A cohort study to assess the new WHO Japanese encephalitis surveillance standards

Molecular and serological evidence of chikungunya virus infection with high case fatality among pediatric population with acute encephalitis syndrome: first report from Eastern Uttar Pradesh, India

Acute encephalitis syndrome (AES) outbreaks in children of Eastern Uttar Pradesh (E-UP) region of India have been a longstanding public health issue, with a significant case fatality rate of 20-25%. Since past decade, a rise in chikungunya (CHIK) cases has been occurring, which is a reported etiology of AES. However, the burden of chikungunya virus (CHIKV) among pediatric AES (pAES) is unknown from E-UP. We included 238 hospitalized pAES cases. The presence of IgM antibodies for CHIKV, and Dengue virus (DENV) was tested, and RT-PCR was performed for CHIKV and DENV in serologically confirmed CHIKV and DENV pAES cases. Positive samples were sequenced using Sangers sequencing. Further, to check for co-infection, IgM antibodies for other AES etiologies including Japanese encephalitis virus (JEV), Leptospira and Orientia tsutsugamushi (OT) in serum were also investigated. IgM ELISA demonstrated 5.04% (12) positivity for CHIKV. Among CHIKV IgM positive, 3 (25%, 3/12) pAES patients died. CHIKV genome was detected in 3 pAES specimens. Among which, 2 CHIKV cases were also positive for OT DNA. Partially sequenced CHIKV were genotyped as ECSA. The overall finding indicates evidence of CHIKV infection with high case fatality among pAES patients from E-UP. This study advocates constant serological and molecular surveillance of CHIKV in AES endemic regions of India.

Integration of IgM ELISA and 56 kDa gene PCR in management of pediatric acute encephalitis syndrome associated with scrub typhus

OBJECTIVES

To identify the potential target genes for detection of Orientia tsutsugamushi (OT) in pediatric acute encephalitis syndrome (pAES).

METHODS

DNA was extracted from whole blood of 100 pAES cases having tested positive (n = 41) and negative (n = 59) for scrub typhus (ST) by IgM ELISA. These samples were subjected to standard PCR for 56 kDa, 47 kDa, 16 s rRNA, groEL, traD genes and the newly identified 27 kDa gene.

RESULTS

Among the selected gene targets, 56 kDa demonstrated its superiority for OT detection over the other tested genes. The presence of OT was confirmed via PCR targeting 56 kDa gene in 17 out of the 41 (41.4 %) IgM-positive ST AES cases and 38 out of the 59 (64.4 %) ST IgM negative cases. None of the other gene targets were amplified.

CONCLUSION

Integration of serological diagnosis with molecular diagnostics targeting the 56 kDa gene for routine testing of AES patients would facilitate detection of OT in AES endemic regions.

Practice patterns in pediatric infectious encephalopathy in four centers in Africa

Introduction

Infectious encephalopathy (IE), including meningitis, infectious encephalitis, and cerebral abscess, remains prevalent and carries high mortality and morbidity in children, especially in low and middle income countries (LMIC). This study aims to describe the usual care and outcomes of pediatric IE in four LMIC hospitals in sub-Saharan Africa to support evidence-based care guideline development.

Methods

This is a secondary analysis of the Prevalence of Acute Critical Neurological disease in children: A Global Epidemiological Assessment-Developing Countries study, a 4-week, prospective, observational study in children (1 week to 17 years) with IE presenting to referral hospitals in Ethiopia, Kenya, Rwanda, and Ghana. Data collection included diagnostic testing, interventions, and patient outcomes [e.g., mortality, Pediatric Cerebral and Overall Performance Category Scores (PCPC and POPC)].

Results

Seventy-two children with IE were enrolled. Most patients were diagnosed with undifferentiated IE (78%, n = 56). Specific etiologies included cerebral malaria (10%, n = 7), viral encephalitis (4%, n = 3), tuberculosis (4%, n = 3), bacterial meningitis (3%, n = 2), and cerebral abscess (1%, n = 1). Fourteen patients (20%) had a head computed tomography performed. Thirty two (44%) children had a lumbar puncture but only 9 samples (28%) were sent for culture. Median time from diagnosis to antimicrobial therapy was 3 h (IQR 1-12 h). Half (51%, n = 33) of inpatients received intracranial pressure (ICP)-directed treatment but none underwent ICP monitoring. Mortality was 13% (n = 9). The percentage of children with a favorable cognitive score decreased from 95% (n = 62) prior to admission to 80% (n = 52) and 77% (n = 50) at discharge for PCPC and POPC respectively.

Discussion

IE led to considerable morbidity and mortality in this cohort, and evaluation and management varied across the care continuum. Resource limitations and diagnostic constraints may have affected diagnosis-directed therapy and other aspects of management. Further studies are needed to describe the epidemiology and management of IE in LMICs to inform future treatment protocols, the role of technological and human capacity building to support both basic monitoring and interventions, as well as creative new solutions to emergency and critical care in these settings.

The spatiotemporal distribution and prognostic factors of Japanese encephalitis in Shanxi Province, China, 2005-2022

Japanese encephalitis (JE) is a naturally occurring localized disease caused by the Japanese encephalitis virus, which is spread by the Culex tritaeniorhynchus. China has a high rate of JE. Shanxi, located in North China, has a high prevalence of adult JE. Adult JE has more severe complications, mortality, and a higher disease burden, making it a public health issue. This retrospective study examined the dynamic epidemic changes, high-risk areas of JE, and clinical characteristics and prognostic factors of adult JE in Shanxi Province. The findings revealed that July to September was the primary epidemic season of JE and that JE cases were mainly in individuals over the age of 40. The incidence of JE from 2005 to 2022 demonstrated a positive spatial correlation with significant clustering characteristics, with high-incidence clusters in the south and southeast. Multivariate logistic regression analysis revealed that higher cerebrospinal fluid pressure, higher white blood cell counts, higher neutrophil percentage, deep coma, and lower albumin were independent factors for poor prognosis of adult JE. The developed risk prediction model holds great promise in early prognosis assessment of patients, providing a basis for clinical decision-making and early clinical intervention.

Machine learning reveals neutrophil-to-lymphocyte ratio as a crucial prognostic indicator in severe Japanese encephalitis patients

Japanese encephalitis (JE) is a severe infectious disease affecting the central nervous system (CNS). However, limited risk factors have been identified for predicting poor prognosis (PP) in adults with severe JE. In this study, we analyzed clinical data from thirty-eight severe adult JE patients and compared them to thirty-three patients without organic CNS disease. Machine learning techniques employing branch-and-bound algorithms were used to identify clinical risk factors. Based on clinical outcomes, patients were categorized into two groups: the PP group (mRs ≥ 3) and the good prognosis (GP) group (mRs ≤ 2) at three months post-discharge. We found that the neutrophil-to-lymphocyte ratio (NLR) and the percentage of neutrophilic count (N%) were significantly higher in the PP group compared to the GP group. Conversely, the percentage of lymphocyte count (L%) was significantly lower in the PP group. Additionally, elevated levels of aspartate aminotransferase (AST) and blood glucose were observed in the PP group compared to the GP group. The clinical parameters most strongly correlated with prognosis, as indicated by Pearson correlation coefficient (PCC), were NLR (PCC 0.45) and blood glucose (PCC 0.45). In summary, our findings indicate that increased serum NLR, N%, decreased L%, abnormal glucose metabolism, and liver function impairment are risk factors associated with poor prognosis in severe adult JE patients.

Defining and measuring objective and subjective spinal stiffness: a scoping review

PURPOSE

Examine and identify the breadth of definitions and measures of objective and subjective spinal stiffness in the literature, with a focus on clinical implications.

METHODS

A scoping review was conducted to determine what is known about definitions and measures of the specific term of spinal stiffness. Following the framework by Arksey and O'Malley, eligible peer-reviewed studies identified using PubMed, Ebsco health, and Scopus were included if they reported definitions or measures of spinal stiffness. Using a data abstraction form, the studies were classified into four themes: biomechanical, surgical, pathophysiological, and segmental spinal assessment. To identify similarities and differences between studies, sixteen categories were generated.

