Encephalitis Research Articles

Complex transmission epidemiology of neglected Australian arboviruses: diverse non-human vertebrate hosts and competent arthropod invertebrate vectors.

More than 75 arboviruses are indigenous to Australia, of which at least 13 are known to cause disease in humans. Alphaviruses are the most common arboviruses, notably including Ross River and Barmah Forest viruses, which contribute a significant public health and economic burden in Australia. Both can cause febrile illness with arthritic symptoms. Each circulates nationally across diverse climates and environments, and has multi-host, multi-vector dynamics. Several medically important flaviviruses also circulate in Australia. Infection with Murray Valley encephalitis or Kunjin viruses is less common but is associated with brain inflammation. Key research priorities for Australian arboviruses aim to understand clinical manifestations, develop timely diagnostics, and identify transmission cycles that permit the maintenance of arboviruses. While these can now be answered for a handful of notifiable alpha- and flaviviruses there are others for which non-human vertebrate hosts and competent arthropod invertebrate vectors are still to be identified and/or whose role in transmission is not well understood. One or more of these 'neglected' arboviruses may be the causative agent of a proportion of the many thousands of fever-related illnesses reported annually in Australia that at present remain undiagnosed. Here, what is known about enzootic cycling of viruses between arthropod vectors and mammalian and avian reservoir hosts is summarised. How and to what extent these interactions influence the epidemiology of arbovirus transmission and infection is discussed.

Secondary parkinsonism associated with focal brain lesions.

Focal imaging abnormalities in patients with parkinsonism suggest secondary etiology and require a distinctive clinical approach to diagnosis and treatment. We review different entities presenting as secondary parkinsonism associated with structural brain lesions, with emphasis on the clinical course and neuroimaging findings. Secondary parkinsonism may be due to vascular causes, hydrocephalus, space-occupying lesions, metabolic causes (including acquired hepatocerebral degeneration, diabetic uremic encephalopathy, basal ganglia calcifications, osmotic demyelination syndrome), hypoxic-ischaemic brain injury, intoxications (including methanol, carbon monoxide, cyanide, carbon disulfide, manganese poisoning and illicit drugs), infections and immune causes. The onset can vary from acute to chronic. Both uni-and bilateral presentations are possible. Rigidity, bradykinesia and gait abnormalities are more common than rest tremor. Coexisting other movement disorders and additional associated neurological signs may point to the underlying diagnosis. Neuroimaging studies are an essential part in the diagnostic work-up of secondary parkinsonism and may point directly to the underlying etiology. We focus primarily on magnetic resonance imaging to illustrate how structural imaging combined with neurological assessment can lead to diagnosis. It is crucial that typical imaging abnormalities are recognized within the relevant clinical context. Many forms of secondary parkinsonism are reversible with elimination of the specific cause, while some may benefit from symptomatic treatment. This heterogeneous group of acquired disorders has also helped shape our knowledge of Parkinson's disease and basal ganglia pathophysiology, while more recent findings in the field garner support for the network perspective on brain function and neurological disorders.

Gestational diabetes mellitus, not obesity, triggers postpartum brain inflammation and premature aging in Sprague-Dawley rats

Previous studies showed that women with gestational diabetes mellitus (GDM) are susceptible to cognitive dysfunction. We investigated the effects of GDM on brain pathologies and premature brain aging in rats. Seven-week-old female Sprague-Dawley rats were fed a normal diet (ND) or a high-fat diet (HFD) after two weeks of acclimatization. On pregnancy day 0, HFD-treated rats received streptozotocin (GDM group) or vehicle (Obese mothers). ND-treated rats received vehicle (ND-control mothers). On postpartum day 21, brains and blood were collected. The GDM group showed increased inflammatory and premature aging markers, mitochondrial changes, and compensatory increases in the blood–brain barrier and synaptic proteins in the prefrontal cortex and hippocampus. GDM triggers maternal brain inflammation and premature aging, suggesting compensatory mechanisms may protect against these effects.

