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Displaying publications 61 - 69 of 69 in total

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Arbovirus infections in Sarawak, October 1968--February 1970: Japanese encephalitis virus isolations from mosquitoes

Simpson DI, Bowen ET, Way HJ, Platt GS, Hill MN, Kamath S, et al.

Ann Trop Med Parasitol, 1974 Dec;68(4):393-404.
PMID: 4155608
Matched MeSH terms: Encephalitis, Japanese/transmission
Serological evidence of DENV, JEV, and ZIKV among the indigenous people (Orang Asli) of Peninsular Malaysia

Khor CS, Mohd-Rahim NF, Hassan H, Tan KK, Zainal N, Teoh BT, et al.

J Med Virol, 2020 08;92(8):956-962.
PMID: 31814135 DOI: 10.1002/jmv.25649

Dengue virus (DENV), Japanese encephalitis virus (JEV), and Zika virus (ZIKV) are mosquito-borne flavivirus of medical importance in tropical countries such as Malaysia. However, much remains unknown regarding their prevalence among the underserved indigenous people (Orang Asli) living in communities in the forest fringe areas of Peninsular Malaysia. Information on the prevalence of diseases is necessary to elevate the effectiveness of disease control and preventive measures. This study aimed to determine the seroprevalence of the three major flaviviruses among the Orang Asli and investigate the association between demographic factors and seropositivities. Sampling activities were conducted in the Orang Asli villages to obtain serum samples and demographic data from consenting volunteers. The presence of DENV, JEV, and ZIKV immunoglobulin G (IgG) antibodies in the sera were examined using commercial enzyme-linked immunosorbent assay kits. A focus reduction neutralization assay was performed to measure virus-specific neutralizing antibodies. A total of 872 serum samples were obtained from the Orang Asli volunteers. Serological assay results revealed that DENV IgG, JEV IgG, and ZIKV IgG seropositivities among the Orang Asli were at 4.9%, 48.4%, and 13.2%, respectively. Neutralizing antibodies (FRNT50 ≥ 1:40) against JEV and ZIKV were found in 86.7% and 100.0%, respectively, out of the samples tested. Positive serology to all three viruses corresponded significantly to the age of the volunteers with increasing seropositivity in older volunteers. Findings from the study suggest that Orang Asli are at significant risk of contracting JEV and ZIKV infections despite the lack of active transmission of the viruses in the country.

Matched MeSH terms: Encephalitis, Japanese/epidemiology*
Nipah viral encephalitis or Japanese encephalitis? MR findings in a new zoonotic disease

Lim CC, Sitoh YY, Hui F, Lee KE, Ang BS, Lim E, et al.

AJNR Am J Neuroradiol, 2000 Mar;21(3):455-61.
PMID: 10730635

BACKGROUND AND PURPOSE: An epidemic of suspected Japanese encephalitis occurred in Malaysia in 1998-1999 among pig farmers. In neighboring Singapore, an outbreak occurred among pig slaughterhouse workers. It was subsequently established that the causative agent in the outbreak was not the Japanese encephalitis virus but a previously unknown Hendra-like paramyxovirus named Nipah virus.
METHODS: The brain MR images of eight patients with Nipah virus infection were reviewed. All patients tested negative for acute Japanese encephalitis virus. Seven patients had contrast-enhanced studies and six had diffusion-weighted examinations.
RESULTS: All patients had multiple small bilateral foci of T2 prolongation within the subcortical and deep white matter. The periventricular region and corpus callosum were also involved. In addition to white matter disease, five patients had cortical lesions, three had brain stem involvement, and a single thalamic lesion was detected in one patient. All lesions were less than 1 cm in maximum diameter. In five patients, diffusion-weighted images showed increased signal. Four patients had leptomeningeal enhancement and four had enhancement of parenchymal lesions.
CONCLUSION: The brain MR findings in patients infected with the newly discovered Nipah paramyxovirus are different from those of patients with Japanese encephalitis. In a zoonotic epidemic, this striking difference in the appearance and distribution of lesions is useful in differentiating these diseases. Diffusion-weighted imaging was advantageous in increasing lesion conspicuity.

