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  1. Vythilingam I, Tan SB, Krishnasamy M
    Trop Med Int Health, 2002 Jun;7(6):539-40.
    PMID: 12031077
    The susceptibility of Culex sitiens to Japanese Encephalitis (JE) virus was examined in the laboratory. Cx. sitiens became infected with JE virus on day 8 and subsequently it is able to transmit the virus when it takes a blood meal. Both parts of the experiment were carried out using artificial membrane feeding technique.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification*
  2. Vythilingam I, Oda K, Mahadevan S, Abdullah G, Thim CS, Hong CC, et al.
    J Med Entomol, 1997 May;34(3):257-62.
    PMID: 9151487
    A 2-yr study of Japanese encephalitis (JE) virus in Sepang District, Selangor, Malaysia, was carried out to identify the mosquito vectors and to determine their seasonal abundance, parity, and infection rates. In total, 81,889 mosquitoes belonging to 9 genera and > 50 species were identified from CDC trap collections augmented with dry ice during 1992 and 1993. Culex tritaeniorhynchus Giles and Culex gelidus Giles were the most abundant species, and both increased in numbers with increases in rainfall. Overall, 45 JE virus isolations were made from 7 species-Cx. tritaeniorhynchus (24), Cx. gelidus (12), Culex fuscocephala Theobald (2), Aedes butleri Theobald (4), Culex quinquefasciatus Say (1), Aedes lineatopennis Ludlow (1), and Aedes (Cancraedes) sp. (1). Based on elevated abundance and JE infection rates, Cx. tritaeniorhynchus appears to be the most important vector of JE virus in Sepang.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification*
  3. Chen WR, Tesh RB, Rico-Hesse R
    J Gen Virol, 1990 Dec;71 ( Pt 12):2915-22.
    PMID: 2273391
    Forty-six strains of Japanese encephalitis (JE) virus from a variety of geographic areas in Asia were examined by primer-extension sequencing of the RNA template. A 240 nucleotide sequence from the pre-M gene region was selected for study because it provided sufficient information for determining genetic relationships among the virus isolates. Using 12% divergence as a cutoff point for virus relationships, the 46 isolates fell into three distinct genotypic groups. One genotypic group consisted of JE virus isolates from northern Thailand and Cambodia. A second group was composed of isolates from southern Thailand, Malaysia, Sarawak and Indonesia. The remainder of the isolates, from Japan, China, Taiwan, the Philippines, Sri Lanka, India and Nepal, made up a third group. The implications of these findings in relation to the epidemiology of JE are discussed. Results of this study demonstrate that the comparison of short nucleotide sequences can provide insight into JE virus evolution, transmission and, possibly, pathogenesis.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification
  4. Yap G, Mailepessov D, Lim XF, Chan S, How CB, Humaidi M, et al.
    Am J Trop Med Hyg, 2020 09;103(3):1234-1240.
    PMID: 32700679 DOI: 10.4269/ajtmh.19-0377
    Mosquito-borne flaviviruses are emerging pathogens of an increasing global public health concern because of their rapid increase in geographical range and the impact of climate change. Japanese encephalitis virus (JEV) and West Nile virus (WNV) are of concern because of the risk of reemergence and introduction by migratory birds. In Singapore, human WNV infection has never been reported and human JEV infection is rare. Four sentinel vector surveillance sites were established in Singapore to understand the potential risk posed by these viruses. Surveillance was carried out from August 2011 to December 2012 at Pulau Ubin, from March 2011 to March 2013 at an Avian Sanctuary (AS), from December 2010 from October 2012 at Murai Farmway, and from December 2010 to December 2013 at a nature reserve. The present study revealed active JEV transmission in Singapore through the detection of JEV genotype II in Culex tritaeniorhynchus collected from an Avian Sanctuary. Culex flavivirus (CxFV), similar to the Quang Binh virus isolated from Cx. tritaeniorhynchus in Vietnam and CxFV-LSFlaviV-A20-09 virus isolated in China, was also detected in Culex spp. (vishnui subgroup). No WNV was detected. This study demonstrates the important role that surveillance plays in public health and strongly suggests the circulation of JEV among wildlife in Singapore, despite the absence of reported human cases. A One Health approach involving surveillance, the collaboration between public health and wildlife managers, and control of mosquito populations remains the key measures in risk mitigation of JEV transmission in the enzootic cycle between birds and mosquitoes.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification*
  5. Vythilingam I, Oda K, Chew TK, Mahadevan S, Vijayamalar B, Morita K, et al.
    J Am Mosq Control Assoc, 1995 Mar;11(1):94-8.
