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PLoS Neglected Tropical Diseases Jul 2022Japanese encephalitis (JE) is a vector-borne zoonosis and the leading cause of human viral encephalitis in Asia. Its transmission cycle is usually described as involving...
Japanese encephalitis (JE) is a vector-borne zoonosis and the leading cause of human viral encephalitis in Asia. Its transmission cycle is usually described as involving wild birds as reservoirs and pigs as amplifying hosts. JE is endemic in Cambodia, where it circulates in areas with low pig densities (<70 pigs per km2), and could be maintained in a multi-host system composed of pigs, but also poultry as competent hosts, and dogs, cattle and humans as non-competent hosts. We used a mathematical model representing Japanese encephalitis virus (JEV) transmission in a traditional Cambodian village that we calibrated with field data collected in 3 districts of Kandal province, Cambodia. First, R0 calculations allowed us to assess the capacity of the epidemiological system to be invaded by JEV and sustain virus transmission in villages in the 3 districts, and we predicted human exposure at the epidemiological equilibrium, based on simulations. Changes in spatial density of livestock, in agricultural practices, and epizootics (e.g., African swine fever), can profoundly alter the composition of host communities, which could affect JEV transmission and its impact on human health. In a second step, we then used the model to analyse how host community composition affected R0 and the predicted human exposure. Lastly, we evaluated the potential use of dog JE seroprevalence as an indicator of human exposure to JEV. In the modeled villages, the calculated R0 ranged from 1.07 to 1.38. Once the equilibrium reached, predicted annual probability of human exposure ranged from 9% to 47%, and predicted average age at infection was low, between 2 and 11 years old, highlighting the risk of severe forms of JEV infection and the need to intensify child immunization. According to the model, increasing the proportion of competent hosts induced a decrease in age at infection. The simulations also showed that JEV could invade a multi-host system with no pigs, reinforcing the assumption of poultry acting as reservoirs. Finally, the annual human exposure probability appeared linearly correlated with dog seroprevalence, suggesting that in our specific study area, dog seroprevalence would be a good proxy for human exposure.
Topics: African Swine Fever; Animals; Asian People; Cattle; Child; Child, Preschool; Dogs; Encephalitis Virus, Japanese; Encephalitis, Japanese; Humans; Seroepidemiologic Studies; Swine
PubMed: 35816555
DOI: 10.1371/journal.pntd.0010572 -
Frontiers in Bioscience (Landmark... Jun 2020Japanese Encephalitis Virus (JEV) is the most common Flavivirus based mosquito borne viral encephalitis in the world, especially in countries of South-East Asia. The... (Review)
Review
Japanese Encephalitis Virus (JEV) is the most common Flavivirus based mosquito borne viral encephalitis in the world, especially in countries of South-East Asia. The conventional methods such as Enzyme-Linked Immunosorbent Assays (ELISA), Reverse Transcriptase Polymerase Chain Reaction (RT-PCR), Plaque Reduction Neutralization Test and virus isolation are still in use today but new advances are being made to develop more efficient, inexpensive, quicker, sensitive and time-saving techniques to detect JEV. Some of these include the use of immunosensors, both lateral flow based assays and electrochemical, as well as the incorporation of nanotechnology into biosensors to develop highly sensitive detection tools. This review focuses on the recent advances that have been made to diagnose Japanese Encephalitis Virus which are critical in breaking the link to zoonotic transmission into the human population where humans are dead-end hosts.
Topics: Animals; Antibodies, Viral; Biosensing Techniques; Encephalitis Virus, Japanese; Encephalitis, Japanese; Enzyme-Linked Immunosorbent Assay; Humans; RNA, Viral; Reverse Transcriptase Polymerase Chain Reaction; Viral Zoonoses
PubMed: 32472762
DOI: 10.2741/4882 -
Brain & Development Feb 2020A hospital-based prospective study was performed to determine: 1) whether Japanese encephalitis (JE) normally triggers anti-N-methyl-d-aspartate receptor (NMDAR)...
