Coronaviruses in spinal fluid of patients with acute monosymptomatic optic neuritis

An engineered A549 cell line expressing CD13 and TMPRSS2 is permissive to clinical isolate of human coronavirus 229E

The lack of suitable in vitro culture model has hampered research on wild-type (WT) human coronaviruses. While 3D tissue or organ cultures have been instrumental for this purpose, such models are challenging, time-consuming, expensive and require extensive cell culture adaptation and directed evolution. Consequently, high-throughput applications are beyond reach in most cases. Here we developed a robust A549 cell line permissive to a human coronavirus 229E (HCoV-229E) clinical isolate by transducing CD13 and transmembrane serine protease 2 (TMPRSS2), henceforth referred to as A549++ cells. This modification allowed for productive infection, and a more detailed analysis showed that the virus might use the TMPRSS2-dependent pathway but can still bypass this pathway using cathepsin-mediated endocytosis. Overall, our data showed that A549++ cells are permissive to HCoV-229E clinical isolate, and applicable for further studies on HCoV-229E infectiology. Moreover, this line constitutes a uniform platform for studies on multiple members of the Coronaviridae family.

SARS-CoV-2 infection and multi-organ system damage: A review

The SARS-CoV-2 infection causes COVID-19, which has affected approximately six hundred million people globally as of August 2022. Organs and cells harboring angiotensin-converting enzyme 2 (ACE2) surface receptors are the primary targets of the virus. However, once it enters the body through the respiratory system, the virus can spread hematogenously to infect other body organs. Therefore, COVID-19 affects many organs, causing severe and long-term complications, even after the disease has ended, thus worsening the quality of life. Although it is known that the respiratory system is most affected by the SARS-CoV-2 infection, many organs/systems are affected in the short and long term. Since the COVID-19 disease simultaneously affects many organs, redesigning diagnostic and therapy policies to fit the damaged organs is strongly recommended. Even though the pathophysiology of many problems the infection causes is unknown, the frequency of COVID-19 cases rises with age and the existence of preexisting symptoms. This study aims to update our knowledge of SARS-CoV-2 infection and multi-organ dysfunction interaction based on clinical and theoretical evidence. For this purpose, the study comprehensively elucidates the most recent studies on the effects of SARS-CoV-2 infection on multiple organs and systems, including respiratory, cardiovascular, gastrointestinal, renal, nervous, endocrine, reproductive, immune, and parts of the integumentary system. Understanding the range of atypical COVID-19 symptoms could improve disease surveillance, limit transmission, and avoid additional multi-organ-system problems.

Acute and post-acute neurological manifestations of COVID-19: present findings, critical appraisal, and future directions

Acute and post-acute neurological symptoms, signs and diagnoses have been documented in an increasing number of patients infected by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which causes Coronavirus Disease 2019 (COVID-19). In this review, we aimed to summarize the current literature addressing neurological events following SARS-CoV-2 infection, discuss limitations in the existing literature and suggest future directions that would strengthen our understanding of the neurological sequelae of COVID-19. The presence of neurological manifestations (symptoms, signs or diagnoses) both at the onset or during SARS-CoV-2 infection is associated with a more severe disease, as demonstrated by a longer hospital stay, higher in-hospital death rate or the continued presence of sequelae at discharge. Although biological mechanisms have been postulated for these findings, evidence-based data are still lacking to clearly define the incidence, range of characteristics and outcomes of these manifestations, particularly in non-hospitalized patients. In addition, data from low- and middle-income countries are scarce, leading to uncertainties in the measure of neurological findings of COVID-19, with reference to geography, ethnicity, socio-cultural settings, and health care arrangements. As a consequence, at present a specific phenotype that would specify a post-COVID (or long-COVID) neurological syndrome has not yet been identified.