RESULTS

In total, 2426 records were identified, and 410 met the eligibility criteria. There were 350 measures (132 subjective; 218 objective measures) and 93 indicators of spinal stiffness. The majority of studies (n = 69%) did not define stiffness.

CONCLUSION

This review highlights the breadth of objective and subjective measures that are both clinically and methodologically diverse. There is no consensus regarding a standardised definition of stiffness in the reviewed literature.

Comparison of Clinical Profile and Outcomes of Japanese Encephalitis and Acute Encephalitis Syndrome among Rural Children

The study compared the clinical profile and outcomes of Japanese encephalitis (JE) and acute encephalitis syndrome (AES) in children. Fifty-six consecutive children with symptoms fulfilling the WHO clinical case definition of AES from June 2018 to June 2020 were included in the study. All patients who tested positive for either serum or cerebrospinal fluid (CSF) anti-JE-IgM antibodies were JE patients (n = 24) and compared with non-JE AES cases (n = 32). Fever, seizures, and altered sensorium were the most common presenting symptoms. Low GCS, status epilepticus, meningeal irritation, raised CSF protein, and INR > 1.5 of JE children showed significant association with mortality (p value < 0.05), whereas only low GCS showed significant association in non-JE AES cases. The JE-specific mortality rate was 29%, which was less than the mortality rate of non-JE AES children at 41%. Both JE and non-JE AES children had a similar clinical profile, but only the JE children's poor clinical and laboratory parameters were associated with adverse outcomes.

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.

Molecular detection of spotted fever group of Rickettsiae in acute encephalitis syndrome cases from eastern Uttar Pradesh region of India

The Eastern Uttar Pradesh region of India is known for its endemicity of acute encephalitis syndrome (AES). Decades of research have established that Orientia tsutsugamushi, a causative of scrub typhus, is a substantial contributor (>60%) for the AES cases besides other aetiology, but additional factors in the remaining proportion are still unidentified. Rickettsial infections are challenging to diagnose in clinical settings due to overlapping clinical symptoms, the absence of definitive indicators, a low index of suspicion, and the lack of low-cost, rapid diagnostic tools. Hence, the present study was designed to determine the load of rickettsial infections among AES cases. Furthermore, we aim to find out the prevalent rickettsial species in AES cases as well as in the vector population at this location. The study included the whole blood/cerebrospinal fluid of AES patients and arthropod specimens from rodents. The molecular identification was performed using the 23S-5S intergenic spacer region and ompB gene with genomic DNA obtained from studied specimens. We detected 5.34% (62/1160) of rickettsial infection in AES cases. Among these, phylogenetic analysis confirmed the presence of 54.8% Rickettsia conorii (n = 34) and 16.1% of Rickettsia felis (n = 10), while the rest proportion of the isolates was unidentified at the species level. Furthermore, R. felis was identified in one CSF sample from AES patients and three flea samples from Xenopsylla cheopis. Rickettsia spp. was also confirmed in one Ornithonyssus bacoti mite sample. The results of this investigation concluded the presence of spotted fever group Rickettsia spp. among AES identified cases as well as in the mite and flea vectors that infest rodents.

Clinical Manifestations and Disability After Acute Encephalitis Syndrome Among Pediatric Patients in Eastern Uttar Pradesh: A Retrospective Analysis

Introduction Acute encephalitis syndrome (AES) in pediatric patients can lead to a range of disabilities, affecting various aspects of their daily lives. The disease is caused by a diverse group of pathogens including viruses, bacteria, fungi, and protozoans. While significant progress has been made in combating the acute phase of the disease, the lingering effects on the physical, cognitive, and emotional well-being of survivors have yet to be comprehensively explored. The present retrospective study was conducted to investigate disabilities including neurological squeals and functional impairment challenges faced by AES survivors as they navigate life with disabilities. Methods We conducted a comprehensive retrospective analysis of medical records of pediatric patients diagnosed with AES and evaluated their follow-up visits at regular intervals during the study period. The Liverpool scoring system and clinical examinations were utilized to assess the presence and severity of disabilities in the patients. Results A total of 134 pediatric AES patients were included in the study; among them, 56% were males, and 44% were females. The mean age of the participants was 4.8 ± 3.1 years, and the mean number of days of hospitalization was 27.8 ± 30.8. Only 9.7% of the patients were found to be Japanese encephalitis (JE)-positive, and 87.5% of the participants were found to have disabilities in some or the other domain of the Liverpool Outcome Score (LOS). There were statistically significant correlations between the age of the patients and the LOS at follow-up. Post-recovery disabilities were more severe among patients who required a prolonged duration of hospitalization. Conclusion A considerable proportion of AES survivors are left with disabilities. Causes other than Japanese encephalitis are now more frequent in AES. The need for prolonged hospitalization is related to more severe disabilities. The early identification of disabilities through the Liverpool scoring system and clinical examination can aid in implementing appropriate intervention strategies.

Individual and Herd-Level Seroprevalence in Association with Potential Risk Factors of Japanese Encephalitis in Pigs Collected from Urban, Periurban, and Rural Areas of Bali, Indonesia

A study to assess the seroprevalence antibodies against JEV in pigs in Denpasar, Badung, and Karangasem as the representatives of urban, periurban, and rural areas in the province of Bali was conducted. Sampled pigs' blood was collected and their sera were tested for antibody detection using commercial IgG ELISA. A standard questionnaire was used to interview the pig owners or farmers to identify the determinants associated with the seropositivity of the antibodies. Overall, 96.6% (95% CI: 94.5-98.1) of 443 pig sera in individual animal-level seroprevalence were seropositive to the ELISA. Karangasem had the highest test prevalence at 97.3% (95% CI: 93.1-99.2) while Badung had a slightly lower prevalence at 96.6% (95% CI: 92.2-98.9), and Denpasar had the lowest prevalence at 96% (95% CI: 91.5-98.5) (p=0.84). In herd-level seroprevalence, all sampled herds contained one or more seropositive pigs (overall herd-level seroprevalence 100% [95% CI: 97.7-100]). No animal-level factors were significantly associated with seropositivity (all p values >0.05). For the herd-level risk factors relating to pig management and husbandry practices adopted, no analysis model could be generated, as all the sampled herds were seropositive. More than 90% seroprevalence detected in this study indicates high natural JEV infection occurred in pigs, which highlights the high public health risk of the infection in the areas.

Clinical characteristics and short-term outcomes of Japanese encephalitis in pediatric and adult patients: a retrospective study in Northern China

Objective

The study aimed to compare the clinical characteristics and short-term outcomes of pediatric and adult Japanese encephalitis (JE) patients in order to find out the differences.

Methods

From August 2006 to October 2019, 107 patients (62 pediatric patients and 45 adult patients) with JE were enrolled. Clinical characteristics and short-term outcomes were analyzed. The short-term outcome of each patient was defined as a good outcome or poor outcome according to their Glasgow Coma Scale (GCS) scores (GCS > 8 vs. GCS ≤ 8) at discharge.

Results

As for acute complications, the incidence of pulmonary infection was higher in 25 adults (25/45, 55.6%) than in 19 children (19/62, 30.6%; P = 0.01). Upper gastrointestinal bleeding was more common in patients with pulmonary infection, with 10 of these patients experiencing the symptom (10/44, 22.7%) compared to only one patient without pulmonary infection (1/63, 1.6%; P = 0.001). The proportion of mechanical ventilation and admission to the intensive care unit (ICU) for supportive care was higher in patients with pulmonary infection than in patients without infection (P < 0.001, P = 0.008, respectively). The GCS scores at discharge in patients with pulmonary infection (7, 4-12.75) were lower than in patients without pulmonary infection (14, 10-14; P < 0.001). Although the GCS scores at the admission of children (9.5, 7-13) were similar to that of adults (7, 6-13), the GCS scores at the discharge of adults (7, 3.5-13) were lower than that of children (13, 10.75-14; P < 0.001).