Matched MeSH terms: Encephalitis, Japanese/diagnosis*
Neuronal transcriptomic responses to Japanese encephalitis virus infection with a special focus on chemokine CXCL11 and pattern recognition receptors RIG-1 and MDA5

Yu SP, Ong KC, Perera D, Wong KT

Virology, 2019 01 15;527:107-115.
PMID: 30481615 DOI: 10.1016/j.virol.2018.10.015

Japanese encephalitis virus (JEV) causes central nervous system neuronal injury and inflammation. A clear understanding of neuronal responses to JEV infection remains elusive. Using the Affymetrix array to investigate the transcriptome of infected SK-N-MC cells, 1316 and 2737 dysregulated genes (≥ 2/-2 fold change, P 

Matched MeSH terms: Encephalitis, Japanese/virology*
Fulltext Paddy, piggy and Japanese encephalitis in Kerian – a case series

Rosilawati A. R., Mohd Zamri M. A.

Malaysian Journal of Medicine and Health Sciences, 2019;15(106):40-40.
MyJurnal

Introduction: Japanese encephalitis (JE) is a vector-borne zoonotic disease caused by the Japanese encephalitis virus (JEV). Paddy fields are high risk area for JEV transmission due the presence of Culex tritaeniorhynchus as vector and wild boar as an amplifier host. Methods: We presented case reports for three patients infected with JEV residing in paddy field area from 2015 to 2018 in Kerian, Perak; illustrating the symptoms and epidemiology trend of the dis-ease. Results: All three cases live next to paddy field and were exposed during peak biting hours. They presented with fever and altered consciousness. IV Acylovir was started as one of the treatments and all had lumbar puncture for CSF testing. Two cases (adult) were confirmed JE after they had passed away. Two cases occurred during fasting month where food wastes were abundance. The source of infection was probably from wild boars that came out at night to hunt for food. Presence of C. tritaeniorhynchus was demonstrated as the main vector in these areas. Conclusion: JE has no cure and human vaccination is the main prevention method. At the moment, vector control, environmental management, chemical control and personal protection are the main mitigation strategies for this area. Further study on JEV and wild board in Kerian will be most beneficial.

Matched MeSH terms: Encephalitis, Japanese
Changing Geographic Distribution of Japanese Encephalitis Virus Genotypes, 1935-2017

Gao X, Liu H, Li X, Fu S, Cao L, Shao N, et al.

Vector Borne Zoonotic Dis, 2019 Jan;19(1):35-44.
PMID: 30207876 DOI: 10.1089/vbz.2018.2291

Japanese encephalitis virus (JEV) is a representative virus of the JEV serogroup in genus Flavivirus, family Flaviviridae. JEV is a mosquito-borne virus that causes Japanese encephalitis (JE), one of the most severe viral encephalitis diseases in the world. JEV is divided into five genotypes (G1-G5), and each genotype has its own distribution pattern. However, the distribution of different JEV genotypes has changed markedly in recent years. JEV G1 has replaced G3 as the dominant genotype in the traditional epidemic areas in Asia, while G3 has spread from Asia to Europe and Africa and caused domestic JE cases in Africa. G2 and G5, which were endemic in Malaysia, exhibited great geographical changes as well. G2 migrated southward and led to prevalence of JE in Australia, while G5 emerged in China and South Korea after decades of silence. Along with these changes, JE occurred in some non-traditional epidemic regions as an emerging infectious disease. The regional changes in JEV pose a great threat to human health, leading to huge disease burdens. Therefore, it is of great importance to strengthen the monitoring of JEV as well as virus genotypes, especially in non-traditional epidemic areas.

Matched MeSH terms: Encephalitis, Japanese
Antiviral and virucidal activities of sulphated polysaccharides against Japanese encephalitis virus

