Japanese encephalitis: a review of the Indian perspective

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.

Japanese encephalitis virus NS5 protein interacts with nucleolin to enhance the virus replication

Japanese encephalitis virus (JEV) is an arthropod-borne, plus-strand flavivirus causing viral encephalitis in humans with a high case fatality rate. The JEV non-structural protein 5 (NS5) with the RNA-dependent RNA polymerase activity interacts with the viral and host proteins to constitute the replication complex. We have identified the multifunctional protein Nucleolin (NCL) as one of the several NS5-interacting host proteins. We demonstrate the interaction and colocalization of JEV NS5 with NCL in the virus-infected HeLa cells. The siRNA-mediated knockdown of NCL indicated that it was required for efficient viral replication. Importantly, JEV grew to higher titers in cells over-expressing exogenous NCL, demonstrating its pro-viral role. We demonstrated that NS5 interacted with the RRM and GAR domains of NCL. We show that the NCL-binding aptamer AS1411 containing the G-quadruplex (GQ) structure and the GQ ligand BRACO-19 caused significant inhibition of JEV replication. The antiviral effect of AS1411 and BRACO-19 could be overcome in HeLa cells by the overexpression of exogenous NCL. We demonstrated that the synthetic RNAs derived from the 3'-NCR of JEV genomic RNA containing the GQ sequence could bind NCL in vitro. The replication complex binding to the 3'-NCR is required for the viral RNA synthesis. It is likely that NCL present in the replication complex destabilizes the GQ structures in the genomic RNA, thus facilitating the movement of the replication complex resulting in efficient virus replication.IMPORTANCEJapanese encephalitis virus (JEV) is endemic in most parts of South-East Asia and the Western Pacific region, causing epidemics of encephalitis with a high case fatality rate. While a tissue culture-derived JEV vaccine is available, no antiviral therapy exists. The JEV NS5 protein has RNA-dependent RNA polymerase activity. Together with several host and viral proteins, it constitutes the replication complex necessary for virus replication. Understanding the interaction of NS5 with the host proteins could help design novel antivirals. We identified Nucleolin (NCL) as a crucial host protein interactor of JEV NS5 having a pro-viral role in virus replication. The NS5-interacting NCL binds to the G-quadruplex (GQ) structure sequence in the 3'-NCR of JEV RNA. This may smoothen the movement of the replication complex along the genomic RNA, thereby facilitating the virus replication. This study is the first report on how NCL, a host protein, helps in JEV replication through GQ-binding.

Development of immunochromatographic strip assay to detect recent infection of Japanese encephalitis virus in swine population

Japanese Encephalitis (JE) is a mosquito borne re-emerging viral zoonotic disease. Sero-conversion in swine occurs 2-3 weeks before human infection, thus swine act as a suitable sentinel for predicting JE outbreaks in humans. The present study was undertaken with the objective of developing immunochromatographic strip (ICS) assay to detect recent infection of Japanese Encephalitis virus (JEV) in swine population. The two formats of ICS assay were standardized. In the first format, gold nanoparticles (GNP) were conjugated with goat anti-pig IgM (50 μg/ml) followed by spotting of recombinant NS1 protein (1 mg/ml) of JEV on NCM as test line and protein G (1 mg/ml) as control line. In the format-II, GNP were conjugated with rNS1 protein (50 μg/ml) followed by spotting of Goat anti-pig IgM (1 mg/ml) as test line and IgG against rNS1 (1 mg/ml) as control line. To decrease the non- specific binding, blocking of serum and nitrocellulose membrane (NCM) was done using 5% SMP in PBS-T and 1% BSA, respectively. Best reaction conditions for the assay were observed when 10 μl of GNP conjugate and 50 μl of 1:10 SMP blocked sera was reacted on BSA blocked NCM followed by reaction time of 15 mins. Samples showing both test and control line were considered positive whereas samples showing only control line were considered negative. A total of 318 field swine sera samples were screened using indirect IgM ELISA and developed ICS assay. Relative diagnostic sensitivity and specificity of format-I was 81.25% and 93.0% whereas of format-II was 87.50% and 62.93%, respectively. Out of 318 samples tested, 32 were positive through IgM ELISA with sero-positivity of 10.06% while sero-positivity with format-I of ICS was 8.1%. Owing to optimal sensitivity and higher specificity of format-I, it was validated in three different labs and the kappa agreement ranged from 0.80 to 1, which signifies excellent repeatability of the developed assay to test field swine sera samples for detecting recent JEV infection.

Japanese Encephalitis Outbreak in Young Adults of Bastar District in Chhattisgarh: A Short Observational Study

Background Instant infections in children due to acute encephalitis syndrome (AES) were reported in a tribal district of Bastar in Chattisgarh, India, between August 2018 and August 2019. Objective The study was conducted to explore the possibility of a viral cause indicating an outbreak. Methods Clinical surveys and serological investigation tests were conducted to identify the viral etiology. The Bastar area in Chhattisgarh reported factors such as paddy fields near homes, a high pig-to-cattle ratio, a significant presence of Culex vishnui mosquitoes, low socioeconomic status, and a lack of health awareness among the tribal people. Result This study, conducted at the Late Baliram Kashyap Memorial Government Medical College in Jagdalpur, Bastar, Chhattisgarh, India, analyzed 128 samples from fever cases out of 213 patients visiting the Japanese encephalitis virus (JEV) testing center. Among these samples, 71 cases exhibited AES, and subsequent JEV IgM ELISA testing identified 18 cases as JEV-positive, signifying recent JEV infections. Notably, the overwhelming majority (94.44%) of JEV-positive patients were under 16 years old, highlighting the heightened vulnerability of children to JEV illness in the Bastar region. Although male patients accounted for 61.11% of the JEV-positive cases compared to 38.88% of female patients, statistical analysis revealed that this gender disparity was not statistically significant (p-value = 0.18). Conclusion The study emphasizes the significance of identifying the etiology and delivering evidence-based care to patients with AES. Improved diagnosis and management of AES may result from a greater comprehension of the advantages and disadvantages associated with the application and administration of common laboratory and diagnostic algorithms.

Antiviral activity of prion protein against Japanese encephalitis virus infection in vitro and in vivo

Flaviviruses are a major cause of viral diseases worldwide, for which effective treatments have yet to be discovered. The prion protein (PrPc) is abundantly expressed in brain cells and has been shown to play a variety of roles, including neuroprotection, cell homeostasis, and regulation of cellular signaling. However, it is still unclear whether PrPc can protect against flaviviruses. In this study, we investigated the role of PrPc in regulating autophagy flux and its potential antiviral activity during Japanese encephalitis virus (JEV) infection. Our in vivo experiment showed that JEV was more lethal to the PrPc knocked out mice which was further supported by histological analysis, western blot and rtPCR results from infected mice brain samples. Role of PrPc against viral propagation in vitro was verified through cell survival study, protein expression and RNA replication analysis, and adenoviral vector assay by overexpressing PrPc. Further analysis indicated that after virus entry, PrPc inhibited autophagic flux that prevented JEV replication inside the host cell. Our results from in vivo and in vitro investigations demonstrate that prion protein effectively inhibited JEV propagation by regulating autophagy flux which is used by JEV to release its genetic material and replication after entering the host cell, suggesting that prion protein may be a promising therapeutic target for flavivirus infection.

Cost of Acute and Sequelae Care for Japanese Encephalitis Patients, Bangladesh, 2011-2021

Japanese encephalitis (JE) is associated with an immense social and economic burden. Published cost-of-illness data come primarily from decades-old studies. To determine the cost of care for patients with acute JE and initial and long-term sequelae from the societal perspective, we recruited patients with laboratory-confirmed JE from the past 10 years of JE surveillance in Bangladesh and categorized them as acute care, initial sequalae, and long-term sequelae patients. Among 157 patients, we categorized 55 as acute, 65 as initial sequelae (53 as both categories), and 90 as long-term sequelae. The average (median) societal cost of an acute JE episode was US $929 ($909), of initial sequelae US $75 ($33), and of long-term sequelae US $47 ($14). Most families perceived the effect of JE on their well-being to be extreme and had sustained debt for JE expenses. Our data about the high cost of JE can be used by decision makers in Bangladesh.

Tinospora cordifolia Miers enhances the immune response in mice immunized with JEV-vaccine: A network pharmacology and experimental approach

BACKGROUND

Tinospora cordifolia Miers. (TC) (Giloya/Guduchi) is a native Indian herb, reported for its wide array of medicinal activities including immunomodulatory activity. However, the exact pharmacological mechanism of TC as an immunomodulatory agent remains unclear. Central to this, to the best of our knowledge, no study has explored the immunoadjuvant potential of TC in response to the Japanese encephalitis (JE) vaccines.

