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

A Special Insight on the Causal Agents and Mode of Occurrence of Japanese Encephalitis (JE) Infections in Rural Regions of Assam, India

INTRODUCTION

Japanese Encephalitis (JE) is a life-threatening disease, especially in the Indian subcontinent. Knowledge about the nature and ecology of the dispersal of JE virus (JEV) vectors needs to be increased. This study mechanistically explores the ecology of JEV vectors and the mode and frequency of occurrence of Acute Encephalitis Syndrome (AES) and JEV infections.

METHODS

We established a linear relationship between environmental variables and JEV infection by JEV vectors (mosquitoes)-Culex tritaeniorhynchus, Culex vishnui, and Culex pseudovishnui. The relative abundance of three mosquito species was evaluated, and the JE Sample Positivity Rate (SPR) and JE Case Fatality Rate (CFR) were computed.

RESULTS

Culex vishnui had a high abundance in residential areas during the transition from hot-dry (77.34%) to hot-wet period (78.66%) at temperatures between 31°C and 34°C and relative humidity of 80%-85.3%; this period also coincided with occurrence of AES (39 cases in hot-dry and 88 cases in hot-wet period) and JE (8 instances in hot-dry and 31 cases in hot-wet period). JE infection dominated near rainfed rice fields (rainfall: R = 0.67 at p < 0.05; rainy days: R = 0.74, p < 0.01). SPR was up to 32.28%, and CFR was as high as 42.86%; JEV infection was concentrated in adult male humans near rice fields (15.66%).

CONCLUSIONS

Climate modulation over the years can influence the distribution of Culex vishnui and, hence, AES and JE cases. JEV infections tend to rise in JE hotspot regions, especially near rice fields. Thus, comprehensive epidemiological investigations will help prevent a silent outbreak of JE.

Prevalence of Japanese encephalitis infection in children below 15 years' age, Bihar

Japanese encephalitis (JE) is the leading cause of acute encephalitis syndromes (AES). Although Bihar has comprehensive data on JE, it ranks third behind Uttar Pradesh and Assam in terms of reported cases. We wanted to determine the incidence of JE cases in Bihar and the endemic districts. In Patna, Muzaffarpur and Gaya, Bihar, this study revealed that JEV is one of the major causes of AES and its epidemiology. We analyzed blood and CSF samples from AES patients delivered to a viral diagnostic laboratory between January 2018 and December 2022 for IgM antibodies against JEV using the enzyme immunoassay recommended by NIV, Pune, India. We detected JEV IgM in 193 (8.79 %) of 2195 individuals. Patient demographics included age, gender and place of residence. Most patients were 6-10 years old and had the disease in June. We need to increase awareness initiatives and cross-sector prevention despite the decline in case fatality rate.

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

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

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.

An Observational Study on Pattern of Empirical Acyclovir Therapy in Children With Acute Encephalitis From Northern India

OBJECTIVES

To identify the prevalence of herpes simplex encephalitis (HSE), factors influencing the duration of empirical acyclovir and frequency of acute kidney injury (AKI) in children with acute encephalitis syndrome (AES).

DESIGN

Prospective observational study.

SETTING

Pediatric Emergency Department and PICU of a tertiary hospital in Northern India.

PATIENTS

All consecutive, eligible children between 1 month and 12 years old presenting with AES, defined as altered consciousness for greater than 24 hours (including lethargy, irritability, or a change in personality) and two or more of the following signs: 1) fever (temperature ≥ 38°C) during the current illness, 2) seizures or focal neurological signs, 3) cerebrospinal fluid (CSF) pleocytosis, 4) electroencephalogram, and/or 5) neuroimaging suggesting encephalitis, who received at least one dose of acyclovir.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 101 children screened, 83 were enrolled. The median (interquartile range [IQR]) age was 3 years (1-6 yr). Thirty-one children (37.3%) were diagnosed with AES, of which four were labeled as probable HSE (three based on MRI brain, one based on serology). Scrub typhus, dengue, Japanese encephalitis, and mumps were the other infective causes. The median (IQR) duration of acyclovir therapy was 72 hours (24-264 hr); 21 children (25.3%) received acyclovir for less than 24 hours and 11 (13.3%) for greater than or equal to 14 days. New-onset AKI was seen in 18 children (21.7%) but was mostly transient. Death ( n = 8, 9.6%) and discontinuation of care due to futility or other reasons ( n = 15, 18%) were noted in 23 children (28%). Factors associated with duration of acyclovir greater than 7 days, on univariable analysis, were lower modified Glasgow Coma Score at admission, requirement of invasive ventilation, invasive intracranial pressure monitoring, and CSF pleocytosis (5-500 cells). On multivariable analysis, only CSF pleocytosis of 5-500 cells was associated with duration of acyclovir greater than 7 days.

