Clinical presentation, etiology, and survival in adult acute encephalitis syndrome in rural Central India

Investigation of acute encephalitis syndrome with implementation of metagenomic next generation sequencing in Nepal

BACKGROUND

The causative agents of Acute Encephalitis Syndrome remain unknown in 68-75% of the cases. In Nepal, the cases are tested only for Japanese encephalitis, which constitutes only about 15% of the cases. However, there could be several organisms, including vaccine-preventable etiologies that cause acute encephalitis, when identified could direct public health efforts for prevention, including addressing gaps in vaccine coverage.

OBJECTIVES

This study employs metagenomic next-generation-sequencing in the investigation of underlying causative etiologies contributing to acute encephalitis syndrome in Nepal.

METHODS

In this study, we investigated 90, Japanese-encephalitis-negative, banked cerebrospinal fluid samples that were collected as part of a national surveillance network in 2016 and 2017. Randomization was done to include three age groups (< 5-years; 5-14-years; >15-years). Only some metadata (age and gender) were available. The investigation was performed in two batches which included total nucleic-acid extraction, followed by individual library preparation (DNA and RNA) and sequencing on Illumina iSeq100. The genomic data were interpreted using Chan Zuckerberg-ID and confirmed with polymerase-chain-reaction.

RESULTS

Human-alphaherpes-virus 2 and Enterovirus-B were seen in two samples. These hits were confirmed by qPCR and semi-nested PCR respectively. Most of the other samples were marred by low abundance of pathogen, possible freeze-thaw cycles, lack of process controls and associated clinical metadata.

CONCLUSION

From this study, two documented causative agents were revealed through metagenomic next-generation-sequencing. Insufficiency of clinical metadata, process controls, low pathogen abundance and absence of standard procedures to collect and store samples in nucleic-acid protectants could have impeded the study and incorporated ambiguity while correlating the identified hits to infection. Therefore, there is need of standardized procedures for sample collection, inclusion of process controls and clinical metadata. Despite challenging conditions, this study highlights the usefulness of mNGS to investigate diseases with unknown etiologies and guide development of adequate clinical-management-algorithms and outbreak investigations in Nepal.

The Worldwide Prevalence of Herpes Simplex Virus Encephalitis and Meningitis: A Systematic Review and Meta-Analysis

Given the relatively high frequency of central nervous system infections and considerable mor- tality and morbidity reported to be caused by herpes simplex viruses among the other viral agents, having a clear knowledge about their epidemiological profile seems necessary. This systematic review and meta-analysis aimed to determine the relative frequency and preva- lence of herpes simplex encephalitis and meningitis in patients tested for viral etiologies. A comprehensive systematic review was performed in PubMed, Scopus, and Web of Science databases, searching for studies on the prevalence and relative frequency of herpes sim- plex virus 1 and herpes simplex virus 2 encephalitis and meningitis. Seventy-one studies were included. Overall, the prevalence of herpes simplex virus encephalitis among patients tested was 8% (95% confidence interval, 6%-11%; I2 = 98%) and the prevalence of herpes simplex virus meningitis among aseptic patients tested was 4% (95% confidence interval, 3%-7%; I2 = 95%), and a significant difference was observed by region. The results of our subgroup analysis for herpes simplex virus encephalitis revealed a prevalence of 8% for pediatric patients and ado- lescents and 12% for adults. The results for herpes simplex virus meningitis showed a prevalence of 4% for pediatric patients and adolescents and 9% for adults. We observed significant differ- ences in the frequency of herpes simplex virus 1 and herpes simplex virus 2 detection rates by region. Having high rates of missed cases due to inadequate, highly sensitive paraclinical tests performed on patients with suspected viral central nervous system infection is one of the pos- sible factors. More studies are needed to detect the possible flaws in the process of diagnosis in different regions.