PURPOSE

The study aims to explore the immunoadjuvant potential of TC ethanolic extract in response to the JE vaccine and illustrates its potential mechanism of immunomodulation using an integrated approach of network pharmacology and in-vivo experimental study.

STUDY DESIGN AND METHODS

Initially, the extract was prepared and the components of TC were identified through high-resolution liquid chromatography mass spectrometry (HR-LC/MS). The compounds were then screened for network pharmacology analysis. Next, the drug and disease targets were identified and the network was constructed using Cytoscape 3.7.2 to obtain different signalling pathways of TC in JEV. We then evaluated the immunoadjuvant potential of TC ethanolic extract in mice immunized with inactivated JE vaccine (SA-14-14-2 strain). BALB/c mice were supplemented with TC extract (30 and 100 mg/kg, i.g.), daily for 56 days, marked with immunization on 28th day of the study, by JE vaccine. Blood was collected for flow cytometry and haematological analysis (total and differential cell counts). The surface expression of immune-cell markers (CD3+, CD4+, CD19+, CD11c+, CD40+) were evaluated on day 0 (pre-immunization), day 14 and 28 post-immunization. Additionally, inflammatory cytokines (IFN-γ+/IL-17A+) were evaluated post-14 and 28 days of immunization.

RESULTS

The HR-LC/MS analysis identified the presence of glycosides, terpenoids, steroids and alkaloids in the TC extract. Through network analysis, 09 components and 166 targets were obtained, including pathways that involve toll-like receptor signalling, pattern-recognition receptor signalling, cytokine receptor and cytokine mediated signalling, etc. The in-vivo results showed that preconditioning with TC ethanolic extract significantly elevated the haematological variables (leucocyte count) as well as the surface expression of CD markers (B and T cell subsets) on day 0 (pre-immunization), day 14 and 28 post-immunization. Furthermore, preconditioning of TC demonstrated a dose-dependant augmentation of immune cells (CD3+, CD4+, CD19+, CD11c+) and inflammatory cytokines (IFN-γ+/IL-17A+) on day 14 and 28 post-immunization when compared to vaccine alone group.

CONCLUSION

Results showed that preconditioning with TC extract before immunization might play a potential role in enhancing the cell-mediated as well as humoral immunity. Altogether, the combinatorial approach of network pharmacology and in-vivo animal experimentation demonstrated the immunoadjuvant potential of TC in response to JEV vaccine.

Mice as an Animal Model for Japanese Encephalitis Virus Research: Mouse Susceptibility, Infection Route, and Viral Pathogenesis

Japanese encephalitis virus (JEV), a zoonotic flavivirus, is principally transmitted by hematophagous mosquitoes, continually between susceptible animals and incidentally from those animals to humans. For almost a century since its discovery, JEV was geographically confined to the Asia-Pacific region with recurrent sizable outbreaks involving wildlife, livestock, and people. However, over the past decade, it has been detected for the first time in Europe (Italy) and Africa (Angola) but has yet to cause any recognizable outbreaks in humans. JEV infection leads to a broad spectrum of clinical outcomes, ranging from asymptomatic conditions to self-limiting febrile illnesses to life-threatening neurological complications, particularly Japanese encephalitis (JE). No clinically proven antiviral drugs are available to treat the development and progression of JE. There are, however, several live and killed vaccines that have been commercialized to prevent the infection and transmission of JEV, yet this virus remains the main cause of acute encephalitis syndrome with high morbidity and mortality among children in the endemic regions. Therefore, significant research efforts have been directed toward understanding the neuropathogenesis of JE to facilitate the development of effective treatments for the disease. Thus far, multiple laboratory animal models have been established for the study of JEV infection. In this review, we focus on mice, the most extensively used animal model for JEV research, and summarize the major findings on mouse susceptibility, infection route, and viral pathogenesis reported in the past and present, and discuss some unanswered key questions for future studies.

Point-of-care detection of Japanese encephalitis virus biomarker in clinical samples using a portable smartphone-enabled electrochemical "Sensit" device

Japanese encephalitis (JE), a neglected tropical zoonotic disease prevalent in south-east Asian and western pacific countries, caused by the flavivirus JE virus (JEV), has a dearth of electrochemical point-of-care (PoC) diagnostic tools available to manage endemic breakouts. To overcome this, we have developed a screen-printed carbon electrode (SPCE) immunosensor for rapid PoC detection of JEV nonstructural 1 (NS1) antigen (Ag), found circulating in serum of infected individuals using a smartphone based portable "Sensit" device. The modification of SPCE surface with JEV NS1 antibody (Ab) was confirmed via observation of globular protein structures via scanning electron microscopy (SEM), increase in electrode surface hydrophilicity via contact angle measurement and decrease in current via differential pulse voltammetry (DPV). The fabrication and testing parameters were optimized based on highest current output obtained using DPV. The SPCE was tested for detection limit of target JEV NS1 Ag ranging from 1 fM to 1 μM, which was determined as 0.45 fM in spiked serum. The disposable immunosensor was also found to be highly specific in detecting JEV NS1 Ag over other flaviviral NS1 Ag. Finally, the modified SPCE was clinically validated by testing 62 clinical JEV samples using both a portable miniaturized electrochemical "Sensit" device coupled with a smartphone and a laboratory-based potentiostat. The results were corroborated with gold-standard RT-PCR and showed 96.77% accuracy, 96.15% sensitivity, and 97.22% specificity. Hence, this technique may further be developed into a one-step rapid diagnostic tool for JEV, especially in rural areas.

Japanese Encephalitis Virus: An Update on the Potential Antivirals and Vaccines

Japanese encephalitis virus (JEV) is the causal agent behind Japanese encephalitis (JE), a potentially severe brain infection that spreads through mosquito bites. JE is predominant over the Asia-Pacific Region and has the potential to spread globally with a higher rate of morbidity and mortality. Efforts have been made to identify and select various target molecules essential in JEV’s progression, but until now, no licensed anti-JEV drug has been available. From a prophylactic point of view, a few licensed JE vaccines are available, but various factors, viz., the high cost and different side effects imposed by them, has narrowed their global use. With an average occurrence of >67,000 cases of JE annually, there is an urgent need to find a suitable antiviral drug to treat patients at the acute phase, as presently only supportive care is available to mitigate infection. This systematic review highlights the current status of efforts put in to develop antivirals against JE and the available vaccines, along with their effectiveness. It also summarizes epidemiology, structure, pathogenesis, and potential drug targets that can be explored to develop a new range of anti-JEV drugs to combat JEV infection globally.

Multisectoral prioritization of zoonotic diseases in Haryana (India) using one health approach

Zoonotic diseases have huge livestock and public health burden worldwide, including India. Prioritizing zoonotic diseases is one of the important tasks under 'One Health' as it facilitates effective policy making, proper allocation of resources and promotion of multisectoral collaboration. Although some efforts have been made to prioritizing zoonotic diseases at national level in India, it is important to identify priority diseases in regional settings due to wide variation in climate and demography of different states. Therefore, the present study aims to prioritize zoonotic diseases for the state of Haryana (India). One Health Zoonotic Disease Prioritization (OHZDP) tool was used in this study to prioritize zoonotic diseases. Based on literature review of the past 23 years (2000-2022) on prevalence, morbidity, and mortality of zoonotic diseases, twenty-three high-scoring zoonotic diseases in Haryana and neighboring states of India were initially shortlisted for prioritization. A three-day participatory workshop was conducted involving 17 experts representing the Health, Animal Husbandry and Wildlife departments of Haryana. The Analytical Hierarchy Process (AHP) was used to rank the criteria, which were used to score the selected diseases using the decision tree analysis. The participants selected the following 7 criteria along with their relative weights to score the diseases: (1) Severity of disease in humans, (2) Severity of disease in animals, (3) Presence of disease in the region, (4) Transmission and outbreak potential, (5) Socio-economic impact, (6) Availability of interventions, and (7) Existing inter-sectoral collaboration for surveillance and reporting. The top scoring eight diseases selected as priority zoonotic diseases for Haryana were rabies, Japanese encephalitis, bovine tuberculosis, leptospirosis, avian influenza (H5N1), brucellosis, glanders and Influenza A (H1N1). Sensitivity analysis did not reveal any significant variation in prioritization results by varying criteria weights. This is the first systemic attempt to prioritize zoonotic diseases in the state and this will help in formulating effective monitoring, prevention, and control strategies for zoonotic diseases in the regional settings.