Neuropathophysiology of coronavirus disease 2019: neuroinflammation and blood brain barrier disruption are critical pathophysiological processes that contribute to the clinical symptoms of SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19) is caused by the novel SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) first discovered in Wuhan, Hubei province, China in December 2019. SARS-CoV-2 has infected several millions of people, resulting in a huge socioeconomic cost and over 2.5 million deaths worldwide. Though the pathogenesis of COVID-19 is not fully understood, data have consistently shown that SARS-CoV-2 mainly affects the respiratory and gastrointestinal tracts. Nevertheless, accumulating evidence has implicated the central nervous system in the pathogenesis of SARS-CoV-2 infection. Unfortunately, however, the mechanisms of SARS-CoV-2 induced impairment of the central nervous system are not completely known. Here, we review the literature on possible neuropathogenic mechanisms of SARS-CoV-2 induced cerebral damage. The results suggest that downregulation of angiotensin converting enzyme 2 (ACE2) with increased activity of the transmembrane protease serine 2 (TMPRSS2) and cathepsin L in SARS-CoV-2 neuroinvasion may result in upregulation of proinflammatory mediators and reactive species that trigger neuroinflammatory response and blood brain barrier disruption. Furthermore, dysregulation of hormone and neurotransmitter signalling may constitute a fundamental mechanism involved in the neuropathogenic sequelae of SARS-CoV-2 infection. The viral RNA or antigenic peptides also activate or interact with molecular signalling pathways mediated by pattern recognition receptors (e.g., toll-like receptors), nuclear factor kappa B, Janus kinase/signal transducer and activator of transcription, complement cascades, and cell suicide molecules. Potential molecular targets and therapeutics of SARS-CoV-2 induced neurologic damage are also discussed.

The neurological sequelae of pandemics and epidemics

Neurological manifestations in pandemics frequently cause short and long-term consequences which are frequently overlooked. Despite advances in the treatment of infectious diseases, nervous system involvement remains a challenge, with limited treatments often available. The under-recognition of neurological manifestations may lead to an increase in the burden of acute disease as well as secondary complications with long-term consequences. Nervous system infection or dysfunction during pandemics is common and its enduring consequences, especially among vulnerable populations, are frequently forgotten. An improved understanding the possible mechanisms of neurological damage during epidemics, and increased recognition of the possible manifestations is fundamental to bring insights when dealing with future outbreaks. To reverse this gap in knowledge, we reviewed all the pandemics, large and important epidemics of human history in which neurological manifestations are evident, and described the possible physiological processes that leads to the adverse sequelae caused or triggered by those pathogens.

Trends in Optic Neuritis Incidence and Prevalence in the UK and Association With Systemic and Neurologic Disease

Importance

Epidemiologic data on optic neuritis (ON) incidence and associations with immune-mediated inflammatory diseases (IMIDs) are sparse.

Objective

To estimate 22-year trends in ON prevalence and incidence and association with IMIDs in the United Kingdom.

Design, Setting, and Participants

This cohort study analyzed data from The Health Improvement Network from January 1, 1995, to September 1, 2019. The study included 10 937 511 patients 1 year or older with 75.2 million person-years' follow-up. Annual ON incidence rates were estimated yearly (January 1, 1997, to December 31, 2018), and annual ON prevalence was estimated by performing sequential cross-sectional studies on data collected on January 1 each year for the same period. Data for 1995, 1996, and 2019 were excluded as incomplete. Risk factors for ON were explored in a cohort analysis from January 1, 1997, to December 31, 2018. Matched case-control and retrospective cohort studies were performed using data from January 1, 1995, to September 1, 2019, to explore the odds of antecedent diagnosis and hazard of incident diagnosis of 66 IMIDs in patients compared with controls.

Exposures

Optic neuritis.

Main Outcomes and Measures

Annual point prevalence and incidence rates of ON, adjusted incident rate ratios (IRRs) for risk factors, and adjusted odds ratios (ORs) and adjusted hazard ratios (HRs) for 66 IMIDs.

Results

A total of 10 937 511 patients (median [IQR] age at cohort entry, 32.6 [18.0-50.4] years; 5 571 282 [50.9%] female) were studied. A total of 1962 of 2826 patients (69.4%) with incident ON were female and 1192 of 1290 92.4%) were White, with a mean (SD) age of 35.6 (15.6) years. Overall incidence across 22 years was stable at 3.7 (95% CI, 3.6-3.9) per 100 000 person-years. Annual point prevalence (per 100 000 population) increased with database maturity, from 69.3 (95% CI, 57.2-81.3) in 1997 to 114.8 (95% CI, 111.0-118.6) in 2018. The highest risk of incident ON was associated with female sex, obesity, reproductive age, smoking, and residence at higher latitude, with significantly lower risk in South Asian or mixed race/ethnicity compared with White people. Patients with ON had significantly higher odds of prior multiple sclerosis (MS) (OR, 98.22; 95% CI, 65.40-147.52), syphilis (OR, 5.76; 95% CI, 1.39-23.96), Mycoplasma (OR, 3.90; 95% CI, 1.09-13.93), vasculitis (OR, 3.70; 95% CI, 1.68-8.15), sarcoidosis (OR, 2.50; 95% CI, 1.21-5.18), Epstein-Barr virus (OR, 2.29; 95% CI, 1.80-2.92), Crohn disease (OR, 1.97; 95% CI, 1.13-3.43), and psoriasis (OR, 1.28; 95% CI, 1.03-1.58). Patients with ON had a significantly higher hazard of incident MS (HR, 284.97; 95% CI, 167.85-483.81), Behçet disease (HR, 17.39; 95% CI, 1.55-195.53), sarcoidosis (HR, 14.80; 95% CI, 4.86-45.08), vasculitis (HR, 4.89; 95% CI, 1.82-13.10), Sjögren syndrome (HR, 3.48; 95% CI, 1.38-8.76), and herpetic infection (HR, 1.68; 95% CI, 1.24-2.28).