The Clinical Profile and Prognostic Factors Influencing Mortality in Patients With Acute Encephalitis Syndrome

Introduction Acute encephalitis syndrome (AES) is a significant global public health concern. AES is a disorder characterized by fever and altered mental status, and it is associated with considerable morbidity and mortality. There is a limited amount of existing literature on the clinical profile and prognostic markers that influence mortality in these patients. Our study seeks to comprehend the etiology, clinical characteristics, complications, and prognostic markers that impact mortality among patients with AES.  Methods The study was a prospective observational study conducted over 18 months, involving a sample size of 105 patients. Patients aged 12 years and older, who met the WHO case definition of Acute Encephalitis Syndrome (AES), were consecutively recruited for this study. The patients' details were recorded, including their medical history and physical and clinical examination findings upon admission. The extent of cognitive impairment was evaluated using the Glasgow Coma Scale (GCS). Additionally, the patient's presenting symptoms, any complications experienced during their hospital stay, and the mortality rate were documented. The etiology, MRI results of the brain, laboratory parameters, and the need for assisted ventilation were also recorded. In-hospital characteristics were analyzed using the t-test for continuous variables and the chi-square test for binary variables. The log-rank test was employed to identify the predictors with the most significant independent influence on prognosis. All participants were selected only after obtaining their written informed consent.  Results Most of the patients were in the age group of 21-30. 60% of the patients were male. Advanced age at presentation was associated with an increased risk of mortality (p-value=0.018). All patients presented to the hospital with symptoms of fever and altered sensorium. The most common agent isolated as the etiologic cause was HSV-1, found in 31.4% of the patients. 28.6% of the patients succumbed to death. The leading cause of death was raised intracranial pressure leading to hemorrhage in the brain. There was no significant correlation between the duration of symptoms and the primary outcome of death (p-value=0.498). The requirement for assisted ventilation was shown to increase the risk of death (p-value=0.001). A low GCS score at presentation was associated with a higher mortality rate (p-value=0.048).    Conclusions The factors that predict mortality in AES involve a complex interplay of patient demographics, viral etiology, clinical severity, neuroimaging findings, and the need for assisted ventilation. Integrating these factors into clinical practice would enable healthcare providers to make informed decisions regarding patient management and interventions. As our comprehension of AES continues to develop, forthcoming advancements in diagnostics and therapeutics could refine prognostic assessments further. These developments could open new avenues for enhancing outcomes and diminishing mortality rates in this complex neurological disorder.

Charting the Next Road Map for CSF Biomarkers in Alzheimer's Disease and Related Dementias

Clinical prediction of underlying pathologic substrates in people with Alzheimer's disease (AD) dementia or related dementia syndromes (ADRD) has limited accuracy. Etiologic biomarkers - including cerebrospinal fluid (CSF) levels of AD proteins and cerebral amyloid PET imaging - have greatly modernized disease-modifying clinical trials in AD, but their integration into medical practice has been slow. Beyond core CSF AD biomarkers (including beta-amyloid 1-42, total tau, and tau phosphorylated at threonine 181), novel biomarkers have been interrogated in single- and multi-centered studies with uneven rigor. Here, we review early expectations for ideal AD/ADRD biomarkers, assess these goals' future applicability, and propose study designs and performance thresholds for meeting these ideals with a focus on CSF biomarkers. We further propose three new characteristics: equity (oversampling of diverse populations in the design and testing of biomarkers), access (reasonable availability to 80% of people at risk for disease, along with pre- and post-biomarker processes), and reliability (thorough evaluation of pre-analytical and analytical factors influencing measurements and performance). Finally, we urge biomarker scientists to balance the desire and evidence for a biomarker to reflect its namesake function, indulge data- as well as theory-driven associations, re-visit the subset of rigorously measured CSF biomarkers in large datasets (such as Alzheimer's disease neuroimaging initiative), and resist the temptation to favor ease over fail-safe in the development phase. This shift from discovery to application, and from suspended disbelief to cogent ingenuity, should allow the AD/ADRD biomarker field to live up to its billing during the next phase of neurodegenerative disease research.