Nor Rashid N, Yusof R, Rothan HA

Trop Biomed, 2020 Sep 01;37(3):713-721.
PMID: 33612784 DOI: 10.47665/tb.37.3.713

Japanese encephalitis virus (JEV), a member of the family Flaviviridae, causes severe neurological disorders in humans. JEV infections represent one of the most widely spread mosquito-borne diseases, and therefore, it has been considered as an endemic disease. An effective antiviral drug is still unavailable to treat JEV, and current drugs only provide supportive treatment to alleviate the symptoms and stabilize patients' conditions. This study was designed to evaluate the antiviral activity of the sulphated polysaccharides "Carrageenan," a linear sulphated polysaccharide that is extracted from red edible seaweeds against JEV replication in vitro. Viral inactivation, attachment, and post-infection assays were used to determine the mode of inhibition of Carrageenan. Virus titters after each application were evaluated by plaque formation assay. MTT assay was used to determine the 50% cytotoxic concentration (CC50), and ELISA-like cell-based assay and immunostaining and immunostaining techniques were used to evaluate the 50% effective concentration (EC50). This study showed that Carrageenan inhibited JEV at an EC50 of 15 µg/mL in a dose-dependent manner with CC50 more than 200 µg/mL in healthy human liver cells (WRL68). The mode of inhibition assay showed that the antiviral effects of Carrageenan are mainly due to their ability to inhibit the early stages of virus infection such as the viral attachment and the cellular entry stages. Our investigation showed that Carrageenan could be considered as a potent antiviral agent to JEV infection. Further experimental and clinical studies are needed to investigate the potential applications of Carrageenan for clinical intervention against JEV infection.

Matched MeSH terms: Encephalitis, Japanese
Mosquito control with green nanopesticides: towards the One Health approach? A review of non-target effects

Benelli G, Maggi F, Pavela R, Murugan K, Govindarajan M, Vaseeharan B, et al.

Environ Sci Pollut Res Int, 2018 Apr;25(11):10184-10206.
PMID: 28755145 DOI: 10.1007/s11356-017-9752-4

The rapid spread of highly aggressive arboviruses, parasites, and bacteria along with the development of resistance in the pathogens and parasites, as well as in their arthropod vectors, represents a huge challenge in modern parasitology and tropical medicine. Eco-friendly vector control programs are crucial to fight, besides malaria, the spread of dengue, West Nile, chikungunya, and Zika virus, as well as other arboviruses such as St. Louis encephalitis and Japanese encephalitis. However, research efforts on the control of mosquito vectors are experiencing a serious lack of eco-friendly and highly effective pesticides, as well as the limited success of most biocontrol tools currently applied. Most importantly, a cooperative interface between the two disciplines is still lacking. To face this challenge, we have reviewed a wide number of promising results in the field of green-fabricated pesticides tested against mosquito vectors, outlining several examples of synergy with classic biological control tools. The non-target effects of green-fabricated nanopesticides, including acute toxicity, genotoxicity, and impact on behavioral traits of mosquito predators, have been critically discussed. In the final section, we have identified several key challenges at the interface between "green" nanotechnology and classic biological control, which deserve further research attention.

Matched MeSH terms: Encephalitis, Japanese
Fulltext Pathological findings in a mouse model of Japanese encephalitis infected via the footpad

Fu, Tzeh Long, Ong, Kien Chai, Wong, Kum Thong

Neurology Asia, 2015;20(4):349-354.
MyJurnal

We have developed and characterised a mouse model of Japanese encephalitis virus (JEV) infection via
footpad inoculation in order to better mimic viral transmission by mosquito bites. Two-week-old and
5-week-old mice consistently developed signs of infection such as ruffled fur, weight loss, hunchback
posture, tremors, mask-like facies and occasionally, hindlimb paralysis at 4 days post infection (dpi)
and 11-13 dpi, respectively. Most of the animals died within 24 to 48 hours following the onset of signs
of infection, with mortalities of 100% and 33.3% in 2-week-old and 5-week-old mice, respectively.
Mild meningitis and variable parenchymal inflammation with formation of microglial nodules, focal
necrosis and neuronophagia, and perivascular cuffing by inflammatory cells were observed in the
caudate nucleus, putamen, thalamus, cerebral cortex, brainstem, and spinal cord. Viral antigens/RNA
were demonstrated by immunohistochemisty and in situ hybridization, respectively, in most of these
areas as well as in the hippocampus and cerebellum, albeit more focally. The pathological findings in
this mouse model were generally similar to human Japanese encephalitis (JE) and other established JE
models but perhaps, compared to other JEV mouse models, it demonstrates lethal encephalitic infection
more consistently. We believe that our mouse model should be useful to study the pathogenesis of JE,
and for testing anti-viral drugs and vaccines

Matched MeSH terms: Encephalitis, Japanese