OBJECTIVES
A hospital-based prospective study was performed to determine: 1) whether Japanese encephalitis (JE) normally triggers anti-N-methyl-d-aspartate receptor (NMDAR) immunoglobulin G (IgG) synthesis, especially in monophasic JE patients; and 2) the incidence of JE-induced anti-NMDAR encephalitis in pediatric patients with JE.
METHODS
We detected the level of anti-NMDAR IgG in the serum and cerebral spinal fluid (CSF) of JE patients within one week of onset. If patients relapsed during the convalescence phase, we detected JE virus RNA in the CSF and anti-NMDAR IgG in both the serum and CSF. For patients who did not relapse during the convalescence phase, serum was collected and anti-NMDAR IgG was detected during the 30-60-day course of the disease.
RESULTS
We enrolled 65 JE patients, who were negative for anti-NMDAR IgG in the serum and CSF during the acute phase, of which 63 patients were successfully followed up. Five patients relapsed during the convalescence phase, for whom JE virus RNA in the CSF was negative and excluded latent JE reactivation. The distinctive symptoms of four younger patients were choreoathetosis, whereas the psychiatric and behavioral manifestations were the distinctive symptoms experienced by the teenager. Anti-NMDAR IgG in the CSF of three patients was positive and they were diagnosed with anti-NMDAR encephalitis. The other two patients were negative for anti-NMDAR IgG in both the serum and CSF. For the 58 patients who did not relapse during the convalescence phase, anti-NMDAR IgG was negative in the serum of all patients at 30-60 days during the course of the disease.
CONCLUSIONS
JE does not typically trigger anti-NMDAR IgG synthesis. Besides anti-NMDAR IgG, other unknown autoantibodies can also cause autoimmune encephalitis in the convalescence phase of JE. The incidence of JE-induced autoimmune encephalitis in pediatric patients with JE was 7.9%, and the incidence of JE-induced anti-NMDAR encephalitis was 4.7%.
Topics: Adolescent; Anti-N-Methyl-D-Aspartate Receptor Encephalitis; Child; Child, Preschool; Encephalitis, Japanese; Female; Follow-Up Studies; Hospitals, Pediatric; Humans; Incidence; Male; Prospective Studies
PubMed: 31563418
DOI: 10.1016/j.braindev.2019.09.003 -
Pediatrics and Neonatology Feb 2020Japanese encephalitis (JE) is a mosquito-borne viral infection which is prevalent in Taiwan. The virus circulates in an enzootic cycle in pigs which serve as amplifying... (Review)
Review
Japanese encephalitis (JE) is a mosquito-borne viral infection which is prevalent in Taiwan. The virus circulates in an enzootic cycle in pigs which serve as amplifying hosts. Outbreaks typically occur during summer. A universal vaccination program using 4-shot mouse brain-derived inactivated vaccine has successfully controlled JE epidemics in Taiwan since 1968. More than 90% of JE cases in recent years were older than 20 years in Taiwan. Because of several drawbacks, mouse brain-derived vaccine has been replaced by newer generation JE vaccines, including inactivated Vero cell-derived vaccine and live chimeric vaccine. The present article describes the recommendations in Taiwan for the use of new JE vaccines and the schedules for shifting between different JE vaccines.
Topics: Encephalitis, Japanese; Humans; Japanese Encephalitis Vaccines; Taiwan; Vaccination; Vaccines, Inactivated
PubMed: 31870559
DOI: 10.1016/j.pedneo.2019.11.009 -
QJM : Monthly Journal of the... Apr 2022
Topics: Dengue; Encephalitis; Encephalitis, Japanese; Humans
PubMed: 35188207
DOI: 10.1093/qjmed/hcac054 -
Journal of Proteome Research Jun 2023Japanese encephalitis virus is a leading cause of neurological infection in the Asia-Pacific region with no means of detection in more remote areas. We aimed to test the...