Strategies for ensuring required service level for COVID-19 herd immunity in Indian vaccine supply chain

Post COVID-19 vaccine development, nations are now getting ready to face another challenge: how to effectively distribute vaccines amongst the masses to quickly achieve herd immunity against the infection. According to some experts, herd immunity for COVID-19 can be achieved by inoculating 67% of the population. India may find it difficult to achieve this service level target, owing to several infrastructural deficiencies in its vaccine supply chain. Effect of these deficiencies is to cause frequent lead time disruptions. In this context, we develop a novel modelling approach to identify few nodes, which require additional inventory allocations (strategic inventory reserves) to ensure minimum service level (67%) under the possibility of lead time disruptions. Later, through an illustrative case study on distribution of Japanese Encephalitis vaccine, we identify conditions under which strategic inventory reserve policy cannot be practically implemented to meet service level targets. Nodes fulfilling these conditions are termed as critical nodes and must be overhauled structurally to make the implementation of strategic inventory policy practically viable again. Structural overhauling may entail installation of better cold storage facilities, purchasing more quality transport vans, improving reliability of transport network, and skills of cold storage manager by training. Ideally, conditions for identifying critical nodes for COVID-19 vaccine distribution must be derived separately by substituting COVID-19 specific parametric values in our model. In the absence of the required data for COVID-19 scenario, JE specific criteria can be used heuristically to identify critical nodes and structurally overhaul them later for efficiently achieving service level targets.

Japanese encephalitis virus induces vasodilation and severe lethality in adult and aged AG129 mice lacking alpha, beta and gamma interferon receptors

Japanese encephalitis virus (JEV) is a single-stranded positive-sense RNA virus belonging to the Flaviviridae family. The JEV is the leading cause of viral encephalitis in children and the elderly which is spread by mosquitoes. JEV infection has been established in different animal models such as mouse, hamster, guinea pig, swine, rat, monkey, rabbit by using the different routes of inoculations. Here, we have shown that the alpha/beta and gamma -receptor deficient AG129 mouse induces fatal encephalitis in both young and aged old mice, when challenged with high titer JEV Indian clinical isolate by both intraperitoneal and intradermal route. The JEV infected AG129 mouse have shown neurological symptoms, JEV-induced pathological features and supported high level viral replication. Additionally, administration of JEV in AG129 mice resulted in the induction of severe peripheral vascular permeability, which is a major hall mark of Dengue infection but not shown in JEV. Taken together, our results demonstrate interferon α/β and γ receptors knock out AG129 mouse does not need adaptation of JEV clinical isolates and could be is a promising JEV challenge mouse model by mimicking the natural intradermal route of administration for rapid screening of novel antivirals and vaccines.

Eco-epidemiological risk factors for Japanese encephalitis in the endemic region of North East India: a hospital-based case-control study

Purpose

Japanese encephalitis (JE) has emerged as a major public health concern in North East India due to its complex eco-epidemiological risk factors. The objective of this study was to understand the various risk factors associated with JE infection in the endemic study location.

Methods

A hospital-based case-control study was conducted at Jorhat Medical College and Hospital from August 2017 to September 2018. The study participants included 49 confirmed JE cases with two control arms, one consisting of non-JE acute encephalitis syndrome (AES) patients (n = 91) and the other of non-JE non-AES patients (n = 140), admitted at the same time in the pediatric and medicine wards. A predesigned, pretested, structured questionnaire was used for data collection.

Results

Univariate analysis revealed the following to be risk factors: age at onset, sex, religion, immunization status, proximity to pigs, proximity to paddy fields (<100 m), use of a mosquito net, impregnated mosquito net, mosquito repellent, and outdoor activities. Multiple logistic regression analysis identified age at onset (adjusted odds ratio [AOR], 20.900; 95% confidence interval [CI], 2.210-31.815) and proximity to pigs (AOR, 4.190; 95% CI, 1.592-11.040) as risk factors for the first control arm and proximity to paddy fields (<100 m) (AOR, 8.470; 95% CI, 2.0251-35.438) was the only risk factor found for second control arm, whereas impregnated mosquito nets (AOR, 0.082; 95% CI, 0.009-0.725) and mosquito repellent (AOR, 0.173; 95% CI, 0.052-0.575) were found to be associated with the second control arm.

Conclusion

Age at onset, proximity to pigs, proximity to paddy fields (<100 m), impregnated mosquito nets, and mosquito repellent were the most significant risk factors for JE in the NE region to warrant public health actions.

Changing Paradigm in the epidemiology of Japanese encephalitis in India

Japanese encephalitis (JE) is a very serious public health problem in India and the conducive environment permit its emergence in non-endemic areas in the country. There are constant changes taking place in the pattern of current agricultural practices and vector breeding habitats which had far-reaching consequences on the epidemiology of JE and the severity of epidemic outbreaks today. Due to the continuous ecological changes taking place, vectors changed in their breeding dynamics, feeding, and resting behavior and started invading previously non-endemic areas. JE has recently spread to new territories due to land-use changes, including forest fragmentation and concentrated livestock production. Changes in the livestock population decreased the cattle pig ratio which enhanced the Japanese encephalitis virus (JEV) infection. This review brings forth the present widespread changes encountered that grossly impact the risk of infection in many places for the emergence of Japanese encephalitis and to address the implications for its control.

Interventions for the Prevention and Treatment of Japanese Encephalitis

Purpose of Review

Japanese encephalitis (JE), a clinical indication of JE virus–induced brain inflammation, is the most prevalent cause of viral encephalitis in the world. This review gives a comprehensive update on the epidemiology, clinical features, therapeutic trials and approaches for preventing the spread of JE. It also outlines the different JE vaccines used in various countries and recommendations for administration of JE vaccines.

Recent Findings

According to the WHO, annual incidence of JE is estimated to be approximately 68,000 cases worldwide. It is widespread across Asia–Pacific, with a potential for worldwide transmission. In endemic locations, JE is believed to affect children below 6 years of age, but in newly affected areas, both adults and children are at risk due to a lack of protective antibodies. Various vaccines have been developed for the prevention of JE and are being administered in endemic countries.

Summary

JE is a neuroinvasive disease that causes symptoms ranging from simple fever to severe encephalitis and death. Despite a vast number of clinical trials on various drugs, there is still no complete cure available, and it can only be prevented by adequate vaccination. Various nanotechnological approaches for the prevention and treatment of JE are outlined in this review.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11908-022-00786-1.

A brief review on novel biomarkers identified and advanced biosensing technologies developed for rapid diagnosis of Japanese Encephalitis Virus

Advanced biosensor technology research is imperative for the management of infectious disease outbreaks such as Japanese Encephalitis (JE), a zoonotic disease caused by the flavivirus JE virus (JEV) which is transmitted to humans (dead-end hosts) from the amplification host, pigs, via mosquitoes. To avoid future pandemic scenarios, proactive research rather than responsive research in the field of diagnostics is a requirement for development of rapid, sensitive and specific screening detection methods. In this mini-review, we have critically compared and evaluated the different types of biomarkers (antigen, antibody, nucleic acid) identified for JEV diagnostics and their specific roles in the manifestation of the infection which may be potentially used for therapeutics and drug development as no treatment is available for JE. Furthermore, different biosensors developed for the detection of JEV biomarkers have been discussed in detail to give an overview of the working principles (electrochemical, optical, etc.), fabrication components (signal amplifier, bioreceptor, etc.), detection limits and response times. This review provides a compact compiled base on available JEV diagnostic research work being currently carried out along with their limitations, future prospective, and major challenges faced. This will enable future development of rapid point-of-care diagnostic screening methods for JEV infection management, which may help reduce number of fatalities.

Immuno-chromatic probe based lateral flow assay for point-of-care detection of Japanese encephalitis virus NS1 protein biomarker in clinical samples using a smartphone-based approach

Lateral flow assays (LFAs) are one of the most economical, point-of-care (PoC) diagnostic assays that exploit the colorimetric properties of gold nanoparticles (AuNPs). Up to the best of our knowledge, no rapid antigen-based LFA exists for Japanese Encephalitis Virus (JEV) detection. Herein, we have reported a novel portable sandwich-type LFA for on-site detection of the non-structural 1 (NS1) secretory protein of JEV. In-house JEV NS1 antibodies (Abs) were generated and labelled with AuNPs as immunoprobes. A glass fibre membrane conjugate pad was soaked with AuNPs-Ab solution, while the JEV NS1 Ab and anti-rabbit IgG 2° Ab were coated as the test and control lines, respectively, on a nitrocellulose (NC) membrane. Different layers of the LFA were fabricated and various parameters were standardised for optimum colour intensity development. JEV negative serum samples spiked with JEV NS1 Ags (linear range - 1 pg ml-1 to 1 μg ml-1) were applied onto the sample pad and the intensity of the red colour developed on the test line increased with increasing concentration of Ag. The visual limit of detection (LOD) determined from the LFA was 10 pg ml-1, which corresponded to the LOD determined by the graphical data obtained from ImageJ software and the Colorimeter smartphone application. Furthermore, the colorimetric based immunosensor showed minimal non-specific detection of other closely related flaviviral NS1 Ags in the spiked serum, provided a rapid result within 10 min, showed storage stability up to a month at 4 °C, successfully detected the JEV NS1 protein in clinically infected pig serum samples, and hence, may be developed into a PoC screening diagnostic kit for JEV.

