A Retrospective Study of the Clinical Characteristics of Japanese Encephalitis in Adults.

OBJECTIVE: This study aimed to explore the diagnostic points and treatment modes of the clinical characteristics of Japanese encephalitis (JE) in the middle-aged and elderly population. METHODS: Six patients aged 47-72 who were diagnosed with JE at the Beijing Chaoyang Hospital Affiliated with the Capital Medical University between August 2018 and September 2019 were enrolled in the study. Their clinical manifestations, biochemical indicators, imaging data, diagnostic methods, and the evolution and outcomes of the treatments they underwent were retrospectively analyzed. RESULTS: (1) All six patients had severe clinical symptoms and poor prognoses that were more likely to be associated with other systemic diseases. (2) Lesions were most commonly distributed in the thalamus, basal ganglia, and midbrain. The appearance of hyperintensity in the corpus callosum, hippocampus, and subcortical white matter was more specific. The hyperperfusion metabolism in the lesion area in head computed tomography perfusion imaging indicated the state of inflammatory activity in the lesion. In cranial magnetic resonance imaging (MRI), T2 and fluid-attenuated inversion recovery (FLAIR) were more sensitive. (3) After a patient has been systematically treated in the intensive care unit (ICU), the patient gradually recovered and the level of consciousness improved (p < 0.05). CONCLUSIONS: In brain MRI-especially T2 and FLAIR-intracranial infection is often accompanied by abnormal signals in the thalamus, midbrain, hippocampus, and white matter hyperintensity (WMH), which is highly suggestive of JE. The positive detection of anti-JE virus immunoglobulin M antibodies in a patient's serum and/or cerebrospinal fluid can confirm the diagnosis of JE, and comprehensive ICU treatment (hormones combined with anti-inflammatory, antiviral, and mild hypothermic cerebral protection therapies) can improve the survival rate.

A Nationwide Survey of Pediatric-onset Japanese Encephalitis in Japan.

BACKGROUND: Japanese encephalitis (JE) is the leading cause of viral encephalitis with high mortality and morbidity in Asia. In Japan, however, the active recommendation of JE vaccine was retracted in 2005 because of the potential risk of acute disseminated encephalomyelitis. We aimed to determine the recent incidence of childhood-onset JE after the domestic change of vaccination policy in Japan, and to analyze the clinical features of affected children. METHODS: A retrospective nationwide survey was conducted for pediatric patients with JE in Japan from 1995 to 2015. The national surveillance system was used to identify the pediatric patients with JE. Follow-up questionnaires were sent to analyze their clinical and neuroimaging profiles. RESULTS: Among a total of 109 patients registered to the national surveillance, 10 (9%) were less than age 15 years. The annual incidence rate of childhood-onset JE was higher during 2005-15 than that during 1995-2004 (4.3 × 10-3 vs 1.1 × 10-3 per 100000, respectively; P = .04). Endemic regions overlapped with prefectures that farmed pigs harboring antibodies against JE virus with high prevalence. Detailed clinical data were collected from 9 patients. None of them died, but 5 of 9 patients (56%) had neurological sequelae after recovery. One patient who was partially vaccinated with 2 doses of JE vaccine fully recovered from a coma. The age of 3 years or less was associated with unfavorable neurological prognosis. CONCLUSIONS: Our data provide evidence for the importance and prophylactic effect of the JE vaccine in young children in the endemic area.

Intravenous immunoglobulin for the treatment of childhood encephalitis.

