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Krambrich J, Akaberi D, Lindahl JF, Lundkvist Å, Hesson JC. Vector competence of Swedish Culex pipiens mosquitoes for Japanese encephalitis virus. Parasit Vectors 2024; 17:220. [PMID: 38741172 DOI: 10.1186/s13071-024-06269-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 04/02/2024] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND Japanese encephalitis virus (JEV) is an emerging mosquito-borne Orthoflavivirus that poses a significant public health risk in many temperate and tropical regions in Asia. Since the climate in some endemic countries is similar to temperate climates observed in Europe, understanding the role of specific mosquito species in the transmission of JEV is essential for predicting and effectively controlling the potential for the introduction and establishment of JEV in Europe. METHODS This study aimed to investigate the vector competence of colonized Culex pipiens biotype molestus mosquitoes for JEV. The mosquitoes were initially collected from the field in southern Sweden. The mosquitoes were offered a blood meal containing the Nakayama strain of JEV (genotype III), and infection rates, dissemination rates, and transmission rates were evaluated at 14, 21, and 28 days post-feeding. RESULTS The study revealed that colonized Swedish Cx. pipiens are susceptible to JEV infection, with a stable infection rate of around 10% at all timepoints. However, the virus was only detected in the legs of one mosquito at 21 days post-feeding, and no mosquito saliva contained JEV. CONCLUSIONS Overall, this research shows that Swedish Cx. pipiens can become infected with JEV, and emphasizes the importance of further understanding of the thresholds and barriers for JEV dissemination in mosquitoes.
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Affiliation(s)
- Janina Krambrich
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, Husargatan 3, 75237, Uppsala, Sweden.
| | - Dario Akaberi
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, Husargatan 3, 75237, Uppsala, Sweden
| | - Johanna F Lindahl
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, Husargatan 3, 75237, Uppsala, Sweden
- International Livestock Research Institute, Hanoi, Vietnam
- Department of Animal Health and Antibiotic Strategies, Swedish National Veterinary Institute, Uppsala, Sweden
| | - Åke Lundkvist
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, Husargatan 3, 75237, Uppsala, Sweden
| | - Jenny C Hesson
- Zoonosis Science Center, Department of Medical Biochemistry and Microbiology, Uppsala University, Husargatan 3, 75237, Uppsala, Sweden
- Biologisk Myggkontroll, Nedre Dalälvens Utvecklings AB, Gysinge, Sweden
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Moore KT, Mangan MJ, Linnegar B, Athni TS, McCallum HI, Trewin BJ, Skinner E. Australian vertebrate hosts of Japanese encephalitis virus; a review of the evidence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.23.590833. [PMID: 38712158 PMCID: PMC11071400 DOI: 10.1101/2024.04.23.590833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Japanese Encephalitis Virus (JEV) transmission in temperate Australia has underscored a critical need to characterise transmission pathways and identify probable hosts of infection within the country. This systematic review consolidates existing research on the vertebrate hosts of JEV that are known to exist in Australia. Specifically, we aim to identify probable species for JEV transmission, their potential role as either a spillover or maintenance host and identify critical knowledge gaps. Data were extracted from studies involving experimental infection, seroprevalence, and virus isolation and were available for 22 vertebrate species known to reside in Australia. A host competence score was calculated to assess the potential for a given species to infect JEV vectors and to quantity their possible role in JEV transmission. Based on the host competence score and ecology of each species, we find ardeid birds, feral pigs, and flying foxes have potential as maintenance hosts for JEV in the Australian context. We also note that brushtail possums and domestic pigs have potential as spillover hosts under certain outbreak conditions. However, evidence to confirm these roles in localized transmission or outbreaks is sparse, emphasizing the need for further targeted research. This review provides a foundation for future investigations into JEV transmission in Australia, advocating for enhanced surveillance and standardized research methodologies to better understand and mitigate the virus's impact.