A review on Japanese Encephalitis virus emergence, pathogenesis and detection: From conventional diagnostics to emerging rapid detection techniques

The virus known as Japanese Encephalitis (JEV) is among the common viral persisting Encephalitis caused by Flavivirus around the Globe, especially in Southeast Asian nations. JEV may be a leading reason for neurological illness in humans, with an estimated 70,000 human cases and 10,000 fatalities per annum. The conventional methods like PRNT (Plaque Reduction Neutralization Test), ELISA (Enzyme-linked immunosorbent assay) RT-PCR (reverse transcription-polymerase chain reaction), and virus isolation are few commercial tests being availed these days, but they have a variety of drawbacks, including being extremely expensive, time-consuming, and requiring expertise. Therefore, researches are being made in the development of improved inexpensive, shorter, sensitive, and time-saving strategies to diagnose the Japanese Encephalitis Virus. A number of these researches encompass the employment of immunosensors, electrochemical sensors and along with the applications of nanotechnology to create highly sensitive detecting device. This review article is based on contemporary breakthroughs in diagnosing Japanese Encephalitis Virus, which are crucial in severing the connection between the propagation of zoonotic disease into the current race, where humans function as dead-end hosts.

Japanese encephalitis viral infection modulates proinflammatory cyto/chemokine profile in primary astrocyte and cell line of astrocytic origin

Japanese Encephalitis Virus (JEV) is a neurotropic virus that invades Central Nervous System (CNS) and causes severe neuroinflammation. Given the abundance and the position of astrocytes in the CNS, we speculate that they might play a critical role in the process of neuroinflammation. Unfortunately, the role of astrocytes in JEV-mediated neuroinflammation has long been understated. In this study, we have attempted to assess the role of astrocyte-mediated neuroinflammation upon JEV infection. Mouse model of JEV infection, generated by intraperitoneal injection, showed severe reactive astrogliosis. To further address our hypothesis, we employed immortalized astrocytic cell line (in vitro) and primary astrocyte-enriched culture (ex vivo) as experimental models. JEV infection in the astrocytes induces proinflammatory cytokines like MCP1/CCL2 and IL6 in both ex vivo and in vitro cultures as observed from the cytometric bead array analysis. A significantly altered cytokine profile was observed using PCR analysis in in vitro and ex vivo models upon infection, with respect to control, validating our previous results. We also show that there exists a major inconsistency in the viral replication kinetics, wherein the cell line showed a robust rate of replication whereas the primary astrocyte-enriched culture showed negligibly low number of plaques, underlining the importance of the selection of appropriate experimental model system. In conclusion, we claim that astrocytes significantly contribute to JEV-mediated neuroinflammation, despite not being a CNS immune cell.

Identifying Japanese Encephalitis Virus Using Metatranscriptomic Sequencing, Xinjiang Province, China

The treat of infectious disease epidemics has increased the critical need for continuous broad-ranging surveillance of pathogens with outbreak potential. Using metatranscriptomic sequencing of blood samples, we identified several cases of Japanese encephalitis virus infection from Xinjiang Uyghur Autonomous Region, China. This discovery highlights the risk for known viral diseases even in nonendemic areas.

Estimates of Japanese Encephalitis mortality and morbidity: A systematic review and modeling analysis

Background

Japanese Encephalitis (JE) is known for its high case fatality ratio (CFR) and long-term neurological sequelae. Over the years, efforts in JE treatment and control might change the JE fatality risk. However, previous estimates were from 10 years ago, using data from cases in the 10 years before this. Estimating JE disease severity is challenging because data come from countries with different JE surveillance systems, diagnostic methods, and study designs. Without precise and timely JE disease severity estimates, there is continued uncertainty about the JE disease burden and the effect of JE vaccination.

Methodology

We performed a systematic review to collate age-stratified JE fatality and morbidity data. We used a stepwise model selection with BIC as the selection criteria to identify JE CFR drivers. We used stacked regression, to predict country-specific JE CFR from 1961 to 2030. JE morbidity estimates were grouped from similar study designs to estimate the proportion of JE survivors with long-term neurological sequelae.

Principal findings

We included 82 and 50 peer-reviewed journal articles published as of March 06 2021 for JE fatality and morbidity with 22 articles in both analyses. Results suggested overall JE CFR estimates of 26% (95% CI 22, 30) in 1961–1979, 20% (95% CI 17, 24) in 1980–1999, 14% (95% CI 11, 17) in 2000–2018, and 14% (95% CI 11, 17) in 2019–2030. Holding other variables constant, we found that JE fatality risk decreased over time (OR: 0.965; 95% CI: 0.947–0.983). Younger JE cases had a slightly higher JE fatality risk (OR: 1.012; 95% CI: 1.003–1.021). The odds of JE fatality in countries with JE vaccination is 0.802 (90% CI: 0.653–0.994; 95% CI: 0.62–1.033) times lower than the odds in countries without JE vaccination. Ten percentage increase in the percentage of rural population to the total population was associated with 15.35% (95% CI: 7.71, 22.57) decrease in JE fatality odds. Ten percentage increase in population growth rate is associated with 3.71% (90% CI: 0.23, 7.18; 95% CI: -0.4, 8.15) increase in JE fatality odds. Adjusting for the effect of year, rural population percent, age of JE cases, and population growth rate, we estimated that there was a higher odds of JE fatality in India compared to China. (OR: 5.46, 95% CI: 3.61–8.31). Using the prediction model we found that, in 2000–2018, Brunei, Pakistan, and Timor-Leste were predicted to have the highest JE CFR of 20%. Bangladesh, Guam, Pakistan, Philippines, and Vietnam had projected JE CFR over 20% for after 2018, whereas the projected JE CFRs were below 10% in China, Indonesia, Cambodia, Myanmar, Malaysia, and Thailand. For disability, we estimated that 36% (min-max 0–85) JE patients recovered fully at hospital discharge. One year after hospital discharge, 46% (min-max 0%-97%) JE survivors were estimated to live normally but 49% (min-max 3% - 86%)till had neurological sequelae.

Conclusion

JE CFR estimates were lower than 20% after 2000. Our study provides an updated estimation of CFR and proportion of JE cases with long-term neurological sequelae that could help to refine cost-benefit assessment for JE control and elimination programs.

Japanese Encephalitis (JE) is known for its high case fatality ratio (CFR) and long-term neurological sequelae. Although JE fatality and morbidity risk might change as the characteristics of the population change with the strengthened surveillance scales, expanded immunization coverage, and healthcare improvements, there have not been any updates in the estimates for JE mortality and morbidity estimates for 10 years. In this paper, we made updated estimates of the JE CFR and the proportion of JE survivors with long-term neurological sequelae by performing a systematic review and developing statistical and machine learning models. We estimated JE CFR decreased over time, with estimates of 26% (95% CI 22, 30) in 1961–1979, 20% (95% CI 17, 24) in 1980–1999, 14% (95% CI 11, 17) in 2000–2018, and 14% (95% CI 11, 17) in 2019–2030. countries without JE vaccination, younger JE cases, higher population growth rate, and lower rural population percentage were associated with higher JE CFR. We estimated that 36% (min-max 0–85) JE patients recovered fully at hospital discharge. One year after hospital discharge, 46% (min-max 0%-97%) JE survivors were estimated to live normally but 49% (min-max 3% - 86%) JE patients still had neurological sequelae. The insights gained will be important in evaluating and updating current JE disease burden among all endemic areas and effectively channeling resources to most needed areas.