Conclusion

The short-term outcome of JE was worse in adults. Pulmonary infection was correlated with a high incidence of upper gastrointestinal bleeding, mechanical ventilation, and ICU hospitalization in JE. Pulmonary infection is a prognostic predictor of short-term outcomes in patients with JE. Vaccination for adults should be initiated.

The Surveillance of Acute Encephalitis Syndrome in Thailand, 2003-2019: A Perspective for Prevention and Control

Background

Acute encephalitis syndrome (AES) is an infection of the central nervous system with high case-fatality rates. Japanese encephalitis virus (JEV) is the most common vaccine preventable cause of AES in Asia and part of the Western Pacific. In 2003, the JE vaccine was introduced into Thailand's National Immunization Program and expanded to all provinces. This study reviews data from the national surveillance system on the incidence of AES, including Japanese encephalitis in Thailand to guide surveillance, control, and prevention strategies.

Materials and Methods

We collected data on all patients diagnosed with AES and reported to the Bureau of Epidemiology, Ministry of Public Health, Thailand, from 2003 to 2019.

Results

A total of 9566 AES patients and 266 death cases were reported during these 17 years. Six hundred and forty-two (6.7%) patients were JE with 16 deaths. The incidence of AES increased from 0.47-0.51-1.36 cases per 100,000 population with a preponderance of cases in adults. CFR reduced from 6.25% - 6.94% in 2003-2005 to 0.78% in 2019. AES cases occurred all year round in all the age groups with a male predilection JE vaccination coverage had reached 83% by 2019. The patients were mainly from the north-eastern region of Thailand.

Conclusion

Integrated surveillance regular monitoring, strengthening, and making immunization sustainable is required to improve and maintain progress toward JE control and prevention.

Association of single nucleotide polymorphisms in the CD209, MMP9, TNFA and IFNG genes with susceptibility to Japanese encephalitis in children from North India

Japanese encephalitis (JE), an acute encephalitis syndrome disease caused by infection with JE virus (JEV), is an important mosquito borne disease in developing countries. The clinical outcomes of JEV infection show inter individual differences. Only in a minor percent of the infected subjects, the disease progresses into acute encephalitis syndrome. Single nucleotide polymorphisms in the host immune response related genes are known to affect susceptibility to JE. In the present study, 238 JE cases and 405 healthy controls (HCs) without any known history of encephalitis were investigated for SNPs in the CD209 MX1, TLR3, MMP9, TNFA and IFNG genes which are important in the immune response against JEV by PCR based methods. The results revealed higher frequencies of heterozygous genotypes of CD209 rs4804803, MMP9 rs17576, TNFA rs1800629 and IFNG rs2430561 in JE cases compared to HCs. These SNPs were associated with JE in an over-dominant genetic model (Odds ratio with 95% CI 1.51 (1.09-2.10) for CD209 rs4804803, 1.52 (1.09-2.11) for MMP9 rs17576, and 1.55 (1.12-2.15) for IFNG rs2430561). The association of G/A genotype of TNFA rs1800629 with JE was confirmed in a larger sample size. The results suggest the association of CD209 rs4804803, MMP9 rs17576, IFNG rs2430561 and TNFA rs1800629 polymorphisms with susceptibility to JE.

Changing spectrum of acute encephalitis syndrome in India and a syndromic approach

Acute encephalitis syndrome (AES) refers to an acute onset of fever and clinical neurological manifestation that includes mental confusion, disorientation, delirium, or coma, which may occur because of infectious or non-infectious causes. Cerebrospinal fluid (CSF) pleocytosis generally favors infectious etiology, and a normal CSF favors an encephalopathy or non-infectious AES. Among the infectious AES, viral, bacterial, rickettsial, fungal, and parasitic causes are the commonest. Geographical and seasonal clustering and other epidemiological characteristics are important in clinical decision making. Clinical markers like eschar, skin rash, myalgia, hepatosplenomegaly, thrombocytopenia, liver and kidney dysfunction, elevated serum CK, fronto-temporal or thalamic involvement on MRI, and anterior horn cell involvement are invaluable clues for the etiological diagnosis. Categorizing the AES cases into neurologic [Herpes simplex encephalitis (HSE), Japanese encephalitis (JE), and West Nile encephalitis (WNE)] and systemic (scrub typhus, malaria, dengue, and Chikungunya) helps in rational utilization of diagnostic and management resources. In neurological AES, cranial CT/MRI revealing frontotemporal lesion is consistent with HSE, and thalamic and basal ganglia lesions are consistent with JE. Cerebrospinal fluid nucleic acid detection test or IgM antibody for JE and HSE are confirmatory. Presence of frontotemporal involvement on MRI indicates acyclovir treatment pending virological confirmation. In systemic AES, CT/MRI, PCR for HSE and JE, and acyclovir therapy may not be useful, rather treatable etiologies such as malaria, scrub typhus, and leptospirosis should be looked for. If smear or antigen for malaria is positive, should receive antimalarial, if negative doxycycline and ceftriaxone should be started pending serological confirmation of scrub typhus, leptospira, or dengue. A syndromic approach of AES based on the prevalent infection in a geographical region may be developed, which may be cost-effective.

Long-term neurological and healthcare burden of adults with Japanese encephalitis: A nationwide study 2000-2015

Objective

To assess the healthcare utilization, economic burden, and long-term neurological complications and mortality of an adult population with Japanese encephalitis (JE).

Methods

This study utilized two nationwide datasets in Taiwan: the Notifiable Disease Dataset of confirmed cases from the Centers for Disease Control to identify JE patients, and the National Health Insurance Research Database to obtain patients’ healthcare utilization. Survival analyses were performed to identify prognostic factors associated with the all-cause mortality of patients.

Results

This study included 352 adult cases with JE (aged≥20 years). The mean age of JE patients was 45 years. Stroke (event rate: 3.49/100 person-years) was the most common neurological complication, followed by epilepsy/convulsions (3.13/100 person-years), encephalopathy/delirium (2.20/100 person-years), and parkinsonism (1.97/100 person-years). Among the 336 hospitalized patients at JE diagnosis, 58.33% required intensive care. Among 79 patients who died following JE diagnosis, 48.84% of death events occurred within the year of diagnosis. The medical costs increased considerably at JE diagnosis and subsequent-year costs remained significantly higher than the costs before diagnosis (p<0.05). Having a four-dose JE vaccination (i.e., born after 1976) versus no JE vaccination history (i.e., born before 1963) was significantly associated with lower all-cause mortality (hazard ratio: 0.221 [95% confidence interval: 0.067, 0.725]). Comorbid diabetes and incident epilepsy/convulsion events significantly increased the mortality risk by 2.47- and 1.85-fold, respectively (p<0.05).

Conclusion

A considerable medical burden associated with JE was observed in affected adults, even in the years following JE diagnosis. Vaccination should be considered to prevent this sporadic, but lethal, viral infection.

The epidemiology of adulthood Japanese encephalitis (JE) remains limited, and data on the economic burden associated with JE is lacking. This study is the first to comprehensively examine the healthcare burden (i.e., healthcare utilization and costs, neurological complications, all-cause mortality) of an adult population with JE, utilizing a nationwide cohort of JE-infected adults with up to 16 years of follow-up. In the first 6 months following JE diagnosis, a higher rate of neurological disorders was found, compared to the years after the diagnosis, with stroke being the most common neurological complication, followed by epilepsy/convulsions. The healthcare utilization of JE patients was higher in the first 6 months after the diagnosis compared to the years following the diagnosis. Medical costs increased considerably at JE diagnosis and subsequent-year costs after diagnosis remained higher than the cost before diagnosis. Having comorbid diabetes or incident epilepsy/convulsion events was a significant risk factor for mortality of adults with JE. Being born after 1976 in Taiwan, and thus likely receiving a four-dose schedule of vaccination, was associated with reduced mortality. Therefore, special attention is required for JE patients with comorbid diabetes or incident epilepsy/convulsion events, and JE vaccination should be considered to prevent this sporadic but lethal viral infection.