Fetal Zika virus inoculation in macaques revealed control of the fetal viral load during pregnancy

BackgroundEarly pregnancy Zika virus (ZIKV) infection is associated with major brain damage in fetuses, leading to microcephaly in 0.6–5.0% of cases, but the underlying mechanisms remain largely unknown.MethodsTo understand the kinetics of ZIKV infection during fetal development in a nonhuman primate model, four cynomolgus macaque fetuses were exposed in utero through echo-guided intramuscular inoculation with 103 PFU of ZIKV at 70–80 days of gestation, 2 controls were mock inoculated. Clinical, immuno-virological and ultrasound imaging follow-ups of the mother/fetus pairs were performed until autopsy after cesarean section 1 or 2 months after exposure (n = 3 per group).ResultsZIKV was transmitted from the fetus to the mother and then replicate in the peripheral blood of the mother from week 1 to 4 postexposure. Infected fetal brains tended to be smaller than those of controls, but not the femur lengths. High level of viral RNA ws found after the first month in brain tissues and placenta. Thereafter, there was partial control of the virus in the fetus, resulting in a decreased number of infected tissue sections and a decreased viral load. Immune cellular and humoral responses were effectively induced.ConclusionsZIKV infection during the second trimester of gestation induces short-term brain injury, and although viral genomes persist in tissues, most of the virus is cleared before delivery.

Impact of vaccination against Japanese encephalitis in endemic countries.

Japanese encephalitis (JE) virus is the leading cause of vaccine-preventable encephalitis and a significant cause of disability in Asia and the western Pacific. Many countries have introduced JE vaccination programs, including several low resource countries following WHO's prioritization of JE vaccination in 2006. We sought to characterize the public health impact of JE vaccination programs. JE case data and vaccination coverage rates, were requested from country health officials in 23 JE endemic countries and Chinese Taipei. Additional data were extracted from meeting presentations and published literature. JE incidence was compared before and after vaccination using a minimum three year period pre and post program introduction or expansion. Data suitable for analysis were available for 13 JE-endemic countries and Chinese Taipei, for either all age groups or for children aged under 15 years only. Five countries and Chinese Taipei introduced vaccine prior to 2006 and the all-age JE incidence was reduced by 73-100% in about 5-20 years following introduction. Six countries have introduced JE vaccine since 2006, and JE incidence in children aged younger than 15 years has been reduced by 14-79% as of 2015-2021. JE-specific data were unavailable before introduction in Thailand and Vietnam, but vaccination programs reduced acute encephalitis incidence by 80% and 74%, respectively. Even in the programs with greatest impact, it took several years to achieve their results. JE vaccination has greatly reduced JE in 13 JE-endemic countries and Chinese Taipei. Highest impact has been observed in countries that introduced prior to 2006, but it often took roughly two decades and substantial resources to achieve that level of success. For greatest possible impact, more recently introducing countries and funding agencies should commit to continuous improvements in delivery systems to sustain coverage after initial vaccine introduction.

Encephalitis lethargica: clinical features and aetiology.

Encephalitis lethargica, an epidemic neurological illness, typically involved a severe sleep disorder and progressive parkinsonism. A century later, our understanding relies on seminal descriptions, more recent historical research and the study of small numbers of possible sporadic cases. Theories around infection, environmental toxins, catatonia and autoimmune encephalitis have been proposed. We aimed to describe the presentation of encephalitis lethargica and test these diagnostic and aetiological theories. Subjects with encephalitis lethargica were identified in the archives of the National Hospital for Neurology and Neurosurgery, UK between 1918 and 1946. Case notes were examined to establish illness temporality, clinical features and cerebrospinal fluid results. Controls from the archives were identified for 10% of cases, matching on discharge year, sex and neurologist. Clinical presentation was compared to modern diagnostic criteria for encephalitis lethargica, catatonia and autoimmune encephalitis. In a case-control design, a multilevel logistic regression was conducted to ascertain whether cases of encephalitis lethargica were associated with febrile illnesses and with environmental exposures. Six hundred and fourteen cases of encephalitis lethargica and 65 controls were identified. Cases had a median age of 29 years (interquartile range 18) and a median time since symptomatic onset of 3.00 years (interquartile range 3.52). Motor features were present in 97.6%, cranial nerve findings in 91.0%, ophthalmological features in 77.4%, sleep disorders in 66.1%, gastrointestinal or nutritional features in 62.1%, speech disorders in 60.8% and psychiatric features in 53.9%. Of the 167 cases who underwent lumbar puncture, 20 (12.0%) had a pleocytosis. The Howard and Lees criteria for encephalitis lethargica had a sensitivity of 28.5% and specificity of 96.9%. Among the cases, 195 (31.8%, 95% confidence interval 28.1-35.6%) had a history of febrile illness within one calendar year prior to illness onset, which was more common than among the controls (odds ratio 2.70, 95% confidence interval 1.02-7.20, P = 0.05), but there was substantial reporting bias. There was no evidence that occupational exposure to solvents or heavy metals was associated with encephalitis lethargica. Two hundred and seventy-six (45.0%) of the cases might meet criteria for possible autoimmune encephalitis, but only 3 (0.5%) might meet criteria for probable NMDA receptor encephalitis. Only 11 cases (1.8%) met criteria for catatonia. Encephalitis lethargica has a distinct identity as a neuropsychiatric condition with a wide range of clinical features. Evidence for a relationship with infectious or occupational exposures was weak. Autoimmune encephalitis may be an explanation, but typical cases were inconsistent with NMDA receptor encephalitis.