Conclusions and Relevance

The UK incidence of ON is stable. Even though predominantly associated with MS, ON has numerous other associations with IMIDs. Although individually rare, together these associations outnumber MS-associated ON and typically require urgent management to preserve sight.

Topical Ocular Povidone-Iodine as an Adjunctive Preventative Practice in the Era of COVID-19

ABSTRACT

Ophthalmologists and patients have an inherent increased risk for transmission of SARS-CoV-2. The human ocular surface expresses receptors and enzymes facilitating transmission of SARS-CoV-2. Personal protective equipment alone provides incomplete protection. Adjunctive topical ocular, nasal, and oral antisepsis with povidone iodine bolsters personal protective equipment in prevention of provider-patient transmission of SARS-CoV-2 in ophthalmology.

Neurological Sequelae in Patients with COVID-19: A Histopathological Perspective

BACKGROUND

Neuroinvasive properties of SARS-CoV-2 have allowed the hypothesis of several pathogenic mechanisms related to acute and chronic neurological sequelae. However, neuropathological correlates have been poorly systematically investigated, being retrieved from reports of single case or limited case series still.

METHODS

A PubMed search was carried out to review all publications on autopsy in subjects with "COronaVIrus Disease-19" (COVID-19). Among them, we focused on histological findings of the brain, which were compared with those from the authors' autoptic studies performed in some COVID-19 patients.

RESULTS

Only seven studies reported histological evidence of brain pathology in patients deceased for COVID-19, including three with reverse transcription-quantitative polymerase chain reaction evidence of viral infection. All these studies, in line with our experience, showed vascular-related and infection-related secondary inflammatory tissue damage due to an abnormal immune response. It is still unclear, however, whether these findings are the effect of a direct viral pathology or rather reflect a non-specific consequence of cardiovascular and pulmonary disease on the brain.

CONCLUSIONS

Notwithstanding the limited evidence available and the heterogeneity of the studies, we provide a preliminary description of the relationship between SARS-CoV-2 and brain sequelae. Systematic autoptic investigations are needed for accurate detection and adequate management of these patients.

Neurological Sequelae in Patients with COVID-19: A Histopathological Perspective

BACKGROUND

Neuroinvasive properties of SARS-CoV-2 have allowed the hypothesis of several pathogenic mechanisms related to acute and chronic neurological sequelae. However, neuropathological correlates have been poorly systematically investigated, being retrieved from reports of single case or limited case series still.

METHODS

A PubMed search was carried out to review all publications on autopsy in subjects with "COronaVIrus Disease-19" (COVID-19). Among them, we focused on histological findings of the brain, which were compared with those from the authors' autoptic studies performed in some COVID-19 patients.

RESULTS

Only seven studies reported histological evidence of brain pathology in patients deceased for COVID-19, including three with reverse transcription-quantitative polymerase chain reaction evidence of viral infection. All these studies, in line with our experience, showed vascular-related and infection-related secondary inflammatory tissue damage due to an abnormal immune response. It is still unclear, however, whether these findings are the effect of a direct viral pathology or rather reflect a non-specific consequence of cardiovascular and pulmonary disease on the brain.

CONCLUSIONS

Notwithstanding the limited evidence available and the heterogeneity of the studies, we provide a preliminary description of the relationship between SARS-CoV-2 and brain sequelae. Systematic autoptic investigations are needed for accurate detection and adequate management of these patients.

