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

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

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.

Aetiological profile of acute encephalitis syndrome in Assam, India, during a 4-year period from 2019 to 2022.

Acute encephalitis syndrome (AES) is a major public health concern in India as the aetiology remains unknown in the majority of cases with the current testing algorithm. We aimed to study the incidence of Japanese encephalitis (JE) and determine the aetiology of non-JE AES cases to develop an evidence-based testing algorithm. Cerebrospinal fluid (CSF) samples were tested for Japanese encephalitis virus by ELISA and polymerase chain reaction (PCR). Multiplex real-time PCR was done for Dengue, Chikungunya, West Nile, Zika, Enterovirus, Epstein Barr Virus, Herpes Simplex Virus, Adenovirus, Cytomegalovirus, Herpesvirus 6, Parechovirus, Parvovirus B19, Varicella Zoster Virus, Scrub typhus, Rickettsia species, Leptospira, Salmonella species, Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Plasmodium species and by ELISA for Mumps and Measles virus. Of the 3173 CSF samples, 461 (14.5%) were positive for JE. Of the 334 non-JE AES cases, 66.2% viz. Scrub typhus (25.7%), Mumps (19.5%), Measles (4.2%), Parvovirus B19 (3.9%) Plasmodium (2.7%), HSV 1 and 2 (2.4%), EBV and Streptococcus pneumoniae (2.1% each), Salmonella and HHV 6 (1.2% each) were predominant. Hence, an improved surveillance system and our suggested expanded testing algorithm can improve the diagnosis of potentially treatable infectious agents of AES in India.

Utility of Film Array Meningoencephalitis Panel in Children With Acute Encephalitis Syndrome: A Single Centre Experience from South India.

OBJECTIVE: To describe the utility of film array meningoencephalitis (FAME) panel in the management of children with acute encephalitis syndrome (AES). METHODS: A retrospective audit was conducted between January 2017 to July 2022. We included children aged < 18 years with a diagnosis of AES for whom a CSF analysis study including FAME panel testing performed within 48 hours of admission was available. Electronic medical records were reviewed for details including demographic profile, clinical presentation, investigations and outcome. RESULTS: Out of 157 CSF samples sent for FAME panel testing, 49 were positive (31.4%.) Viral pathogens were identified in 42 (Enterovirus: 31, Human herpes virus 6: 9, Varicella zoster virus: 1, and Cytomegalovirus: 1) Bacterial pathogens were identified in 6 (Streptococcus pneumoniae: 2, Streptococcus agalactiae: 2, Hemophilus influenzae: 1, and Escherischia coli: 1). Fungal etiology (Cryptococcus neoformans) was detected in one child. Antibiotics could be stopped within 72 hours of initiation in 42 children in whom a viral etiology was established. Acyclovir could be stopped in 21 out of 32 children within 72 hours after the FAME panel testing. FAME panel was presumed to be false positive in 4 children. CONCLUSION: Etiology of AES could be established in nearly a third of children with AES using the rapid diagnostic FAME panel testing in CSF and it was found to be effective in reducing empirical antibiotic/antiviral therapy.

Diagnostic markers of acute encephalitis syndrome and COVID-associated multisystem inflammatory syndrome in children from Southern India.

Acute encephalitis syndrome (AES) in children poses a significant public health challenge in India. This study aims to explore the utility of host inflammatory mediators and neurofilament (NfL) levels in distinguishing etiologies, assessing disease severity, and predicting outcomes in AES. We assessed 12 mediators in serum (n = 58) and 11 in cerebrospinal fluid (CSF) (n = 42) from 62 children with AES due to scrub typhus, viral etiologies, and COVID-associated multisystem inflammatory syndrome (MIS-C) in Southern India. Additionally, NfL levels in serum (n = 20) and CSF (n = 18) were examined. Clinical data, including Glasgow coma scale (GCS) and Liverpool outcome scores, were recorded. Examining serum and CSF markers in the three AES etiology groups revealed notable distinctions, with scrub typhus differing significantly from viral and MIS-C causes. Viral causes had elevated serum CCL11 and CCL2 compared with scrub typhus, while MIS-C cases showed higher HGF levels than scrub typhus. However, CSF analysis showed a distinct pattern with the scrub typhus group exhibiting elevated levels of IL-1RA, IL-1ß, and TNF compared with MIS-C, and lower CCL2 levels compared with the viral group. Modeling the characteristic features, we identified that age ≥3 years with serum CCL11 < 180 pg/mL effectively distinguished scrub typhus from other AES causes. Elevated serum CCL11, HGF, and IL-6:IL-10 ratio were associated with poor outcomes (p = 0.038, 0.005, 0.02). Positive CSF and serum NfL correlation, and negative GCS and serum NfL correlation were observed. Median NfL levels were higher in children with abnormal admission GCS and poor outcomes. Measuring immune mediators and brain injury markers in AES provides valuable diagnostic insights, with the potential to facilitate rapid diagnosis and prognosis. The correlation between CSF and serum NfL, along with distinctive serum cytokine profiles across various etiologies, indicates the adequacy of blood samples alone for assessment and monitoring. The association of elevated levels of CCL11, HGF, and an increased IL-6:IL-10 ratio with adverse outcomes suggests promising avenues for therapeutic exploration, warranting further investigation.