BACKGROUND: Encephalitis is a syndrome of neurological dysfunction due to inflammation of the brain parenchyma, caused by an infection or an exaggerated host immune response, or both. Attenuation of brain inflammation through modulation of the immune response could improve patient outcomes. Biological agents such as immunoglobulin that have both anti-inflammatory and immunomodulatory properties may therefore be useful as adjunctive therapies for people with encephalitis. OBJECTIVES: To assess the efficacy and safety of intravenous immunoglobulin (IVIG) as add-on treatment for children with encephalitis. SEARCH METHODS: The Cochrane Multiple Sclerosis and Rare Diseases of the CNS group's Information Specialist searched the following databases up to 30 September 2016: CENTRAL, MEDLINE, Embase, CINAHL, ClinicalTrials.gov, and the WHO ICTRP Search Portal. In addition, two review authors searched Science Citation Index Expanded (SCI-EXPANDED) & Conference Proceedings Citation Index - Science (CPCI-S) (Web of Science Core Collection, Thomson Reuters) (1945 to January 2016), Global Health Library (Virtual Health Library), and Database of Abstracts of Reviews of Effects (DARE). SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing IVIG in addition to standard care versus standard care alone or placebo. DATA COLLECTION AND ANALYSIS: Two review authors independently selected articles for inclusion, extracted relevant data, and assessed quality of trials. We resolved disagreements by discussion among the review authors. Where possible, we contacted authors of included studies for additional information. We presented results as risk ratios (RR) or mean differences (MD) with 95% confidence intervals (CI). MAIN RESULTS: The search identified three RCTs with 138 participants. All three trials included only children with viral encephalitis, one of these included only children with Japanese encephalitis, a specific form of viral encephalitis. Only the trial of Japanese encephalitis (22 children) contributed to the primary outcome of this review and follow-up in that study was for three to six months after hospital discharge. There was no follow-up of participants in the other two studies. We identified one ongoing trial.For the primary outcomes, the results showed no significant difference between IVIG and placebo when used in the treatment of children with Japanese encephalitis: significant disability (RR 0.75, 95% CI 0.22 to 2.60; P = 0.65) and serious adverse events (RR 1.00, 95% CI 0.07 to 14.05; P = 1.00).For the secondary outcomes, the study of Japanese encephalitis showed no significant difference between IVIG and placebo when assessing significant disability at hospital discharge (RR 1.00, 95% CI 0.60 to 1.67). There was no significant difference (P = 0.53) in Glasgow Coma Score at discharge between IVIG (median score 14; range 3 to 15) and placebo (median 14 score; range 7 to 15) in the Japanese encephalitis study. The median length of hospital stay in the Japanese encephalitis study was similar for IVIG-treated (median 13 days; range 9 to 21) and placebo-treated (median 12 days; range 6 to 18) children (P = 0.59).Pooled analysis of the results of the other two studies resulted in a significantly lower mean length of hospital stay (MD -4.54 days, 95% CI -7.47 to -1.61; P = 0.002), time to resolution of fever (MD -0.97 days, 95% CI -1.25 to -0.69; P < 0.00001), time to stop spasms (MD -1.49 days, 95% CI -1.97 to -1.01; P < 0.00001), time to regain consciousness (MD -1.10 days, 95% CI -1.48 to -0.72; P < 0.00001), and time to resolution of neuropathic symptoms (MD -3.20 days, 95% CI -3.34 to -3.06; P < 0.00001) in favour of IVIG when compared with standard care.None of the included studies reported other outcomes of interest in this review including need for invasive ventilation, duration of invasive ventilation, cognitive impairment, poor adaptive functioning, quality of life, number of seizures, and new diagnosis of epilepsy.The quality of evidence was very low for all outcomes of this review. AUTHORS' CONCLUSIONS: The findings suggest a clinical benefit of adjunctive IVIG treatment for children with viral encephalitis for some clinical measures (i.e. mean length of hospital stay, time (days) to stop spasms, time to regain consciousness, and time to resolution of neuropathic symptoms and fever. For children with Japanese encephalitis, IVIG had a similar effect to placebo when assessing significant disability and serious adverse events.Despite these findings, the risk of bias in the included studies and quality of the evidence make it impossible to reach any firm conclusions on the efficacy and safety of IVIG as add-on treatment for children with encephalitis. Furthermore, the included studies involved only children with viral encephalitis, therefore findings of this review cannot be generalised to all forms of encephalitis. Future well-designed RCTs are needed to assess the efficacy and safety of IVIG in the management of children with all forms of encephalitis. There is a need for internationally agreed core outcome measures for clinical trials in childhood encephalitis.