SARS-CoV-2 pathophysiology and its clinical implications: An integrative overview of the pharmacotherapeutic management of COVID-19

Common manifestations of COVID-19 are respiratory and can extend from mild symptoms to severe acute respiratory distress. The severity of the illness can also extend from mild disease to life-threatening acute respiratory distress syndrome (ARDS). SARS-CoV-2 infection can also affect the gastrointestinal tract, liver and pancreatic functions, leading to gastrointestinal symptoms. Moreover, SARS-CoV-2 can cause central and peripheral neurological manifestations, affect the cardiovascular system and promote renal dysfunction. Epidemiological data have indicated that cancer patients are at a higher risk of contracting the SARS-CoV-2 virus. Considering the multitude of clinical symptoms of COVID-19, the objective of the present review was to summarize their pathophysiology in previously healthy patients, as well as in those with comorbidities. The present review summarizes the current, though admittedly fluid knowledge on the pathophysiology and symptoms of COVID-19 infection. Although unclear issues still remain, the present study contributes to a more complete understanding of the disease, and may drive the direction of new research. The recognition of the severity of the clinical symptoms of COVID-19 is crucial for the specific therapeutic management of affected patients.

Emerging Neurological and Psychobiological Aspects of COVID-19 Infection

The SARS-CoV-2 virus, first reported in December 2019 in China, is the causative agent of the current COVID-19 pandemic that, at the time of writing (1 November 2020) has infected almost 43 million people and caused the death of more than 1 million people. The spectrum of clinical manifestations observed during COVID-19 infection varies from asymptomatic to critical life-threatening clinical conditions. Emerging evidence shows that COVID-19 affects far more organs than just the respiratory system, including the heart, kidneys, blood vessels, liver, as well as the central nervous system (CNS) and the peripheral nervous system (PNS). It is also becoming clear that the neurological and psychological disturbances that occur during the acute phase of the infection may persist well beyond the recovery. The aim of this review is to propel further this emerging and relevant field of research related to the pathophysiology of neurological manifestation of COVID-19 infection (Neuro-COVID). We will summarize the PNS and CNS symptoms experienced by people with COVID-19 both during infection and in the recovery phase. Diagnostic and pharmacological findings in this field of study are strongly warranted to address the neurological and psychological symptoms of COVID-19.

COVID-19: A Review for the Pediatric Neurologist

Children are susceptible to infection with the novel coronavirus SARS-CoV-2. In this time of uncertainty, this review attempts to compile information that may be helpful to pediatric neurologists. This review consolidates current data on the disease associated with SARS-CoV-2, called COVID-19, and information from past coronavirus epidemics, to discuss diseases of pediatric neurology including Guillain-Barre syndrome (acute inflammatory demyelinating polyradiculoneuropathy); central demyelinating diseases like multiple sclerosis and acute disseminated encephalomyelitis; infantile spasms; febrile seizures; and maternal-fetal transmission of virus.

Neurological Aspects of SARS-CoV-2 Infection: Mechanisms and Manifestations

The human infection of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a public health emergency of international concern that has caused more than 16.8 million new cases and 662,000 deaths as of July 30, 2020. Although coronavirus disease 2019 (COVID-19), which is associated with this virus, mainly affects the lungs, recent evidence from clinical and pathological studies indicates that this pathogen has a broad infective ability to spread to extrapulmonary tissues, causing multiorgan failure in severely ill patients. In this regard, there is increasing preoccupation with the neuroinvasive potential of SARS-CoV-2 due to the observation of neurological manifestations in COVID-19 patients. This concern is also supported by the neurotropism previously documented in other human coronaviruses, including the 2002-2003 SARS-CoV-1 outbreak. Hence, in the current review article, we aimed to summarize the spectrum of neurological findings associated with COVID-19, which include signs of peripheral neuropathy, myopathy, olfactory dysfunction, meningoencephalitis, Guillain-Barré syndrome, and neuropsychiatric disorders. Furthermore, we analyze the mechanisms underlying such neurological sequela and discuss possible therapeutics for patients with neurological findings associated with COVID-19. Finally, we describe the host- and pathogen-specific factors that determine the tissue tropism of SARS-CoV-2 and possible routes employed by the virus to invade the nervous system from a pathophysiological and molecular perspective. In this manner, the current manuscript contributes to increasing the current understanding of the neurological aspects of COVID-19 and the impact of the current pandemic on the neurology field.