    PMID: 7616198
    Detection and isolation of Japanese encephalitis (JE) virus were attempted from female mosquitoes collected in Kampong Pasir Panjang, Sabak Bernam, Selangor, from May to November 1992. A total of 7,400 mosquitoes consisting of 12 species in 148 pools were processed and inoculated into Aedes albopictus clone C6/36 cell cultures. Of these, 26 pools showed the presence of viral antigens in the infected C6/36 cells by specific immunoperoxidase staining using an anti-JE virus polyclonal antibody. Presence of JE virus genome was confirmed in the infected culture fluid for 16 pools by using reverse transcriptase-polymerase chain reaction and JE virus-specific primers. Of these, 3 pools were from Culex tritaeniorhynchus, 4 from Culex vishnui, 3 from Culex bitaeniorhynchus, 2 from Culex sitiens, one from Aedes species, and 3 from Culex species. Isolation of JE virus from Cx. sitiens, Cx. bitaeniorhynchus, and Aedes sp. (Aedes butleri and Ae. albopictus) is reported for the first time in Malaysia.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification*
  6. Platt GS, Way HJ, Bowen ET, Simpson DI, Hill MN, Kamath S, et al.
    Ann Trop Med Parasitol, 1975 Mar;69(1):65-71.
    PMID: 235907
    Thirty isolations of Tembusu virus and four of Sindbis virus were obtained from approximately 280 000 mosquitoes collected between October 1968 and February 1970 in Sarawak, particularly from K. Tijirak, a Land Dyak village 19 miles South of Kuching. Twenty-two isolations of Tembusu virus and two of Sindbis virus were from Culex tritaeniorhynchus; two of Tembusu virus and two of Sindbis virus came from Culex gelidus. Tembusu virus was active throughout the year at K. Tijirak, the highest infection rates in C. tritaeniorhynchus being in January-March and May-August, when the C. tritaeniorhynchus population was declining and ageing. These results confirm that C. tritaeniorhynchus is the principal arthopod host of Tembusu virus in Sarawak. Antibody studies suggest that birds, particularly domestic fowl, are probably vertebrate maintenance hosts of Tembusu and Sindbis viruses in Sarawak.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification
  7. Pyke AT, Williams DT, Nisbet DJ, van den Hurk AF, Taylor CT, Johansen CA, et al.
    Am J Trop Med Hyg, 2001 Dec;65(6):747-53.
    PMID: 11791969
    In mid-January 2000, the reappearance of Japanese encephalitis (JE) virus activity in the Australasian region was first demonstrated by the isolation of JE virus from 3 sentinel pigs on Badu Island in the Torres Strait. Further evidence of JE virus activity was revealed through the isolation of JE virus from Culex gelidus mosquitoes collected on Badu Island and the detection of specific JE virus neutralizing antibodies in 3 pigs from Saint Pauls community on Moa Island. Nucleotide sequencing and phylogenetic analyses of the premembrane and envelope genes were performed which showed that both the pig and mosquito JE virus isolates (TS00 and TS4152, respectively) clustered in genotype I, along with northern Thai, Cambodian, and Korean isolates. All previous Australasian JE virus isolates belong to genotype II, along with Malaysian and Indonesian isolates. Therefore, for the first time, the appearance and transmission of a second genotype of JE virus in the Australasian region has been demonstrated.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification
  8. Gao X, Liu H, Wang H, Fu S, Guo Z, Liang G
    PLoS Negl Trop Dis, 2013;7(9):e2459.
    PMID: 24069502 DOI: 10.1371/journal.pntd.0002459
    Although a previous study predicted that Japanese encephalitis virus (JEV) originated in the Malaysia/Indonesia region, the virus is known to circulate mainly on the Asian continent. However, there are no reported systematic studies that adequately define how JEV then dispersed throughout Asia.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification
  9. Schuh AJ, Tesh RB, Barrett AD
    J Gen Virol, 2011 Mar;92(Pt 3):516-27.