Geographic Expansion of Japanese Encephalitis Virus to Australia: Neuroinflammatory Sequelae and Consideration of Immunomodulation.

We report a child from Southern Australia (New South Wales) who presented during a La Niña event with encephalopathy and acute flaccid paralysis. Magnetic resonance imaging suggested Japanese encephalitis (JE). Steroids and intravenous immunoglobulin did not improve symptoms. Therapeutic plasma exchange (TPE) resulted in rapid improvement and tracheostomy decannulation. Our case illustrates the complex pathophysiology of JE, its' geographic expansion into Southern Australia and potential use of TPE for neuroinflammatory sequelae.

Clinical spectrum and management of dystonia in patients with Japanese encephalitis: A systematic review.

BACKGROUND: Japanese encephalitis (JE) is a potentially fatal viral infection with a wide range of manifestations and can also present with a variety of movement disorders (MD) including dystonia. Dystonic features in JE are uncommon. Here, we have tried to summarize the clinical features and management of dystonia among JE patients with a comprehensive literature search. METHODS: Various databases, including PubMed, Embase, and Google Scholar, were searched against the predefined criteria using suitable keywords combination and boolean operations. Relevant information from observational and case studies was extracted according to the author, dystonic features, radiological changes in the brain scans, treatment options, and outcome wherever provided. RESULT: We identified 19 studies with a total of 1547 JE patients, the diagnosis of which was confirmed by IgM detection in serum and/or cerebrospinal fluid in the majority of the patients (88.62%). 234 (15.13%) of JE patients had dystonia with several types of focal dystonia being present in 131 (55.98%) either alone or in combination. Neuroimaging showed predominant involvement of thalami, basal ganglia, and brainstem. Oral medications including anticholinergics, GABA agonists, and benzodiazepines followed by botulinum toxin were the most common treatment modalities. CONCLUSION: Dystonia can be a disabling consequence of JE, and various available medical therapies can significantly improve the quality of life. Owing to insufficient studies on the assessment of dystonia associated with JE, longitudinal studies with a larger number of patients are warranted to further clarify the clinical course, treatment, and outcome of dystonia.

Treatment of Severe Japanese Encephalitis Complicated With Hashimoto's Thyroiditis and Guillain-Barré Syndrome With Protein A Immunoadsorption: A Case Report.

A severely comatose female patient was diagnosed with Japanese encephalitis (JE). Her condition was complicated by Hashimoto's thyroiditis (HT) and Guillain-Barré syndrome (GBS). After antiviral, glucocorticoid, and immunoglobulin treatment, the patient's consciousness was restored, and she could breathe spontaneously. Following this, new-onset, primarily demyelinating GBS developed, which progressed to demyelination combined with axonal injury. The patient was switched to protein A immunoadsorption (PAIA) therapy, and her Hughes score decreased rapidly, from 4 to 1 after 6 months. This patient is the first to receive PAIA combined with an antiviral-glucocorticoid-immunoglobulin regimen to treat encephalitis, meningitis, HT, and GBS caused by JE infection, thereby reflecting the importance of clinical application of PAIA in the treatment of immunological complications of JE.

Co-infection of neurocysticercosis with Japanese encephalitis: coincidence or synchronism?

We report the case of an eight-year-old boy who presented with an acute encephalitis and was confirmed to have Japanese encephalitis (JE). In addition, we found the vesicular stage of neurocysticercosis (NCC). The co-occurrence of JE and NCC was thought to be synergistic as there is some evidence that in presence of NCC, the neuroinvasiveness and virulence of JE is greater and associated with poor outcome.

'More than devastating'-patient experiences and neurological sequelae of Japanese encephalitis§.