Japanese encephalitis virus is a leading cause of neurological infection in the Asia-Pacific region with no means of detection in more remote areas. We aimed to test the hypothesis of a Japanese encephalitis (JE) protein signature in human cerebrospinal fluid (CSF) that could be harnessed in a rapid diagnostic test (RDT), contribute to understanding the host response and predict outcome during infection. Liquid chromatography and tandem mass spectrometry (LC-MS/MS), using extensive offline fractionation and tandem mass tag labeling (TMT), enabled comparison of the deep CSF proteome in JE vs other confirmed neurological infections (non-JE). Verification was performed using data-independent acquisition (DIA) LC-MS/MS. 5,070 proteins were identified, including 4,805 human proteins and 265 pathogen proteins. Feature selection and predictive modeling using TMT analysis of 147 patient samples enabled the development of a nine-protein JE diagnostic signature. This was tested using DIA analysis of an independent group of 16 patient samples, demonstrating 82% accuracy. Ultimately, validation in a larger group of patients and different locations could help refine the list to 2-3 proteins for an RDT. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD034789 and 10.6019/PXD034789.
Topics: Humans; Encephalitis, Japanese; Encephalitis Virus, Japanese; Chromatography, Liquid; Proteomics; Tandem Mass Spectrometry; Proteome
PubMed: 37219084
DOI: 10.1021/acs.jproteome.2c00563 -
PLoS Neglected Tropical Diseases Jul 2022Japanese encephalitis virus (JEV) is the emerging and geographically expanding flavivirus and the major causative agent of encephalitis in humans in Asia. There are...
Japanese encephalitis virus (JEV) is the emerging and geographically expanding flavivirus and the major causative agent of encephalitis in humans in Asia. There are risks of JEV introduction into the Americas given a large population of amplifying hosts-pigs and wild boars, and insect vectors-Culex mosquitoes. There are emerging concerns about vector-free ways of flavivirus transmission, for example sexual and transplacental Zika virus transmissions, which may change flavivirus epidemiology and expand the geographical range to territories with no insect vectors. It is unknown whether JEV has tropism in the female lower reproductive tract and the potential for sexual transmission in humans. While clinical outcomes of transplacental JEV infection are described in humans and pigs, cellular targets and tissue tropism in the upper reproductive tract are also unknown. Here, we studied JEV infection phenotypes and host transcriptional responses in human reproductive epithelial cells. We found that JEV caused persistent infection and cytopathology in the vaginal epithelium, endometrial epithelium, and trophoblast. Human vaginal epithelial cells infected with JEV had altered transcriptional responses associated with inflammation and disruption of epithelial barrier function. Also, using pigs-the native amplifying host for JEV, we confirmed JEV tropism in the female lower and upper reproductive tracts. We discovered that JEV persists in the vaginal mucosa for at least 28 days and pigs shed the virus in vaginal secretions. We also found JEV persistence in the endometrium and placenta with transplacental and fetal infections. Altogether, we discovered that JEV targets the vaginal epithelium and has the potential for sexual transmission in humans. We also contributed to a better understanding of JEV pathogenesis during transplacental infection. Further studies are needed to better understand the interactions of JEV with reproductive tissues, how persistent infection affects female reproductive functions, and the risks for non-vector transmission.
Topics: Animals; Culex; Encephalitis Virus, Japanese; Encephalitis, Japanese; Epithelium; Female; Humans; Mosquito Vectors; Swine; Zika Virus; Zika Virus Infection
PubMed: 35905074
DOI: 10.1371/journal.pntd.0010656 -
Japanese Journal of Infectious Diseases Mar 2023Japanese encephalitis virus (JEV) is a mosquito-borne virus belonging to the JEV serocomplex within the genus Flavivirus, family Flaviviridae. It has 5 genotypes, G1-G5,...
