A71, CVB2, and E11, as the most prevalent, along with the first documented occurrence of CVA19 in Brazil. These findings emphasize the importance of NPEV genotyping in distinguishing AFP from poliomyelitis, enhancing understanding of these viruses' epidemiology. Moreover, it ensures that AFP cases are correctly classified, contributing to the effective surveillance and eradication efforts for poliomyelitis.

Caboxamycin Inhibits Heart Inflammation in a Coxsackievirus B3-Induced Myocarditis Mouse Model

Coxsackievirus B3 (CVB3) is a positive single-strand RNA genome virus which belongs to the enterovirus genus in the picornavirus family, like poliovirus. It is one of the most prevalent pathogens that cause myocarditis and pancreatitis in humans. However, a suitable therapeutic medication and vaccination have yet to be discovered. Caboxamycin, a benzoxazole antibiotic isolated from the culture broth of the marine strain Streptomyces sp., SC0774, showed an antiviral effect in CVB3-infected HeLa cells and a CVB3-induced myocarditis mouse model. Caboxamycin substantially decreased CVB3 VP1 production and cleavage of translation factor eIF4G1 from CVB3 infection. Virus-positive and -negative strand RNA was dramatically reduced by caboxamycin treatment. In addition, the cleavage of the pro-apoptotic molecules BAD, BAX, and caspase3 was significantly inhibited by caboxamycin treatment. In animal experiments, the survival rate of mice was improved following caboxamycin treatment. Moreover, caboxamycin treatment significantly decreased myocardial damage and inflammatory cell infiltration. Our study showed that caboxamycin dramatically suppressed cardiac inflammation and mouse death. This result suggests that caboxamycin may be suitable as a potential antiviral drug for CVB3.

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.

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.

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.

Viral meningitis and encephalitis: an update

PURPOSE OF REVIEW

The most common infectious etiologies of meningitis and encephalitis are viruses. In this review, we will discuss current epidemiology, prevention, diagnosis, and treatment of the most common causes of viral meningitis and encephalitis worldwide.

RECENT FINDINGS

Viral meningitis and encephalitis are increasingly diagnosed as molecular diagnostic techniques and serologies have become more readily available worldwide but recent progress in novel antiviral therapies remains limited. Emerging and re-emerging viruses that have caused endemic or worldwide outbreaks or epidemics are arboviruses (e.g., West Nile virus, Japanese encephalitis, Tick borne encephalitis, Dengue, Zika, Toscana), enteroviruses (e.g., Enterovirus 71, Enterovirus D68), Parechoviruses, respiratory viruses [e.g., severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza, metapneumoviruses, measles, mumps], and herpes viruses [e.g., herpes simplex virus (HSV) type 1 (HSV-1), HSV-2, human herpes (HV) 6, varicella zoster virus (VZV)]. Future efforts should concentrate in increasing availability for those viruses with effective vaccination [e.g., Japanese encephalitis, Tick borne encephalitis, varicella zoster viruses, SARS-CoV-2, influenza], prompt initiation of those with encephalitis with treatable viruses (e.g., HSV-1, VZV), increasing the diagnostic yield by using novel techniques such as metagenomic sequencing and avoiding unnecessary antibiotics in those with viral meningitis or encephalitis.

SUMMARY

We review the current epidemiology, clinical presentation, diagnosis, and treatment of the common causative agents of viral meningitis and encephalitis worldwide.