Risk factors for neurological complications in children with Flavivirus infection

This study aims to characterize the acute neurological manifestations caused by DENV, ZIKV, and YFV during hospitalization; identify the risk factors associated with persistent neurological complications after discharge; and evaluate the time to resolution during clinical follow-up. A prospective study evaluated 505 children, between March 2014 and July 2019, hospitalized with neurological manifestations and that doctors suspected infection of the central nervous system (CNS). Viral infection of collected cerebrospinal fluid (CSF) was confirmed by real-time reverse transcription-polymerase chain reaction (RT-PCR). Patients were clinically followed up after hospital discharge. Analysis of predictive factors and survival curves was performed. This study identified clinical symptoms and changes in the CSF laboratory, electroencephalogram (EEG), and CNS image as predictors of complications in children with confirmed infection in the CNS by DENV, ZIKV, or YFV. No statistical difference was found (p value 0.574) in the time to the resolution of complications in children after hospital discharge between the three types of flaviviruses. Children with YFV, detected in CSF samples, had a 53% higher risk of developing neurological complications. Performing etiological diagnosis by RT-PCR of CSF samples of children with neurological manifestations, especially during Flavivirus outbreaks, is an essential tool for improving the prognosis and clinical follow-up of these patients.

Molecular Detection and Genetic Characterization of Orientia tsutsugamushi from Hospitalized Acute Encephalitis Syndrome Cases During Two Consecutive Outbreaks in Eastern Uttar Pradesh, India

Background: Seasonal outbreaks of acute encephalitis syndrome (AES) have been reported especially in the pediatric population with a high case fatality rate in Eastern Uttar Pradesh, India. Orientia tsutsugamushi (OT) is a causative agent of scrub typhus that has been recently identified as a major cause of AES. However, the specific genotypes of OT responsible for AES cases of this region are not known. Therefore, the present study was undertaken to understand the molecular epidemiology of OT prevailing in the AES endemic Eastern Uttar Pradesh region of India. Methods: The study was conducted on 2529 hospitalized AES cases from August 2016 to December 2017. The presence of antibodies against OT from cerebrospinal fluid (CSF) and serum samples were tested using OT IgM enzyme-linked immunosorbent assay (ELISA), whereas OT DNA was tested from whole blood and CSF specimens targeting the partial gene of 56 kDa using nested PCR. Phylogenetic analysis was conducted with sequences (n = 241) generated in this study. Findings: Among the studied AES cases, 50% were found positive for antibodies against OT, whereas 37% of cases were positive for OT DNA. The genetic analysis study revealed that Gilliam (93.8%) is the prevailing genotype of OT followed by Karp (6.16%) genotype in AES cases. Furthermore, the Gilliam strains of this study showed they were >99% identical to earlier reported Gilliam strains from AES cases. Conclusion: We observed the presence of two main OT genotypes in AES cases, among which the majority of OT genotypes fall under the Gilliam clade. The understanding of predominant genotype will be beneficial for its future implications in vaccine development strategies and the development of rapid diagnostic tests.

Cerebrospinal Fluid and Serum C-Reactive Protein among Children with Acute Encephalitis Syndrome

Objectives This study aimed to evaluate the positivity of C-reactive protein (CRP) in cerebrospinal fluid (CSF) and serum in children presented with clinical diagnosis of acute encephalitis syndrome (AES).

Methods A total of 164 children between 6 months and 14 years with clinical diagnosis of AES were investigated. Qualitative CRP (slide agglutination) was determined in CSF and serum sample of each patient. On the basis of clinical examination and investigations, all the patients were divided into four groups as pyogenic meningitis, viral encephalitis, tuberculous meningitis, and cerebral malaria. The positivity of CRP in CSF and serum were compared in these groups.

Results CSF CRP was found to be positive in the majority of patients with pyogenic meningitis and a statistically significant (p ≤ 0.001) association was found between CSF CRP and final diagnosis of AES, while this association was nonsignificant (p = 0.141) in case of serum CRP. When we compared the CSF and serum CRP, serum CRP was found to be more suggestive of tuberculous meningitis, viral encephalitis, and cerebral malaria while CSF CRP was more sensitive and specific for the diagnosis of pyogenic meningitis.

Conclusion The sensitivity and specificity of CSF CRP for pyogenic meningitis was quite high. Serum CRP with a high sensitivity can be used as a screening test for different types of meningitis and cerebral malaria; however, its diagnostic accuracy has yet to be established.

A need to raise the bar - A systematic review of temporal trends in diagnostics for Japanese encephalitis virus infection, and perspectives for future research

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Japanese encephalitis virus (JEV) remains a leading cause of neurological infection in Asia.

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A systematic review identified 20,212 published human cases of laboratory-confirmed JEV infections from 205 studies.

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15,167 (75%) of cases were confirmed with the lowest confidence diagnostic test, i.e., level 3 or 4, or level 4.

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Only 109 (53%) of the studies reported contemporaneous testing for dengue-specific antibodies.

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A fundamental pre-requisite for the control of JE is lacking — that of a simple and specific diagnostic procedure that can be adapted for point-of-care tests and readily used throughout JE endemic regions of the world.

Objective

Japanese encephalitis virus infection (JE) remains a leading cause of neurological disease in Asia, mainly involving individuals living in remote areas with limited access to treatment centers and diagnostic facilities. Laboratory confirmation is fundamental for the justification and implementation of vaccination programs. We reviewed the literature on historical developments and current diagnostic capability worldwide, to identify knowledge gaps and instill urgency to address them.

Methods

Searches were performed in Web of Science and PubMed using the term 'Japanese encephalitis' up to 13th October 2019. Studies reporting laboratory-confirmed symptomatic JE cases in humans were included, and data on details of diagnostic tests were extracted. A JE case was classified according to confirmatory levels (Fischer et al., 2008; Campbell et al., 2011; Pearce et al., 2018; Heffelfinger et al., 2017), where level 1 represented the highest level of confidence.

Findings

20,212 published JE cases were identified from 205 studies. 15,167 (75%) of these positive cases were confirmed with the lowest-confidence diagnostic tests (level 3 or 4, or level 4). Only 109 (53%) of the studies reported contemporaneous testing for dengue-specific antibodies.

Conclusion

A fundamental pre-requisite for the control of JEV is lacking — that of a simple and specific diagnostic procedure that can be adapted for point-of-care tests and readily used throughout JE-endemic regions of the world.

Zoonotic causes of febrile illness in malaria endemic countries: a systematic review

Fever is one of the most common reasons for seeking health care globally and most human pathogens are zoonotic. We conducted a systematic review to describe the occurrence and distribution of zoonotic causes of human febrile illness reported in malaria endemic countries. We included data from 53 (48·2%) of 110 malaria endemic countries and 244 articles that described diagnosis of 30 zoonoses in febrile people. The majority (17) of zoonoses were bacterial, with nine viruses, three protozoa, and one helminth also identified. Leptospira species and non-typhoidal salmonella serovars were the most frequently reported pathogens. Despite evidence of profound data gaps, this Review reveals widespread distribution of multiple zoonoses that cause febrile illness. Greater understanding of the epidemiology of zoonoses in different settings is needed to improve awareness about these pathogens and the management of febrile illness.

Rift Valley Fever Virus, Japanese Encephalitis Virus, and African Swine Fever Virus: Three Transboundary, Vector-Borne, Veterinary Biothreats With Diverse Surveillance, and Response Capacity Needs

Early detection of emerging foreign animal diseases is critical to pathogen surveillance and control programs. Rift valley fever virus (RVFV), Japanese encephalitis virus (JEV), and African swine fever virus (ASFV) represent three taxonomically and ecologically diverse vector-borne viruses with the potential to be introduced to the United States. To promote preparedness for such an event, we reviewed the current surveillance strategies and diagnostic tools in practice around the world for these emerging viruses, and summarized key points pertaining to the availability of existing guidelines and strategic approaches for early detection, surveillance, and disease management activities. We compare and contrast the surveillance and management approaches of these three diverse agents of disease as case studies to emphasize the importance of the ecological context and biology of vectors and vertebrate hosts. The information presented in this review will inform stakeholders of the current state of surveillance approaches against these transboundary foreign animal disease which threaten the United States.