Characterizing dengue transmission in rural areas: A systematic review

Dengue has historically been considered an urban disease associated with dense human populations and the built environment. Recently, studies suggest increasing dengue virus (DENV) transmission in rural populations. It is unclear whether these reports reflect recent spread into rural areas or ongoing transmission that was previously unnoticed, and what mechanisms are driving this rural transmission. We conducted a systematic review to synthesize research on dengue in rural areas and apply this knowledge to summarize aspects of rurality used in current epidemiological studies of DENV transmission given changing and mixed environments. We described how authors defined rurality and how they defined mechanisms for rural dengue transmission. We systematically searched PubMed, Web of Science, and Embase for articles evaluating dengue prevalence or cumulative incidence in rural areas. A total of 106 articles published between 1958 and 2021 met our inclusion criteria. Overall, 56% (n = 22) of the 48 estimates that compared urban and rural settings reported rural dengue incidence as being as high or higher than in urban locations. In some rural areas, the force of infection appears to be increasing over time, as measured by increasing seroprevalence in children and thus likely decreasing age of first infection, suggesting that rural dengue transmission may be a relatively recent phenomenon. Authors characterized rural locations by many different factors, including population density and size, environmental and land use characteristics, and by comparing their context to urban areas. Hypothesized mechanisms for rural dengue transmission included travel, population size, urban infrastructure, vector and environmental factors, among other mechanisms. Strengthening our understanding of the relationship between rurality and dengue will require a more nuanced definition of rurality from the perspective of DENV transmission. Future studies should focus on characterizing details of study locations based on their environmental features, exposure histories, and movement dynamics to identify characteristics that may influence dengue transmission.

Etiological Profile and Clinico Epidemiological Patterns of Acute Encephalitis Syndrome in Tamil Nadu, India

Introduction

Establishing the etiological cause of acute encephalitis syndrome (AES) is challenging due to the distinct distribution of various etiological agents. This study aims to determine the etiological profiles of both viruses and bacteria and their associated clinico-epidemiological features among the AES suspected cases in Tamil Nadu, India.

Methods

Samples of 5136 suspected AES cases from January 2016 to December 2020 (5 years) were subjected to the detection of etiological agents for AES through serological and molecular diagnosis methods. Further, the clinical profile, age- and gender-wise susceptibility of cases, co-infection with other AES etiological agents, and seasonality pattern with respect to various etiological agents were examined.

Results

AES positivity was established in 1480 cases (28.82%) among the 5136 suspected cases and the positivity for male and female groups were 57.77% and 42.23%, respectively. The pediatric group was found to be more susceptible than others. Among the etiological agents tested, the Japanese encephalitis virus (JEV) was the predominant followed by Cytomegalovirus, Herpes Simplex virus, Epstein-Barr virus, Varicella Zoster virus, and others. Co-infection with other AES etiological agents was observed in 3.5% of AES-positive cases. Seasonality was observed only for vector-borne diseases such as JEV, dengue virus, and West Nile virus infections in this study.

Conclusion

AES was found to be a significant burden for Tamil Nadu with a diverse etiological spectrum including both sporadic and outbreak forms. Overlapping clinical manifestations of AES agents necessitate the development of region-specific diagnostic algorithm with distinct etiological profiles for early detection and effective case management.

Pathogen and Antibody Identification in Children with Encephalitis in Myanmar

OBJECTIVE

Prospective studies of encephalitis are rare in regions where encephalitis is prevalent, such as low middle-income Southeast Asian countries. We compared the diagnostic yield of local and advanced tests in cases of pediatric encephalitis in Myanmar.

METHODS

Children with suspected subacute or acute encephalitis at Yangon Children's Hospital, Yangon, Myanmar, were prospectively recruited from 2016-2018. Cohort 1 (n = 65) had locally available diagnostic testing, whereas cohort 2 (n = 38) had advanced tests for autoantibodies (ie, cell-based assays, tissue immunostaining, studies with cultured neurons) and infections (ie, BioFire FilmArray multiplex Meningitis/Encephalitis multiplex PCR panel, metagenomic sequencing, and pan-viral serologic testing [VirScan] of cerebrospinal fluid).