Antiviral drug research for Japanese encephalitis: an updated review

Japanese encephalitis (JE) caused by the Japanese encephalitis virus (JEV) is one of Asia's most common viral encephalitis. JEV is a flavivirus, common in rural and sub-urban regions of Asian countries. Although only 1% of JEV-infected individuals develop JE, there is a 20-30% chance of death among these individuals and possible neurological sequelae post-infection. No licensed anti-JE drugs are currently available, despite extensive efforts to develop them. Literature search was performed using databases such as PubMed Central, Google Scholar, Wiley Online Library, etc. using keywords such as Japanese encephalitis virus, antiviral drugs, antiviral drug screening, antiviral drug targets, etc. From around 230 papers/abstracts and research reviews retrieved and reviewed for this study, approximately 180 most relevant and important ones have been cited. Different approaches in drug testing and various antiviral drug targets explored so far have been thoroughly searched from the literature and compiled, besides addressing the future perspectives of the antiviral drug development strategies. Although the development of effective anti-JE drugs is an urgent issue, only supportive care is currently available. Recent advancements in understanding the biology of infection and new drug targets have been promising improvements. Despite hindrances such as the unavailability of a proper drug delivery system or a treatment regimen irrespective of the stage of infection, several promising anti-JE candidate molecules are in different phases of clinical trials. Nonetheless, efficient therapy against JEV is expected to be achieved with drug combinations and a highly targeted drug delivery system soon.

Electroactive reduced graphene oxide for highly sensitive detection of secretory non-structural 1 protein: A potential diagnostic biomarker for Japanese encephalitis virus

Fluorine Doped Tin Oxide (FTO) electrode was fabricated with reduced Graphene Oxide (rGO) for sensitive detection of Japanese encephalitis virus (JEV) non-structural 1 (NS1) protein. Beforehand, in-silico 3D structure, stability, and docking of recombinant JEV NS1 antigen (NS1-Ag) and antibody (Ab) was evaluated. The recombinant NS1 Ag of 42 kDa was produced in-house by successful cloning into pET-28a(+) plasmid and further expressed using BL21 Escherichia coli (E. coli) cells. The NS1 Ag was used to raise polyclonal antibodies (Ab) and both were characterized via Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE), Western Blot, Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF), and Enzyme-Linked Immunosorbent Assay (ELISA). Further characterisation of all binding events such as rGO synthesis, and its conjugation with NS1 Ab, and NS1 Ag were confirmed through Fourier-Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, Energy Dispersive X-Ray Analysis (EDX), Scanning Electron Microscopy (SEM), Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV). The fabricated FTO electrode was optimised for various parameters such as pH, response time, temperature, concentration, and scan rate. The detection of JEV NS1 Ag was performed in buffer (LOD- 0.92 fM) as well in spiked serum (LOD- 1.3 fM) samples. The JEV NS1 Ab showed negligible cross-reactivity with other flaviviral NS1 Ag, provided a rapid response within 5 s, and remained stable up to 4 weeks. Furthermore, the fabricated immunosensor may be a potential candidate for further miniaturisation for accurate and early diagnosis of JEV in clinical samples.

Abscisic acid and aloe-emodin against NS2B-NS3A protease of Japanese encephalitis virus

There are no specific drugs for the treatment of Japanese Encephalitis. Thus, new chemical entities or exploration of existing molecules is required. We have tested the antiviral potential of abscisic acid and aloe-emodin against protease of the Japanese encephalitis virus (JEV) using the computational and target-based assay. Maestro Schrödinger glide suite 2019 was used for molecular docking and dynamic studies, and NS2B-NS3A JEV protease kit was used to confirm protease inhibitory activity of abscisic acid and aloe-emodin. The abscisic acid and aloe-emodin have shown optimum binding affinity towards NS2B-NS3A protease of JEV. Furthermore, molecular dynamic simulation results have also shown the stability of abscisic acid and aloe-emodin within the binding pocket of NS2B-NS3A protease. The ADME parameters of both compounds were also found in an acceptable range. The IC50 values were found to be 100 μg/ml and 7.3 μg/ml for abscisic acid and aloe-emodin respectively which indicate more potency of aloe-emodin over the abscisic acid. However, the toxicity prediction results have shown a good safety profile of abscisic acid as compared to aloe-emodin. Thus, further, more detailed experimental studies are required to develop abscisic acid and aloe-emodin as a specific protease inhibitor of JEV.

Acute neurologic emerging flaviviruses

The COVID-19 pandemic has shed light on the challenges we face as a global society in preventing and containing emerging and re-emerging pathogens. Multiple intersecting factors, including environmental changes, host immunological factors, and pathogen dynamics, are intimately connected to the emergence and re-emergence of communicable diseases. There is a large and expanding list of communicable diseases that can cause neurological damage, either through direct or indirect routes. Novel pathogens of neurotropic potential have been identified through advanced diagnostic techniques, including metagenomic next-generation sequencing, but there are also known pathogens which have expanded their geographic distribution to infect non-immune individuals. Factors including population growth, climate change, the increase in animal and human interface, and an increase in international travel and trade are contributing to the expansion of emerging and re-emerging pathogens. Challenges exist around antimicrobial misuse giving rise to antimicrobial-resistant infectious neurotropic organisms and increased susceptibility to infection related to the expanded use of immunomodulatory treatments. In this article, we will review key concepts around emerging and re-emerging pathogens and discuss factors associated with neurotropism and neuroinvasion. We highlight several neurotropic pathogens of interest, including West Nile virus (WNV), Zika Virus, Japanese Encephalitis Virus (JEV), and Tick-Borne Encephalitis Virus (TBEV). We emphasize neuroinfectious diseases which impact the central nervous system (CNS) and focus on flaviviruses, a group of vector-borne pathogens that have expanded globally in recent years and have proven capable of widespread outbreak.

Vector Specificity of Arbovirus Transmission

More than 25% of human infectious diseases are vector-borne diseases (VBDs). These diseases, caused by pathogens shared between animals and humans, are a growing threat to global health with more than 2.5 million annual deaths. Mosquitoes and ticks are the main vectors of arboviruses including flaviviruses, which greatly affect humans. However, all tick or mosquito species are not able to transmit all viruses, suggesting important molecular mechanisms regulating viral infection, dissemination, and transmission by vectors. Despite the large distribution of arthropods (mosquitoes and ticks) and arboviruses, only a few pairings of arthropods (family, genus, and population) and viruses (family, genus, and genotype) successfully transmit. Here, we review the factors that might limit pathogen transmission: internal (vector genetics, immune responses, microbiome including insect-specific viruses, and coinfections) and external, either biotic (adult and larvae nutrition) or abiotic (temperature, chemicals, and altitude). This review will demonstrate the dynamic nature and complexity of virus–vector interactions to help in designing appropriate practices in surveillance and prevention to reduce VBD threats.

SARS-CoV-2 infection in India bucks the trend: Trained innate immunity?

SARS-CoV-2, the causative agent of COVID-19 pandemic caught the world unawares by its sudden onset in early 2020. Memories of the 1918 Spanish Flu were rekindled raising extreme fear for the virus, but in essence, it was the host and not the virus, which was deciding the outcome of the infection. Age, gender, and preexisting conditions played critical roles in shaping COVID-19 outcome. People of lower socioeconomic strata were disproportionately affected in industrialized countries such as the United States. India, a developing country with more than 1.3 billion population, a large proportion of it being underprivileged and with substandard public health provider infrastructure, feared for the worst outcome given the sheer size and density of its population. Six months into the pandemic, a comparison of COVID-19 morbidity and mortality data between India, the United States, and several European countries, reveal interesting trends. While most developed countries show curves expected for a fast-spreading respiratory virus, India seems to have a slower trajectory. As a consequence, India may have gained on two fronts: the spread of the infection is unusually prolonged, thus leading to a curve that is "naturally flattened"; concomitantly the mortality rate, which is a reflection of the severity of the disease has been relatively low. I hypothesize that trained innate immunity, a new concept in immunology, may be the phenomenon behind this. Biocultural, socioecological, and socioeconomic determinants seem to be influencing the outcome of COVID-19 in different regions/countries of the world.

Pro-inflammatory and anti-inflamatory cytokine genes polymorphisms and susceptibility to Japanese encephalitis disease in the North Indian population

BACKGROUND

Japanese encephalitis virus (JEV) is the major cause of viral encephalitis in many regions of Asia. Cytokines, including pro-inflammatory and anti-inflammatory are key regulators playing a detrimental role in the host response to JE infection, pathogenesis and disease outcome. Evidently, the host's cytokine response is genetically determined, representing the complexity of interindividual differences regarding immune response to viral infection. The current study assesses the association of single nucleotide polymorphisms of classical interleukin IL-1β and IL-10 with JEV susceptibility and disease severity in north Indian population.

METHODS

We performed a case-control study using 85 JE patients and 85 healthy controls. Polymorphisms in the IL-1β (-511 C/T) and IL-10 (-1082 A/G) genes were genotyped using PCR-RFLP. All continuous variables were expressed as mean ± standard deviation, and categorical variables were expressed in percentage.