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Affiliation(s)
- Kevin T. Moore
- Centre for Planetary Health and Food Security, Griffith University, Gold Coast, QLD 4222, Australia
| | - Madelyn J. Mangan
- Centre for Planetary Health and Food Security, Griffith University, Gold Coast, QLD 4222, Australia
| | - Belinda Linnegar
- Centre for Planetary Health and Food Security, Griffith University, Gold Coast, QLD 4222, Australia
| | - Tejas S. Athni
- Harvard Medical School, Boston, MA 02115, USA
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Hamish I. McCallum
- Centre for Planetary Health and Food Security, Griffith University, Gold Coast, QLD 4222, Australia
| | | | - Eloise Skinner
- Centre for Planetary Health and Food Security, Griffith University, Gold Coast, QLD 4222, Australia
- Department of Biology, Stanford University, Stanford, CA 94305, USA
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Morris RS, Bingham PC. Japanese encephalitis virus: epidemiology and risk-based surveillance approaches for New Zealand. N Z Vet J 2023; 71:283-294. [PMID: 37621178 DOI: 10.1080/00480169.2023.2248054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 08/06/2023] [Indexed: 08/26/2023]
Abstract
The introduction and subsequent rapid spread of Japanese encephalitis virus genotype IV across all Australian mainland states and the Northern Territory since late 2021 has increased the risk of an incursion of this mosquito-transmitted zoonotic virus disease into New Zealand, with serious implications for both animal and human health. The potential modes of entry are through introduction of infected mosquitoes as hitchhikers on ships or aircraft, windborne transfer of mosquitoes, or arrival of infected reservoir bird species. A competent vector mosquito, Culex quinquefasciatus, is endemic in New Zealand and other mosquito species may also become involved. If infection becomes established in New Zealand, the scale of transmission may be considerably less than has occurred in Australia because climatic and epidemiological factors are not so favourable. Early evidence of an incursion could come from detection of clinical disease in horses or pigs, or from human cases. Targeted surveillance to confirm or refute indications of an incursion could be undertaken by antibody detection in a number of species. Dogs have been shown to be a particularly valuable sentinel species due to their cohabitation with people and high seroconversion rate. Other novel methods of surveillance could include reverse transcriptase PCR (RT-PCR) on oronasal secretions of pigs. Should evidence of the disease be detected, prompt action would be required to vaccinate at-risk human populations and clarify the epidemiological situation with respect to mammalian hosts and mosquito vector species, including whether a new mosquito species had arrived in the country.Abbreviations: AHL: Animal Health Laboratory; JE: Japanese encephalitis disease; JEV: Japanese encephalitis virus; RT-PCR: Reverse transcriptase PCR.
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Affiliation(s)
- R S Morris
- MorVet Ltd., Masterton, New Zealand
- Tāwharau Ora - School of Veterinary Science, Massey University, Palmerston North, New Zealand
| | - P C Bingham
- Diagnostic and Surveillance Services Directorate, Operations Branch, Ministry for Primary Industries, Wallaceville, New Zealand
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4
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Modelling Japanese encephalitis virus transmission dynamics and human exposure in a Cambodian rural multi-host system. PLoS Negl Trop Dis 2022; 16:e0010572. [PMID: 35816555 PMCID: PMC9302853 DOI: 10.1371/journal.pntd.0010572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/21/2022] [Accepted: 06/08/2022] [Indexed: 11/26/2022] Open
Abstract
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. Japanese encephalitis virus (JEV) is endemic in Cambodia and remains the most common cause of acute viral encephalitis, particularly in children and adolescents. The traditionally described cycle of JEV, involving wild birds as reservoirs, pigs as amplifying hosts and Culex mosquitoes as vectors is questioned, with increasing evidence of a more complex multi-host system involved in areas where densities of pigs are low. In Cambodia, the infection could be maintained in a multi-host system consisting of pigs and poultry as competent hosts, and dogs, cattle and humans as non-competent hosts. We defined a compartmental dynamic model of JEV transmission in a multi-host system representing a rural Cambodian village, to predict human exposure to JEV in the studied area, and to analyse how host community composition may affect human exposure and R0 value. Our theoretical approach showed that variations of the composition of the multi-host system may have an impact on human exposure to JEV, and thus on the disease burden in humans, especially in young children. Besides children vaccination in JEV endemic areas, a proper evaluation of the impact on human health is needed to target prevention actions and reduce JEV burden in Cambodia.
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Kardena IM, Adi AAAM, Astawa NM, O'Dea M, Laurence M, Sahibzada S, Bruce M. Japanese encephalitis in Bali, Indonesia: ecological and socio-cultural perspectives. Int J Vet Sci Med 2021; 9:31-43. [PMID: 34589543 PMCID: PMC8451599 DOI: 10.1080/23144599.2021.1975879] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The increasing number of cases of acute encephalitis syndrome, a key presenting clinical sign of Japanese encephalitis infection in humans, along with increasing laboratory confirmed cases in Bali over recent years have led to the Indonesian government developing a national program of vaccination against Japanese encephalitis virus. In order to inform multidisciplinary management, a review was conducted to assess Japanese encephalitis virus-related cases in humans and animals including their determinants and detection in vectors. Along with published literature, key data from local authorized officers in Bali have been used to convey the recent situation of the disease. Related surveys detected up to 92% of the local children had antibodies against the virus with the annual incidence estimated to be 7.1 per 100,000 children. Additionally, reports on young and adult cases of infection within international travellers infected in Bali were documented with both non-fatal and fatal outcomes. Further seroprevalence surveys detected up to 90% with antibodies to the virus in animal reservoirs. The detection of the virus in certain Culex mosquito species and high levels of seropositivity may be associated with greater risk of the virus transmission to the human population. It was also highlighted that local sociocultural practices for agriculture and livestock were potentially associated with the high density of the vector and the reservoirs, which then may lead to the risk of the disease transmission in the ecology of Bali.