CONCLUSIONS

Given the low prevalence of HSE, and the risk of AKI, this study sensitizes the need to review our practice on initiation and stopping of empirical acyclovir in children with acute encephalitis.

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.

Coverage of Japanese encephalitis routine vaccination among children in central India

We aimed to estimate the coverage of Japanese encephalitis (JE) vaccination in central India to help explain the continued occurrence of JE disease despite routine vaccination. We implemented a 30-cluster survey for estimating the coverage of JE vaccination in the medium-endemic areas implemented with JE vaccination in central India. The parents were enquired about the uptake of the JE vaccine by their children aged 2-6 years, followed by verification of the immunization cards at home along with reasons for non-vaccination. Vaccination coverage was reported as a percentage with 95% confidence intervals (CI). We estimated high coverage of live-attenuated SA 14-14-2 JE vaccination in Maharashtra (94.8%, 95% CI: 92.7-96.3) and Telangana (92.8%, 95% CI: 90.0-94.9). The vaccination card retention was 90.3% in Maharashtra and 70.4% in Telangana state. There were no gender differences in coverage in both states. A similar level of JE vaccination coverage was observed during the year 2013-2021 in both states. In Maharashtra, the maximum age-wise coverage was 96.6% in the >60 months age category, whereas in Telangana it was in the <24 months age category (97.2%). The timeliness of JE vaccination was appropriate and similar in both states. We found a very good agreement between JE and measles-rubella vaccinations administered simultaneously. The reasons for non-vaccination were the shortage of vaccines and the parental migration for work. The coverage of JE vaccination was high in medium-endemic regions in central India. Vaccination effectiveness studies may help further explain the continued incidence of JE.

Infectious causes of acute encephalitis syndrome hospitalizations in Central India, 2018-20

BACKGROUND

We enhanced surveillance of hospitalizations of all ages for acute encephalitis syndrome (AES) along with infectious aetiologies, including the Japanese encephalitis virus (JEV).

METHODS

From October 2018 to September 2020, we screened neurological patients for AES in all age groups in Maharashtra and Telangana States. AES cases were enrolled at study hospitals along with other referrals and sampled with cerebrospinal fluid, acute and convalescent sera. We tested specimens for non-viral aetiologies viz. leptospirosis, typhoid, scrub typhus, malaria and acute bacterial meningitis, along with viruses - JEV, Dengue virus (DENV), Chikungunya virus (CHIKV), Chandipura virus (CHPV) and Herpes simplex virus (HSV).

RESULTS

Among 4977 neurological hospitalizations at three study site hospitals over two years period, 857 (17.2%) were AES. However, only 287 (33.5%) AES cases were eligible. Among 278 (96.9%) enrolled AES cases, infectious aetiologies were identified in 115 (41.4%) cases, including non-viral in 17 (6.1%) cases - leptospirosis (8), scrub-typhus (3) and typhoid (6); and viral in 98 (35.3%) cases - JEV (58, 20.9%), HSV (22, 7.9%), DENV (15, 5.4%) and CHPV (3, 1.1%). JEV confirmation was significantly higher in enrolled cases than referred cases (10.2%) (p < 0.05). However, the contribution of JEV in AES cases was similar in both children and adults. JE was reported year-round and from adjacent non-endemic districts.

CONCLUSIONS

The Japanese encephalitis virus continues to be the leading cause of acute encephalitis syndrome in central India despite vaccination among children. Surveillance needs to be strengthened along with advanced diagnostic testing for assessing the impact of vaccination.