Efficacy and safety of phenytoin and levetiracetam for acute symptomatic seizures in children with acute encephalitis syndrome: an open label, randomised controlled trial.

INTRODUCTION: Seizures represent a significant comorbidity in children with acute encephalitis syndrome (AES). Despite this, there is a notable absence of randomized controlled trials (RCTs) directly comparing antiseizure medications (ASMs) in children with AES. MATERIALS AND METHODS: This RCT aimed to assess the efficacy and safety of phenytoin and levetiracetam in controlling seizures among children with AES. Both ASMs were administered with a loading followed by maintenance dose. After a 12-week period, children exhibiting a normal electroencephalogram and no seizure recurrence underwent tapering and discontinuation of ASM. Clinical follow-up occurred daily for the first week, and subsequently at 4, 12, and 24 weeks, evaluating seizure recurrence, incidence of status epilepticus, cognition, behavior, functional status, ASM acquisition cost, and adverse effects. RESULTS: A total of 100 children (50 in each group) were enrolled. Within the first week, 5 and 3 children in the phenytoin and levetiracetam groups expired. Up to 1 week or death (whichever occurred earliest), 46 (92 %) and 44 (88 %) children remained seizure-free. Intention-to-treat analysis for both best and worst-case scenarios showed insignificant differences (p=0.52 and 1.0). No children experienced seizure recurrence after 1 week in either group. The number of patients with breakthrough status epilepticus, need for mechanical ventilation, duration of hospital stay, presence of epileptiform abnormalities in repeat electroencephalogram at 12 weeks, functional outcomes at 1, 12, and 24 weeks, as well as cognition and behavioral profiles at 24 weeks, were comparable in both groups (p>0.05 for all). However, the incidence of treatment-emergent adverse events (TEAEs) causally related to study medications was significantly higher in the phenytoin group (p=0.04). CONCLUSION: Levetiracetam and phenytoin are comparable in efficacy in terms of achieving clinical seizure control in children with acute encephalitis syndrome, although levetiracetam group demonstrated fewer adverse effects.

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.

Acute Encephalitis Syndrome in Children and Adolescents: A Five-Year Descriptive Study From South India.

OBJECTIVE: Acute encephalitis syndrome (AES) in children results in significant neurocognitive deficits or mortality. It is pertinent to study the AES patterns periodically to identify the changes in the etiological trends and outcomes. Our objective was to find the etiological agents of AES, mode of diagnosis, treatment given, and outcomes. METHODS: We reviewed the electronic records of children aged 1 month to 15 years who were admitted with AES in our centre from January 2015 to December 2019. We analyzed the the clinical, laboratory, and radiological profile of these children and adolescents in relation to their outcome. Poor outcome was defined as death, discharge against medical advice with neurological deficits, or Glasgow Outcome Score Extended (GOS-E) d≤ 5 at the time of discharge. RESULTS: Among 250 patients admitted with AES during the study period, a definitive etiological diagnosis was established in 56.4% of children (30.4% viral, 22% bacterial). Scrub typhus (11.2%) and dengue (9%) were the two most common underlying illnesses. Serology helped in clinching the diagnosis in 30% of children. A surge in AES cases in the post-monsoon season was observed in our cohort. Third-generation cephalosporin drugs (85.7%) and acyclovir (77.7%) were the most commonly used empiric antimicrobial drugs. About one-third of children (n = 80) had a poor outcome. GCS ≤ 8 at presentation and requirement for invasive ventilation were found to be significant predictors of poor outcome. CONCLUSION: A definitive diagnosis was obtained in about half of the children with AES. Viral (30.4%) and rickettsial infections (22%) were the common etiologies identified. Poor outcome was observed in 32% of patients.