RIPK1 inhibition mitigates neuroinflammation and rescues depressive-like behaviors in a mouse model of LPS-induced depression

BackgroundDepression is often linked to inflammation in the brain. Researchers have been exploring ways to reduce this inflammation to improve depression symptoms. One potential target is a protein called RIPK1, which is known to contribute to brain inflammation. However, it’s unclear how RIPK1 influences depression. Our study aims to determine whether RIPK1 inhibition could alleviate neuroinflammation-associated depression and elucidate its underlying mechanisms.MethodsTo investigate our research objectives, we established a neuroinflammation mouse model by administering LPS. Behavioral and biochemical assessments were conducted on these mice. The findings were subsequently validated through in vitro experiments.ResultsUsing LPS-induced depression models, we investigated RIPK1’s role, observing depressive-like behaviors accompanied by elevated cytokines, IBA-1, GFAP levels, and increased inflammatory signaling molecules and NO/H2O2. Remarkably, Necrostatin (Nec-1 S), a RIPK1 inhibitor, mitigated these changes. We further found altered expression and phosphorylation of eIF4E, PI3K/AKT/mTOR, and synaptic proteins in hippocampal tissues, BV2, and N2a cells post-LPS treatment, which Nec-1 S also ameliorated. Importantly, eIF4E inhibition reversed some of the beneficial effects of Nec-1 S, suggesting a complex interaction between RIPK1 and eIF4E in LPS-induced neuroinflammation. Moreover, citronellol, a RIPK1 agonist, significantly altered eIF4E phosphorylation, indicating RIPK1’s potential upstream regulatory role in eIF4E and its contribution to neuroinflammation-associated depression.ConclusionThese findings propose RIPK1 as a pivotal mediator in regulating neuroinflammation and neural plasticity, highlighting its significance as a potential therapeutic target for depression.

The emergence of parvovirus B19 as a pathogen in acute encephalitis syndrome.

Despite scarcity of data, in recent years, human parvovirus B19 (PVB19) has been emerging as an important pathogen in acute encephalitis syndrome (AES). But, PVB19 virus is mostly looked for only after the exclusion of other common pathogens implicated in AES. Hence, this study was conducted to correlate clinical, radiological, and sequencing data to establish the crucial role of PVB19 in AES. Cerebrospinal fluid and/or serum samples were collected from AES patients as per WHO criteria and tested by ELISA, real-time PCR and bacterial culture sensitivity for various pathogens. PVB19 positive samples were subjected to sequencing. PVB19 attributed to 5% of total AES cases in the present study with fatalities in two of eight cases. Two isolates of PVB19 belonged to Genotype 1 A whereas one belonged to Genotype 3B. On multivariate analysis of predictive symptoms of PVB19 AES cases, blurring of vision (odds ratio [OR] 20.67; p = 0.001) was found to be significant independent predictor of PVB19 AES. Six of eight patients (two encephalitis specific and four nonspecific) had abnormal radiological findings. Hence, being an emerging viral pathogen, PVB19 should be included in the diagnostic algorithm of AES for prompt diagnosis and definitive management to prevent undesired neurological sequelae.