RESULTS

The mRNA level of IL-1β and IL-10 were found significantly increased in JE patients. In severe JE patients, IL-1β mRNA level was significantly higher with heterozygous (C/T) and homozygous (C/C) genotype compared to wild (T/T) genotype and mRNA level of IL-10 was higher in heterozygous genotype (A/G) compared to wild genotype (A/A). The C/T and C/C genotypes of IL-1β were significantly associated with higher risk of JE infection (p < 0.05, OR = 7.25 and 4.40) whereas, the A/G genotype of IL-10 was associated with a reduced risk of JEV infection (p < 0.05, OR = 0.30). The C allele of IL-1β was associated with fever and neck stiffness (p < 0.05) and CT genotype was associated with disease severity and worse outcomes in JE patients. Along with this, IL-10 polymorphism was found associated with fever, and AG genotype was found to be associated with worse disease outcomes such as neurological sequelae (p < 0.05).

CONCLUSION

Mutant allele and genotype at IL-1β (-511 C/T) and IL-10 (-1082 A/G) gene polymorphism show increased expression of IL-1β and IL-10 in JE patients which contribute to disease severity as well as adverse outcomes of disease. Overall this is the first report from northern India, which shows the association of IL-1β and IL-10 polymorphisms with JEV infection.

De Novo Movement Disorders and COVID-19: Exploring the Interface

Background

Neurological manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are being widely documented. However, movement disorders in the setting of 2019 coronavirus infectious disease (COVID-19) have been a strikingly less discussed topic.

Objectives

To summarize available pieces of evidence documenting de novo movement disorders in COVID-19.

Methods

We used the existing PRISMA consensus statement. Data were collected from PubMed, EMBASE, Web of Science, and Scopus databases up to the 29th January, 2021, using pre-specified searching strategies.

Results

Twenty-two articles were selected for the qualitative synthesis. Among these, a total of 52 patients with de novo movement disorders were reported. Most of these had myoclonus, ataxia, tremor or a combination of these, while three had parkinsonism and one a functional disorder. In general, they were managed successfully by intravenous immunoglobulin or steroids. Some cases, primarily with myoclonus, could be ascribed to medication exposures, metabolic disturbances or severe hypoxia, meanwhile others to a post-or para-infectious immune-mediated mechanism. SARS-CoV-2 could also invade the central nervous system, through vascular or retrograde axonal pathways, and cause movement disorders by two primary mechanisms. Firstly, through the downregulation of angiotensin-converting enzyme 2 receptors, resulting in the imbalance of dopamine and norepinephrine; and secondly, the virus could cause cellular vacuolation, demyelination and gliosis, leading to encephalitis and associated movement disorders.

Conclusion

De novo movement disorders are scantly reported in COVID-19. The links between SARS-CoV-2 and movement disorders are not yet established. However, we should closely monitor COVID-19 survivors for the possibility of post-COVID movement disorders.

Japanese Encephalitis Virus as Cause of Acute Encephalitis, Bhutan

In 2011, Bhutan's Royal Centre for Disease Control began Japanese encephalitis (JE) surveillance at 5 sentinel hospitals throughout Bhutan. During 2011-2018, a total of 20 JE cases were detected, indicating JE virus causes encephalitis in Bhutan. Maintaining JE surveillance will help improve understanding of JE epidemiology in this country.

Health system preparedness & community participation in Japanese encephalitis/acute encephalitis syndrome (JE/AES) prevention in a tribal district of Odisha, India

Background & Objectives

Japanese encephalitis/acute encephalitis syndrome (JE/AES) is one of the major zoonotic arbodiseases that has a significant effect on human and animal health. Though many studies have been published on the epidemiology and transmission mechanisms of JE/AES, but there is little evidence on health system preparedness, including community-based engagement. This study was undertaken to explore a multi-stakeholder perspective on health system preparedness for the prevention of JE/AES in a tribal district of Odisha, India.

Methods

This study was conducted at Malkangiri district of Odisha. A total of nine focus group discussions (FGDs) among women having under-five children, community volunteers, and community health workers (CHWs), and 20 in-depth-interviews (IDIs) among community leaders, healthcare providers, and programme managers were conducted. The FGDs and IDIs were digitally recorded, transcribed, translated and analysed using content analysis approach.

Results

Health system preparedness for the prevention of JE/AES was improved, including effective vector management, implementation of the surveillance system, and vaccination programme. The JE vaccine was introduced under Universal Immunization Programme in Odisha in 2016. Behavioural Change Communication activities were provided with the support of community volunteers on Village Health Nutrition and Sanitation Day (VHNSD) under Gaon Kalyan Samiti (GKS) platforms. The CHWs were actively involved in vector management and raising sanitation and hygiene awareness.

Interpretation & conclusions

Community participation and coordination between different stakeholders have a significant impact on the successful implementation of the programme. It was suggested that there was a need for a sustainability approach to active participation, orientation and capacity building training among CHWs and community volunteers to successfully implement the programme.

Pre-treatment with Scopolamine Naturally Suppresses Japanese Encephalitis Viral Load in Embryonated Chick Through Regulation of Multiple Signaling Pathways

Suitable recognition of invasive microorganisms is a crucial factor for evoking a strong immune response that can combat the pathogen. Toll-like receptors (TLRs) play a pivotal role in the induction of this innate immune response through stimulation of interferons (IFNs) that control viral replication in the host via distinct signaling pathways. Though the antiviral property of Atropa belladonna has been established, yet the role of one of its active components scopolamine in modulating various factors of the innate immune branch has not yet been investigated until date. Thus, the present study was conducted to assess the antiviral effects of scopolamine and its immunomodulatory role against Japanese encephalitis virus (JEV) infections in embryonated chick. Pre-treatment with scopolamine hydrobromide showed a significant decrease in the viral loads of chorioallantoic membrane (CAM) and brain tissues. Molecular docking analysis revealed that scopolamine hydrobromide binds to the active site of non-structural protein 5 (NS5) that has enzymatic activities required for replication of JEV, making it a highly promising chemical compound against the virus. The binding contributions of different amino acid residues at or near the active site suggest a potential binding of this compound. Pre-treatment with the scopolamine hydrobromide showed significant upregulation of different TLRs like TLR3, TLR7, and TLR8, interleukins like IL-4, and IL-10, as well as IFNs and their regulatory factors. However, virus-infected tissues (direct infection group) exhibited higher TLR4 expression as compared to scopolamine hydrobromide pre-treated, virus-infected tissues (medicine pre-treated group). These results indicate that scopolamine hydrobromide contributes much to launch antiviral effects by remoulding the TLR and IFN signaling pathways that are involved in sensing and initiating the much-needed anti-JEV responses.

Japanese encephalitis in Uttar Pradesh, India: A situational analysis

Introduction:

Japanese encephalitis (JE) is a vector-borne, viral illness caused by the Japanese Encephalitis Virus. Permanent neurologic or psychiatric sequelae can occur in 30%–50% of those with encephalitis; hence, JE is a cause of major public health concern. For the ease of diagnosis and facilitation of surveillance, National Vector Borne Disease Control Programme uses the term Acute Encephalitis Syndrome (AES). In this study, an attempt has been made to ascertain the status and trends of AES and JE in Uttar Pradesh, India.

Methodology:

This is a record-based retrospective study. The data were obtained from the Directorate of Medical and Health Services of Uttar Pradesh and analyzed using software SPSS version 24.0.

Results:

In Uttar Pradesh, there were 47,509 reported cases of AES from 2005 to 2018,. With yearly fluctuations, the average Case Fatality Rate of AES was 17.49% with highest in 2005 (24.76%) and lowest in 2018 (8%). Among the patients with AES, 9.98% were found positive for JE. The most commonly affected age group is 1-5 years for both AES and JE, closely followed by the age group of 5-10 years. Peak occurrence of both AES and JE was recorded in month of September. Among the AES-affected patients 53.8% were males and 46.2% were females.

Conclusion:

The most commonly affected age group was 1-5 years with peak occurrence in the month of September. Though there was a downward trend in CFR, awareness activities like “Dastak” campaign and intersectoral preventive activities, needs to be strengthened.