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.

c.202_204del in NUP214 causes late onset form of febrile encephalopathy.

Nucleoporins (NUPs) are a group of transporter proteins that maintain homeostasis of nucleocytoplasmic transport of proteins and ribonucleic acids under physiological conditions. Biallelic pathogenic variants in NUP214 are known to cause susceptibility to acute infection-induced encephalopathy-9 (IIAE9, MIM#618426), which is characterized by severe and early-onset febrile encephalopathy causing neuroregression, developmental delay, microcephaly, epilepsy, ataxia, brain atrophy, and early death. NUP214-related IIAE9 has been reported in eight individuals from four distinct families till date. We identified a novel in-frame deletion, c.202_204del p.(Leu68del), in NUP214 by exome sequencing in a 20-year-old male with episodic ataxia, seizures, and encephalopathy, precipitated by febrile illness. Neuroimaging revealed progressive cerebellar atrophy. In silico predictions show a change in the protein conformation that may alter the downstream protein interactions with the NUP214 N-terminal region, probably impacting the mRNA export. We report this novel deletion in NUP214 as a cause for a late onset and less severe form of IIAE9.

Evidence on the prevalence of emerging and re-emerging tick- and flea-borne rickettsial agents in acute encephalitis syndrome endemic areas of northeast Uttar Pradesh, India.

Outbreaks of acute encephalitis syndrome (AES) with unknown aetiology are reported every year in Gorakhpur district, Uttar Pradesh, India, and Orientia tsutsugamushi, the rickettsial pathogen, responsible for scrub typhus has been attributed as the primary cause of AES problem. However, information on the prevalence of other rickettsial infections is lacking. Hence, this study was carried out to assess any occurrence of tick- and flea-borne rickettsial agents in villages reporting AES cases in this district. In total, 825 peridomestic small mammals were trapped, by setting 9254 Sherman traps in four villages with a trap success rate of 8.9%. The Asian house shrew, Suncus murinus, constituted the predominant animal species (56.2%) and contributed to the maximum number (87.37%) of ectoparasites. In total, 1552 ectoparasites comprising two species of ticks and one species each of flea and louse were retrieved from the trapped rodents/shrews. Rhipicephalus sanguineus, the brown dog tick, was the predominant species retrieved from the trapped rodents/shrews, and the overall infestation rate was 1.75 per animal. In total, 4428 ectoparasites comprising five tick species, three louse species and one flea species were collected from 1798 domestic animals screened. Rhipicephalus microplus was the predominant tick species collected from the domestic animals. The cat flea, Ctenocephalides felis, constituted 1.5% of the total ectoparasites. Of all the ectoparasite samples (5980) from domestic animals and rodents, tested as 1211 pools through real-time PCR assays, 64 pools were positive for 23S rRNA gene of rickettsial agents. The PCR-positive samples were subjected to multi-locus sequence typing (MLST). In BLAST and phylogenetic analysis, the ectoparasites were found to harbour Rickettsia asembonensis (n = 9), Rickettsia conorii (n = 3), Rickettsia massiliae (n = 29) and Candidatus Rickettsia senegalensis (n = 1). A total of 22 pools were detected to have multiple rickettsial agents. The prevalence of fleas and high abundance of tick vectors with natural infections of rickettsial agents indicates the risk of transmission of tick- and flea-borne rickettsial diseases in rural villages of Gorakhpur. Further epidemiological studies are required to confirm the transmission of these agents to humans.

Association of transient mitochondrial functional impairment with acute heat exposure in children from Muzaffarpur region of Bihar, India.

