Flourishing Japanese Encephalitis, Associated with Global Warming and Urbanisation in Asia, Demands Widespread Integrated Vaccination Programmes

Movement disorders in Indochina: Resource challenges and future solutions

Movement disorders are a major cause of disability worldwide and their increasing prevalence predicts a substantial future burden of care. Impactful patient care requires availability of, and accessibility to, effective medications, knowledge, and disease awareness among both medical professionals and patients, driven by skilled personnel to harness and manage resources. The highest burden of movement disorders is in low-to-middle income countries where resources are often limited and infrastructure is insufficient to meet growing demands. This article focuses on the specific challenges faced in the management and delivery of care for movement disorders in Indochina, the mainland region of Southeast Asia comprising the neighboring countries of Cambodia, Laos, Malaysia, Myanmar, Thailand, and Vietnam. The first Indochina Movement Disorders Conference was held in August 2022 in Ho Chi Minh City, Vietnam, to provide a platform to better understand the situation in the region. Future management of movement disorders in Indochina will require progressive adaptation of existing practices to reflect modern approaches to care delivery. Digital technologies offer an opportunity to strengthen these processes and address the challenges identified in the region. Ultimately, a long-term collaborative approach by regional healthcare providers is key.

The spatial-temporal pattern of Japanese encephalitis and its influencing factors in Guangxi, China

Japanese encephalitis (JE) is a major global public health threat. Using Japanese encephalitis incidence data from 2004 to 2010 in Guangxi Province, China, this study comprehensively explored the driving forces and the interactive effects between environmental and social factors of Japanese encephalitis using the Geo-detector method. The results indicated that the incidence of Japanese encephalitis showed a fluctuating downward trend from 2004 to 2010. The onset of JE was seasonal, mainly concentrated in June-July, and highly aggregated in northwestern Guangxi. Among the factors associated with Japanese encephalitis, days with temperatures >30 °C, accumulated temperatures >25 °C, slope, the normalized difference vegetation index, the gross domestic product of tertiary industries, the gross domestic product of primary industries and the number of pigs slaughtered showed higher contributions to Japanese encephalitis incidence. An enhanced interactive effect was found between environmental and social factors, and the interaction between days with humidity levels >80% and the gross domestic product of tertiary industries had the greatest combined effect on JE. These findings enhanced the understanding of the combined effect of social and environmental factors on the incidence of Japanese encephalitis and could help improve Japanese encephalitis transmission control and prevention strategies.

Japanese Encephalitis Enzootic and Epidemic Risks across Australia

Japanese encephalitis virus (JEV) is an arboviral, encephalitogenic, zoonotic flavivirus characterized by its complex epidemiology whose transmission cycle involves reservoir and amplifying hosts, competent vector species and optimal environmental conditions. Although typically endemic in Asia and parts of the Pacific Islands, unprecedented outbreaks in both humans and domestic pigs in southeastern Australia emphasize the virus' expanding geographical range. To estimate areas at highest risk of JEV transmission in Australia, ecological niche models of vectors and waterbirds, a sample of piggery coordinates and feral pig population density models were combined using mathematical and geospatial mapping techniques. These results highlight that both coastal and inland regions across the continent are estimated to have varying risks of enzootic and/or epidemic JEV transmission. We recommend increased surveillance of waterbirds, feral pigs and mosquito populations in areas where domestic pigs and human populations are present.

A systematic review of brain imaging findings in neurological infection with Japanese encephalitis virus compared with Dengue virus

OBJECTIVES

Japanese encephalitis virus (JEV) and dengue virus (DENV) represent important causes of encephalitis in Asia. Brain imaging may provide diagnostic clues about the etiology of infectious encephalitis. We performed a systematic review of brain imaging findings in Japanese encephalitis (JE) and DENV neurological infection (dengue) to identify characteristic lesions.

METHODOLOGY

Five databases were searched. We included all study types and imaging techniques. Laboratory methods were categorized using diagnostic confidence levels. Imaging data were synthesized, and focal findings are presented as proportions for JE and dengue and for subgroups based on diagnostic confidence.

PRINCIPAL FINDINGS

Thalamic lesions were the most reported magnetic resonance imaging finding in both diseases but appeared to occur more often in JE (74% in 23 studies) than dengue (29.4% in 58 studies). In cases diagnosed with antigen or nucleic acid tests, thalamic lesions were reported frequently in both JE (76.5% in 17 studies) and dengue (65.2% in 23 studies).

SIGNIFICANCE

The results suggest that thalamic lesions frequently occur in both JE and dengue encephalitis. No radiological findings were found to be pathognomonic of either disease. Although brain imaging may support a diagnosis, laboratory confirmation with highly specific tests remains crucial.

