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At least 19 recordsLinked to original sources
PubMed2005

[An unusual cause of meningo-encephalitis: Japanese encephalitis].

Two women, 29 and 30 years of age, who had visited Indonesia and Thailand, respectively, during the summer, presented with diarrhoea, headache, fever and later neurological symptoms. The first patient had to be sedated because of restlessness and was admitted to the intensive-care unit for intravenous antimicrobial therapy; the second became comatose and received intravenous rehydration and antipyretics. No diagnosis was made during the acute phase ofthe illness, but later there was serological evidence of Japanese encephalitis. Both patients recovered, but memory and concentration difficulties persisted for a long time. Due to the increase in travelling, we see more and more cases of (rare) imported diseases. Japanese encephalitis is a viral infection that causes 50,000 cases each year in Asia with a mortality of 30%. The risk of transmission for tourists is very low. Most infections with Japanese encephalitis virus do not lead to symptomatic disease; only 0.1-5% of infections lead to clinical disease. The symptoms are initially non-specific, consisting of general discomfort and diarrhoea. After this, patients can develop headache, decreased consciousness and sometimes convulsions. Therapy consists of supportive care. For travellers at high risk of exposure, a formalin-inactivated vaccine is available. For the proper diagnosis of rare imported diseases, it is advisable to consult an infectious-disease specialist or microbiologist at an early stage when evaluating a patient who has recently returned from the tropics.

Adult↗
PubMed2005

[Japanese encephalitis].

Japanese encephalitis is an arboviral disease due to a flavivirus transmitted by a mosquito of the genus Culex. It is a major public health problem in Southeast Asia where it is endemo-epidemic. The socio-economic impact of Japanese encephalitis is great since most cases occur in children and young adults and lead to death in 25 to 30 % and neurological sequelae in survivors. The tendency of Japanese encephalitis to spread geographically and the existence of imported cases are particularly important issues. The clinical features are the same as other viral encephalitis. Suspicion of imported Japanese encephalitis depends on awareness of the epidemiological setting (return from endemic areas). Diagnosis must be confirmed by serology using ELISA capture method to detect anti-viral antibodies in blood and cerebrospinal fluid. Unlike herpes encephalitis, there is currently no specific treatment for Japanese encephalitis. Only preventive measures can be effective against infection. At the present time the most widely used vaccine is Biken's lyophilized vaccine produced from a reference strain (Nakayama strain), but its high cost prevents mass vaccination in endemic areas. Recent progress in molecular biology has raised hope for the discovery of a genetically engineered vaccine to improve overall protection against Japanese encephalitis.

Encephalitis, Japanese↗
PubMed2006

Polymorphisms of the gene coding for copper/zinc superoxide dismutase (SOD1) in patients with Japanese encephalitis.

Japanese encephalitis is the commonest form of encephalitis globally. Most cases develop characteristic encephalitis but some also present with flaccid paralysis. The paralysis is secondary to damage at the alpha motor neurone, the site that is also damaged in amyotrophic lateral sclerosis (ALS). The gene coding for superoxide dismutase 1 (SOD1) is thought to be involved in ALS and may also be linked to susceptibility to Japanese encephalitis. To investigate this possibility, polymorphisms in the SOD1 gene were investigated, in 61 cases of Japanese encephalitis, 61 matched controls and 171 population controls, in Vietnam. Novel polymorphisms, found only in three of the cases and one of the population controls, may be involved with susceptibility to Japanese encephalitis and potentially to other flavivirus infections that lead to damage to the cells of the anterior horn. Further research on this possible association is required.

Adolescent↗
PubMed2005

[Clinical and epidemiological aspects of Japanese encephalitis].

Japanese encephalitis has been well controlled in Japan. On the other hand, the Japanese encephalitis virus (JEV) transmission cycle still exists, as does the risk of exposure to JEV infection. Although Culex tritaeniorhynchus has been considered the major mosquito vector in Japan, recent surveys suggested Culex pipiens complex and Aedes albopictus as potential alternatives. Similarly, swine have reduced the role in amplification of JEV in paradomestic environments. Another surveys suggested attenuation of recent JEV strains and a shift in the major clinical manifestation caused by JEV infection from encephalitis to meningitis. This paper describes current situation of Japanese encephalitis in Japan from clinical and epidemiological aspects.

Aedes↗
PubMed2003

Development of a recombinant vaccine against Japanese encephalitis.

Japanese encephalitis (JE) is the major form of viral encephalitis in much of the South-East Asia, India, and China. The disease is caused by a mosquito-borne virus known as Japanese encephalitis virus (JEV). The virus spreads in the form of epidemics, although several endemic areas for JEV activity are known. In recent years, JEV has spread to newer geographic locations such as Australia and Pakistan, and thus has become an important emerging virus infection in these areas. A mouse brain-derived, formalin-inactivated vaccine is available for immunization against JE. Because the formalin-inactivated JEV vaccine has limitations in terms of safety, availability, and cost, attempts are being made to develop improved vaccine using the recombinant DNA technology. This article reviews various attempts in this direction and summarizes the latest developments such as the recombinant yellow fever virus- or the plasmid DNA-based JEV vaccine.