Over the past several years, the Muzaffarpur district of Bihar (India) has witnessed recurrent outbreaks of acute encephalitis illness of unknown etiology, called acute encephalitis syndrome (AES) among young children, especially during the peak-summer season. Pesticide exposure, viral encephalitis, and litchi toxin intake have all been postulated as potential sources of the ailment. However, no conclusive etiology for AES has been identified in the affected children. During recent rounds of the outbreak, metabolic abnormalities have been documented in these children, and a direct correlation was observed between higher environmental temperature during the peak-summer month and AES caseload. The clinical and metabolic profiles of these children suggested the possible involvement of mitochondrial dysfunction during heat stress as one of the several contributory factors leading to multisystem metabolic derangement. The present study observed that mitochondrial function parameters such as cell death, mitochondrial membrane potential, oxidative stress, and mitochondrial pathway-related gene expression in peripheral blood mononuclear cells (PBMCs) isolated from children were affected in peak-summer when compared to post-summer months. Similar observations of mitochondrial function parameters along with impaired bioenergetic parameters were demonstrated in the heat-exposed model of PBMCs isolated from healthy adult individuals. In conclusion, the results suggested that there is an association of transient mitochondrial dysfunction when exposed to sustained heat during the summer months. One may consider mitochondrial dysfunction as one of the important factors leading to an outbreak of AES among the children from affected regions though this needs to be substantiated with further studies.

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.

Emergence of Japanese encephalitis in eastern parts of Madhya Pradesh, India.

BACKGROUND & OBJECTIVES: Emerging zoonotic and vector-borne diseases are posing new challenges to public health authorities. Morbidities and mortalities due to acute encephalitis syndrome (AES) is a serious health problem in paediatric patients. We conducted serological investigations on AES cases from six districts of north eastern Madhya Pradesh (MP), India for Japanese encephalitis (JE). METHODS: The paired serum and CSF samples were collected from paediatric patients having signs and symptoms of encephalitis and admitted at a tertiary care hospital during the study period from August 2020 to October 2021. Demographic and clinical information was collected in predesigned formats. Serum and CSF were subjected to JE IgM specific ELISA. RESULTS: Samples from 110 patients were collected during the study period of which 28 (25.4%) were reactive for JE IgM antibodies. JE IgM positivity was marginally higher in male children (26.6%) as compared to female children (22.8%). Out of 28 positive cases, 11 (39.2%) deaths were attributed to JE. Four districts of north eastern Madhya Pradesh showed JE activity. Maximum cases were observed in post-monsoon season. INTERPRETATION & CONCLUSION: Our results show that JEV is an emerging threat in eastern central India and health authorities need to be vigilant. A systematic molecular and serological survey among humans and animals along with xenomonitoring will help in understanding intricacies of JE epidemiology in the region.

The spatio-temporal distribution of acute encephalitis syndrome and its association with climate and landcover in Vietnam.

BACKGROUND: Acute encephalitis syndrome (AES) differs in its spatio-temporal distribution in Vietnam with the highest incidence seen during the summer months in the northern provinces. AES has multiple aetiologies, and the cause remains unknown in many cases. While vector-borne disease such as Japanese encephalitis and dengue virus and non-vector-borne diseases such as influenza and enterovirus show evidence of seasonality, associations with climate variables and the spatio-temporal distribution in Vietnam differs between these. The aim of this study was therefore to understand the spatio-temporal distribution of, and risk factors for AES in Vietnam to help hypothesise the aetiology. METHODS: The number of monthly cases per province for AES, meningitis and diseases including dengue fever; influenza-like-illness (ILI); hand, foot, and mouth disease (HFMD); and Streptococcus suis were obtained from the General Department for Preventive Medicine (GDPM) from 1998-2016. Covariates including climate, normalized difference vegetation index (NDVI), elevation, the number of pigs, socio-demographics, JEV vaccination coverage and the number of hospitals were also collected. Spatio-temporal multivariable mixed-effects negative binomial Bayesian models with an outcome of the number of cases of AES, a combination of the covariates and harmonic terms to determine the magnitude of seasonality were developed. RESULTS: The national monthly incidence of AES declined by 63.3% over the study period. However, incidence increased in some provinces, particularly in the Northwest region. In northern Vietnam, the incidence peaked in the summer months in contrast to the southern provinces where incidence remained relatively constant throughout the year. The incidence of meningitis, ILI and S. suis infection; temperature, relative humidity with no lag, NDVI at a lag of one month, and the number of pigs per 100,000 population were positively associated with the number of cases of AES in all models in which these covariates were included. CONCLUSIONS: The positive correlation of AES with temperature and humidity suggest that a number of cases may be due to vector-borne diseases, suggesting a need to focus on vaccination campaigns. However, further surveillance and research are recommended to investigate other possible aetiologies such as S. suis or Orientia tsutsugamushi.