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Affiliation(s)
- I Made Kardena
- Department of Biopathology, Faculty of Veterinary Medicine, Udayana University, Denpasar, Indonesia.,School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Western Australia
| | - Anak Agung Ayu Mirah Adi
- Department of Biopathology, Faculty of Veterinary Medicine, Udayana University, Denpasar, Indonesia
| | - Nyoman Mantik Astawa
- Department of Biopathology, Faculty of Veterinary Medicine, Udayana University, Denpasar, Indonesia
| | - Mark O'Dea
- Department of Primary Industries and Regional Development, Dpird Diagnostics and Laboratory Services, Sustainability and Biosecurity, South Perth, Western Australia
| | - Michael Laurence
- School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Western Australia
| | - Shafi Sahibzada
- School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Western Australia
| | - Mieghan Bruce
- School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Western Australia
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Kulprasertsri S, Kobayashi S, Aoshima K, Kobayashi A, Kimura T. Duck Tembusu virus induces stronger cellular responses than Japanese encephalitis virus in primary duck neurons and fibroblasts. Microbiol Immunol 2021; 65:481-491. [PMID: 34260084 DOI: 10.1111/1348-0421.12933] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 05/20/2021] [Accepted: 07/12/2021] [Indexed: 11/30/2022]
Abstract
Duck Tembusu virus (DTMUV) and Japanese encephalitis virus (JEV) are mosquito-borne flaviviruses. These two viruses infect ducks; however, they show different neurological outcomes. The mechanism of DTMUV- and JEV-induced neuronal death has not been well investigated. In the present study, we examined the differences in the mechanisms involved in virus-induced cell death and innate immune responses between DTMUV KPS54A61 strain and JEV JaGAr-01 strain using primary duck neurons (DN) and duck fibroblasts (CCL-141). DN and CCL-141 were permissive for the infection and replication of these two viruses, which upregulated the expression of innate immunity genes. Both DTMUV and JEV induced cell death via a caspase-3-dependent manner; however, DTMUV triggered more cell death than JEV did in both CCL-141 and DN. These findings suggest that DTMUV infection causes apoptosis in duck neurons and fibroblasts more strongly than JEV. Levels of the mRNA expression of innate immunity-related genes after DTMUV infection were generally higher than levels after JEV infection, suggesting that DTMUV-induced immune response in duck cells may exhibit toxic effect rather than protective effects. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Sittinee Kulprasertsri
- Laboratory of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, 060-0818, Japan
| | - Shintaro Kobayashi
- Laboratory of Public Health, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, 060-0818, Japan
| | - Keisuke Aoshima
- Laboratory of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, 060-0818, Japan
| | - Atsushi Kobayashi
- Laboratory of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, 060-0818, Japan
| | - Takashi Kimura
- Laboratory of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, 060-0818, Japan
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Auerswald H, Maquart PO, Chevalier V, Boyer S. Mosquito Vector Competence for Japanese Encephalitis Virus. Viruses 2021; 13:v13061154. [PMID: 34208737 PMCID: PMC8234777 DOI: 10.3390/v13061154] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/02/2021] [Accepted: 06/02/2021] [Indexed: 12/30/2022] Open
Abstract
Japanese encephalitis virus (JEV) is a zoonotic pathogen mainly found in East and Southeast Asia and transmitted by mosquitoes. The objective of this review is to summarize the knowledge on the diversity of JEV mosquito vector species. Therefore, we systematically analyzed reports of JEV found in field-caught mosquitoes as well as experimental vector competence studies. Based on the investigated publications, we classified 14 species as confirmed vectors for JEV due to their documented experimental vector competence and evidence of JEV found in wild mosquitoes. Additionally, we identified 11 mosquito species, belonging to five genera, with an experimentally confirmed vector competence for JEV but lacking evidence on their JEV transmission capacity from field-caught mosquitoes. Our study highlights the diversity of confirmed and potential JEV vector species. We also emphasize the variety in the study design of vector competence investigations. To account for the diversity of the vector species and regional circumstances, JEV vector competence should be studied in the local context, using local mosquitoes with local virus strains under local climate conditions to achieve reliable data. In addition, harmonization of the design of vector competence experiments would lead to better comparable data, informing vector and disease control measures.
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Affiliation(s)
- Heidi Auerswald
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh 120210, Cambodia
- Correspondence:
| | - Pierre-Olivier Maquart
- Medical and Veterinary Entomology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh 120210, Cambodia; (P.-O.M.); (S.B.)
| | - Véronique Chevalier
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh 120210, Cambodia;
- UMR ASTRE, CIRAD, INRA, Université de Montpellier, 34000 Montpellier, France
| | - Sebastien Boyer
- Medical and Veterinary Entomology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh 120210, Cambodia; (P.-O.M.); (S.B.)