Add-on homeopathic treatment to institutional management protocol in children suffering from acute encephalitis syndrome: A retrospective comparative cohort study

Background and objectives: Acute encephalitis syndrome is a health burden to a populous country like India. It is characterized by a sudden onset of fever, altered sensorium with or without seizures, irritability, abnormal behaviour, or unconsciousness. This study aims to augment further evidence on the effects of add-on homeopathic treatment in reducing mortality and morbidity in children. Methods: This comparative retrospective study included children hospitalized with acute encephalitis syndrome between July 2016 to December 2016. We compared the parameters of children for whom decisions on Glasgow Outcome scale and Liverpool outcome score aided by add-on homeopathy against those of children from the same year when the add-on homeopathy was not used. All the children were on conventional supportive care and treatment tailored to each child. We also counted the days until the resumption of oral feeding and the length of hospital stay. Results: Ordinal regression analysis on analyses on 622 children (IH +CSC=329; IMP only=293) was done. Odds of a shift towards increased recovery were superior in the homeopathy-added group than in the IMP group without adjustment (crude OR 2·30, 95% CI 1·66 to 3·20; p=0·0001) and with adjustment (adjusted OR 3.38, 95% CI 2·38 to 4.81; p=0·0001). There was 14.8% less mortality and 17.4% more recovery in the add-on homeopathy group compared to CSC alone. Individualized homeopathic remedies commonly used were: Belladonna (n =238), Stramonium (n =17), Opium (n = 14), Sulphur (n=11) and Hyoscyamus niger (n = 7). Conclusion : This retrospective cohort study advocates for add-on homoeopathy in children suffering acute encephalitis which can produce notable improvements in terms of mortality and morbidity. Further studies in different settings are warranted.

Re-emerging Chandipura vesiculovirus: A cause of concern for global health.

Chandipura vesiculovirus(CHPV) is an emerging neurotropic virus primarily affecting children and causing acute encephalitis syndrome (AES) in India. The virus, transmitted mainly by sand flies, has led to multiple outbreaks with high mortality rates, particularly in rural and resource-limited settings. CHPV infection is characterized by rapid disease progression, with symptoms ranging from fever and seizures to coma and death, often within 24 to 48h of onset. The current management of CHPV is limited to supportive care due to the lack of specific antiviral therapies. Diagnosis relies on laboratory methods such as RT-PCR, serology, and immunofluorescence, though these face challenges due to the rapid progression of the disease and the need for timely sample collection and analysis. Prevention strategies are focused on vector control through insecticide use and public health interventions, including community education and early detection programs. Despite some progress in understanding CHPV, significant research gaps remain, particularly in developing effective antiviral treatments and vaccines, understanding transmission dynamics, and improving diagnostic capabilities. The potential for the virus to spread globally due to factors like climate change and increased human movement underscores the need for international collaboration in surveillance and response efforts. Strengthening public health infrastructure, enhancing vector control measures, and fostering global partnerships are crucial steps toward mitigating the impact of CHPV and preventing future outbreaks. Continued research and proactive public health strategies are essential to protect vulnerable populations and control the spread of this potentially deadly virus.

Diagnostic Dilemma between Scrub Typhus Meningoencephalitis and Dengue Encephalopathy Resolved! - A Novel Prediction Score.

Scrub typhus and dengue, common etiologies of acute encephalitis syndrome, present with similar clinico-laboratory profiles but differ in management protocol. We aimed to devise a score differentiating between scrub typhus meningoencephalitis (STM) and dengue encephalopathy (DE). A prospective cohort of 204 children, (aged 6 months to 14 years) presenting with acute encephalitis syndrome in a public teaching hospital in northern India was subjected to standardized workup including serum IgM against Orientia tsutsugamushi and Dengue virus. Clinico-laboratory features were compared between STM and DE using univariate and multivariate analysis. Area under the receiver operating characteristic (ROC) curve (AUROC) for the score derived from independent predictors and its sensitivity, specificity, predictive values was calculated at cutoffs. STM and DE IgM ELISA were positive in 38 (18.6%) and 41 (20.1%) children, respectively. Longer duration of fever, prodromal stage, respiratory complaints and pneumonia were significantly frequent in STM; however, swelling, petechiae and myalgia were significantly prevalent in DE. STM had higher blood total leukocyte count (TLC), higher CSF protein and lower CSF sugar compared to DE. At admission, TLC >10,000/mm3, pneumonia, absence of myalgia and petechiae were independent predictors for differentiating STM from DE. AUROC of novel score (range: -5 to 5) was 0.879 (95% CI: 0.805-0.952). Score at cutoff ≥5 had 100% specificity and 100% PPV for differentiating STM from DE. Prediction score may benefit physicians to differentiate between these two infections and treat them accordingly.