Determining the clinical characteristics and prognostic factors for the outcomes of Japanese encephalitis in adults: A multicenter study from southern Taiwan

BACKGROUND

In Southeast Asia, Japanese encephalitis (JE) is an important cause of viral encephalitis which may cause severe neurological sequelae. JE affects mostly children; therefore, clinical presentations and prognosis of adult JE patients are seldom addressed. This study aimed to describe the clinical characteristics and prognostic factors for the outcome of adult JE patients.

METHODS

Medical records of adult JE patients with acute encephalitis syndrome during 2001-2018 from five medical centers in southern Taiwan were reviewed. Clinical characteristics, brain images, and prognostic factors for outcomes were analyzed. Patients were divided into the good outcome (GO) group and poor outcome (PO) group according to their Glasgow Coma Scale (GCS) scores (GCS >8 vs. ≤ 8) at discharge.

RESULTS

Sixty-eight patients (men, 61.8%; median age, 50 years) were included. Summer is the epidemic season, and the number of cases peaked in June. The most common symptoms at initial presentation were altered consciousness and fever (both 94.1%), followed by headache (51.4%). The most commonly involved brain regions were thalamus (55.7%) and basal ganglion (37.7%). The median GCS score at nadir was 8, and the median time from onset to nadir was five days. Fifty-two patients were included in the GO group, while 16 were included in the PO group. On multivariate analysis, flaccidity, rigidity, and elevated CSF protein level were identified as independent prognostic factors for PO.

CONCLUSION

Initial clinical presentations of abnormal muscle tone including flaccidity, rigidity and high CSF protein levels are independent prognostic factors for PO in adult JE patients.

Association of single nucleotide polymorphisms in TNFA and CCR5 genes with Japanese Encephalitis: A study from an endemic region of North India

TNFA, IL1B, HMGB1, IL10, CXCL8, CCL2 and CCR5 gene polymorphisms were investigated in 183 Japanese Encephalitis (JE) cases and 361 healthy controls from North India. Higher frequency of TNFA rs1800629 G/A, CCR5 rs1799987 genotypes with A allele and lower frequency of combination lacking TNFA rs1800629 A, CCR5 rs333 Δ32, andCCR5 rs1799987 A alleles and CCL2 rs1024611 G/G genotype was observed in JE cases. TNFA rs1800629 A and CCR5 rs1799987 A alleles were associated with susceptibility while combination lacking TNFA rs1800629 A, CCR5 rs333 Δ32, and rs1799987 A alleles and CCL2 rs1024611 G/G genotype was associated with protection to JE.

Incidence of Japanese Encephalitis amongst acute encephalitis syndrome cases in upper Assam districts from 2012 to 2014: A report from a tertiary care hospital

Background & objectives:

Japanese encephalitis (JE) is a major public health problem in India because of high mortality rate and residual neuropsychiatric damage in the survivors. The present study was undertaken to investigate JE positivity amongst patients admitted with acute encephalitis syndrome (AES) in upper Assam districts and different parameters with their changing trends related to it.

Methods:

It was a hospital-based prospective cross-sectional study conducted from January 2012 to December 2014. A total of 1707 consecutive non-repetitive hospitalized patients, satisfying the clinical case definition of AES as per the WHO guidelines, were included in the study. Cerebrospinal fluid (CSF) and serum samples were tested for JEV-specific IgM antibodies.

Results:

Of the 1707 patients admitted, 696 (40.77 %) were diagnosed as JE with male-to-female ratio 1.7:1 and adult to paediatric ratio 2.2:1. Fever (100%), change in mental status (100%), headache (80.02%), neck rigidity (52.01%), unconsciousness (48.99%), seizure (37.64%) and paralysis (11.06%) were the major clinical findings. The majority of cases (94%) were from rural areas. There was a significant association of JE cases with rainy season of the year i.e., June to August (P <0.001). Overall, 14.94 per cent deaths were reported in JE positive cases.

Interpretation & conclusions:

A higher occurrence of JE was observed in above 15 yr age group. Cases were mainly from rural areas, and there was clustering of cases in rainy season.

Evolving Epidemiology of Japanese Encephalitis: Implications for Vaccination

PURPOSE OF REVIEW

We examine the present global burden of Japanese encephalitis (JE) in endemic populations, summarize published cases in travelers since 2009, examine current guidelines for vaccination for international travelers, and consider challenges in prevention of this vector-borne disease.

RECENT FINDINGS

We identified 11 JE cases in travelers that were published in peer-reviewed literature since 2009. JE incidence in endemic countries appears to be declining but the number of JE cases reported to the World Health Organization (WHO) varied from estimates derived from other published reports based on serosurveys or sentinel surveillance. Current JE vaccines appear to be safe and are not associated with delayed hypersensitivity in contrast to the older mouse brain vaccine. Given differences between WHO-reported cases and local surveillance data, future research on true incidence is needed. Regular assessment will inform JE risk in travelers. National and international guidelines on JE vaccination varied; we suggest areas for improvement.

The inter-rater reliability and prognostic value of coma scales in Nepali children with acute encephalitis syndrome

Background Acute encephalitis syndrome (AES) is a common cause of coma in Nepali children. The Glasgow coma scale (GCS) is used to assess the level of coma in these patients and predict outcome. Alternative coma scales may have better inter-rater reliability and prognostic value in encephalitis in Nepali children, but this has not been studied. The Adelaide coma scale (ACS), Blantyre coma scale (BCS) and the Alert, Verbal, Pain, Unresponsive scale (AVPU) are alternatives to the GCS which can be used. Methods Children aged 1-14 years who presented to Kanti Children's Hospital, Kathmandu with AES between September 2010 and November 2011 were recruited. All four coma scales (GCS, ACS, BCS and AVPU) were applied on admission, 48 h later and on discharge. Inter-rater reliability (unweighted kappa) was measured for each. Correlation and agreement between total coma score and outcome (Liverpool outcome score) was measured by Spearman's rank and Bland-Altman plot. The prognostic value of coma scales alone and in combination with physiological variables was investigated in a subgroup (n = 22). A multivariable logistic regression model was fitted by backward stepwise. Results Fifty children were recruited. Inter-rater reliability using the variables scales was fair to moderate. However, the scales poorly predicted clinical outcome. Combining the scales with physiological parameters such as systolic blood pressure improved outcome prediction. Conclusion This is the first study to compare four coma scales in Nepali children with AES. The scales exhibited fair to moderate inter-rater reliability. However, the study is inadequately powered to answer the question on the relationship between coma scales and outcome. Further larger studies are required.

Significance of CCL2, CCL5 and CCR2 polymorphisms for adverse prognosis of Japanese encephalitis from an endemic population of India

Japanese encephalitis (JE) is a major contributor for viral encephalitis in Asia. Vaccination programme has limited success for largely populated JE endemic countries like India and disease exposure is unavoidable. Involvement of chemokines and its co-receptors for adverse prognosis of JE have been documented both in vitro and in vivo. Identification of the genetic predisposing factor for JE infection in humans is crucial but not yet established. Therefore, we investigated the association of single nucleotide polymorphisms (SNPs) in chemokines (CCL2 and CCL5) and its co-receptors (CCR2 and CCR5) with their protein level for JE. The study enrolled 87 symptomatic JE cases (mild: severe = 24:63) and 94 asymptomatic controls. Our study demonstrated that CCL2 (rs1024611G), CCL5 (rs2280788G) and CCR2 (rs1799864A) significantly associated with JE (Odds ratio = 1.63, 2.95 and 2.62, respectively and P = 0.045, P = 0.05 and P = 0.0006, respectively). The study revealed that rs1024611G allele was associated with elevated level of CCL2. CCL5 elevation associated with JE mortality having a Cox proportional hazard of 1.004 (P = 0.033). In conclusion, SNPs of chemokine viz. CCL2 (rs1024611G) and its receptor CCR2 (rs1799864A) significantly associated with JE which may serve as possible genetic predisposing factor and CCL5 protein level may act as marker for disease survival.