- Institut Pasteur, 75015 Paris, France
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Hameed M, Wahaab A, Nawaz M, Khan S, Nazir J, Liu K, Wei J, Ma Z. Potential Role of Birds in Japanese Encephalitis Virus Zoonotic Transmission and Genotype Shift. Viruses 2021; 13:357. [PMID: 33668224 PMCID: PMC7996159 DOI: 10.3390/v13030357] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/15/2021] [Accepted: 02/20/2021] [Indexed: 12/13/2022] Open
Abstract
Japanese encephalitis (JE) is a vaccine-preventable disease caused by the Japanese encephalitis virus (JEV), which is primarily prevalent in Asia. JEV is a Flavivirus, classified into a single serotype with five genetically distinct genotypes (I, II, III, IV, and V). JEV genotype III (GIII) had been the most dominant strain and caused numerous outbreaks in the JEV endemic countries until 1990. However, recent data shows the emergence of JEV genotype I (GI) as a dominant genotype and it is gradually displacing GIII. The exact mechanism of this genotype displacement is still unclear. The virus can replicate in mosquito vectors and vertebrate hosts to maintain its zoonotic life cycle; pigs and aquatic wading birds act as an amplifying/reservoir hosts, and the humans and equines are dead-end hosts. The important role of pigs as an amplifying host for the JEV is well known. However, the influence of other domestic animals, especially birds, that live in high abundance and close proximity to the human is not well studied. Here, we strive to briefly highlight the role of birds in the JEV zoonotic transmission, discovery of birds as a natural reservoirs and amplifying host for JEV, species of birds susceptible to the JEV infection, and the proposed effect of JEV on the poultry industry in the future, a perspective that has been neglected for a long time. We also discuss the recent in vitro and in vivo studies that show that the newly emerged GI viruses replicated more efficiently in bird-derived cells and ducklings/chicks than GIII, and an important role of birds in the JEV genotype shift from GIII to GI.
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Affiliation(s)
- Muddassar Hameed
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.N.); (S.K.); (K.L.)
| | - Abdul Wahaab
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.N.); (S.K.); (K.L.)
| | - Mohsin Nawaz
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.N.); (S.K.); (K.L.)
| | - Sawar Khan
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.N.); (S.K.); (K.L.)
| | - Jawad Nazir
- Vaccinologist/Head Virology, Tréidlia Biovet Pty Ltd. Units, Seven Hills, NSW 2147, Australia;
| | - Ke Liu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.N.); (S.K.); (K.L.)
| | - Jianchao Wei
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.N.); (S.K.); (K.L.)
| | - Zhiyong Ma
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.N.); (S.K.); (K.L.)
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Faizah AN, Kobayashi D, Amoa-Bosompem M, Higa Y, Tsuda Y, Itokawa K, Miura K, Hirayama K, Sawabe K, Isawa H. Evaluating the competence of the primary vector, Culex tritaeniorhynchus, and the invasive mosquito species, Aedes japonicus japonicus, in transmitting three Japanese encephalitis virus genotypes. PLoS Negl Trop Dis 2020; 14:e0008986. [PMID: 33370301 PMCID: PMC7793266 DOI: 10.1371/journal.pntd.0008986] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 01/08/2021] [Accepted: 11/12/2020] [Indexed: 01/13/2023] Open
Abstract
Japanese encephalitis virus (JEV) is maintained in an enzootic cycle between swine, water birds, and mosquitoes. JEV has circulated indigenously in Asia, with Culex tritaeniorhynchus as the primary vector. In some areas where the primary vector is scarce or absent, sporadic cases of Japanese encephalitis have been reported, with Aedes japonicus japonicus presumed to have the potential as a secondary vector. As one of the world's most invasive culicid species, Ae. j. japonicus carries a considerable health risk for spreading diseases to wider areas, including Europe and North America. Thus, evaluation of its competency as a JEV vector, particularly in a native population, will be essential in preventing potential disease spread. In this study, the two mosquito species' vector competence in transmitting three JEV genotypes (I, III, and V) was assessed, with Cx. tritaeniorhynchus serving as a point of reference. The mosquitoes were virus-fed and the infection rate (IR), dissemination rate (DR), and transmission rate (TR) evaluated individually by either RT-qPCR or focus forming assay. Results showed striking differences between the two species, with IR of 95% (261/274) and 9% (16/177) in Cx. tritaeniorhynchus and Ae. j. japonicus, respectively. Both mosquitoes were susceptible to all three JEV genotypes with significant differences in IR and mean viral titer. Results confirm the primary vector's competence, but the fact that JEV was able to establish in Ae. j. japonicus is of public health significance, and with 2%-16% transmission rate it has the potential to successfully transmit JEV to the next host. This may explain the human cases and infrequent detection in primary vector-free areas. Importantly, Ae. j. japonicus could be a relevant vector spreading the disease into new areas, indicating the need for security measures in areas where the mosquito is distributed or where it may be introduced.