Encephalitis Virus, Japanese↗
PubMed2004

A chimeric live attenuated vaccine against Japanese encephalitis.

Japanese encephalitis is a disease of the CNS, endemic in Asia and Oceania. The disease is refractory to drug treatments and whilst the rural economies remain heavily dependent on agriculture, conditions for propagation of the disease will persist. Thus, there is a need for effective vaccines. Although some currently exist, they have their shortcomings. ChimeriVax-JE (Acambis Inc.) is a chimeric, live attenuated vaccine which expresses protective Japanese encephalitis antigens and to date has proven to be safe, effective and well-tolerated in clinical trials. It therefore appears to be a cost-effective prophylactic vaccine against this debilitating disease.

Cost-Benefit Analysis↗
PubMedDate not supplied

[Recent data on the epidemiology of Japanese encephalitis].

Japanese encephalitis is an arbovirosis the incidence and geographic distribution of which are increasing in rural areas of tropical and temperate Asia. A total of about 45,000 to 50,000 clinical cases occur annually. The Flavivirus responsible for the disease shows birds as usual hosts, and Culex mosquitoes as vectors. After a first amplification cycle in birds, the virus can be transmitted to domestic pigs, then to man. This scheme, however, shows large variations in the different regions, according to the climate which determines the dynamics of mosquito and bird populations, and to the ways of life of human populations, particularly for the rice-growing technics and pig breeding. The epidemiologists schematically distinguish tropical endemic areas, subtropical endemic-epidemic zones, and temperate epidemic zones. However, our knowledge on the epidemiology of Japanese encephalitis carries many incompletely understood aspects, for instance the reasons of the actual geographic distribution of the disease, or the mechanisms for persistence of the virus between epidemics. Furthermore, these epidemiological situations are changing with time, particularly with the-development of the new agrosystems linked with demographic increase, while recent technics of genomic analysis allow the recognition of several viral genotypes. The prevention of Japanese encephalitis presently involves vector control, vaccination and, in some cases, particular modifications of environment. Each of these measures shows proper logistic, technical or financial difficulties, which often prevent their generalized use. However, one can observe that, in the countries where vaccination is systematically carried out, the incidence of the disease seems considerably decreasing, while elsewhere it shows a tendency to increase. The main difficulties lie in the high cost of the vaccine and in the weight of immunization scheme, which make uneasy its integration in the Expanded Vaccination Programme. For these reasons, the virologists are looking for other vaccine types, particularly recombinant vaccines relying on obtaining, by genetical manipulation, envelop proteins with protection effect. Finally, remains the question of immunization of travellers and expatriate people. It seems desirable to recommand this vaccine only to the really exposed persons; this means persons performing a rather long stay in a rural area of an endemo-epidemic region, or during the season of transmission in an epidemic region. However, the risk cannot be completely absent, and it is necessary to draw attention to other methods aiming at decreasing man-vector contact.

Asia↗
PubMed2000

Japanese encephalitis.

Japanese encephalitis (JE) virus is a mosquito-borne flavivirus that can cause encephalitis and death in horses and humans. It is an emerging disease of international concern because it has been spreading into previously nonendemic areas. Major epidemics may occur where the virus moves into new areas, but many infections are subclinical. This article presents information on the virus, its epidemiology, and what little information has been published on the disease in horses. The methods available for the diagnosis and control of JE are described and issues raised, particularly for those countries faced with the threat of imminent incursions as the virus extends its range.

Animals↗
PubMed2000

[What are the indications in France for vaccination against Japanese encephalitis?].

Japanese encephalitis is a mosquito-borne viral disease occurring in rural and rice-growing areas of Asia, where mosquitoes proliferate, transmitting the Flavivirus from viremic animals, mostly pigs, to humans. Japanese encephalitis has recently spread to previously non-affected regions, leading to serious outbreaks among non-immune populations. Although it has a high proportion of unsymptomatic infection, clinical encephalitis is usually severe, resulting in a very high mortality rate, and neurologic sequellae are common among survivors. Vaccines are used in several Asian countries. One of these vaccines is now available to French travellers, but only in international vaccination centres with an authorization from the French drug agency (Agence française de sécurité sanitaire des produits de santé). The aim of this paper is to clarify the recommendations for immunisation in each country of the affected regions. The area can be divided into three epidemiological zones, with tropical, subtropical and temperate characteristics. For the first two, vaccination is recommended before a long stay in a rural area, especially during the rainy season; in temperate climates, outbreaks occur in summer and autumn. However, local variations such as intensive rice-growing or development of pig breeding may interfere with these patterns. Long-term visitors should consult a local physician and prevention of mosquito bites is always recommended.