BACKGROUND: Japanese encephalitis (JE), caused by the mosquito-borne JE virus, is a vaccine-preventable disease endemic to much of Asia. Travellers from non-endemic areas are susceptible if they travel to a JE endemic area. Although the risk to travellers of JE is low, the consequences may be severe. METHODS: Here, we describe three cases of JE in British travellers occurring in 2014-15. In addition, we report, through interviews with survivors and their families, personal experiences of life after JE. RESULTS: Three cases of JE were diagnosed in British travellers in 2014/15. One was acquired in Thailand, one in China and one in either Thailand, Laos or Cambodia. All three patients suffered severe, life-threatening illnesses, all were admitted to intensive care units and required medical evacuation back to the UK. One patient suffered a cardiac arrest during the acute stage but made a good recovery. The other two patients remain significantly paralysed and ventilator dependent. All three cases had clear indications for vaccination, and all have been left with life-changing neurological sequelae. CONCLUSIONS: Travel health providers should be aware of the severity of JE, as well as the risk, allowing travellers to make fully informed decisions on JE vaccination.

Nucleic acid-based inhibition of flavivirus infections.

The genus Flavivirus in the family Flaviviridae consists of many arthropod-transmitted human pathogens, including dengue, yellow fever, Japanese encephalitis, West Nile, St. Louis encephalitis, Murray Valley encephalitis, and tick-borne encephalitis viruses. Treatment options against flaviviral disease are extremely limited, with no effective drugs yet commercially available. Recent advances in virology, synthetic organic chemistry, and the discovery of RNA interference (RNAi), have provided the basis for advances in the development of antisense-based approaches to address flaviviral infections. Oligomers of various antisense structural types, targeted to different locations in the flaviviral RNA genome, have now been used to successfully suppress viral gene expression and thereby inhibit flavivirus replication. Double-stranded RNA, containing viral sequence and designed to induce the endogenous cellular machinery of RNAi, has also been shown capable of potently interfering with flavivirus production and transmission. These studies provide insights into flaviviral molecular biology and the basis for the development of novel therapeutic approaches. The goal of this review is to summarize the findings of many of the significant reports that have appeared on the topic of antisense-mediated strategies for the development of antiviral therapy for flaviviruses.

Japanese encephalitis - the prospects for new treatments.

Japanese encephalitis is a mosquito-borne disease that occurs in Asia and is caused by Japanese encephalitis virus (JEV), a member of the genus Flavivirus. Although many flaviviruses can cause encephalitis, JEV causes particularly severe neurological manifestations. The virus causes loss of more disability-adjusted life years than any other arthropod-borne virus owing to the frequent neurological sequelae of the condition. Despite substantial advances in our understanding of Japanese encephalitis from in vitro studies and animal models, studies of pathogenesis and treatment in humans are lagging behind. Few mechanistic studies have been conducted in humans, and only four clinical trials of therapies for Japanese encephalitis have taken place in the past 10 years despite an estimated incidence of 69,000 cases per year. Previous trials for Japanese encephalitis might have been too small to detect important benefits of potential treatments. Many potential treatment targets exist for Japanese encephalitis, and pathogenesis and virological studies have uncovered mechanisms by which these drugs could work. In this Review, we summarize the epidemiology, clinical features, prevention and treatment of Japanese encephalitis and focus on potential new therapeutic strategies, based on repurposing existing compounds that are already suitable for human use and could be trialled without delay. We use our newly improved understanding of Japanese encephalitis pathogenesis to posit potential treatments and outline some of the many challenges that remain in tackling the disease in humans.

Human monoclonal antibodies against West Nile virus from Japanese encephalitis-vaccinated volunteers.

West Nile virus (WNV) is a positive-sense single-stranded RNA flavivirus belonging to the Japanese encephalitis virus (JEV) serocomplex of the Flaviviridae family and causes mosquito-borne infections. Although most human infection cases are asymptomatic, approximately one in 150 infected individuals develops meningoencephalitis, with a mortality rate of 4-14%. While the development of human neutralizing antibody therapeutics against WNV is strongly anticipated, WNV is difficult to study in conventional laboratories due to its high safety level requirement. In this study, we established fully human WNV-neutralizing monoclonal antibodies from the peripheral blood mononuclear cells of inactivated-JEV-vaccinated individuals, and these antibodies exhibited WNV neutralization both in vitro and in vivo. Our results demonstrate a new antibody cross-reactivity strategy to develop immunological therapeutic reagents for WNV and other JEV serotype viruses.