RESULTS

A total of 20 cases (13 in cohort 1 and 7 in cohort 2) were found to have illnesses other than encephalitis. Of the 52 remaining cases in cohort 1, 43 (83%) had presumed infectious encephalitis, of which 2 cases (4%) had a confirmed infectious etiology. Nine cases (17%) had presumed autoimmune encephalitis. Of the 31 cases in cohort 2, 23 (74%) had presumed infectious encephalitis, of which one (3%) had confirmed infectious etiology using local tests only, whereas 8 (26%) had presumed autoimmune encephalitis. Advanced tests confirmed an additional 10 (32%) infections, 4 (13%) possible infections, and 5 (16%) cases of N-methyl-D-aspartate receptor antibody encephalitis.

INTERPRETATION

Pediatric encephalitis is prevalent in Myanmar, and advanced technologies increase identification of treatable infectious and autoimmune causes. Developing affordable advanced tests to use globally represents a high clinical and research priority to improve the diagnosis and prognosis of encephalitis. ANN NEUROL 2023;93:615-628.

Arboviral Infections in Neurological Disorders in Hospitalized Patients in São José do Rio Preto, São Paulo, Brazil

Arbovirus infections are increasingly important causes of disease, whose spectrum of neurological manifestations are not fully known. This study sought to retrospectively assess the incidence of arboviruses in cerebrospinal fluid samples of patients with neurological symptoms to inform diagnosis of central and peripheral nervous system disorders. A total of 255 cerebrospinal fluid (CSF) samples collected from January 2016 to December 2017 were tested for dengue virus (DENV 1-4), Zika virus (ZIKV), and Chikungunya virus (CHIKV) in addition to other neurotropic arboviruses of interest, using genetic and serologic assays. Of the 255 CSF samples analyzed, 3.53% (09/255) were positive for arboviruses presenting mainly as meningitis, encephalitis, and cerebrovascular events, of which ZIKV was detected in 2.74% (7/255), DENV in 0.78% (2/255), in addition to an identified ILHV infection that was described previously. All the cases were detected in adults aged 18 to 74 years old. Our findings highlight the scientific and clinical importance of neurological syndromes associated with arboviruses and demonstrate the relevance of specific laboratory methods to achieve accurate diagnoses as well as highlight the true dimension of these diseases to ultimately improve public health planning and medical case management.

Evaluating cognitive outcomes in adult patients with acute encephalitis syndrome: a prospective study from a tertiary care center in Nepal

Purpose

Although cognitive impairment is a known complication of acute encephalitis syndrome (AES), few studies have evaluated cognitive outcomes in patients with encephalitis. The primary objective of this study was to assess the cognitive profiles of patients diagnosed with AES, which is pivotal for improving rehabilitation strategies and prognostic measures.

Methods

This study was conducted at the Tribhuvan University Teaching Hospital. Adult patients with AES who met inclusion criteria were enrolled. The Montreal Cognitive Assessment (MoCA) tool was used to assess cognitive function at admission, discharge, and 3-month follow-up.

Results

Thirty-six patients were enrolled in our study. The mean age of the participants was 43 ± 18 years. Fourteen patients (38.9%) were female, and 22 (61.1%) were male. Tuberculous (TB) meningoencephalitis was present in 14 cases (38.9%), with herpes simplex virus (HSV) encephalitis in 14 (38.9%), bacterial meningoencephalitis in 4 (11.1%), autoimmune encephalitis in 2 (5.6%), and Japanese encephalitis in 2 (5.6%). Patients with bacterial meningoencephalitis had the highest MoCA scores at admission, whereas those with HSV encephalitis had the highest scores at discharge and follow-up. Compared with the scores at admission, the scores at discharge and follow-up increased significantly in patients with TB meningoencephalitis and HSV encephalitis. The MoCA score at discharge was established as a significant predictor of cognitive function at follow-up.

Conclusion

We found that active treatment can improve the outcomes of AES patients with cognitive impairment. Although infectious etiologies are most common in low-income countries such as Nepal, autoimmune etiologies should not be overlooked.