    PMID: 21123550 DOI: 10.1099/vir.0.027110-0
    Japanese encephalitis virus (JEV), the prototype member of the JEV serocomplex, genus Flavivirus, family Flaviviridae, is the most significant arthropod-borne encephalitis worldwide in terms of morbidity and mortality. At least four genotypes (GI-GIV) of the virus have been identified; however, to date, the genomic nucleotide sequence of only one GII virus has been determined (FU strain, Australia, 1995). This study sequenced three additional GII strains of JEV isolated between 1951 and 1978 in Korea, Malaysia and Indonesia, respectively, and compared them with the FU strain, as well as with virus strains representing the other three genotypes. Based on nucleotide and amino acid composition, the genotype II strains were the most similar to GI strains; however, these two genotypes are epidemiologically distinct. Selection analyses revealed that the strains utilized in this study are under predominantly purifying selection, and evidence of positive selection was detected at aa 24 of the NS4B protein, a protein that functions as an alpha/beta interferon signalling inhibitor.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification
  10. Tsuchie H, Oda K, Vythilingam I, Thayan R, Vijayamalar B, Sinniah M, et al.
    Jpn. J. Med. Sci. Biol., 1994 Apr;47(2):101-7.
    PMID: 7853748
    Two hundred and forty nucleotides from the pre-M gene region of 10 Japanese encephalitis (JE) virus strains isolated in Malaysia in 1992 were sequenced and compared with the other JE virus strains from different geographic areas in Asia. Our JE virus strains belong to the largest genotypic group that includes strains isolated in temperate regions such as Japan, China, and Taiwan. Our Malaysian JE virus strains differed in 32 nucleotides (13.3%) from WTP/70/22 strain isolated from Malaysia in 1970, which belonged to another distinct genotypic group.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification
  11. Cardosa MJ, Hooi TP, Kaur P
    PMID: 8629059
    This study was carried out to determine if Japanese encephalitis virus is an important causative agent of viral encephalitis among pediatric admissions in Penang, Malaysia. 195 children with CNS symptoms and 482 children with non-specific febrile illness admitted into the Pediatric Ward of Penang Hospital during a 16 month period were entered into the study. The presence in serum of cerebrospinal fluid (csf) of Japanese encephalitis virus (JEV) specific IgM was determined by an IgM capture ELISA and cytomegalovirus (CMV) specific IgM was determined using a commercially available kit (Behringwerke AG). It was determined that 5 of 13 children with a discharge diagnosis of viral encephalitis had JEV specific IgM in csf, indicating that 38.5% of the viral encephalitis cases was due to JEV. One of the non-JEV cases was found to have mumps virus specific IgM in csf, while no etiology was determined for the other cases. It was also determined that 4 of the 195 (2.1%) cases with CNS symptoms had IgM to CMV, suggesting CMV may be an agent of encephalopathy in children in Penang. Other viruses found to be associated with CNS symptoms in children admitted into our study were measles and herpes simplex virus. A viral etiology was confirmed for 13 or the 195 cases (6.7%). We also screened 482 non-specific febrile cases for IgM to JEV and to dengue viruses and found that 2 (0.4%) had IgM specific for JEV and 9 (1.9%) had IgM specific for dengue virus.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification*
  12. 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 Virus, Japanese/isolation & purification*
  13. Schuh AJ, Guzman H, Tesh RB, Barrett AD
    Vector Borne Zoonotic Dis, 2013 Jul;13(7):479-88.