Artificial MicroRNA-Mediated Inhibition of Japanese Encephalitis Virus Replication in Neuronal Cells.

Artificial microRNA (amiRNA)-mediated inhibition of viral replication has recently gained importance as a strategy for antiviral therapy. In this study, we evaluated the benefit of using the amiRNA vector against Japanese encephalitis virus (JEV). We designed three single amiRNA sequences against the consensus sequence of 3' untranslated region (3'UTR) of JEV and tested their efficacy against cell culture-grown JEV Vellore strain (P20778) in neuronal cells. The binding ability of three amiRNAs on 3'UTR region was tested in vitro in HEK293T cells using a JEV 3'UTR tagged with luciferase reporter vector. Transient transfection of amiRNAs was nontoxic to cells as evident from the MTT assay and caused minimal induction in interferon-stimulated gene expression. Furthermore, our result suggested that transient expression of two amiRNAs (amiRNA #1 and amiRNA #2) significantly reduced intracellular viral RNA and nonstructural 1 (NS1) protein, as well as diminished infectious viral particle release up to 95% in the culture supernatant as evident from viral plaque reduction assay. Overall, our results indicated that RNA interference based on amiRNAs targeting viral conserved regions at 3'UTR was a useful approach for improvements of nucleic acid inhibitors against JEV.

Structural basis for neutralization of Japanese encephalitis virus by two potent therapeutic antibodies.

Japanese encephalitis virus (JEV), closely related to dengue, Zika, yellow fever and West Nile viruses, remains neglected and not well characterized 1 . JEV is the leading causative agent of encephalitis, and is responsible for thousands of deaths each year in Asia. Humoral immunity is essential for protecting against flavivirus infections and passive immunization has been demonstrated to be effective in curing disease2,3. Here, we demonstrate that JEV-specific monoclonal antibodies, 2F2 and 2H4, block attachment of the virus to its receptor and also prevent fusion of the virus. Neutralization of JEV by these antibodies is exceptionally potent and confers clear therapeutic benefit in mouse models. A single 20 µg dose of these antibodies resulted in 100% survival and complete clearance of JEV from the brains of mice. The 4.7 Å and 4.6 Å resolution cryo-electron microscopy structures of JEV-2F2-Fab and JEV-2H4-Fab complexes, together with the crystal structure of 2H4 Fab and our recent near-atomic structure of JEV 4 , unveil the nature and location of epitopes targeted by the antibodies. Both 2F2 and 2H4 Fabs bind quaternary epitopes that span across three adjacent envelope proteins. Our results provide a structural and molecular basis for the application of 2F2 and 2H4 to treat JEV infection.

Genotype I of Japanese Encephalitis Virus Virus-like Particles Elicit Sterilizing Immunity against Genotype I and III Viral Challenge in Swine.

Swine are a critical amplifying host involved in human Japanese encephalitis (JE) outbreaks. Cross-genotypic immunogenicity and sterile protection are important for the current genotype III (GIII) virus-derived vaccines in swine, especially now that emerging genotype I (GI) JE virus (JEV) has replaced GIII virus as the dominant strain. Herein, we aimed to develop a system to generate GI JEV virus-like particles (VLPs) and evaluate the immunogenicity and protection of the GI vaccine candidate in mice and specific pathogen-free swine. A CHO-heparan sulfate-deficient (CHO-HS(-)) cell clone, named 51-10 clone, stably expressing GI-JEV VLP was selected and continually secreted GI VLPs without signs of cell fusion. 51-10 VLPs formed a homogeneously empty-particle morphology and exhibited similar antigenic activity as GI virus. GI VLP-immunized mice showed balanced cross-neutralizing antibody titers against GI to GIV viruses (50% focus-reduction micro-neutralization assay titers 71 to 240) as well as potent protection against GI or GIII virus infection. GI VLP-immunized swine challenged with GI or GIII viruses showed no fever, viremia, or viral RNA in tonsils, lymph nodes, and brains as compared with phosphate buffered saline-immunized swine. We thus conclude GI VLPs can provide sterile protection against GI and GIII viruses in swine.