Is The Peri-Implantitis Involved With Brain Inflammation And May Contribute To Neurodegenerative Disorders?

Oral rehabilitation encompasses the restoration of oral function, addressing issues related to the teeth, gums, and other oral structures. Dental implants have become the gold standard for the replacement of single or multiple missing teeth, but in individuals with poor oral hygiene, the accumulation of dental plaque biofilm can trigger a local immune and inflammatory host response leading to peri-implant mucositis (a reversible condition with localized therapies) or peri-implantitis (characterized by bone loss accompanied by a persistent immune and inflammatory host response). The presence of periodontal pathogens at sites with peri-implantitis has been reported in several studies, and there is extensive documentation of similarities in microbial profiles between periodontitis sites and peri-implantitis sites. Thus, periodontitis/apical periodontitis can reach distant organs, especially the brain. This can lead to the development or exacerbation of inflammatory conditions. Similarly, the microorganisms and their products responsible for inducing peri-implantitis can potentially cause inflammatory conditions in the brain like periodontitis/apical periodontitis. Then, it is plausible to infer that peri-implantitis may be used the same way to induce and/or potentialize brain inflammation

E3 ubiquitin ligase MARCH1 reduces inflammation and pyroptosis in cerebral ischemia-reperfusion injury via PCSK9 downregulation.

Pyroptosis has been regarded as caspase-1-mediated monocyte death that induces inflammation, showing a critical and detrimental role in the development of cerebral ischemia-reperfusion injury (IRI). MARCH1 is an E3 ubiquitin ligase that exerts potential anti-inflammatory functions. Therefore, the study probed into the significance of MARCH1 in inflammation and pyroptosis elicited by cerebral IRI. Middle cerebral artery occlusion/reperfusion (MCAO/R)-treated mice and oxygen glucose deprivation/reoxygenation (OGD/R)-treated hippocampal neurons were established to simulate cerebral IRI in vivo and in vitro. MARCH1 and PCSK9 expression was tested in MCAO/R-operated mice, and their interaction was identified by means of the cycloheximide assay and co-immunoprecipitation. The functional roles of MARCH1 and PCSK9 in cerebral IRI were subsequently determined by examining the neurological function, brain tissue changes, neuronal viability, inflammation, and pyroptosis through ectopic expression and knockdown experiments. PCSK9 expression was increased in the brain tissues of MCAO/R mice, while PCSK9 knockdown reduced brain damage and neurological deficits. Additionally, inflammation and pyroptosis were inhibited in OGD/R-exposed hippocampal neurons upon PCSK9 knockdown, accompanied by LDLR upregulation and NLRP3 inflammasome inactivation. Mechanistic experiments revealed that MARCH1 mediated ubiquitination and degradation of PCSK9, lowering PCSK9 protein expression. Furthermore, it was demonstrated that MARCH1 suppressed inflammation and pyroptosis after cerebral IRI by downregulating PCSK9 both in vivo and in vitro. Taken together, the present study demonstrate the protective effect of MARCH1 against cerebral IRI through PCSK9 downregulation, which might contribute to the discovery of new therapies for improving cerebral IRI.

Effects of fingolimod on focal and diffuse damage in patients with relapsing-remitting multiple sclerosis - The "EVOLUTION" study.