SARS-CoV-2 and the Nervous System: From Clinical Features to Molecular Mechanisms

Increasing evidence suggests that Severe Acute Respiratory Syndrome-coronavirus-2 (SARS-CoV-2) can also invade the central nervous system (CNS). However, findings available on its neurological manifestations and their pathogenic mechanisms have not yet been systematically addressed. A literature search on neurological complications reported in patients with COVID-19 until June 2020 produced a total of 23 studies. Overall, these papers report that patients may exhibit a wide range of neurological manifestations, including encephalopathy, encephalitis, seizures, cerebrovascular events, acute polyneuropathy, headache, hypogeusia, and hyposmia, as well as some non-specific symptoms. Whether these features can be an indirect and unspecific consequence of the pulmonary disease or a generalized inflammatory state on the CNS remains to be determined; also, they may rather reflect direct SARS-CoV-2-related neuronal damage. Hematogenous versus transsynaptic propagation, the role of the angiotensin II converting enzyme receptor-2, the spread across the blood-brain barrier, the impact of the hyperimmune response (the so-called "cytokine storm"), and the possibility of virus persistence within some CNS resident cells are still debated. The different levels and severity of neurotropism and neurovirulence in patients with COVID-19 might be explained by a combination of viral and host factors and by their interaction.

SARS-CoV-2 and the Nervous System: From Clinical Features to Molecular Mechanisms

Increasing evidence suggests that Severe Acute Respiratory Syndrome-coronavirus-2 (SARS-CoV-2) can also invade the central nervous system (CNS). However, findings available on its neurological manifestations and their pathogenic mechanisms have not yet been systematically addressed. A literature search on neurological complications reported in patients with COVID-19 until June 2020 produced a total of 23 studies. Overall, these papers report that patients may exhibit a wide range of neurological manifestations, including encephalopathy, encephalitis, seizures, cerebrovascular events, acute polyneuropathy, headache, hypogeusia, and hyposmia, as well as some non-specific symptoms. Whether these features can be an indirect and unspecific consequence of the pulmonary disease or a generalized inflammatory state on the CNS remains to be determined; also, they may rather reflect direct SARS-CoV-2-related neuronal damage. Hematogenous versus transsynaptic propagation, the role of the angiotensin II converting enzyme receptor-2, the spread across the blood-brain barrier, the impact of the hyperimmune response (the so-called "cytokine storm"), and the possibility of virus persistence within some CNS resident cells are still debated. The different levels and severity of neurotropism and neurovirulence in patients with COVID-19 might be explained by a combination of viral and host factors and by their interaction.

Neuropathogenic human coronaviruses: A review

Human Coronaviruses (HCoVs) have long been known as respiratory viruses. However, there are reports of neurological findings in HCoV infections, particularly in patients infected with the novel severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) amid Coronavirus disease 2019 (COVID‐19) pandemic. Therefore, it is essential to interpret the interaction of HCoVs and the nervous system and apply this understanding to the COVID‐19 pandemic. This review of the literature analyses how HCoVs, in general, and SARS‐CoV‐2, in particular, affect the nervous system, highlights the various underlying mechanisms, addresses the associated neurological and psychiatric manifestations, and identifies the neurological risk factors involved. This review of literature shows the magnitude of neurological conditions associated with HCoV infections, including SARS‐CoV‐2. This review emphasises, that, during HCoV outbreaks, such as COVID‐19, a focus on early detection of neurotropism, alertness for the resulting neurological complications, and the recognition of neurological risk factors are crucial to reduce the workload on hospitals, particularly intensive‐care units and neurological departments.

COVID-19 Infection and Neurological Complications: Present Findings and Future Predictions

The present outbreak caused by SARS-CoV-2, an influenza virus with neurotropic potential, presents with neurological manifestations in a large proportion of the affected individuals. Disorders of the central and peripheral nervous system are all present, while stroke, ataxia, seizures, and depressed level of consciousness are more common in severely affected patients. People with these severe complications are most likely elderly with medical comorbidities, especially hypertension and other vascular risk factors. However, postinfectious complications are also expected. Neurological disorders as sequelae of influenza viruses have been repeatedly documented in the past and include symptoms, signs, and diseases occurring during the acute phase and, not rarely, during follow-up. Postinfectious neurological complications are the result of the activation of immune mechanisms and can explain the insurgence of immune-mediated diseases, including the Guillain-Barré syndrome and other diseases of the central and peripheral nervous system that in the past occurred as complications of viral infections and occasionally with vaccines. For these reasons, the present outbreak calls for the introduction of surveillance systems to monitor changes in the frequency of several immune-mediated neurological diseases. These changes will determine a reorganization of the measures apt to describe the interaction between the virus, the environment, and the host in areas of different dimensions, from local communities to regions with several millions of inhabitants. The public health system, mainly primary care, needs to be strengthened to ensure that research and development efforts are directed toward right needs and directions. To cope with the present pandemic, better collaboration is required between international organizations along with more research funding, and tools in order to detect, treat, and prevent future epidemics.