    PMID: 23590316 DOI: 10.1089/vbz.2011.0870
    Five genotypes (GI-V) of Japanese encephalitis virus (JEV) have been identified, all of which have distinct geographical distributions and epidemiologies. It is thought that JEV originated in the Indonesia-Malaysia region from an ancestral virus. From that ancestral virus GV diverged, followed by GIV, GIII, GII, and GI. Genotype IV appears to be confined to the Indonesia-Malaysia region, as GIV has been isolated in Indonesia from mosquitoes only, while GV has been isolated on three occasions only from a human in Malaysia and mosquitoes in China and South Korea. In contrast, GI-III viruses have been isolated throughout Asia and Australasia from a variety of hosts. Prior to this study only 13 JEV isolates collected from the Indonesian archipelago had been studied genetically. Therefore the sequences of the envelope (E) gene of 24 additional Indonesian JEV isolates, collected throughout the archipelago between 1974 and 1987, were determined and a series of molecular adaptation analyses were performed. Phylogenetic analysis indicated that over a 14-year time span three genotypes of JEV circulated throughout Indonesia, and a statistically significant association between the year of virus collection and genotype was revealed: isolates collected between 1974 and 1980 belonged to GII, isolates collected between 1980 and 1981 belonged to GIV, and isolates collected in 1987 belonged to GIII. Interestingly, three of the GII Indonesian isolates grouped with an isolate that was collected during the JE outbreak that occurred in Australia in 1995, two of the GIII Indonesian isolates were closely related to a Japanese isolate collected 40 years previously, and two Javanese GIV isolates possessed six amino acid substitutions within the E protein when compared to a previously sequenced GIV isolate collected in Flores. Several amino acids within the E protein of the Indonesian isolates were found to be under directional evolution and/or co-evolution. Conceivably, the tropical climate of the Indonesia/Malaysia region, together with its plethora of distinct fauna and flora, may have driven the emergence and evolution of JEV. This is consistent with the extensive genetic diversity seen among the JEV isolates observed in this study, and further substantiates the hypothesis that JEV originated in the Indonesia-Malaysia region.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification
  14. Chong HY, Leow CY, Leow CH
    Int J Biol Macromol, 2021 Aug 31;185:485-493.
    PMID: 34174313 DOI: 10.1016/j.ijbiomac.2021.06.146
    Co-existence of Japanese Encephalitis virus (JEV) with highly homologous antigenic epitopes results in antibody-based serodiagnosis being inaccurate at detecting and distinguishing JEV from other flaviviruses. This often causes misdiagnosis and inefficient treatments of flavivirus infection. Generation of JEV NS1 protein remains a challenge as it is notably expressed in the form of inactive aggregates known as inclusion bodies using bacterial expression systems. This study evaluated two trxB and gor E. coli strains in producing soluble JEV NS1 via a cold-shock expression system. High yield of JEV NS1 inclusion bodies was produced using cold-shocked expression system. Subsequently, a simplified yet successful approach in generating soluble, active JEV NS1 protein through solubilization, purification and in vitro refolding of JEV NS1 protein from inclusion bodies was developed. A step-wise dialysis refolding approach was used to facilitate JEV NS1 refolding. The authenticity of the refolded JEV NS1 was confirmed by specific antibody binding on indirect ELISA commercial anti-NS1 antibodies which showed that the refolded JEV NS1 was highly immunoreactive. This presented approach is cost-effective, and negates the need for mammalian or insect cell expression systems in order to synthesize this JEV NS1 protein of important diagnostic and therapeutic relevance in Japanese Encephalitis disease.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification*
  15. Fu TL, Ong KC, Tan SH, Wong KT
    J. Neuropathol. Exp. Neurol., 2019 12 01;78(12):1160-1170.
    PMID: 31675093 DOI: 10.1093/jnen/nlz103
    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.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification
  16. Kumar K, Arshad SS, Selvarajah GT, Abu J, Toung OP, Abba Y, et al.
    Trop Anim Health Prod, 2018 Apr;50(4):741-752.