In multiple sclerosis (MS), MRI markers can measure the potential neuroprotective effects of fingolimod beyond its anti-inflammatory activity. In this study we aimed to comprehensively explore, in the real-word setting, whether fingolimod not only reduces clinical/MRI inflammatory activity, but also influences the progression of irreversible focal and whole brain damage in relapsing-remitting [RR] MS patients. The "EVOLUTION" study, a 24-month observational, prospective, single-arm, multicenter study, enrolled 261 RRMS patients who started fingolimod at 32 Italian MS centers and underwent biannual neurological assessments and annual MRI evaluations. Study outcomes included the proportions of evaluable RRMS patients achieving at 24months: (1) no new/enlarging T2-hyperintense white matter (WM) lesions and/or clinical relapses; (2) a modified classification of "No Evidence of Disease Activity 4" ("modified NEDA-4") defined as no new/enlarging T2-hyperintense WM lesions, clinical relapses, and 6-month confirmed disability progression, and a yearly percentage lateral ventricular volume change on T2-FLAIR images < 2%; (3) less than 40% of active lesions at baseline and month 12 evolving to permanent black holes (PBHs). At month 24, 76/160 (47.5%; 95% confidence interval [CI] = 39.8%;55.2%) RRMS patients had no clinical/MRI activity. Thirty-nine of 170 RRMS patients (22.9%; 95% CI = 16.6%;29.3%) achieved "modified NEDA-4" status. Forty-four of 72 RRMS patients (61.1%; 95% CI = 49.8%;72.4%) had less than 40% of active WM lesions evolving to PBHs. The study confirmed the established safety and tolerability profile of fingolimod. By comparing our results with those from the literature, the EVOLUTION study seems to indicate a neuroprotective effect of fingolimod, limiting inflammatory activity, brain atrophy and PBH development.

Anti-seizure Medications: Challenges and Opportunities.

Epilepsy is a chronic neurological condition characterized by unprovoked, recurrent seizures. There are several types of epilepsy, and the cause of the condition can vary. Some cases of epilepsy have a genetic component, while others may be caused by brain injuries, infections, or other underlying conditions. Treatment for epilepsy typically involves anti-seizure medications (ASMs), although different approaches, such as surgery or a special diet, may be considered in specific cases. The treatment aims to effectively manage and potentially eliminate seizures while minimizing any accompanying side effects. Many different ASMs are available, and the choice of medication depends on several factors, including the type of seizures, the patient's age, general health, and potential drug interactions. For the treatment of epilepsy, there have been significant advancements in recent decades, which have led to the approval of many different ASMs. Newer ASMs offer a broader range of mechanisms of action, improved tolerability profiles, and reduced drug interactions compared to older drugs. This review aims to discuss the pharmacological characteristics, clinical applications, effectiveness, and safety of ASMs, with a particular emphasis on various age groups, especially children. Moreover, this review seeks to provide a comprehensive understanding of ASM therapy for epilepsy management, assisting physicians in selecting suitable ASMs for their patients.

Brain-penetrant complement inhibition mitigates neurodegeneration in an Alzheimer's disease mouse model.

Complement activation is implicated in driving brain inflammation, self-cell damage and progression of injury in Alzheimer's disease and other neurodegenerative diseases. Here, we investigate the impact of brain delivery of a complement-blocking antibody on neurodegeneration in an Alzheimer's mouse model. We engineered a brain-penetrant recombinant antibody targeting the pro-inflammatory membrane attack complex. Systemic administration of this antibody in APPNL-G-F mice reduced brain levels of complement activation products, demonstrating successful brain entry and target engagement. Prolonged treatment decreased synapse loss, amyloid burden and brain inflammatory cytokine levels, concomitant with cognitive improvement compared to controls. These results underscore the potential of brain-penetrant complement-inhibiting drugs as promising therapeutics, targeting downstream of amyloid plaques in Alzheimer's disease.

Neurovirulence of Usutu virus in human fetal organotypic brain slice cultures partially resembles Zika and West Nile virus