Animals↗
PubMed2003

Recent advances in Japanese encephalitis.

Japanese encephalitis (JE), the most important cause of epidemic encephalitis worldwide, is confined to Asia, but its geographical area is spreading. West Nile virus, and other closely related flaviviruses, cause similar disease elsewhere. Recent cryoelectron microscopic studies have characterized the flavivirus envelope protein as a new class of viral fusion protein (class II), and examined its arrangement on the virion surface. Changes in the envelope protein's hinge region, or its putative receptor-binding domain, are associated with changes in neurovirulence in animal models of JE. Clinically, JE causes a wide range of presentations, including a poliolike flaccid paralysis. Seizures and raised intracranial pressure are associated with a poor outcome, and may be potentially treatable. A safe efficacious formalin-inactivated vaccine against JE has been available for many years, but is too expensive for use in most Asian countries. A newer live attenuated vaccine has been used in China, but its use elsewhere has been restricted by regulatory concerns. A chimeric vaccine in which JE structural proteins are inserted into the 17D yellow fever vaccine backbone is one of several vaccines in development. There are no established antiviral treatments against JE. Interferon alpha was the most promising drug in small open trials, but a recent double-blind placebo controlled trial showed that it did not affect the outcome in children with JE.

Animals↗
PubMed1992

Epidemiology and control of Japanese encephalitis.

Japanese encephalitis (JE) remains endemo-epidemic in several countries in East, South-East and South Asia. The disease has been under control in Japan since the 1970s owing to mass immunization using mouse-brain-derived inactivated vaccine and to reduced vector mosquito populations. The vector density which was once reduced by wide spraying of insecticides in rice fields showed an increasing trend after the 1980s as a result of mosquito resistance. In the Republic of Korea, the number of JE cases showed a significant decrease after 1983 also because of mass immunization using mouse-brain-derived vaccine. On the other hand, large outbreaks of JE continued to occur in China, Viet Nam, Thailand, India, Nepal and Sri Lanka. In China, a hamster-kidney cell-derived vaccine was developed and used for human immunization. Besides human JE, the fatal outcome of equine JE is an economic problem in China. Current JE vaccine derived from mouse brain is highly purified and its safety and efficacy have been proved by field-tests as well as laboratory experiments. In spite of slight antigenic differences among JE virus isolates, JE vaccine produced by a classical Nakayama strain was effective in preventing overt JE in a field study in Thailand. The technology of mouse-brain-derived inactivated JE vaccine production was transferred from Japan to India, Thailand and Viet Nam. The production of JE vaccine in these countries is still on a pilot scale and insufficient for mass-immunization of susceptible target populations.(ABSTRACT TRUNCATED AT 250 WORDS)

Encephalitis Virus, Japanese↗
PubMed2002

Seizures and raised intracranial pressure in Vietnamese patients with Japanese encephalitis.

Japanese encephalitis (JE) causes at least 10 000 deaths each year. Death is presumed to result from infection, dysfunction and destruction of neurons. There is no antiviral treatment. Seizures and raised intracranial pressure (ICP) are potentially treatable complications, but their importance in the pathophysiology of JE is unknown. Between 1994 and 1997 we prospectively studied patients with suspected CNS infections referred to an infectious disease referral hospital in Ho Chi Minh City, Vietnam. We diagnosed Japanese encephalitis virus (JEV), using antibody detection, culture of serum and CSF, and immunohistochemistry of autopsy material. We observed patients for seizures and clinical signs of brainstem herniation, measured CSF opening pressures (OP) and, on a subset of patients, performed EEGs. Of 555 patients with suspected CNS infections, 144 (26%) were infected with JEV (134 children and 10 adults). Seventeen (12%) patients died and 33 (23%) had severe sequelae. Of the 40 patients with witnessed seizures, 24 (62%) died or had severe sequelae, compared with 26 (14%) of 104 with no witnessed seizures [odds ratio (OR) 4.50, 95% confidence interval (CI) 1.94-10.52, P < 0.0001]. Patients in status epilepticus (n = 25), including 15 with subtle motor seizures, were more likely to die than those with other seizures (P = 0.003). Patients with seizures were more likely to have an elevated CSF OP (P = 0.033) and to develop brainstem signs compatible with herniation syndromes (P < 0.0001). Of 11 patients with CSF OP > or =25 cm, five (46%) died, compared with seven (9%) of 80 patients with lower pressures [OR 8.69, 95% CI 1.73-45.39, P = 0.005). Of the 50 patients with a poor outcome, 35 (70%) had signs compatible with herniation syndromes (including 19 with signs of rostro-caudal progression), compared with nine (10%) of those with better outcomes (P < 0.0001). Of 11 patients with CSF OP > or =25 cm, five (46%) died, compared with seven (9%) of 80 patients with lower pressures (OR 8.69, 95% CI 1.73-45.39, P = 0.005). The combination of coma, multiple seizures, brainstem signs and illness for 7 or more days was an accurate predictor of outcome, correctly identifying 42 (84%) of 50 patients with a poor outcome and 82 (87%) of 94 with a better outcome. These findings suggest that in JE, seizures and raised ICP may be important causes of death. The outcome may be improved by measures aimed at controlling these secondary complications.