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Affiliation(s)
- Astri Nur Faizah
- Laboratory of Veterinary Public Health, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan
- Department of Medical Entomology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
| | - Daisuke Kobayashi
- Department of Medical Entomology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
| | - Michael Amoa-Bosompem
- Department of Medical Entomology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
- Department of Environmental Parasitology, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Yukiko Higa
- Department of Medical Entomology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
| | - Yoshio Tsuda
- Department of Medical Entomology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
| | - Kentaro Itokawa
- Pathogen Genomics Center, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
| | - Kozue Miura
- Laboratory of Veterinary Public Health, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Kazuhiro Hirayama
- Laboratory of Veterinary Public Health, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Kyoko Sawabe
- Department of Medical Entomology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
| | - Haruhiko Isawa
- Department of Medical Entomology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
- * E-mail:
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Wilson WC, Mitzel D, Savini G, Zientara S, Richt JA. Editorial: Emerging Arboviruses. Front Vet Sci 2020; 7:593872. [PMID: 33240963 PMCID: PMC7677233 DOI: 10.3389/fvets.2020.593872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 09/23/2020] [Indexed: 11/13/2022] Open
Affiliation(s)
- William C Wilson
- Arthropod-Borne Animal Diseases Research Unit, United States Department of Agriculture (USDA), Agricultural Research Service, Manhattan, KS, United States
| | - Dana Mitzel
- Arthropod-Borne Animal Diseases Research Unit, United States Department of Agriculture (USDA), Agricultural Research Service, Manhattan, KS, United States
| | - Giovanni Savini
- OIE Reference Laboratory for Bluetongue, IZS Istituto Zooprofilattico Sperimentale, Teramo, Italy
| | - Stéphan Zientara
- French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Maisons Alfort, France
| | - Juergen A Richt
- Department of Diagnostic Medicine/Pathobiology and Center of Excellence for Emerging and Zoonotic Animal Diseases, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
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11
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Essential Oils of Zingiber Species from Vietnam: Chemical Compositions and Biological Activities. PLANTS 2020; 9:plants9101269. [PMID: 32993137 PMCID: PMC7601767 DOI: 10.3390/plants9101269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/23/2020] [Accepted: 09/25/2020] [Indexed: 11/16/2022]
Abstract
Mosquito-borne diseases are a large problem in Vietnam as elsewhere. Due to environmental concerns regarding the use of synthetic insecticides as well as developing insecticidal resistance, there is a need for environmentally-benign alternative mosquito control agents. In addition, resistance of pathogenic microorganisms to antibiotics is an increasing problem. As part of a program to identify essential oils as alternative larvicidal and antimicrobial agents, the leaf, stem, and rhizome essential oils of several Zingiber species, obtained from wild-growing specimens in northern Vietnam, were acquired by hydrodistillation and investigated using gas chromatography. The mosquito larvicidal activities of the essential oils were assessed against Culex quinquefasciatus, Aedes albopictus, and Ae. aegypti, and for antibacterial activity against a selection of Gram-positive and Gram-negative bacteria, and for activity against Candida albicans. Zingiber essential oils rich in α-pinene and β-pinene showed the best larvicidal activity. Zingiber nudicarpum rhizome essential oil showed excellent antibacterial activity against Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus, with minimum inhibitory concentrations (MIC) of 2, 8, and 1 μg/mL, respectively. However, the major components, α-pinene and β-pinene, cannot explain the antibacterial activities obtained.