Usutu (USUV), West Nile (WNV), and Zika virus (ZIKV) are neurotropic arthropod-borne viruses (arboviruses) that cause severe neurological disease in humans. However, USUV-associated neurological disease is rare, suggesting a block in entry to or infection of the brain. We determined the replication, cell tropism and neurovirulence of these arboviruses in human brain tissue using a well-characterized human fetal organotypic brain slice culture model. Furthermore, we assessed the efficacy of interferon-β and 2′C-methyl-cytidine, a synthetic nucleoside analogue, in restricting viral replication. All three arboviruses replicated within the brain slices, with WNV reaching the highest titers, and all primarily infected neuronal cells. USUV- and WNV-infected cells exhibited a shrunken morphology, not associated with detectable cell death. Pre-treatment with interferon-β inhibited replication of all arboviruses, while 2′C-methyl-cytidine reduced only USUV and ZIKV titers. Collectively, USUV can infect human brain tissue, showing similarities in tropism and neurovirulence as WNV and ZIKV. These data suggest that a blockade to infection of the human brain may not be the explanation for the low clinical incidence of USUV-associated neurological disease. However, USUV replicated more slowly and to lower titers than WNV, which could help to explain the reduced severity of neurological disease resulting from USUV infection.

Fatigue and depression at 8 weeks and 1 year after bacterial brain abscess and their relationship with cognitive status

ABSTRACT A bacterial brain abscess (BA) is a focal brain infection with largely unknown long-term implications. This prospective study assessed the frequency of fatigue and symptoms of depression at 8 weeks and 1 year after BA and examined the relationship between fatigue, depressive symptoms, and cognitive status. Twenty BA-patients (age 17–73; 45% female) were assessed for fatigue, depression, memory, and executive functions. Fatigue rates were 40-65% at 8 weeks and 25-33% at 1 year on various fatigue questionnaires. Patient Health Questionnaire indicated symptoms of depression in 10% at the 8-week follow-up only. Relevant comorbidities and vocational outcomes were not associated with fatigue or symptoms of depression. Mean fatigue scores improved significantly between the two-time points. Greater fatigue was related to subjective problems with working memory, inhibition, self-monitoring, and emotional control and worse objective verbal memory performance. Symptoms of depression were associated with one out of two fatigue measures. We conclude that fatigue is common in the first year after BA, and higher levels of fatigue are related to more cognitive problems. Symptoms of clinical depression were rare. These findings underscore fatigue as an important consequence of BA and emphasize the necessity for targeted rehabilitation interventions.

Porcine Astrovirus Infection in Brains of Pigs in Korea.

Recently, neurological diseases associated with astroviruses (AstVs) have been reported in pigs, ruminants, minks, and humans. In 2017, neuro-invasive porcine astrovirus (Ni-PAstV) 3 was detected in the central nervous system (CNS) of pigs with encephalomyelitis in Hungary and the USA. In the process of diagnosing domestic pigs exhibiting neurological signs, histopathologic lesions of non-suppurative encephalomyelitis with meningitis, neuronal vacuolation, and gliosis were detected, and PAstV was identified using reverse transcriptase PCR in CNS samples of four pigs in three farms from August to September in 2020, South Korea. Subsequently, the ORF2 region was successfully acquired from three brain samples, facilitating subsequent analysis. Four genotypes of PAstV (PAstV1, 3, 4, and 5) were detected, and coinfection of PAstV with multiple genotypes was observed in brain samples. This is the first study to report Ni-PAstV infection in pigs in South Korea.

Long Neuro-COVID-19: Current Mechanistic Views and Therapeutic Perspectives.

Long-lasting COVID-19 (long COVID) diseases constitute a real life-changing burden for many patients around the globe and, overall, can be considered societal and economic issues. They include a variety of symptoms, such as fatigue, loss of smell (anosmia), and neurological-cognitive sequelae, such as memory loss, anxiety, brain fog, acute encephalitis, and stroke, collectively called long neuro-COVID-19 (long neuro-COVID). They also include cardiopulmonary sequelae, such as myocardial infarction, pulmonary damage, fibrosis, gastrointestinal dysregulation, renal failure, and vascular endothelial dysregulation, and the onset of new diabetes, with each symptom usually being treated individually. The main unmet challenge is to understand the mechanisms of the pathophysiologic sequelae, in particular the neurological symptoms. This mini-review presents the main mechanistic hypotheses considered to explain the multiple long neuro-COVID symptoms, namely immune dysregulation and prolonged inflammation, persistent viral reservoirs, vascular and endothelial dysfunction, and the disruption of the neurotransmitter signaling along various paths. We suggest that the nucleoprotein N of SARS-CoV-2 constitutes a "hub" between the virus and the host inflammation, immunity, and neurotransmission.