    PMID: 29243139 DOI: 10.1007/s11250-017-1490-6
    Japanese encephalitis (JE) is vector-borne zoonotic disease which causes encephalitis in humans and horses. Clinical signs for Japanese encephalitis virus (JEV) infection are not clearly evident in the majority of affected animals. In Malaysia, information on the prevalence of JEV infection has not been established. Thus, a cross-sectional study was conducted during two periods, December 2015 to January 2016 and March to August in 2016, to determine the prevalence and risk factors in JEV infections among animals and birds in Peninsular Malaysia. Serum samples were harvested from the 416 samples which were collected from the dogs, cats, water birds, village chicken, jungle fowls, long-tailed macaques, domestic pigs, and cattle in the states of Selangor, Perak, Perlis, Kelantan, and Pahang. The serum samples were screened for JEV antibodies by commercial IgG ELISA kits. A questionnaire was also distributed to obtain information on the animals, birds, and the environmental factors of sampling areas. The results showed that dogs had the highest seropositive rate of 80% (95% CI: ± 11.69) followed by pigs at 44.4% (95% CI: ± 1.715), cattle at 32.2% (95% CI: ± 1.058), birds at 28.9% (95% CI: ± 5.757), cats at 15.6% (95% CI: ± 7.38), and monkeys at 14.3% (95% CI: ± 1.882). The study also showed that JEV seropositivity was high in young animals and in areas where mosquito vectors and migrating birds were prevalent.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification*
  17. Takhampunya R, Kim HC, Tippayachai B, Kengluecha A, Klein TA, Lee WJ, et al.
    Virol J, 2011;8:449.
    PMID: 21943222 DOI: 10.1186/1743-422X-8-449
    Japanese encephalitis virus (JEV) genotype V reemerged in Asia (China) in 2009 after a 57-year hiatus from the continent, thereby emphasizing a need to increase regional surveillance efforts. Genotypic characterization was performed on 19 JEV-positive mosquito pools (18 pools of Culex tritaeniorhynchus and 1 pool of Cx. bitaeniorhynchus) from a total of 64 positive pools collected from geographically different locations throughout the Republic of Korea (ROK) during 2008 and 2010.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification
  18. Mackenzie JS
    J Neurovirol, 2005 Oct;11(5):434-40.
    PMID: 16287684
    The last decade of the 20th Century saw the introduction of an unprecedented number of encephalitic viruses emerge or spread in the Southeast Asian and Western Pacific regions (Mackenzie et al, 2001; Solomon, 2003a). Most of these viruses are zoonotic, either being arthropod-borne viruses or bat-borne viruses. Thus Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, has spread through the Indonesian archipelago to Papua New Guinea (PNG) and to the islands of the Torres Strait of northern Australia, to Pakistan, and to new areas in the Indian subcontinent; a strain of tick-borne encephalitis virus (TBEV) was described for the first time in Hokkaido, Japan; and a novel mosquito-borne alphavirus, Me Tri virus, was described from Vietnam. Three novel bat-borne viruses emerged in Australia and Malaysia; two, Hendra and Nipah viruses, represent the first examples of a new genus in the family Paramyxoviridae, the genus Henipaviruses, and the third, Australian bat lyssavirus (ABLV) is new lyssavirus closely related to classical rabies virus. These viruses will form the body of this brief review.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification
  19. Darwish NT, Sekaran SD, Alias Y, Khor SM
    J Pharm Biomed Anal, 2018 Feb 05;149:591-602.
    PMID: 29197806 DOI: 10.1016/j.jpba.2017.11.064
    The sharp increase in incidence of dengue infection has necessitated the development of methods for the rapid diagnosis of this deadly disease. Here we report the design and development of a reliable, sensitive, and specific optical immunosensor for the detection of the dengue nonstructural protein 1 (NS1) biomarker in clinical samples obtained during early stages of infection. The present optical NS1 immunosensor comprises a biosensing surface consisting of specific monoclonal NS1 antibody for immunofluorescence-based NS1 antigen determination using fluorescein isothiocyanate (FITC) conjugated to IgG antibody. The linear range of the optical immunosensor was from 15-500ngmL-1, with coefficient of determination (R2) of 0.92, high reproducibility (the relative standard deviation obtained was 2%), good stability for 21days at 4°C, and low detection limit (LOD) at 15ngmL-1. Furthermore, the optical immunosensor was capable of detecting NS1 analytes in plasma specimens from patients infected with the dengue virus, with low cross-reaction with plasma specimens containing the Japanese encephalitis virus (JEV) and Zika virus. No studies have been performed on the reproducibility and cross-reactivity regarding NS1 specificity, which is thus a limitation for optical NS1 immunosensors. In contrast, the present study addressed these limitations carefully where these two important experiments were conducted to showcase the robustness of our newly developed optical-based fluorescence immunosensor, which can be practically used for direct NS1 determination in any untreated clinical sample.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification
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