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Ladreyt H, Auerswald H, Tum S, Ken S, Heng L, In S, Lay S, Top C, Ly S, Duong V, Dussart P, Durand B, Chevalier V. Comparison of Japanese Encephalitis Force of Infection in Pigs, Poultry and Dogs in Cambodian Villages. Pathogens 2020; 9:pathogens9090719. [PMID: 32882890 PMCID: PMC7558861 DOI: 10.3390/pathogens9090719] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/25/2020] [Accepted: 08/28/2020] [Indexed: 12/22/2022] Open
Abstract
Japanese encephalitis virus (JEV) is the main cause of human viral encephalitis in Asia, with a mortality rate reaching 30%, mostly affecting children. The traditionally described cycle involving wild birds as reservoirs, pigs as amplifying hosts and Culex mosquitoes as vectors is questioned, with increasing evidence of a more complex multi-host system involved in areas where densities of pigs are low, such as in Cambodia. In 2018, we examined pigs, chickens, ducks and dogs from Kandal province, Cambodia, for antibody response against JEV by hemagglutination inhibition and virus neutralization assays. Forces of infection (FOI) for flaviviruses and JEV were estimated per species and per unit of body surface area (BSA). JEV seroprevalence reached 31% (95% CI: 23-41%) in pigs, 1% (95% CI: 0.1-3%) in chickens, 12% (95% CI: 7-19%) in ducks and 35% (95% CI: 28-42%) in dogs. Pigs were most likely to be infected (FOI: 0.09 per month), but the FOI was higher in ducks than in pigs for a given BSA (ratio of 0.13). Dogs had a lower FOI than ducks but a higher FOI than chickens (0.01 per month). For a given BSA, dogs were less likely to be infected than pigs (ratio of 1.9). In Cambodia, the virus may be circulating between multiple hosts. Dogs live in close contact with humans, and estimating their exposure to JEV infection could be a relevant indicator of the risk for humans to get infected, which is poorly known due to underdiagnosis. Understanding the JEV cycle and developing tools to quantify the exposure of humans is essential to adapt and support control measures for this vaccine-preventable disease.
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Affiliation(s)
- Héléna Ladreyt
- Epidemiology Unit, Laboratory for Animal Health, French Agency for Food, Environmental and Occupational Health and Safety (ANSES), University Paris-Est, 14 rue Pierre et Marie Curie, 94700 Maisons-Alfort, France; (H.L.); (B.D.)
- International Center of Research in Agriculture for Development (CIRAD), UMR ASTRE, F-34090 Montpellier, France
| | - Heidi Auerswald
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Boulevard, P.O Box. 983, Phnom Penh 12201, Cambodia; (H.A.); (S.K.); (L.H.); (S.I.); (C.T.); (V.D.); (P.D.)
| | - Sothyra Tum
- National Animal Health and Production Research Institute, General Directorate for Animal Health and Production, Ministry of Agriculture, Forestry and Fisheries, Phnom Penh 12201, Cambodia;
| | - Sreymom Ken
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Boulevard, P.O Box. 983, Phnom Penh 12201, Cambodia; (H.A.); (S.K.); (L.H.); (S.I.); (C.T.); (V.D.); (P.D.)
| | - Leangyi Heng
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Boulevard, P.O Box. 983, Phnom Penh 12201, Cambodia; (H.A.); (S.K.); (L.H.); (S.I.); (C.T.); (V.D.); (P.D.)
| | - Saraden In
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Boulevard, P.O Box. 983, Phnom Penh 12201, Cambodia; (H.A.); (S.K.); (L.H.); (S.I.); (C.T.); (V.D.); (P.D.)
| | - Sokchea Lay
- Immunology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Boulevard, P.O Box. 983, Phnom Penh 12201, Cambodia;
| | - Chakriyouth Top
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Boulevard, P.O Box. 983, Phnom Penh 12201, Cambodia; (H.A.); (S.K.); (L.H.); (S.I.); (C.T.); (V.D.); (P.D.)
| | - Sowath Ly
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Boulevard, PO Box 983, Phnom Penh 12201, Cambodia;
| | - Veasna Duong
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Boulevard, P.O Box. 983, Phnom Penh 12201, Cambodia; (H.A.); (S.K.); (L.H.); (S.I.); (C.T.); (V.D.); (P.D.)
| | - Philippe Dussart
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Boulevard, P.O Box. 983, Phnom Penh 12201, Cambodia; (H.A.); (S.K.); (L.H.); (S.I.); (C.T.); (V.D.); (P.D.)
| | - Benoit Durand
- Epidemiology Unit, Laboratory for Animal Health, French Agency for Food, Environmental and Occupational Health and Safety (ANSES), University Paris-Est, 14 rue Pierre et Marie Curie, 94700 Maisons-Alfort, France; (H.L.); (B.D.)