Clinical Characteristics of Severe Japanese Encephalitis: A Case Series from South Korea

Japanese encephalitis (JE) virus is a major cause of devastating viral encephalitis, especially in Asia. Although a successful vaccination program led to its near-elimination over three decades in South Korea, the incidence of JE has increased since 2010. The present study investigated the clinical manifestations, laboratory findings, and factors affecting neurological outcomes of reemerging JE. We retrospectively reviewed medical records of laboratory-confirmed JE patients who presented with acute encephalitis syndrome at three tertiary hospitals between 2010 and 2015. A total of 17 patients with JE were identified. Their median age was 51 years, and 10 (58.5%) were men. The most common symptoms and signs were fever (94.1%), altered consciousness (94.1%), and headache (80.2%). Hyporeflexia (47.1%), seizures (35.2%), abnormal brainstem reflex (23.5%), and flaccid weakness (17.6%) were also noted. Brain imaging revealed thalamic lesions in all patients, with the hippocampus, midbrain, basal ganglia, and cerebral cortex affected to varying degrees. Sixteen patients (94.1%) required management in the intensive care unit with mechanical ventilation due to neurological deterioration. At the time of discharge, 11 (64.7%) had poor recovery, defined as Glasgow coma scale scores of less than 8, and remained ventilator dependent. Comparison between the two outcome groups indicated that midbrain involvement (P = 0.028) and rapid deterioration (P = 0.005) were associated with severe neurological sequelae. Given that JE is a vaccine-preventable disease, vaccination for adults should be considered in response to the reemergence of JE.

Central Nervous System Infection Associated with Orientia tsutsugamushi in South Korea

Orientia tsutsugamushi is a major cause of vector-borne infection in Asia. Prompt recognition and appropriate treatment are crucial because of its potentially fatal complications and lack of response to beta-lactam antibiotics. The present study retrospectively evaluated the clinical characteristics and laboratory findings of 16 patients with scrub typhus-related central nervous system (CNS) infections. Single titers ≥ 1:40 of total serum antibodies against O. tsutsugamushi detected by an indirect immunofluorescent assay were considered as positive results. The median age was 35.5 (range, 14-72) years, and 10 (62.5%) patients were female. The most common symptoms were headache (81.3%) and fever (81.3%). Eschar formation was found in three (18.8%) patients. Among patients with encephalitis, seizures and altered consciousness occurred in five (83.3%) and four (66.7%) patients, respectively. An abnormal liver function was noted in seven (43.8%) patients. The median antibody titer was 1:120 (range, 1:40-1:2,560). Typical cerebrospinal fluid profiles were lymphocytic pleocytosis, mild protein elevations, and normal glucose levels. All patients received an empirical treatment with doxycycline and most (93.8%) of them recovered without neurological sequelae. None of the patients reported side effects of the doxycycline treatment. An empirical treatment with doxycycline is needed in patients with CNS infections in scrub typhus endemic areas.

Dengue Associated Acute Encephalitis Syndrome Cases in Son La Province, Vietnam in 2014

Acute encephalitis syndrome (AES) is associated with high morbidity and mortality, and affects both children and adults. The main etiologic agent is Japanese encephalitis virus (JEV); however, there are also reports of Dengue virus (DENV) encephalitis. The objectives of this study were to determine the proportion of patients with encephalitis due to JEV during the 2014 outbreak in Son La Province in Vietnam and to explore the association of DENV in non-JEV viral encephalitis cases. Of 90 patients, 6 (6.7%) were positive for anti-JEV immunoglobulin M (IgM), 5 (5.6%) were positive for anti-DENV IgM, 30 (33.3%) were positive for both anti-JEV and anti-DENV IgM, and 56 (62.2%) were positive for flavivirus immunoglobulin G (IgG). In 5 patients with AES, who had positive anti-DENV IgM results in at least one of the paired serum samples, DENV was confirmed by neutralization testing. The incidence of JEV infection was high. There is still a need to maintain and strengthen the national JEV immunization program. This noticeable occurrence of DENV infection was not reported in Son La Province in 2013-2014. Our data suggested that in addition to JEV, DENV was also a causative agent of AES in 2014 in Son La Province, and this finding also confirmed the local occurrence of DENV infection.

A Study of Hyponatremia in Acute Encephalitis Syndrome: A Prospective Study From a Tertiary Care Center in India

PURPOSE:

To evaluate the frequency and causes of hyponatremia in acute encephalitis syndrome (AES) and its effect on outcome.

PATIENTS AND METHODS:

Consecutive patients with AES were subjected to neurological evaluation including Glasgow Coma Scale, focal weakness, movement disorder, and reflex changes. The etiology of AES was based on blood and cerebrospinal fluid enzyme-linked immunosorbent assay and polymerase chain reaction. We have categorized patients into neurological or systemic AES. Hyponatremia was diagnosed if 2 consecutive serum sodium levels were below 135 mEq/L, 24 hours apart. Serum and urinary osmolality and electrolytes were measured on alternate days. Fluid intake, output, and body weight were measured daily. The hyponatremia was categorized into syndrome of inappropriate secretion of antidiuretic hormone (SIADH), cerebral salt wasting (CSW), or miscellaneous group. Outcome at 1 month was assessed by modified Rankin scale.

RESULTS:

Of 79 patients, 34 had neurologic AES and 45 had systemic AES; 22 (27.8%) patients had hyponatremia. The neurologic AES as compared to systemic AES was more commonly associated with hyponatremia (38.2% vs 20%, P = .07), need longer hospitalization (25.0 vs 12.5 days, P = .003), and longer time for sodium correction (13.3 vs 8.2 days, P = .05). The hyponatremia was due to CSW in 12 patients, SIADH in 2 patients, and indeterminate in 8 patients. Thirty-six patients had poor outcome (15 died) and 43 had good outcome which was not related to hyponatremia.

CONCLUSION:

Hyponatremia occurs in one-third of patients with AES, being commoner in neurologic AES, and CSW is the commonest cause.

An outbreak of Japanese encephalitis after two decades in Odisha, India

Sudden deaths in children due to acute encephalitis syndrome (AES) from a tribal dominated district of Malkangiri in Odisha, India, was reported during September-November, 2012. The investigation was carried out to search for the possible viral aetiology that caused this outbreak. Clinico-epidemiological survey and seromolecular investigation were carried out to confirm the viral aetiology. Two hundred seventy two suspected cases with 24 deaths were observed. The patients presented with low to moderate grade fever (87%), headache (43%), vomiting (27%), cold (18%), cough (17%), body ache (15%), joint pain (15%), rash (15%), abdomen pain (9%), lethargy (5%), altered sensorium (8%), convulsion (2%), diarrhoea (3%), and haematemesis (3%). Laboratory investigation showed Japanese encephalitis virus (JEV) IgM in 13.8 per cent (13/94) in blood samples and JEV RNA in one of two cerebrospinal fluid (CSF) samples. Paddy fields close to the houses, high pig to cattle ratio, high density (33 per man hour density) of Culex vishnui mosquitoes, low socio-economic status and low health awareness in the tribal population were observed. This report confirmed the outbreak of JEV infection in Odisha after two decades.

