The second half of 2005 saw one of the largest outbreaks of Japanese encephalitis in northern India in recent years. Dr. Tom Solomon writes that the best hope for controlling Japanese encephalitis ...lies in vaccination.
The second half of 2005 saw one of the largest outbreaks of Japanese encephalitis that has occurred in northern India in recent years. Cases were first reported in the state of Uttar Pradesh in July 2005; by November, there had been nearly 5000 cases and 1300 deaths, as well as outbreaks in neighboring Nepal. At the height of the outbreak, some hospitals had no beds available, and even their corridors were full of patients.
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Although the number of cases was especially high for this part of India, for Asia as a whole, the outbreak was nothing new. Unusual outbreaks of . . .
Japanese encephalitis is a mosquito-borne disease that occurs in Asia and is caused by Japanese encephalitis virus (JEV), a member of the genus Flavivirus. Although many flaviviruses can cause ...encephalitis, JEV causes particularly severe neurological manifestations. The virus causes loss of more disability-adjusted life years than any other arthropod-borne virus owing to the frequent neurological sequelae of the condition. Despite substantial advances in our understanding of Japanese encephalitis from in vitro studies and animal models, studies of pathogenesis and treatment in humans are lagging behind. Few mechanistic studies have been conducted in humans, and only four clinical trials of therapies for Japanese encephalitis have taken place in the past 10 years despite an estimated incidence of 69,000 cases per year. Previous trials for Japanese encephalitis might have been too small to detect important benefits of potential treatments. Many potential treatment targets exist for Japanese encephalitis, and pathogenesis and virological studies have uncovered mechanisms by which these drugs could work. In this Review, we summarize the epidemiology, clinical features, prevention and treatment of Japanese encephalitis and focus on potential new therapeutic strategies, based on repurposing existing compounds that are already suitable for human use and could be trialled without delay. We use our newly improved understanding of Japanese encephalitis pathogenesis to posit potential treatments and outline some of the many challenges that remain in tackling the disease in humans.
Scully and colleagues report 23 cases of abnormal clotting, primarily involving the cerebral veins, 6 to 24 days after the first dose of the ChAdOx1 nCoV-19 vaccine. The syndrome was incited by ...antibodies to platelet factor 4, independent of heparin therapy. Early recognition and avoidance of platelet transfusion are key.
Summary First isolated in California, USA, in 1969, enterovirus 71 (EV71) is a major public health issue across the Asia-Pacific region and beyond. The virus, which is closely related to ...polioviruses, mostly affects children and causes hand, foot, and mouth disease with neurological and systemic complications. Specific receptors for this virus are found on white blood cells, cells in the respiratory and gastrointestinal tract, and dendritic cells. Being an RNA virus, EV71 lacks a proofreading mechanism and is evolving rapidly, with new outbreaks occurring across Asia in regular cycles, and virus gene subgroups seem to differ in clinical epidemiological properties. The pathogenesis of the severe cardiopulmonary manifestations and the relative contributions of neurogenic pulmonary oedema, cardiac dysfunction, increased vascular permeability, and cytokine storm are controversial. Public health interventions to control outbreaks involve social distancing measures, but their effectiveness has not been fully assessed. Vaccines being developed include inactivated whole-virus, live attenuated, subviral particle, and DNA vaccines.
Summary Over the past several decades, the incidence of bacterial meningitis in children has decreased but there remains a significant burden of disease in adults, with a mortality of up to 30%. ...Although the pathogenesis of bacterial meningitis is not completely understood, knowledge of bacterial invasion and entry into the CNS is improving. Clinical features alone cannot determine whether meningitis is present and analysis of cerebrospinal fluid is essential for diagnosis. Newer technologies, such as multiplex PCR, and novel diagnostic platforms that incorporate proteomics and genetic sequencing, might help provide a quicker and more accurate diagnosis. Even with appropriate antimicrobial therapy, mortality is high and so attention has focused on adjunctive therapies; adjunctive corticosteroids are beneficial in certain circumstances. Any further improvements in outcome are likely to come from either modulation of the host response or novel approaches to therapy, rather than new antibiotics. Ultimately, the best hope to reduce the disease burden is with broadly protective vaccines.
The scientific community has responded to the coronavirus disease 2019 (COVID-19) pandemic by rapidly undertaking research to find effective strategies to reduce the burden of this disease. ...Encouragingly, researchers from a diverse array of fields are collectively working towards this goal. Research with infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is undertaken in high-containment laboratories; however, it is often desirable to work with samples at lower-containment levels. To facilitate the transfer of infectious samples from high-containment laboratories, we have tested methods commonly used to inactivate virus and prepare the sample for additional experiments. Incubation at 80°C, a range of detergents, Trizol reagents, and UV energies were successful at inactivating a high titer of SARS-CoV-2. Methanol and paraformaldehyde incubation of infected cells also inactivated the virus. These protocols can provide a framework for in-house inactivation of SARS-CoV-2 in other laboratories, ensuring the safe use of samples in lower-containment levels.