| | - Véronique Chevalier
- International Center of Research in Agriculture for Development (CIRAD), UMR ASTRE, F-34090 Montpellier, France
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, 5 Monivong Boulevard, PO Box 983, Phnom Penh 12201, Cambodia;
- International Center of Research in Agriculture for Development (CIRAD), UMR ASTRE, Phnom Penh 12201, Cambodia
- Correspondence:
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13
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Oliveira ARS, Cohnstaedt LW, Noronha LE, Mitzel D, McVey DS, Cernicchiaro N. Perspectives Regarding the Risk of Introduction of the Japanese Encephalitis Virus (JEV) in the United States. Front Vet Sci 2020; 7:48. [PMID: 32118069 PMCID: PMC7019853 DOI: 10.3389/fvets.2020.00048] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/20/2020] [Indexed: 12/15/2022] Open
Abstract
Japanese encephalitis (JE) is a zoonotic, emerging disease transmitted by mosquito vectors infected with the Japanese encephalitis virus (JEV). Its potential for emergence into susceptible regions is high, including in the United States (US), and is a reason of economic concern among the agricultural community, and to public health due to high morbidity and mortality rates in humans. While exploring the complexities of interactions involved with viral transmission, we proposed a new outlook on the role of vectors, hosts and the environment under changing conditions. For instance, the role of feral pigs may have been underappreciated in our previous work, given research keeps pointing to the importance of susceptible populations of wild swine in naïve regions as key elements for the introduction of emergent vector-borne diseases. High risk of JEV introduction has been associated with the transportation of infected mosquitoes via aircraft. Nonetheless, no JEV outbreaks have been reported in the US to date and results from a qualitative risk assessment considered the risk of establishment to be negligible under the current conditions (environmental, vector, pathogen, and host). In this work, we discuss virus-vector-host interactions and ecological factors important for virus transmission and spread, review research on the risk of JEV introduction to the US considering the implications of risk dismissal as it relates to past experiences with similar arboviruses, and reflect on future directions, challenges, and implications of a JEV incursion.
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Affiliation(s)
- Ana R S Oliveira
- Center for Outcomes Research and Epidemiology, Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
| | - Lee W Cohnstaedt
- Arthropod-Borne Animal Diseases Research, Agricultural Research Service, United States Department of Agriculture, Manhattan, KS, United States
| | - Leela E Noronha
- Arthropod-Borne Animal Diseases Research, Agricultural Research Service, United States Department of Agriculture, Manhattan, KS, United States
| | - Dana Mitzel
- Arthropod-Borne Animal Diseases Research, Agricultural Research Service, United States Department of Agriculture, Manhattan, KS, United States
| | - D Scott McVey
- Arthropod-Borne Animal Diseases Research, Agricultural Research Service, United States Department of Agriculture, Manhattan, KS, United States
| | - Natalia Cernicchiaro
- Center for Outcomes Research and Epidemiology, Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States
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Auerswald H, Ruget AS, Ladreyt H, In S, Mao S, Sorn S, Tum S, Duong V, Dussart P, Cappelle J, Chevalier V. Serological Evidence for Japanese Encephalitis and West Nile Virus Infections in Domestic Birds in Cambodia. Front Vet Sci 2020; 7:15. [PMID: 32064271 PMCID: PMC7000427 DOI: 10.3389/fvets.2020.00015] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 01/09/2020] [Indexed: 12/30/2022] Open
Abstract
Mosquito-borne flaviviruses with an enzootic transmission cycle like Japanese encephalitis virus (JEV) and West Nile virus (WNV) are a major public health concern. The circulation of JEV in Southeast Asia is well-documented, and the important role of pigs as amplification hosts for the virus is long known. The influence of other domestic animals especially poultry that lives in high abundance and close proximity to humans is not intensively analyzed. Another understudied field in Asia is the presence of the closely related WNV. Such analyses are difficult to perform due to the intense antigenic cross-reactivity between these viruses and the lack of suitable standardized serological assays. The main objective of this study was to assess the prevalence of JEV and WNV flaviviruses in domestic birds, detailed in chickens and ducks, in three different Cambodian provinces. We determined the flavivirus seroprevalence using an hemagglutination inhibition assay (HIA). Additionally, we investigated in positive samples the presence of JEV and WNV neutralizing antibodies (nAb) using foci reduction neutralization test (FRNT). We found 29% (180/620) of the investigated birds positive for flavivirus antibodies with an age-depended increase of the seroprevalence (OR = 1.04) and a higher prevalence in ducks compared to chicken (OR = 3.01). Within the flavivirus-positive birds, we found 43% (28/65) with nAb against JEV. We also observed the expected cross-reactivity between JEV and WNV, by identifying 18.5% double-positive birds that had higher titers of nAb than single-positive birds. Additionally, seven domestic birds (10.7%) showed only nAb against WNV and no nAb against JEV. Our study provides evidence for an intense JEV circulation in domestic birds in Cambodia, and the first serological evidence for WNV presence in Southeast Asia since decades. These findings mark the need for a re-definition of areas at risk for JEV and WNV transmission, and the need for further and intensified surveillance of mosquito-transmitted diseases in domestic animals.