Molecular Analysis of the Bloodmeals of Culex spp. Mosquitoes at Natural Habitats in Singapore to Investigate the Potential Risk of Japanese Encephalitis Virus and West Nile Virus Transmission

Japanese encephalitis virus (JEV) and West Nile virus (WNV) are arboviruses primarily transmitted by Culex spp. mosquitoes. Birds are the primary hosts for JEV and WNV. Recent WNV outbreaks in Europe and United States and their association with migratory birds highlight the importance of understanding the feeding host preference of potential vectors for outbreak preparedness, especially in nonendemic settings. Singapore is nonendemic to JEV and WNV, but is a stopover site for migratory birds of the East Asian-Australasian Flyway. Therefore, we elucidated the feeding host range of Culex spp. mosquitoes captured in four natural (bird) habitats in Singapore from January 2011 to December 2012. We characterized feeding host DNA in field-caught mosquitoes using a PCR sequencing-based assay targeting the mitochondrial gene regions. Of 22,648 mosquitoes captured, 21,287 belonged to the Culex vishnui subgroup. The host DNA analysis showed that mosquitoes from the Cx. vishnui subgroup are opportunistic biters, feeding on a range of birds and mammals. Cx. vishnui subgroup, Culex sitiens and Culex bitaeniorhynchus, was primarily ornithophagic, although they fed opportunistically on mammals, including humans. Culex gelidus and Culex quinquefasciatus, in contrast, fed mainly on mammals. The presence of ornitho- and anthropophilic mosquito vectors and susceptible avian and mammalian hosts poses a risk spill-over transmission of JEV and WNV among humans, should these viruses be introduced through migratory birds and establish persistent transmission in resident birds and animal hosts in Singapore.

Mixed Upper and Lower Motor Neuron Damage in Japanese Encephalitis Virus Infection

Cerebral manifestations in Japanese B encephalitis are well known. However, there are very few studies focusing on extra-cerebral manifestations, among which focal anterior horn cell involvement is exceedingly rare. We herein report a case of Japanese B encephalitis with focal anterior horn cell involvement and unfurl how stepwise clinical approach and targeted investigations helped to solve the diagnostic conundrum. A 27-year-old female was admitted with fever, headache, altered sensorium, and convulsions. She tested positive for Japanese B encephalitis-IgM. Following conservative management, she regained consciousness after 5 days when neurological examination revealed marked cognitive impairment, medial convergence of eyeballs, upward gaze restriction, upper limbs dystonia with brisk tendon jerks, and flaccid paraparesis. A repeat neurological examination, on day 15 of admission, showed marked wasting and intermittent fasciculation in both lower limbs. Brain magnetic resonance imaging showed asymmetrical (right > left) bilateral thalamic and midbrain lesions, hyperintense on T2 and T2-fluid-attenuated inversion recovery (FLAIR)-weighted imaging with mild diffusion restriction on diffusion-weighted imaging and apparent diffusion coefficient map, suggestive of encephalitis. Nerve conduction study revealed decreased compound muscle action potentials exclusively in lower limbs with intact sensory nerve action potentials. Electromyogram showed chronic denervation potentials and presence of spontaneous activity in lower limbs, but not in upper limbs, indicative of focal anterior horn cell involvement. Prognosis of Japanese B encephalitis does not only depend on cerebral sequelae. Anterior horn cell involvement can dictate poor outcome and can easily be missed if not carefully dealt with.

Japanese Encephalitis Virus Infects the Thalamus Early Followed by Sensory-Associated Cortex and Other Parts of the Central and Peripheral Nervous Systems

Japanese encephalitis (JE) is a known CNS viral infection that often involves the thalamus early. To investigate the possible role of sensory peripheral nervous system (PNS) in early neuroinvasion, we developed a left hindlimb footpad-inoculation mouse model to recapitulate human infection by a mosquito bite. A 1-5 days postinfection (dpi) study, demonstrated focal viral antigens/RNA in contralateral thalamic neurons at 3 dpi in 50% of the animals. From 4 to 5 dpi, gradual increase in viral antigens/RNA was observed in bilateral thalami, somatosensory, and piriform cortices, and then the entire CNS. Infection of neuronal bodies and adjacent nerves in dorsal root ganglia (DRGs), trigeminal ganglia, and autonomic ganglia (intestine, etc.) was also observed from 5 dpi. Infection of explant organotypic whole brain slice cultures demonstrated no viral predilection for the thalamus, while DRG and intestinal ganglia organotypic cultures confirmed sensory and autonomic ganglia susceptibility to infection, respectively. Early thalamus and sensory-associated cortex involvement suggest an important role for sensory pathways in neuroinvasion. Our results suggest that JE virus neuronotropism is much more extensive than previously known, and that the sensory PNS and autonomic system are susceptible to infection.

The influence of vaccination on the control of JE with a standard incidence rate of mosquitoes, pigs and humans

In this article, a nonlinear mathematical model used for the impact of vaccination on the control of infectious disease, Japanese encephalitis with a standard incidence rate of mosquitoes, pigs and humans has been planned and analyzed. During the modeling process, it is expected that the disease spreads only due to get in touch with the susceptible and infected class only. It is also assumed that due to the effect of vaccination, the total human population forms a separate class and avoids contact with the infection. The dynamical behaviors of the system have been explored by using the stability theory of differential equations and numerical simulations. The local and global stability of the system for both equilibrium states under certain conditions has been studied. We have set up a threshold condition in the language of the vaccine-induced reproduction number R ( α 1 ) , which is fewer than unity, the disease dies in the absence of the infected population, otherwise, the infection remains in the population. Furthermore, it is found that vaccine coverage has a substantial effect on the basic reproduction number. Also, by continuous efforts and effectiveness of vaccine coverage, the disease can be eradicated. It is also found a more sensitive parameter for the transmission of Japanese encephalitis virus by using sensitivity analysis. In addition, numerical results are used to investigate the effect of some parameters happening the control of JE infection, for justification of analytical results.

Beyond HIV infection: Neglected and varied impacts of CCR5 and CCR5Δ32 on viral diseases

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CCR5 regulates multiple cell types (e.g., T regulatory and Natural Killer cells) and immune responses.

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The effects of CCR5, CCR5Δ32 (variant associated with reduced CCR5 expression) and CCR5 antagonists vary between infections.

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CCR5 affects the pathogenesis of flaviviruses, especially in the brain.

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The genetic variant CCR5Δ32 increases the risk of symptomatic West Nile virus infection.

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The triad “CCR5, extracellular vesicles and infections” is an emerging topic.

The interactions between chemokine receptors and their ligands may affect susceptibility to infectious diseases as well as their clinical manifestations. These interactions mediate both the traffic of inflammatory cells and virus-associated immune responses. In the context of viral infections, the human C-C chemokine receptor type 5 (CCR5) receives great attention from the scientific community due to its role as an HIV-1 co-receptor. The genetic variant CCR5Δ32 (32 base-pair deletion in CCR5 gene) impairs CCR5 expression on the cell surface and is associated with protection against HIV infection in homozygous individuals. Also, the genetic variant CCR5Δ32 modifies the CCR5-mediated inflammatory responses in various conditions, such as inflammatory and infectious diseases. CCR5 antagonists mimic, at least in part, the natural effects of the CCR5Δ32 in humans, which explains the growing interest in the potential benefits of using CCR5 modulators for the treatment of different diseases. Nevertheless, beyond HIV infection, understanding the effects of the CCR5Δ32 variant in multiple viral infections is essential to shed light on the potential effects of the CCR5 modulators from a broader perspective. In this context, this review discusses the involvement of CCR5 and the effects of the CCR5Δ32 in human infections caused by the following pathogens: West Nile virus, Influenza virus, Human papillomavirus, Hepatitis B virus, Hepatitis C virus, Poliovirus, Dengue virus, Human cytomegalovirus, Crimean-Congo hemorrhagic fever virus, Enterovirus, Japanese encephalitis virus, and Hantavirus. Subsequently, this review addresses the impacts of CCR5 gene editing and CCR5 modulation on health and viral diseases. Also, this article connects recent findings regarding extracellular vesicles (e.g., exosomes), viruses, and CCR5. Neglected and emerging topics in “CCR5 research” are briefly described, with focus on Rocio virus, Zika virus, Epstein-Barr virus, and Rhinovirus. Finally, the potential influence of CCR5 on the immune responses to coronaviruses is discussed.

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.

PD1+CCR2+CD8+ T Cells Infiltrate the Central Nervous System during Acute Japanese Encephalitis Virus Infection

Japanese encephalitis (JE) is a viral encephalitis disease caused by Japanese encephalitis virus (JEV) infection. Uncontrolled inflammatory responses in the central nervous system (CNS) are a hallmark of severe JE. Although the CCR2-CCL2 axis is important for monocytes trafficking during JEV infection, little is known about its role in CNS trafficking of CD8⁺ T cells. Here, we characterized a mouse model of JEV infection, induced via intravenous injection (i.v.) and delineated the chemokines and infiltrating peripheral immune cells in the brains of infected mice. The CNS expression of chemokines, Ccl2, Ccl3, and Ccl5, and their receptors, Ccr2 or Ccr5, was significantly up-regulated after JEV infection and was associated with the degree of JE pathogenesis. Moreover, JEV infection resulted in the migration of a large number of CD8⁺ T cells into the CNS. In the brains of JEV-infected mice, infiltrating CD8⁺ T cells expressed CCR2 and CCR5 and were found to comprise mainly effector T cells (CD44⁺CD62L^-). JEV infection dramatically enhanced the expression of programmed death 1 (PD-1) on infiltrating CD8⁺ T cells in the brain, as compared to that on peripheral CD8⁺ T cells in the spleen. This effect was more pronounced on infiltrating CCR2⁺CD8⁺ T cells than on CCR2^-CD8⁺ T cells. In conclusion, we identified a new subset of CD8⁺ T cells (PD1⁺CCR2⁺CD8⁺ T cells) present in the CNS of mice during acute JEV infection. These CD8⁺ T cells might play a role in JE pathogenesis.