Study of Demographic Profile, Etiology, and Clinical Outcome in Patients Admitted With Acute Encephalitis Syndrome From the Western Part of India

Background

Determining the etiology of encephalitis always remains a challenge to clinicians, and also, variables that predict outcome in acute phase settings are not known precisely. The autoimmune causes of acute encephalitis are increasing due to the availability of newer diagnostic markers, whereas earlier studies were primarily focused on infectious causes. We conducted a prospective study to determine the demographic profile, etiological aspect, and in-hospital outcome of patients admitted with acute encephalitis syndrome (AES) in our tertiary care center.

Materials and method

This observational prospective study was carried out at a tertiary care hospital between November 2016 and October 2018. With a sample size of 72, appropriate statistical analysis was done.

Results

The incidence of AES usually escalates during the rainy season, with arboviral etiologies being predominant. The majority of the patients with AES with a likely infectious etiology could not be diagnosed with presently available viral marker studies. Among various clinical variables, a low Glasgow Coma Scale (GCS) score on admission, a high CSF protein value, and diffusion restriction on brain MRI was associated with poor outcome.

Conclusion

Acute encephalitis and encephalitis-related mortality impose a considerable burden on current medical practice. The reported demographics of hospitalized patients with encephalitis may be changing, which are important factors to consider for etiological workup.

Childhood encephalitis hospitalizations associated with virus agents in medium-endemic states in India

BACKGROUND

Japanese encephalitis (JE) is the leading cause of childhood acute encephalitis syndrome (AES) in India. We enhanced the AES surveillance in sentinel hospitals to determine trends and virus etiologies in central India.

METHODS

The neurological hospitalizations among children ≤15 years were tracked by using the AES case definition implemented by the national program. Acute and convalescent sera along with cerebrospinal fluid (CSF) specimens were collected and tested at the strengthened site hospital laboratories for anti-JE, anti-Dengue and anti-Chikungunya virus by IgM ELISA; along with Chandipura virus RT-PCR. Herpes simplex and enterovirus testing was undertaken at the reference laboratory.

RESULTS

Among 1619 pediatric neurological hospitalizations reported during 2015-16, AES case definition was fulfilled in 332 (20.5%) cases. After excluding 52 non-AES cases, 280 AES cases resident from study districts were considered eligible for study. The treating physicians diagnosed non-viral causes in 90 cases, therefore 190 (67.9%) of 280 AES cases were suspected with viral etiologies. We enrolled 140 (73.7%) of 190 eligible AES cases. Viral etiologies were confirmed in 31 (22.1%) of 140 enrolled AES cases. JE (n = 22) was the leading cause. Additional non-JE viral agents included Chikungunya (5), Dengue (2) and Chandipura (2). However, only 21 (9.4%) of 222 additional AES cases referred from peripheral hospitals were confirmed as JE.

CONCLUSIONS

Japanese encephalitis virus continues to be the leading cause of childhood acute encephalitis syndrome in central India despite vaccination program. Surveillance needs to be intensified for assessing the true disease burden of Japanese encephalitis following vaccination program implementation.

Clinical spectrum, aetiology and predictors of acute febrile encephalopathy at a tertiary hospital in south India - A prospective observational study

Acute febrile encephalopathy is a common syndrome in the tropics with high mortality encountered by emergency physicians. In order to study the aetiology of acute febrile encephalopathy and its mortality and functional outcome over one year, data on all patients >18 years of age with short duration of fever (<14 days) and altered mental status were collected and followed up until one month after discharge. Non-infectious aetiology, found in 29%, portends a poor outcome.

Central nervous system infections in a tropical area: influence of emerging and rare infections

BACKGROUND AND PURPOSE

The frequency of infectious encephalitis and the distribution of causative pathogens in tropical areas are poorly known and may be influenced by emerging and rare infections. The aim was to characterize a large series of acute infectious encephalitis and myelitis in immunocompetent patients from the Caribbean island of Guadeloupe identifying clinical, biological and radiological features according to pathogens.