Infectious Causes of Acute Encephalitis Syndrome in India - Decadal Change and the Way Forward.

The diagnosis and management of encephalitis were previously largely based on clinical grounds and minimal laboratory investigations. Japanese encephalitis (JE) gets considered as the probable diagnosis in most encephalitis cases. However, reports of JE in adults and the elderly are increasing after the JE vaccine introduction among children in 2006. The Nipah virus (NiV) emerged in 2002 and continues to afflict humans in new geographic areas. Many other infections cause encephalitis, including Chandipura, chikungunya, dengue, and West Nile. Significant advances in diagnostic testing like multiplex testing panels and metagenomic approaches along with sequencing have helped in the detection of new etiologies. Recent years have witnessed an increase in climate-sensitive zoonotic diseases with encephalitis. This highlights the importance of the One Health approach in studying the impact of climate change-associated infectious diseases on human health. The government of India's efforts to develop health research infrastructure would help future responses to emerging infectious disease epidemics.

Biallelic variants in ribonuclease inhibitor (RNH1), an inflammasome modulator, are associated with a distinctive subtype of acute, necrotizing encephalopathy.

PURPOSE: Mendelian etiologies for acute encephalopathies in previously healthy children are poorly understood, with the exception of RAN binding protein 2 (RANBP2)-associated acute necrotizing encephalopathy subtype 1 (ANE1). We provide clinical, genetic, and neuroradiological evidence that biallelic variants in ribonuclease inhibitor (RNH1) confer susceptibility to a distinctive ANE subtype. METHODS: This study aimed to evaluate clinical data, neuroradiological studies, genomic sequencing, and protein immunoblotting results in 8 children from 4 families who experienced acute febrile encephalopathy. RESULTS: All 8 healthy children became acutely encephalopathic during a viral/febrile illness and received a variety of immune modulation treatments. Long-term outcomes varied from death to severe neurologic deficits to normal outcomes. The neuroradiological findings overlapped with ANE but had distinguishing features. All affected children had biallelic predicted damaging variants in RNH1: a subset that was studied had undetectable RNH1 protein. Incomplete penetrance of the RNH1 variants was evident in 1 family. CONCLUSION: Biallelic variants in RNH1 confer susceptibility to a subtype of ANE (ANE2) in previously healthy children. Intensive immunological treatments may alter outcomes. Genomic sequencing in children with unexplained acute febrile encephalopathy can detect underlying genetic etiologies, such as RNH1, and improve outcomes in the probands and at-risk siblings.

Incidence of Japanese Encephalitis and Acute Encephalitis Syndrome Hospitalizations in the Medium-Endemic Region in Central India.

BACKGROUND: We estimated the incidence of Japanese encephalitis (JE) and acute encephalitis syndrome (AES) following routine immunization with the live-attenuated SA 14-14-2 JE vaccine. METHODS: We implemented enhanced surveillance of AES and JE hospitalizations in endemic districts in Maharashtra and Telangana States during 2015-2016 and 2018-2020. We estimated incidence and compared differences in the incidence of JE and AES between two states, and vaccinated and unvaccinated districts during two study periods. We also considered secondary data from public health services to understand long-term trends from 2007 to 2020. RESULTS: The annual AES incidence rate of 2.25 cases per 100,000 children in Maharashtra during 2018-2020 was significantly lower than 3.36 cases per 100,000 children during 2015-2016. The six JE-vaccinated districts in Maharashtra had significantly lower incidence rates during 2018-2020 (2.03, 95% CI 1.73-2.37) than in 2015-16 (3.26, 2.86-3.70). In addition, the incidence of both JE and AES in two unvaccinated districts was higher than in the vaccinated districts in Maharashtra. Telangana had a lower incidence of both JE and AES than Maharashtra. The AES incidence rate of 0.95 (0.77-1.17) during 2018-2020 in Telangana was significantly lower than 1.67 (1.41-1.97) during 2015-2016. CONCLUSIONS: The annual incidence rate of Japanese encephalitis was < 1 case per 100,000 children. It indicated accelerated control of Japanese encephalitis after routine immunization. However, the annual incidence of acute encephalitis syndrome was still > 1 case per 100,000 children. It highlights the need for improving surveillance and evaluating the impacts of vaccination.

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.