[Fever and Headache after a Vacation in Thailand]. / Fieber und Kopfschmerzen nach Thailandurlaub.

History 50 year-old man with fever and headache starting one week after returning from his vacation in Thailand. His general practitioner prescribed amoxicillin/clavulanic acid, without further analyses to pinpoint the infection. Examinations The examination of cerebro-spinal fluid was crucial for the final diagnosis. Lumbar puncture demonstrated a predominantly mononuclear pleocytosis of 80 cells/µl (< 5) with an elevated protein of 782 mg/l (< 450); glucose and lactate were within normal limits. Treatment and course Initially we tried to treat a broad range of organisms potentially causing meningitis or encephalitis. Typical bacteria and viruses endemic to Switzerland were not found, thus anti-infective treatment was stopped. Also the search for malaria, HIV, Chikungunya and Dengue infections yielded negative results. After 10 days we received a positive serologic test for Japanese encephalitis virus (JEV). Conclusions The Japanese encephalitis virus is transmitted by mosquitoes and is epidemiologically one of the most important transmissible neurologic diseases in Asia. Although only a minority of infected patients are gravely ill, their sequelae and death toll are considerable. Since 2009 a well-tolerated vaccine is available.

Mesenchymal stem cells alleviate Japanese encephalitis virus-induced neuroinflammation and mortality.

BACKGROUND: Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis in Asia. Japanese encephalitis (JE) caused by JEV is characterized by extensive inflammatory cytokine secretion, microglia activation, blood-brain barrier (BBB) breakdown, and neuronal death, all of which contribute to the vicious cycle of inflammatory damage. There are currently no effective treatments for JE. Mesenchymal stem cells (MSCs) have been demonstrated to have a therapeutic effect on many central nervous system (CNS) diseases by regulating inflammation and other mechanisms. METHODS: In vivo, 8- to 10-week-old mice were infected intraperitoneally with JEV and syngeneic bone marrow MSCs were administered through the caudal vein at 1 and 3 days post-infection. The mortality, body weight, and behavior were monitored daily. Brains from each group were harvested at the indicated times for hematoxylin and eosin staining, immunohistochemical observation, flow cytometric analysis, TUNEL staining, Western blot, quantitative real-time polymerase chain reaction, and BBB permeability assays. In vitro, co-culture and mixed culture experiments of MSCs with either microglia or neurons were performed, and then the activation state of microglia and survival rate of neurons were tested 48 h post-infection. RESULTS: MSC treatment reduced JEV-induced mortality and improved the recovery from JE in our mouse model. The inflammatory response, microglia activation, neuronal damage, BBB destruction, and viral load (VL) were significantly decreased in the MSC-treated group. In co-culture experiments, MSCs reprogrammed M1-to-M2 switching in microglia and improved neuron survival. Additionally, the VL was decreased in Neuro2a cells in the presence of MSCs accompanied by increased expression of interferon-α/ß. CONCLUSION: MSC treatment alleviated JEV-induced inflammation and mortality in mice.

Antisense Oligonucleotides Targeting Raf-1 Block Japanese Encephalitis Virus In Vitro and In Vivo.