Adolescent↗
PubMed2005

Bilateral intracerebral haemorrhages: an atypical presentation of Japanese encephalitis.

Japanese encephalitis is common human endemic encephalitis seen over various parts of the world. Usual presenting features include an encephalitic syndrome, symptoms of frontal lobe, basal ganglia and thalamic involvement. Characteristic radiological picture is bilateral thalamic and basal ganglia hypo density in the CT scan and hypo-intensity in T1 and hyperintensity in T2 weighted image in MRI. Very rarely occurrence of bilateral hemorrhage may be seen in these regions. This radiological change may be early indicator of the disease before serological confirmation by the available diagnostic modalities. In this communication, we have reported a case of Japanese encephalitis presented with bilateral basal ganglia hemorrhages.

Adult↗
PubMedDate not supplied

Japanese encephalitis.

Japanese encephalitis (JE) is an acute encephalomyelitis which is a primary viral encephalitis accompanying a viral infection. Clinically, the patient who either resides in an endemic region or who has been exposed to the viral vector (mosquito) may have symptoms including high fever, headache, and impaired consciousness. JE involves many portions of the supratentorial and infratentorial compartments including the brain stem, hippocampus, thalamus, basal ganglia, and white matter. Classically MR imaging demonstrates the lesions of JE as hyperintense on T2-weighted images and hypointense on T1-weighted images. Hemorrhagic transformations have also been described in JE lesions, with corresponding expected T1 and T2 changes. Differential considerations based on the MRI appearance are somewhat broad, including but not limited to primary viral encephalitis, acute encephalopathy, limbic encephalitis, and acute disseminated encephalomyelitis. The therapy for JE is primarily conservative and supportive since there is no specific treatment for JE, and the disease has a high fatality rate. The prognosis depends on the extent of involvement at primary presentation, and on the autoimmune mechanisms of this disease.

Adult↗
PubMed1986

Immunohistochemical demonstration of viral antigens in Japanese encephalitis.

Japanese encephalitis virus antigens were immunohistochemically demonstrated in formalin-fixed paraffin sections from an autopsied brain. Glial nodules were always associated with antigen-positive cell debris. Glia shrubs in the cerebellar cortex appeared to be formed along the apical dendrite of Purkinje cells. Most, but not all, of the neurons involved in neuronophagia were viral antigen positive. Antigenic masses were occasionally encountered in the center of so-called acellular plaques. Neurons with strong viral antigens were sporadically found in normal-appearing regions in the thalamus and cerebral cortex. Viral antigens were demonstrable only in neurons and not in glial or vascular endothelial cells.

Adult↗
PubMed1999

Brainstem auditory evoked potential in Japanese encephalitis.

Japanese encephalitis (JE) is associated with varying degrees of coma and brainstem involvement is frequent which can be evaluated and monitored by brainstem auditory evoked potential (BAEP). The present study has been undertaken to evaluate the BAEP changes and their role in predicting the outcome. Twelve adult patients with JE were subjected to CT scan, MRI and BAEP studies after detailed neurological evaluation. The severity of coma was assessed by Glasgow coma scale and outcome was defined at the end of 3 months into good and poor recovery on the basis of Barthel Index score (BI). The mean age of the patients was 28.3 years (range 14-50), and four of them were females. Most of the patients were comatose. The mean Glasgow coma scale (GCS) score was 7 (range 4-11). There were no brainstem signs or cranial nerve palsy. Cranial CT scan revealed thalamic hypodensity in four, whitematter oedema in three and left putaminal hypodensity in one patient. Cranial MRI was carried out in eight patients which revealed bilateral thalamic lesions in all, basal ganglia and midbrain lesions in three each and pontine and cerebellar lesions in one patient each. Brainstem auditory evoked potentials were recordable bilaterally. The absolute latency of wave I, II, III, IV and V and interpeak latencies (IPL) of I-V, III-V, and I-III were normal. The V/I amplitude ratio were significantly reduced in five patients. The BAEP abnormalities correlated with brainstem lesions on CT or MRI but not with severity of coma or outcome. The reduced amplitude ratio of wave V/I may be due to raised intracranial tension or brainstem involvement in JE.

Acute Disease↗