METHODS

Using a hospital database, detailed information on a comprehensive series of immunocompetent patients with acute infectious myelitis and encephalitis over the 2012-2018 period was retrospectively collected.

RESULTS

From 259 suspected cases with acute central nervous system infection, 171 cases were included for analysis, comprising 141 encephalitis, 22 myelitis and eight encephalomyelitis. The annual incidence peaked at 15.0/100 000 during the Zika 2016 outbreak. Children accounted for 22.2% of cases. Eight adults died during hospital stay, all encephalitis. Seventeen infectious agents, two of which had never been described in Guadeloupe so far, were identified in 101 cases (59.1%), including 35 confirmed cases (34.7%), 48 probable cases (47.5%), 15 possible cases (14.9%) and three clinical cases (3.0%). The most frequent etiologic agents were Zika virus in 23 cases (13.5%), herpes simplex in 12 (7.0%), varicella zoster virus in 11 (6.4%), dengue virus in 11 (6.4%) and leptospirosis in 11 (6.4%).

CONCLUSIONS

The Zika outbreak had a major influence on the annual incidence of acute central nervous system infection. Acute neuroleptospirosis is over-represented in our series. Further efforts are mandatory to develop new diagnostic tools for pathogen profiling.

Epidemiology of viral disease outbreaks in Odisha, India (2010-2019)

Despite consistent public health efforts, the burden of viral disease in India remains high. The present study was undertaken to understand the aetiology, frequency and distribution of viral disease outbreaks in the state of Odisha between 2010 and 2019. This was a prospective study conducted at the Virology Research and Diagnostic Laboratory located at ICMR-Regional Medical Research Centre, Bhubaneswar, Odisha, wherein all the outbreaks of viral aetiologies were investigated and analysed to provide a comprehensive picture of the state of viral disease outbreaks in the region. A total of 191 suspected viral outbreaks were investigated by the team from VRDL during September 2010 and September 2019 reported from all the 30 districts of Odisha. Annual number of suspected cases ranged from 185 to 1002. The most commonly suspected outbreaks were of viral hepatitis (55 outbreaks; 1223 cases) followed by dengue (45 outbreaks; 1185 cases), chickenpox (30 outbreaks; 421 cases), viral encephalitis (27 outbreaks; 930 cases), measles (23 outbreaks; 464 cases), chikungunya (10 outbreaks; 593 cases) and rubella (1 outbreak; 60). The outbreaks peaked in frequency and intensity during the months of July and September. The epidemiology of viral disease outbreaks in the region is presented in the study. Health system preparedness based on evidence is essential for early detection and adequate response to such viral outbreaks.

Clinico-epidemiological characteristics of hospitalized acute encephalitis syndrome children and their correlation with case fatality rate

Background:

Acute Encephalitis Syndrome (AES) in children contributes considerable morbidity and mortality in endemic region. A study was conducted to see the clinico-epidemiological characteristics of hospitalized AES children and to find out if there is any correlation of clinico-epidemiological factors with case fatality rate (CFR).

Methods:

This hospital-based observational prospective study was conducted in a tertiary care teaching hospital of Assam, India from 16^th May, 2019 to 15^th May, 2020. We enrolled clinically diagnosed 140 hospitalized AES children consecutively as per WHO case definition. Cerebrospinal fluid and serum samples were tested for JEV-specific IgM antibodies.

Results:

Out of 140 AES children 84 (60%) were male and 5–12 years age group had the highest 79 (56.4%) number of cases. Primarily cases were from rural areas 132 (94.3%). In addition to fever, major clinical manifestations were seizures 114 (81.4%), altered sensorium 128 (91.4%), meningeal signs 62 (44.3%), and <8 GCS 42 (30%). CFR was 27.7%. Significantly high CFR was seen among AES children with GCS <8 (P-value 0.0001) and presence of meningeal signs (P-value 0.0007). A higher proportion of non-survivors 55.6% were non JE AES. Monthly incidence of AES/Death showed a peak in the month of July.