Japanese encephalitis virus (JEV) infections represent a major health concern in Southeast Asia since no effective treatments are available. Recently, several reports have demonstrated that inhibition of certain host cell proteins prevents viral infection. Raf-1 kinase is a central component of many signaling pathways involved in normal cell growth and oncogenic transformation, and Ras/Raf/ERK signaling activation has been observed during viral infections (including JEV infection). In this study, Raf-1 was confirmed to be upregulated by JEV infection, which suggested that Raf-1 might be important for JEV infection and might be a target for novel anti-JEV drugs. To determine the role of Raf-1 during the JEV infection process, antisense oligonucleotides (ASODNs) were used to downregulate Raf-1 expression in JEV-infected baby hamster kidney (BHK-21) cells and African green monkey kidney (Vero) cells. From five ASODNs candidates tested, Raf-1-1 (Raf-1 antisense) significantly downregulated Raf-1 protein expression levels, significantly inhibited cytopathic effect (CPE) in cultured cells, and reduced JEV RNA levels in cell medium without affecting cell viability. Furthermore, it also demonstrated that ASODN Raf-1-1 possessed therapeutic effects by using a lethal JEV infection mouse model. In conclusion, data presented in this report demonstrated that ASODN Raf-1-1 could suppress Raf-1 protein and that Raf-1 inhibition suppressed JEV replication in vitro and in vivo. These data provided evidence for targeting Raf-1 in the development of novel anti-JEV therapies. In addition, Raf-1-1 represents potential drugs that can be adapted for treating JEV infections.

A single siRNA suppresses fatal encephalitis induced by two different flaviviruses.

BACKGROUND: Japanese encephalitis virus (JEV) and West Nile virus (WNV) are neurotropic flaviviruses that can cause acute encephalitis with a high fatality rate. Currently there is no effective treatment for these infections. METHODS AND FINDINGS: We tested RNA interference (RNAi)-based intervention to suppress lethal JE and WN encephalitis in mice. To induce RNAi, we used either lentivirally expressed short hairpin RNA (shRNA) or synthetic short interfering RNA (siRNA). As target, we selected the cd loop-coding sequence in domain II of the viral Envelope protein, which is highly conserved among all flaviviruses because of its essential role in membrane fusion. Using as a target a species-specific sequence in the cd loop that is conserved only among the different strains of either JEV or WNV, we could achieve specific protection against the corresponding virus. However, by targeting a cross-species conserved sequence within the cd loop, we were able to protect mice against encephalitis induced by both viruses. A single intracranial administration of lentivirally delivered shRNA or lipid-complexed siRNA before viral challenge or siRNA treatment after viral challenge was sufficient for protection against lethal encephalitis. CONCLUSIONS: RNAi-based intervention affords near complete protection from both JEV- and WNV- induced encephalitis in mice. Our results show, to our knowledge for the first time, that siRNA can be used as a broad-spectrum antiviral agent for treating encephalitis caused by multiple related viruses.

Tropical infections in the ICU.

Certain arthropod-borne infections are common in tropical regions because of favorable climatic conditions. Water-borne infections like leptospirosis are common due to contamination of water especially during the monsoon floods. Infections like malaria, leptospirosis, dengue fever and typhus sometimes cause life threatening organ dysfunction and have several overlapping features. Most patients present with classicial clinical syndromes: fever and thrombocytopenia are common in dengue, malaria and leptospirosis; coagulopathy is frequent in leptospirosis and viral hepatitis. Hepatorenal syndrome is seen in leptospirosis, falciparum malaria and scrub typhus. The pulmonary renal syndrome is caused by falciparium malaria, leptospirosis, Hantavirus infection and scrub typhus. Fever with altered mental status is produced by bacterial meningitis, Japanese B encephalitis, cerebral malarial, typhoid encephalopathy and fulminant hepatic failure due to viral hepatitis. Subtle differences in features of the organ failure exist among these infections. The diagnosis in some of these diseases is made by demonstration of antibodies in serum, and these may be negative in the first week of the illness. Hence empiric therapy for more than one disorder may be justified in a small proportion of cases. In addition to specific anti-infective therapy, management of organ dysfunction includes use of mechanical ventilation, vasopressor drugs, continuous renal replacement therapy and blood products. Timely transfer of these patients to well-equipped ICUs with experience in managing these cases can considerably decrease mortality and morbidity.