Re-Examining the Importance of Pigs in the Transmission of Japanese Encephalitis Virus

Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, is the leading cause of pediatric encephalitis in Southeast Asia. The enzootic transmission of JEV involves two types of amplifying hosts, swine and avian species. The involvement of pigs in the transmission cycle makes JEV a unique pathogen because human Japanese encephalitis cases are frequently linked to the epizootic spillover from pigs, which can not only develop viremia to sustain transmission but also signs of neurotropic and reproductive disease. The existing knowledge of the epidemiology of JEV largely suggests that viremic pigs are a source of infectious viruses for competent mosquito species, especially Culex tritaeniorhynchus in the endemic regions. However, several recently published studies that applied molecular detection techniques to the characterization of JEV pathogenesis in pigs described the shedding of JEV through multiple routes and persistent infection, both of which have not been reported in the past. These findings warrant a re-examination of the role that pigs are playing in the transmission and maintenance of JEV. In this review, we summarize discoveries on the shedding of JEV during the course of infection and analyze the available published evidence to discuss the possible role of the vector-free JEV transmission route among pigs in viral maintenance.

Nervous System Manifestations of Arboviral Infections

Purpose of Review

Complex environmental factors and human intervention influence the spread of arthropod vectors and the cycle of transmission of arboviruses. The spectrum of clinical manifestations is diverse, ranging from serious presentations like viral hemorrhagic fever (e.g., dengue, yellow fever, rift valley fever) or shock syndromes (e.g., dengue virus) to organ-specific illness like meningoencephalitis.

Recent Findings

A spectrum of clinical neurologic syndromes with potential acute devastating consequences or long-term sequelae may result from some arboviral infections.

Summary

In this review, we describe some of the most frequent and emerging neuro-invasive arboviral infections, spectrum of neurologic disorders including encephalitis, meningitis, myelitis or poliomyelitis, acute demyelinating encephalomyelitis, Guillain-Barré syndrome, and ocular syndromes.

The Ecology and Evolution of Japanese Encephalitis Virus

Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus mainly spread by Culex mosquitoes that currently has a geographic distribution across most of Southeast Asia and the Western Pacific. Infection with JEV can cause Japanese encephalitis (JE), a severe disease with a high mortality rate, which also results in ongoing sequalae in many survivors. The natural reservoir of JEV is ardeid wading birds, such as egrets and herons, but pigs commonly play an important role as an amplifying host during outbreaks in human populations. Other domestic animals and wildlife have been detected as hosts for JEV, but their role in the ecology and epidemiology of JEV is uncertain. Safe and effective JEV vaccines are available, but unfortunately, their use remains low in most endemic countries where they are most needed. Increased surveillance and diagnosis of JE is required as climate change and social disruption are likely to facilitate further geographical expansion of Culex vectors and JE risk areas.

Japanese encephalitis vaccination in pregnancy among U.S. active duty military women

INTRODUCTION

Japanese encephalitis (JE) vaccine is an inactivated vaccine that has shown no risks in pregnancy in animal models, but epidemiologic studies are lacking. U.S. military service members located in JE endemic regions are required to be vaccinated; understanding the potential adverse events (AEs), including AEs that may occur in pregnancy, is needed. Here, we assessed pregnancy and infant health outcomes in association with JE vaccination in pregnancy.

METHODS

The study population consisted of 192,570 pregnancies to active duty women (2003-2014), captured in the Department of Defense Birth and Infant Health Research program. JE vaccine in pregnancy, vaccine count, formulation, trimester, and whether first career dose coincided with pregnancy were compared with unexposed pregnancies to assess risk of pregnancy and infant health outcomes. Adjusted risk estimates and 95% confidence intervals (CIs) were calculated by multivariable models.

RESULTS

Of the 192,570 identifed pregnancies, 513 were exposed to the JE vaccine; 474 exposures occurred in the first trimester. For all outcomes, elevated risk estimates ranging from 1.53 to 1.70, were observed with receipt of >1 JE vaccine in pregnancy, though 95% CIs were wide and encompassed the null. First dose of JE vaccination in pregnancy was associated with a 1.87 (95% CI: 1.12-3.13) times increased risk of low birthweight (LBW) when excluding pregnancies exposed to other non-routinely recommended vaccinations in pregnancy. All other associations were null in both main and subset analyses.

CONCLUSIONS

The overall results of these analyses provide reassuring findings for the safety of JE vaccination in pregnancy. Higher counts of JE vaccine received in pregnancy yielded large yet non-statistically significant risk estimates for all outcomes, though likely driven by lack of pregnancy awareness. An association was observed with LBW in subset analyses, but it was limited to women receiving their first JE vaccine and not observed in the larger main analyses.