Coronaviruses and Central Nervous System Manifestations

SARS-CoV-2 is a highly pathogenic coronavirus that has caused an ongoing worldwide pandemic. Emerging in Wuhan, China in December 2019, the virus has spread rapidly around the world. Corona virus disease 2019 (COVID-19), which is caused by SARS-CoV-2, has resulted in significant morbidity and mortality. The most prominent symptoms of SARS-CoV-2 infection are respiratory. However, accumulating evidence highlights involvement of the central nervous system (CNS). This includes headache, anosmia, meningoencephalitis, acute ischemic stroke, and several presumably post/para-infectious syndromes and altered mental status not explained by respiratory etiologies. Interestingly, previous studies in animal models emphasized the neurotropism of coronaviruses; thus, these CNS manifestations of COVID-19 are not surprising. This minireview scans the literature regarding the involvement of the CNS in coronavirus infections in general, and in regard to the recent SARS-CoV-2, specifically.

Coronavirus Infections in Children Including COVID-19: An Overview of the Epidemiology, Clinical Features, Diagnosis, Treatment and Prevention Options in Children

Coronaviruses (CoVs) are a large family of enveloped, single-stranded, zoonotic RNA viruses. Four CoVs commonly circulate among humans: HCoV2-229E, -HKU1, -NL63 and -OC43. However, CoVs can rapidly mutate and recombine leading to novel CoVs that can spread from animals to humans. The novel CoVs severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in 2002 and Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012. The 2019 novel coronavirus (SARS-CoV-2) is currently causing a severe outbreak of disease (termed COVID-19) in China and multiple other countries, threatening to cause a global pandemic. In humans, CoVs mostly cause respiratory and gastrointestinal symptoms. Clinical manifestations range from a common cold to more severe disease such as bronchitis, pneumonia, severe acute respiratory distress syndrome, multi-organ failure and even death. SARS-CoV, MERS-CoV and SARS-CoV-2 seem to less commonly affect children and to cause fewer symptoms and less severe disease in this age group compared with adults, and are associated with much lower case-fatality rates. Preliminary evidence suggests children are just as likely as adults to become infected with SARS-CoV-2 but are less likely to be symptomatic or develop severe symptoms. However, the importance of children in transmitting the virus remains uncertain. Children more often have gastrointestinal symptoms compared with adults. Most children with SARS-CoV present with fever, but this is not the case for the other novel CoVs. Many children affected by MERS-CoV are asymptomatic. The majority of children infected by novel CoVs have a documented household contact, often showing symptoms before them. In contrast, adults more often have a nosocomial exposure. In this review, we summarize epidemiologic, clinical and diagnostic findings, as well as treatment and prevention options for common circulating and novel CoVs infections in humans with a focus on infections in children.

Coronavirus Infections in Children Including COVID-19: An Overview of the Epidemiology, Clinical Features, Diagnosis, Treatment and Prevention Options in Children

Coronaviruses (CoVs) are a large family of enveloped, single-stranded, zoonotic RNA viruses. Four CoVs commonly circulate among humans: HCoV2-229E, -HKU1, -NL63 and -OC43. However, CoVs can rapidly mutate and recombine leading to novel CoVs that can spread from animals to humans. The novel CoVs severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in 2002 and Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012. The 2019 novel coronavirus (SARS-CoV-2) is currently causing a severe outbreak of disease (termed COVID-19) in China and multiple other countries, threatening to cause a global pandemic. In humans, CoVs mostly cause respiratory and gastrointestinal symptoms. Clinical manifestations range from a common cold to more severe disease such as bronchitis, pneumonia, severe acute respiratory distress syndrome, multi-organ failure and even death. SARS-CoV, MERS-CoV and SARS-CoV-2 seem to less commonly affect children and to cause fewer symptoms and less severe disease in this age group compared with adults, and are associated with much lower case-fatality rates. Preliminary evidence suggests children are just as likely as adults to become infected with SARS-CoV-2 but are less likely to be symptomatic or develop severe symptoms. However, the importance of children in transmitting the virus remains uncertain. Children more often have gastrointestinal symptoms compared with adults. Most children with SARS-CoV present with fever, but this is not the case for the other novel CoVs. Many children affected by MERS-CoV are asymptomatic. The majority of children infected by novel CoVs have a documented household contact, often showing symptoms before them. In contrast, adults more often have a nosocomial exposure. In this review, we summarize epidemiologic, clinical and diagnostic findings, as well as treatment and prevention options for common circulating and novel CoVs infections in humans with a focus on infections in children.