Epidemiological Features of Japanese Encephalitis in Taiwan from 2000 to 2014

The incidence of Japanese encephalitis (JE) decreased sharply after the national vaccination program was implemented in Taiwan in 1968. However, cases of JE still occur. The purpose of this study was to assess the epidemiology and vaccination policy for JE in Taiwan. We analyzed the data on JE cases reported to the Taiwan Centers for Disease Control (Taiwan CDC) between 2000 and 2014. During the 15-year study period, a total of 4,474 cases were reported to the Taiwan CDC. Of these, 379 (8.5%) were classified as confirmed cases, and 4,095 (91.5%) were classified as suspected cases. The incidence of JE ranged from 0.59 to 1.61 per 1,000,000 people and peaked in 2007. Men had a higher incidence of JE than women (1.37 versus 0.84 per 1,000,000; P = 0.03). Patients who were 40-59 years of age had a higher incidence than did patients younger than 20 years (1.82 versus 0.23; P < 0.001). Patients who lived in the eastern region of Taiwan had the highest incidence rate of JE (P < 0.001). Compared with those who were not vaccinated with the JE vaccine, patients who received four doses of JE vaccine had a lower risk of suffering from death and/or hospitalization (adjusted odds ratio: 0.26; 95% confidence interval: 0.08-0.90; P = 0.04). JE is still a public health problem in Taiwan, and monitoring JE via diagnostic testing to determine the best vaccination program along with enforcing JE vaccine boosters for adults is necessary to eliminate JE in Taiwan.

Seroprevalence of Cysticercus Antibodies in Japanese Encephalitis Patients in Upper Assam, India: A Hospital Based Study

INTRODUCTION

Co-infection of Japanese Encephalitis (JE) and Cysticercosis is attributed mainly to the common epidemiological features between the two diseases. Not much is known about the clinical implications of one infection over the other.

AIM

The study aimed at establishing whether JE-Cysticercosis co-infection is prevalent in the Upper Assam districts and to explore additional details about such co-infections both clinically and epidemiologically.

MATERIALS AND METHODS

The present study was a retrospective cross-sectional hospital based study conducted between July 2013 and June 2014 and included 272 Acute Encephalitis Syndrome (AES) patients. Out of this, 137 JE positive and 135 non-JE Acute encephalitis patients were taken as cases and controls respectively. The diagnosis of JE and Cysticercosis was established by ELISA.

STATISTICAL ANALYSIS

EpiInfo ver. 7 was used for statistical analysis. Chi-square was used and p-value < 0.05 was considered to be statistically significant.

RESULTS

The association of Cysticercosis with JE was found to be statistically significant (14.6%, p = 0.0019) in the cases with reference to the controls (3.7%). Moreover, the co-infections were found to be more common in case of adults (19.32%, p = 0.0360); with males having a greater odds (5.25, p = 0.0008) of harbouring the parasite as compared to females.

CONCLUSION

The study proves that the association of Cysticercosis and JE holds true in this region.

Pre-cut Filter Paper for Detecting Anti-Japanese Encephalitis Virus IgM from Dried Cerebrospinal Fluid Spots

BACKGROUND

The use of filter paper as a simple, inexpensive tool for storage and transportation of blood, 'Dried Blood Spots' or Guthrie cards, for diagnostic assays is well-established. In contrast, there are a paucity of diagnostic evaluations of dried cerebrospinal fluid (CSF) spots. These have potential applications in low-resource settings, such as Laos, where laboratory facilities for central nervous system (CNS) diagnostics are only available in Vientiane. In Laos, a major cause of CNS infection is Japanese encephalitis virus (JEV). We aimed to develop a dried CSF spot protocol and to evaluate its diagnostic performance using the World Health Organisation recommended anti-JEV IgM antibody capture enzyme-linked immunosorbent assay (JEV MAC-ELISA).

METHODOLOGY AND PRINCIPAL FINDINGS

Sample volumes, spotting techniques and filter paper type were evaluated using a CSF-substitute of anti-JEV IgM positive serum diluted in Phosphate Buffer Solution (PBS) to end-limits of detection by JEV MAC-ELISA. A conventional protocol, involving eluting one paper punch in 200 μl PBS, did not detect the end-dilution, nor did multiple punches utilising diverse spotting techniques. However, pre-cut filter paper enabled saturation with five times the volume of CSF-substitute, sufficiently improving sensitivity to detect the end-dilution. The diagnostic accuracy of this optimised protocol was compared with routine, neat CSF in a pilot, retrospective study of JEV MAC-ELISA on consecutive CSF samples, collected 2009-15, from three Lao hospitals. In comparison to neat CSF, 132 CSF samples stored as dried CSF spots for one month at 25-30 °C showed 81.6% (65.7-92.3 95%CI) positive agreement, 96.8% (91.0-99.3 95%CI) negative agreement, with a kappa coefficient of 0.81 (0.70-0.92 95%CI).

CONCLUSIONS/SIGNIFICANCE

The novel design of pre-cut filter paper saturated with CSF could provide a useful tool for JEV diagnostics in settings with limited laboratory access. It has the potential to improve national JEV surveillance and inform vaccination policies. The saturation of filter paper has potential use in the wider context of pathogen detection, including dried spots for detecting other analytes in CSF, and other body fluids.

Establishment of an Algorithm Using prM/E- and NS1-Specific IgM Antibody-Capture Enzyme-Linked Immunosorbent Assays in Diagnosis of Japanese Encephalitis Virus and West Nile Virus Infections in Humans

The front-line assay for the presumptive serodiagnosis of acute Japanese encephalitis virus (JEV) and West Nile virus (WNV) infections is the premembrane/envelope (prM/E)-specific IgM antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA). Due to antibody cross-reactivity, MAC-ELISA-positive samples may be confirmed with a time-consuming plaque reduction neutralization test (PRNT). In the present study, we applied a previously developed anti-nonstructural protein 1 (NS1)-specific MAC-ELISA (NS1-MAC-ELISA) on archived acute-phase serum specimens from patients with confirmed JEV and WNV infections and compared the results with prM/E containing virus-like particle-specific MAC-ELISA (VLP-MAC-ELISA). Paired-receiver operating characteristic (ROC) curve analyses revealed no statistical differences in the overall assay performances of the VLP- and NS1-MAC-ELISAs. The two methods had high sensitivities of 100% but slightly lower specificities that ranged between 80% and 100%. When the NS1-MAC-ELISA was used to confirm positive results in the VLP-MAC-ELISA, the specificity of serodiagnosis, especially for JEV infection, was increased to 90% when applied in areas where JEV cocirculates with WNV, or to 100% when applied in areas that were endemic for JEV. The results also showed that using multiple antigens could resolve the cross-reactivity in the assays. Significantly higher positive-to-negative (P/N) values were consistently obtained with the homologous antigens than those with the heterologous antigens. JEV or WNV was reliably identified as the currently infecting flavivirus by a higher ratio of JEV-to-WNV P/N values or vice versa. In summary of the above-described results, the diagnostic algorithm combining the use of multiantigen VLP- and NS1-MAC-ELISAs was developed and can be practically applied to obtain a more specific and reliable result for the serodiagnosis of JEV and WNV infections without the need for PRNT. The developed algorithm should provide great utility in diagnostic and surveillance activities in which test accuracy is of utmost importance for effective disease intervention.

Investigation of the genotype III to genotype I shift in Japanese encephalitis virus and the impact on human cases

Japanese encephalitis is a mosquito borne disease and is the leading cause of viral encephalitis in the Asia-Pacific area. The causative agent, Japanese encephalitis virus (JEV) can be phylogenetically classified into five genotypes based on nucleotide sequence. In recent years, genotype I (GI) has displaced genotype III (GIII) as the dominant lineage, but the mechanisms behind this displacement event requires elucidation. In an earlier study, we compared host variation over time between the two genotypes and observed that GI appears to have evolved to achieve more efficient infection in hosts in the replication cycle, with the tradeoff of reduced infectivity in secondary hosts such as humans. To further investigate this phenomenon, we collected JEV surveillance data on human cases and, together with sequence data, and generated genotype/case profiles from seven Asia-Pacific countries and regions to characterize the GI/GIII displacement event. We found that, when comprehensive and consistent vaccination and surveillance data was available, and the GIII to GI shift occurred within a well-defined time period, there was a statistically significant drop in JEV human cases. Our findings provide further support for the argument that GI is less effective in infecting humans, who represent a dead end host. However, experimental investigation is necessary to confirm this hypothesis. The study highlights the value of alternative approaches to investigation of epidemics, as well as the importance of effective data collection for disease surveillance and control.