Conclusion:

AES in children is a significant public health problem in the study area with high CFR. Presence of GCS <8 and meningeal irritation are the important predictors of mortality in AES children. Preponderance of non-JE AES case fatality in children warrant further exploration and appropriate public health interventions.

Clinical Features, Diagnosis, and Outcome of Encephalitis in French Guiana

The aim of our study was to describe the clinical features, the etiologies, and the factors associated with poor outcome of encephalitis in French Guiana. Our study was retrospective, including all cases of encephalitis hospitalized in the Cayenne General Hospital, from January 2007 to July 2017. Patients were included through the 2013 encephalitis consortium criteria and the outcome was evaluated using the Glasgow outcome scale at 3 months from the diagnosis of encephalitis. We included 108 patients, giving an approximate incidence rate of four cases/100,000 inhabitants/year. The origin of the encephalitis was diagnosed in 81 cases (75%), and 72 of them (66.7%) were from an infectious origin. The most common infectious causes were Cryptococcus sp. (18.5%) independently of the immune status, Toxoplasma gondii (13.9%), and Streptococcus pneumoniae (5.5%). In the follow-up, 48 patients (46.6%) had poor outcome. Independent risk factors associated with poor outcome at 3 months were “coming from inside area of the region” (P = 0.036, odds ratio [OR] = 4.19; CI 95% = 1.09–16.06), need for mechanical ventilation (P = 0.002, OR = 5.92; CI 95% = 1.95–17.95), and age ≥ 65 years (P = 0.049, OR = 3.99; CI 95% = 1.01–15.89). The most identified cause of encephalitis in French Guiana was Cryptococcus. The shape of the local epidemiology highlights the original infectious situation with some local specific pathogens.

Acute Encephalitis Syndrome in Gorakhpur, Uttar Pradesh, 2016: Clinical and Laboratory Findings

BACKGROUND

Seasonal outbreaks of acute encephalitis syndrome (AES) with high fatality have been occurring in Gorakhpur, Uttar Pradesh, India, for several years. We conducted investigations during the 2016 outbreak to identify the etiology.

METHODS

We included 407 hospitalized AES patients with cerebrospinal fluid pleocytosis (>5 cells/mm) in our study. These patients were clinically examined; their blood and cerebrospinal fluid samples were collected and investigated for scrub typhus (ST), Japanese encephalitis virus (JEV), dengue virus and spotted fever group of Rickettsia by serology and/or polymerase chain reaction.

RESULTS

Of the 407 AES patients, 266 (65.4%), 42 (10.3%) and 29 (7.1%) were diagnosed to have ST, JEV and dengue infection, respectively. Four patients were diagnosed to have spotted fever group of Rickettsia infection. A significantly higher proportion of ST patients with AES had hepatomegaly, splenomegaly and facial edema. The common hematologic and biochemical abnormalities among ST-positive patients include thrombocytopenia, raised liver enzymes and bilirubin levels. The case fatality ratio was significantly higher among ST-negative AES patients (36.2% vs. 15.2%; P < 0.05).

CONCLUSIONS

ST accounted for approximately two third of the AES case-patients. Efforts are required to identify the etiology of AES case-patients who are negative for ST, JEV and dengue fever.

Epidemiology of infectious encephalitis causes in 2016

We performed a literature search in the Medline database, using the PubMed website. The incidence of presumably infectious encephalitis is estimated at 1.5-7 cases/100,000 inhabitants/year, excluding epidemics. Infectious encephalitis and immune-mediated encephalitis share similar clinical signs and symptoms. The latter accounts for a significant proportion of presumably infectious encephalitis cases without any established etiological diagnosis; as shown from a prospective cohort study where 21% of cases were due to an immune cause. Several infectious agents are frequently reported in all studies: Herpes simplex virus (HSV) is the most frequent pathogen in 65% of studies, followed by Varicella-zoster virus (VZV) in several studies. Enteroviruses are also reported; being the most frequent viruses in two studies, and the 2nd or 3rd viruses in five other studies. There are important regional differences, especially in case of vector-borne transmission: Asia and the Japanese encephalitis virus, Eastern and Northern Europe/Eastern Russia and the tick-borne encephalitis virus, Northern America and Flavivirus or Alphavirus. Bacteria can also be incriminated: Mycobacterium tuberculosis and Listeria monocytogenes are the most frequent, after HSV and VZV, in a French prospective study. The epidemiology of encephalitis is constantly evolving. Epidemiological data may indicate the emergence and/or dissemination of new causative agents. The dissemination and emergence of causative agents are fostered by environmental, social, and economical changes, but prevention programs (vaccination, vector controls) help reduce the incidence of other infectious diseases and associated encephalitis (e.g., measles).