Summary HIV infection can result in stroke via several mechanisms, including opportunistic infection, vasculopathy, cardioembolism, and coagulopathy. However, the occurrence of stroke and HIV ...infection might often be coincidental. HIV-associated vasculopathy describes various cerebrovascular changes, including stenosis and aneurysm formation, vasculitis, and accelerated atherosclerosis, and might be caused directly or indirectly by HIV infection, although the mechanisms are controversial. HIV and associated infections contribute to chronic inflammation. Combination antiretroviral therapies (cART) are clearly beneficial, but can be atherogenic and could increase stroke risk. cART can prolong life, increasing the size of the ageing population at risk of stroke. Stroke management and prevention should include identification and treatment of the specific cause of stroke and stroke risk factors, and judicious adjustment of the cART regimen. Epidemiological, clinical, biological, and autopsy studies of risk, the pathogenesis of HIV-associated vasculopathy (particularly of arterial endothelial damage), the long-term effects of cART, and ideal stroke treatment in patients with HIV are needed, as are antiretrovirals that are without vascular risk.
Summary Although poliomyelitis has been mostly eradicated worldwide, large outbreaks of the related enterovirus 71 have been seen in Asia-Pacific countries in the past 10 years. This virus mostly ...affects children, manifesting as hand, foot, and mouth disease, aseptic meningitis, poliomyelitis-like acute flaccid paralysis, brainstem encephalitis, and other severe systemic disorders, including especially pulmonary oedema and cardiorespiratory collapse. Clinical predictors of severe disease include high temperature and lethargy, and lumbar puncture might reveal pleocytosis. Many diagnostic tests are available, but PCR of throat swabs and vesicle fluid, if available, is among the most efficient. Features of inflammation, particularly in the anterior horns of the spinal cord, the dorsal pons, and the medulla can be clearly seen on MRI. No established antiviral treatment is available. Intravenous immunoglobulin seems to be beneficial in severe disease, perhaps through non-specific anti-inflammatory mechanisms, but has not been tested in any formal trials. Milrinone might be helpful in patients with cardiac dysfunction.
IMPORTANCE: Antibodies to myelin oligodendrocyte glycoprotein IgG (MOG-IgG) are increasingly detected in patients with non–multiple sclerosis–related demyelination, some of whom manifest a ...neuromyelitis optica (NMO) phenotype. Cortical involvement, encephalopathy, and seizures are rare in aquaporin 4 antibody (AQP4-IgG)–related NMO in the white European population. However, the authors encountered several patients with seizures associated with MOG-IgG disease. OBJECTIVE: To compare incidence of seizures and encephalitis-like presentation, or both between AQP4-IgG–positive and MOG-IgG–positive patients. DESIGN, SETTING, AND PARTICIPANTS: Retrospective case series of all patients who were seropositive for MOG-IgG (n = 34) and the last 100 patients with AQP4-IgG disease (NMO spectrum disorder) seen in the NMO service between January 2013 and December 2016, and analysis was completed January 4, 2017. All patients were seen in a tertiary neurological center, The Walton Centre NHS Foundation Trust in Liverpool, England. MAIN OUTCOMES AND MEASURES: The difference in seizure frequency between the AQP4-IgG–positive and MOG-IgG–positive patient groups was determined. RESULTS: Thirty-four patients with MOG-IgG disease (20 female) with a median age at analysis of 30.5 years (interquartile range IQR, 15-69 years), and 100 AQP4-IgG–positive patients (86 female) with a median age at analysis of 54 years (IQR, 12-91 years) were studied. Most patients were of white race. Five of the 34 patients with MOG-IgG (14.7%) had seizures compared with 1 patient with AQP4-IgG (2-sided P < .008, Fisher test). On magnetic resonance imaging, all 5 MOG-IgG–positive patients had inflammatory cortical brain lesions associated with the seizures. In 3 of the 5 MOG-IgG–positive patients, seizures occurred as part of the index event. Four of the 5 presented with encephalopathy and seizures, and disease relapsed in all 5 patients. Four of these patients were receiving immunosuppressant medication at last follow-up, and 3 continued to take antiepileptic medication. In contrast, the only AQP4-IgG–positive patient with seizures had a diagnosis of complex partial epilepsy preceding the onset of NMO by several years and experienced no encephalitic illness; her magnetic resonance imaging results demonstrated no cortical, subcortical, or basal ganglia involvement. CONCLUSIONS AND RELEVANCE: Patients with MOG-IgG–associated disease were more likely to have seizures and encephalitis-like presentation than patients with AQP4-IgG–associated disease.
Antibodies to myelin oligodendrocyte glycoprotein (MOG-IgG) have been described in patients with neuromyelitis optica spectrum disorders (NMOSD) without aquaporin-4 antibodies (AQP4-IgG). We aimed to ...identify the proportion of AQP4-IgG-negative NMOSD patients who are seropositive for MOG-IgG. In a cross sectional study, we reviewed all patients seen in the National NMO clinic over the last 4 years (after the availability of MOG-IgG testing), including clinical information, MRI, and antibody tests. 261 unique patients were identified. 132 cases satisfied the 2015 NMOSD diagnostic criteria. Of these, 96 (73%) were AQP4-IgG positive and 36 (27%) were AQP4-IgG negative. These 36 patients were tested for MOG-IgG and 15/36 (42%) tested positive. 20% (25/125) of the patients who did not satisfy NMOSD criteria had MOG-IgG. Approximately half of seronegative NMOSD is MOG-Ig seropositive and one in five of non-NMOSD/non-MS demyelination is MOG-IgG positive. Since MOG-associated demyelinating disease is likely different from AQP4-IgG disease in terms of underlying disease mechanisms, relapse risk and possibly treatment, testing for MOG-IgG in patients with AQP4-IgG-negative NMOSD and other non-MS demyelination may have significant implications to management and clinical trials.
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