Japanese encephalitis associated acute encephalitis syndrome cases in West Bengal, India: A sero-molecular evaluation in relation to clinico-pathological spectrum

Japanese encephalitis (JE) is a major public health problem in Asia and worldwide and it is responsible mainly for viral acute encephalitis syndrome (AES). The sole etiologic agent of JE is Japanese encephalitis virus (JEV). Although JE/AES cases have been regarded traditionally as a disease of children, a growing number of patients with JE/AES cases are also seen in the adult age group every year in the state of West Bengal, India in spite of vaccination. Therefore, a systematic study was performed to differentiate and characterize the clinico-pathological parameters and viral diversity among the patients of different age groups. Viral diversity was also evaluated from the JE/AES cases, depending on their disease severity. A total of 441 JE/AES cases were included in this study. By MAC-ELISA, 111 samples were found JEV IgM positive and among the IgM negative cases, 26 samples were found RT-PCR positive against JEV infection. Neck rigidity, abnormal behavior, convulsion, protein in CSF, WBC in CSF, and aspartate transaminase in blood differed significantly among the patients of pediatric-adolescent and adult group in both IgM positive and RT-PCR positive cases. Viral diversity was increased significantly in the pediatric-adolescent group compared to adult patients. Interestingly, with the rise in disease severity the viral diversity was found to be increased among the patients, irrespective of their age distribution. Based on clinico-pathological parameters and analysis of viral diversity, it can be concluded that viral diversity which occurs naturally is likely to affect disease severity, especially in the patients of pediatric-adolescent group.

A randomized study of the immunogenicity and safety of Japanese encephalitis chimeric virus vaccine (JE-CV) in comparison with SA14-14-2 vaccine in children in the Republic of Korea

A new live attenuated Japanese encephalitis chimeric virus vaccine (JE-CV) has been developed based on innovative technology to give protection against JE with an improved immunogenicity and safety profile. In this phase 3, observer-blind study, 274 children aged 12−24 months were randomized 1:1 to receive one dose of JE-CV (Group JE-CV) or the SA14–14–2 vaccine currently used to vaccinate against JE in the Republic of Korea (Group SA14–14–2). JE neutralizing antibody titers were assessed using PRNT₅₀ before and 28 days after vaccination. The primary endpoint of non-inferiority of seroconversion rates on D28 was demonstrated in the Per Protocol analysis set as the difference between Group JE-CV and Group SA14–14–2 was 0.9 percentage points (95% confidence interval [CI]: −2.35; 4.68), which was above the required −10%. Seroconversion and seroprotection rates 28 days after administration of a single vaccine dose were 100% in Group JE-CV and 99.1% in Group SA14–14–2; all children except one (Group SA14–14–2) were seroprotected. Geometric mean titers (GMTs) increased in both groups from D0 to D28; GM of titer ratios were slightly higher in Group JE-CV (182 [95% CI: 131; 251]) than Group SA14–14–2 (116 [95% CI: 85.5, 157]). A single dose of JE-CV was well tolerated and no safety concerns were identified. In conclusion, a single dose of JE-CV or SA14–14–2 vaccine elicited a comparable immune response with a good safety profile. Results obtained in healthy Korean children aged 12−24 months vaccinated with JE-CV are consistent with those obtained in previous studies conducted with JE-CV in toddlers.

IXIARO updated: overview of clinical trials and developments with the inactivated vaccine against Japanese encephalitis

The mosquito-borne Japanese encephalitis virus causes an estimated 50,000 cases in Asia, accounting for at least 10,000 deaths and 15,000 cases of neuropsychiatric sequelae. IXIARO (Intercell AG, Vienna, Austria), an inactivated, Vero cell-derived vaccine against Japanese encephalitis was introduced in 2009. The vaccine is highly immunogenic, showing significantly higher geometric mean antibody titers compared with previous, mouse brain-derived vaccines. Postmarketing studies have confirmed the excellent safety profile. Studies on children aged 2 months to 18 years have been published. Based on these data, positive opinion from the EMA for vaccination of children has recently been given. Since a safe and effective vaccine against Japanese encephalitis is now available, outdated guidelines and recommendations have to be revised: travelers to rural areas of Asia should generally be recommended vaccination.

Concomitant administration of live attenuated Japanese encephalitis chimeric virus vaccine (JE-CV) and measles, mumps, rubella (MMR) vaccine: randomized study in toddlers in Taiwan

BACKGROUND

Japanese encephalitis (JE) is the most important cause of viral encephalitis in Asia.

METHODS

In this randomized, open-label, multicenter trial in 550 children aged 12 to 18 months in Taiwan, children received one dose of JE-CV and one dose of MMR vaccine. Vaccines were either administered separately 6 weeks apart (Groups 'JE-CV' and 'MMR', named after which vaccine was given first), or concomitantly (Group 'Co-Ad'). JE neutralizing antibody titers were assessed using PRNT50. MMR antibody levels were determined by ELISA.

RESULTS

All groups had low seroprotection/seropositivity rates (<10%) before vaccination for all antigens. Forty two days after vaccination, on either Study Day 42 or 84, seroconversion rates for all antigens were high in all groups, irrespective of the order of vaccinations. Seroconversion for JE ranged from 96.9% in Group Co-Ad on D42 to 100% in Group MMR. Non-inferiority was demonstrated for all analyses as the lower bound of the 95% CI of the difference in seroconversion rates between groups was above the pre-defined limit of -10.0%. The immune responses remained high for all antigens and well above the level of protection 12 months after vaccination in all groups. There were no safety concerns.

CONCLUSIONS

JE-CV is safe and induces a strong protective immune response which persists over 1 year when co-administered with MMR vaccine.

Estimating the burden of Japanese encephalitis virus and other encephalitides in countries of the mekong region

Diverse aetiologies of viral and bacterial encephalitis are widely recognized as significant yet neglected public health issues in the Mekong region. A robust analysis of the corresponding health burden is lacking. We retrieved 75 articles on encephalitis in the region published in English or in French from 1965 through 2011. Review of available data demonstrated that they are sparse and often derived from hospital-based studies with significant recruitment bias. Almost half (35 of 75) of articles were on Japanese encephalitis virus (JEV) alone or associated with dengue. In the Western Pacific region the WHO reported 30,000-50,000 annual JEV cases (15,000 deaths) between 1966 and 1996 and 4,633 cases (200 deaths) in 2008, a decline likely related to the introduction of JEV vaccination in China, Vietnam, or Thailand since the 1980s. Data on dengue, scrub typhus and rabies encephalitis, among other aetiologies, are also reviewed and discussed. Countries of the Mekong region are undergoing profound demographic, economic and ecological change. As the epidemiological aspects of Japanese encephalitis (JE) are transformed by vaccination in some countries, highly integrated expert collaborative research and objective data are needed to identify and prioritize the human health, animal health and economic burden due to JE and other pathogens associated with encephalitides.

Viral aetiology and clinico-epidemiological features of acute encephalitis syndrome in eastern India

This study reports clinico-epidemiological features and viral agents causing acute encephalitis syndrome (AES) in the eastern Indian region through hospital-based case enrolment during April 2011 to July 2012. Blood and CSF samples of 526 AES cases were investigated by serology and/or PCR. Viral aetiology was identified in 91 (17·2%) cases. Herpes simplex virus (HSV; types I or II) was most common (16·1%), followed by measles (2·6%), Japanese encephalitis virus (1·5%), dengue virus (0·57%), varicella zoster virus (0·38%) and enteroviruses (0·19%). Rash, paresis and cranial nerve palsies were significantly higher (P < 0·05) with viral AES. Case-fatality rates were 10·9% and 6·2% in AES cases with and without viral aetiology, respectively. Simultaneous infection of HSV I and measles was observed in seven cases. This report provides the first evidence on viral aetiology of AES viruses from eastern India showing dominance of HSV that will be useful in informing the public health system.