Encephalitic Arboviruses: Emergence, Clinical Presentation, and Neuropathogenesis

Arboviruses are arthropod-borne viruses that exhibit worldwide distribution, contributing to systemic and neurologic infections in a variety of geographical locations. Arboviruses are transmitted to vertebral hosts during blood feedings by mosquitoes, ticks, biting flies, mites, and nits. While the majority of arboviral infections do not lead to neuroinvasive forms of disease, they are among the most severe infectious risks to the health of the human central nervous system. The neurologic diseases caused by arboviruses include meningitis, encephalitis, myelitis, encephalomyelitis, neuritis, and myositis in which virus- and immune-mediated injury may lead to severe, persisting neurologic deficits or death. Here we will review the major families of emerging arboviruses that cause neurologic infections, their neuropathogenesis and host neuroimmunologic responses, and current strategies for treatment and prevention of neurologic infections they cause.

High prevalence of mumps in Lao People's Democratic Republic

In the Lao People's Democratic Republic (PDR), mumps is not a notifiable disease and mumps vaccine is currently not included in the routine childhood immunization programme. In order to assess the burden of disease, we investigated the seroprevalence of mumps-specific IgG antibodies across four provinces. In addition, we genetically characterized mumps viruses from the past 3 years from several outbreaks and single cases. Blood and/or throat swabs from suspected cases were investigated for specific IgM antibodies or viral RNA. Mumps cases occurred between March and November in 2011-2013 and 5- to 15-year-olds were most affected. Four sequences from an outbreak in the north of Lao PDR in 2011 were identical and belonged to genotype G. Eight sequences from two outbreaks and two individual cases from 2012 and 2013 belonged to genotype J. In addition, sera collected from 2379 healthy infants and school pupils aged between 9 months and 19 years and from pregnant women aged between 16 and 46 years were investigated for mumps-specific IgG. Overall, 58.2% were positive, 39.5% were negative and the remaining 2.3% were equivocal. The seropositivity increased with age, with the lowest percentage found in <1-year-old infants (9.1%) and the highest in the cohort of pregnant women (69.2%). More female subjects than male subjects were seropositive (60.4 vs. 54.9%). There were some differences between the locations. Mumps should be a notifiable disease in Lao PDR in order to get more accurate case numbers and cost estimates for public health-care, and vaccination of children and high-risk groups should be considered.

Aetiologies of central nervous system infections in adults in Kathmandu, Nepal: a prospective hospital-based study

We conducted a prospective hospital based study from February 2009-April 2011 to identify the possible pathogens of central nervous system (CNS) infections in adults admitted to a tertiary referral hospital (Patan Hospital) in Kathmandu, Nepal. The pathogens of CNS infections were confirmed in cerebrospinal fluid (CSF) using molecular diagnostics, culture (bacteria) and serology. 87 patients were recruited for the study and the etiological diagnosis was established in 38% (n = 33). The bacterial pathogens identified were Neisseria meningitidis (n = 6); Streptococcus pneumoniae (n = 5) and Staphylococcus aureus (n = 2) in 13/87(14%). Enteroviruses were found in 12/87 (13%); Herpes Simplex virus (HSV) in 2/87(2%). IgM against Japanese encephalitis virus (JEV) was detected in the CSF of 11/73 (15%) tested samples. This is the first prospective molecular and serology based CSF analysis in adults with CNS infections in Kathmandu, Nepal. JEV and enteroviruses were the most commonly detected pathogens in this setting.