Analysis of dengue specific memory B cells, neutralizing antibodies and binding antibodies in healthy adults from India

BACKGROUND

The Indian population is facing highest dengue burden worldwide supporting an urgent need for vaccines. For vaccine introduction, evaluation and interpretation it is important to gain a critical understanding of immune memory induced by natural exposure. However, immune memory to dengue remains poorly characterized in this region.

METHODS

We enumerated levels of dengue specific memory B cells (MBC), neutralizing (NT) and binding antibodies in healthy adults (n=70) from New Delhi.

RESULTS

NT-antibodies, binding antibodies and MBC were detectable in 86%, 86.56% and 81.63% of the subjects respectively. Among the neutralizing positive subjects, 58%, 27%, 5% and 10% neutralized all four, any three, any two and any one dengue serotypes respectively. The presence of the neutralizing antibodies was associated with the presence of the MBC and binding antibodies. However, a massive interindividual variation was observed in the levels of the neutralizing antibodies (range, <1:50-1:30,264), binding antibodies (range, 1:3,000-1:134,000,) as well as the MBC (range=0.006%-5.05%).

CONCLUSION

These results indicate that a vast majority of the adults are immune to multiple dengue serotypes and show massive interindividual variation in neutralizing/binding antibodies and MBCs - emphasizing the importance of monitoring multiple parameters of immune memory in order to properly plan, evaluate and interpret dengue vaccines.

Knowledge, attitude and practices relating to zoonotic diseases among livestock farmers in Punjab, India

Zoonotic diseases cause significant health and economic impact in developing countries such as India. Many zoonotic diseases are prevalent in the livestock and as an occupational zoonosis in the livestock farmers in India. Lack of knowledge on the disease transmission, prevention and control measures is a potential high risk for the occurrence of zoonotic diseases in the livestock and its keepers in India. We conducted this study to understand knowledge, attitude and practices of livestock farmers regarding zoonoses. Five villages from each of the 22 districts of the state were conveniently selected (n = 110). Farmers available at village community sites were enrolled in the study and requested to complete a custom designed questionnaire (n = 558). In addition, livestock farmers attending basic livestock husbandry training were also surveyed (n = 301). Data from questionnaires was used to create three index variables: (a) knowledge score; (b) attitude score and (c) practice score. Association between demographic and other explanatory variables with knowledge score was evaluated using linear regression analyses. Similarly, the association between knowledge and attitude score with practice score was evaluated. Of the 859 participants, 685 (80%) livestock farmers had heard the term 'zoonoses' but only 345 (40%), 264 (31%) and 214 (25%) farmers were aware of the zoonotic nature of tuberculosis, Japanese encephalitis and taeniosis, respectively. For practices, 23% farmers reported consumption of raw milk and only 10% and 8% livestock farmers ever got their animals tested for brucellosis and tuberculosis, respectively. The low level of education and being a cattle farmer were negatively associated with the farmer's knowledge on zoonotic diseases. The attitude score was positively associated with the practice score of the participants. The results indicate need for educating the livestock farmers particularly those with a low level of education to reduce the health and economic impact of zoonotic diseases in India.

Larvivorous potentiality of Puntius tetrazona and Hyphessobrycon rosaceus against Culex vishnui subgroup in laboratory and field based bioassay

Objectives

This study assessed the predatory potentiality of two unexplored fishes, Puntius tetrazona and Hyphessobrycon rosaceus on Culex vishnui subgroup larvae in order to utilize natural resources to diminish mosquito population. Larval feeding rate was evaluated in laboratory under varying prey density and volume of water. The experiment was extended to semi field condition.

Results

Puntius tetrazona and H. rosaceus consumed from 66 to 600 and from 87 to 718 Cx. vishnui larvae respectively in laboratory condition at 10 prey density levels (100–1000 larvae) at an increment of 100 larvae at 2 l water volume. In semi field condition, a 78% reduction in larval density was observed at day 30 post introduction of P. tetrazona, whereas 91% reduction was noted on day 21 for H. rosaceus and in the subsequent samples no mosquito larvae were found in ditches. Withdrawal of predators from the ditches resulted gradual increase in larval density. Laboratory and semi field bioassay of both the species indicated their potentiality as efficient mosquito larval predator though H. rosaceus exhibited better performance than P. tetrazona. It is recommended to utilize these natural resources to diminish mosquito population in the countries of their native range.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3902-8) contains supplementary material, which is available to authorized users.

Emergence of human West Nile Virus infection among pediatric population in Madhya Pradesh, India

Human infections caused by West Nile virus (WNV) mostly remain subclinical and self-limited. However, nearly 20% infected people suffer from febrile illness and very few of them (<1%) may get neuroinvasive illness. Mortality has been reported among children. India somehow has reported very less number of WNV cases in the past. We collected cerebrospinal fluid (CSF) samples from 75 pediatric age group patients clinically suffering from acute encephalitis syndrome. Three of these samples were positive by reverse transcriptase polymerase chain reaction using pan flavivirus primers. On sequencing of the 212 bp long-amplified fragment, it was found to be WNV belonging to lineage 1. This is probably the first report of WNV causing encephalitis from this central part of India.

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.

Development of a Japanese encephalitis virus genotype V virus-like particle vaccine in silkworms

To counter the spread of multiple Japanese encephalitis virus (JEV) variants harboured in alternative host species and highly neurotoxic variants with new antigenicity, such as genotype V (Muar), methods for developing more effective and low-cost vaccines against a variety of epidemic JEV strains are required. Here, we successfully synthesized large amounts of a Muar virus-like particle (MVLP) vaccine for JEV in silkworm pupae by using a Bombyx mori nuclear polyhedrosis virus recombinant consisting of JEV codon-optimized envelope (E) DNA. In particular, histopathological examination suggested that MVLP was efficiently synthesized in body fat tissues as well as epithelial cells. Quantitative analysis indicated that one silkworm pupa produced 724.8 µg of E protein in the MVLP vaccine. Electron microscopic examination of purified MVLP vaccine defined a typical MVLP morphological structure. Detailed MVLP antigen assessment by immune-electron microscopy revealed that the majority of MVLPs were covered with approximately 10 nm projections. Boosted immunization with MVLP antigens in mice and rabbits tended to show improved plaque inhibition potency against homologous Muar and heterologous Nakayama, but less potency to Beijing-1 strains. Notably, mixed immune rabbit antisera against Nakayama and Muar VLP antigens led to an increase in the low antibody reaction to Beijing-1. Additionally, a stopgap divalent JEV vaccine consisting of MVLP and Nakayama VLP and its immune mouse serum significantly increased plaque inhibition titre against Muar, Nakayama and Beijing-1 strains. These findings suggested that low-cost MVLP vaccines prepared in silkworm pupae are suitable for providing simultaneous protection of individuals in developing countries against various JEV strains.

Endemic and emerging acute virus infections in Indonesia: an overview of the past decade and implications for the future

Being the largest archipelago country in the world, with a tropical climate and a unique flora and fauna, Indonesia habitats one of the most diverse biome in the world. These characteristics make Indonesia a popular travel destination, with tourism numbers increasing yearly. These characteristics also facilitate the transmission of zoonosis and provide ideal living and breading circumstances for arthropods, known vectors for viral diseases. A review of the past 10 years of literature, reports of the Ministry of Health, Republic of Indonesia and ProMED-mail shows a significant increase in dengue infection incidence. Furthermore, chikungunya, Japanese encephalitis and rabies are proven to be endemic in Indonesia. The combination of cohort studies, governmental data and ProMED-mail reveals an integrated overview for those working in travel medicine and public health, focusing on both endemic and emerging acute virus infections. This review summarizes the epidemiology of acute virus infections in Indonesia, including outbreak reports, as well as public health response measurements and their potential or efficacy. Knowledge about human behaviour, animal reservoirs, climate factors, environment and their role in emerging virus infection are discussed. We aim to support public health authorities and health care policy makers in a One Health approach.