Japanese encephalitis virus (JEV) is a mosquito-borne virus belonging to the JEV serocomplex within the genus Flavivirus, family Flaviviridae. It has 5 genotypes, G1-G5, based on the envelope (E) protein nucleotide sequence. JEV G3 circulated in Japan until the early 1990s when it was replaced by G1. JEV G3 was isolated from swine serum samples (sw/Kochi/1/2004) in the Kochi Prefecture, western Japan, in 2004. In addition, the 2018 isolates from pigs and cows (sw/Kochi/492/2018 and bo/Kochi/211/2018) in the same prefecture were identified as G3. The nucleotide sequencing results of the sw/Kochi/492/2018 and bo/Kochi/211/2018 polyprotein region differed from those of the sw/Kochi/1/2004 strain described in our previous report. Seven JEV isolates were identified as G1 in the same geographical area as that in this study. This result indicates that both JEV G1 and G3 are present in the Kochi area.
Topics: Female; Animals; Swine; Cattle; Encephalitis Virus, Japanese; Encephalitis, Japanese; Japan; Genotype; Swine Diseases; Phylogeny
PubMed: 36450570
DOI: 10.7883/yoken.JJID.2020.941 -
Journal of Medical Microbiology Dec 2022Japanese encephalitis (JE) is an infection that occurs predominantly in Asia and the Pacific Islands. It is transmitted by mosquito bites, with the main vector being...
Japanese encephalitis (JE) is an infection that occurs predominantly in Asia and the Pacific Islands. It is transmitted by mosquito bites, with the main vector being and is maintained in enzootic cycles involving pigs, wild birds and mosquitoes. JE is caused by infection with Japanese encephalitis virus (JEV), a zoonotic pathogen that also causes disease in mammals such as pigs and horses. In humans, most symptoms are mild or flu-like but can progress to encephalitis. Pigs are considered amplification hosts, and sows may have gestational complications. Horses may exhibit neurological signs. Detection of the virus can be confirmed by serological or molecular laboratory tests. Vaccination offers protection against JEV infection in humans, pigs and horses. Whilst there is no effective treatment of JE, human cases may require hospitalization for supportive therapy, which may include administration of fluids, oxygen and medication to treat symptoms.
Topics: Animals; Swine; Female; Humans; Horses; Encephalitis Virus, Japanese; Mosquito Vectors; Encephalitis, Japanese; Asia; Birds; Mammals
PubMed: 36748429
DOI: 10.1099/jmm.0.001620 -
MMWR. Morbidity and Mortality Weekly... Jun 2017Japanese encephalitis (JE) virus is the most important vaccine-preventable cause of encephalitis in the Asia-Pacific region. The World Health Organization (WHO)...
Japanese encephalitis (JE) virus is the most important vaccine-preventable cause of encephalitis in the Asia-Pacific region. The World Health Organization (WHO) recommends integration of JE vaccination into national immunization schedules in all areas where the disease is a public health priority (1). This report updates a previous summary of JE surveillance and immunization programs in Asia and the Western Pacific in 2012 (2). Since 2012, funding for JE immunization has become available through the GAVI Alliance, three JE vaccines have been WHO-prequalified,* and an updated WHO JE vaccine position paper providing guidance on JE vaccines and vaccination strategies has been published (1). Data for this report were obtained from a survey of JE surveillance and immunization practices administered to health officials in countries with JE virus transmission risk, the 2015 WHO/United Nations Children's Fund Joint Reporting Form on Immunization, notes and reports from JE meetings held during 2014-2016, published literature, and websites. In 2016, 22 (92%) of 24 countries with JE virus transmission risk conducted JE surveillance, an increase from 18 (75%) countries in 2012, and 12 (50%) countries had a JE immunization program, compared with 11 (46%) countries in 2012. Strengthened JE surveillance, continued commitment, and adequate resources for JE vaccination should help maintain progress toward prevention and control of JE.
Topics: Adolescent; Asia; Child; Child, Preschool; Encephalitis, Japanese; Humans; Immunization Programs; Immunization Schedule; Infant; Japanese Encephalitis Vaccines; Pacific Islands; Population Surveillance
PubMed: 28594790
DOI: 10.15585/mmwr.mm6622a3