Autoimmunity in visual loss

There are a number of autoimmune disorders which can affect visual function. There are a very large number of mechanisms in the visual pathway which could potentially be the targets of autoimmune attack. In practice it is the retina and the anterior visual pathway (optic nerve and chiasm) that are recognised as being affected in autoimmune disorders. Multiple Sclerosis is one of the commonest causes of visual loss in young adults because of the frequency of attacks of optic neuritis in that condition, however the basis of the inflammation in Multiple Sclerosis and the confirmation of autoimmunity is lacking. The immune process is known to be highly unusual in that it is not systemic and confined to the CNS compartment. Previously an enigmatic partner to Multiple Sclerosis, Neuromyelitis Optica is now established to be autoimmune and two antibodies - to Aquaporin4 and to Myelin Oligodendrocyte Glycoprotein - have been implicated in the pathogenesis. The term Chronic Relapsing Inflammatory Optic Neuropathy is applied to those cases of optic neuritis which require long term immunosuppression and hence are presumed to be autoimmune but where no autoimmune pathogenesis has been confirmed. Optic neuritis occurring post-infection and post vaccination and conditions such as Systemic Lupus Erythematosus and various vasculitides may cause direct autoimmune attack to visual structures or indirect damage through occlusive vasculopathy. Chronic granulomatous disorders such as Sarcoidosis affect vision commonly by a variety of mechanisms, whether and how these are placed in the autoimmune panoply is unknown. As far as the retina is concerned Cancer Associated Retinopathy and Melanoma Associated Retinopathy are well characterised clinically but a candidate autoantibody (recoverin) is only described in the former disorder. Other, usually monophasic, focal retinal inflammatory disorders (Idiopathic Big Blind Spot Syndrome, Acute Zonal Occult Outer Retinopathy and Acute Macular Neuroretinitis) are of obscure pathogenesis but an autoimmune disorder of the post-infectious type is plausible. Visual loss in autoimmunity is an expanding field: the most significant advances in research have resulted from taking a well characterised phenotype and making educated guesses at the possible molecular targets of autoimmune attack.

Detection of coronavirus in the central nervous system of a child with acute disseminated encephalomyelitis

We present a case in which human coronavirus was detected in the cerebrospinal fluid of a child presumed to have acute disseminated encephalomyelitis. In murine models, coronavirus has been found to cause a chronic demyelinating condition that resembles multiple sclerosis. Additionally, there is in vitro evidence of human coronavirus's ability to infect neural cells. This case report provides additional support for the hypothesis that coronavirus may be an important etiologic factor in the pathogenesis of demyelinating disease in humans.

Molecular analysis of cerebrospinal fluid in viral diseases of the central nervous system

The use of nucleic acid (NA) amplification techniques has transformed the diagnosis of viral infections of the central nervous system (CNS). Because of their enhanced sensitivity, these methods enable detection of even low amounts of viral genomes in cerebrospinal fluid. Following more than 10 years of experience, the polymerase chain reaction or other NA-based amplification techniques are nowadays performed in most diagnostic laboratories and have become the test of choice for the diagnosis of several viral CNS infections, such as herpes encephalitis, enterovirus meningitis and other viral infections occurring in human immunodeficiency virus-infected persons. Furthermore, they have been useful to establish a viral etiology in neurological syndromes of dubious origin and to recognise unusual or poorly characterised CNS diseases. Quantitative methods have provided a valuable additional tool for clinical management of these diseases, whereas post-amplification techniques have enabled precise genome characterisation. Current efforts are aiming at further improvement of the diagnostic efficiency of molecular techniques, their speed and standardisation, and to reduce the costs. The most relevant NA amplification strategies and clinical applications of to date will be the object of this review.