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Affiliation(s)
- Heidi Auerswald
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh, Cambodia
| | - Anne-Sophie Ruget
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh, Cambodia.,Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Unité Mixte de Recherche ASTRE, Montpellier, France
| | - Helena Ladreyt
- Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Unité Mixte de Recherche ASTRE, Montpellier, France.,ASTRE, Université Montpellier, CIRAD, INRAE, Montpellier, France.,Epidemiology Unit, Laboratory for Animal Health, French Agency for Food, Environmental and Occupational Health and Safety (ANSES), University Paris-Est, Maisons-Alfort, France
| | - Saraden In
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh, Cambodia
| | - Sokthearom Mao
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh, Cambodia
| | - San Sorn
- General Directorate for Animal Health and Production, Ministry of Agriculture, Forestry and Fisheries, Phnom Penh, Cambodia
| | - Sothyra Tum
- National Animal Health and Production Research Institute, General Directorate for Animal Health and Production, Ministry of Agriculture, Forestry and Fisheries, Phnom Penh, Cambodia
| | - Veasna Duong
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh, Cambodia
| | - Philippe Dussart
- Virology Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh, Cambodia
| | - Julien Cappelle
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh, Cambodia.,Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Unité Mixte de Recherche ASTRE, Montpellier, France.,ASTRE, Université Montpellier, CIRAD, INRAE, Montpellier, France.,UMR EpiA, INRAE, VetAgro Sup, Marcy lÉtoile, France
| | - Véronique Chevalier
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Institut Pasteur International Network, Phnom Penh, Cambodia.,Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Unité Mixte de Recherche ASTRE, Montpellier, France.,ASTRE, Université Montpellier, CIRAD, INRAE, Montpellier, France
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Fan YC, Liang JJ, Chen JM, Lin JW, Chen YY, Su KH, Lin CC, Tu WC, Chiou MT, Ou SC, Chang GJJ, Lin YL, Chiou SS. NS2B/NS3 mutations enhance the infectivity of genotype I Japanese encephalitis virus in amplifying hosts. PLoS Pathog 2019; 15:e1007992. [PMID: 31381617 PMCID: PMC6695206 DOI: 10.1371/journal.ppat.1007992] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 08/15/2019] [Accepted: 07/20/2019] [Indexed: 12/12/2022] Open
Abstract
Genotype I (GI) virus has replaced genotype III (GIII) virus as the dominant Japanese encephalitis virus (JEV) in the epidemic area of Asia. The mechanism underlying the genotype replacement remains unclear. Therefore, we focused our current study on investigating the roles of mosquito vector and amplifying host(s) in JEV genotype replacement by comparing the replication ability of GI and GIII viruses. GI and GIII viruses had similar infection rates and replicated to similar viral titers after blood meal feedings in Culex tritaeniorhynchus. However, GI virus yielded a higher viral titer in amplifying host-derived cells, especially at an elevated temperature, and produced an earlier and higher viremia in experimentally inoculated pigs, ducklings, and young chickens. Subsequently we identified the amplification advantage of viral genetic determinants from GI viruses by utilizing chimeric and recombinant JEVs (rJEVs). Compared to the recombinant GIII virus (rGIII virus), we observed that both the recombinant GI virus and the chimeric rJEVs encoding GI virus-derived NS1-3 genes supported higher replication ability in amplifying hosts. The replication advantage of the chimeric rJEVs was lost after introduction of a single substitution from a GIII viral mutation (NS2B-L99V, NS3-S78A, or NS3-D177E). In addition, the gain-of-function assay further elucidated that rGIII virus encoding GI virus NS2B-V99L/NS3-A78S/E177E substitutions re-gained the enhanced replication ability. Thus, we conclude that the replication advantage of GI virus in pigs and poultry is the result of three critical NS2B/NS3 substitutions. This may lead to more efficient transmission of GI virus than GIII virus in the amplifying host-mosquito cycle. Flaviviral vertebrate amplifying host(s), invertebrate vector(s), genetics, and environmental factors shape the viral geographical distribution and epidemic disease pattern. Newly emerging dengue virus genotypes, West Nile virus clades, or Zika virus strains exhibited an enhancement in mosquito vector competence. However, hosts and viral determinants responsible for the occurrence of JEV genotype replacement remains unclear. Here, we demonstrated that emerging GI viruses with enhanced transmission potential in amplifying hosts such as pigs and avian species was encoded by three critical GI-specific mutations in NS2B/NS3 proteins. This discovery provides insight into the viral genetic mechanism underlying the GI virus advantage and adaptation in the pig/avian species-mosquito cycle. Our results also emphasize the importance of monitoring viral evolution in amplifying vertebrate hosts to clarify the role of avian species in local transmission of GI virus in JE endemic and epidemic countries.
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Affiliation(s)
- Yi-Chin Fan
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
- Institute of Epidemiology and Preventive Medicine, National Taiwan University, Taipei, Taiwan
| | - Jian-Jong Liang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Jo-Mei Chen
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
| | - Jen-Wei Lin
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
| | - Yi-Ying Chen
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
| | - Kuan-Hsuan Su
- Department of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Chang-Chi Lin
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Wu-Chun Tu
- Department of Entomology, National Chung Hsing University, Taichung, Taiwan
| | - Ming-Tang Chiou
- Department of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Shan-Chia Ou
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
| | - Gwong-Jen J. Chang
- Arboviral Diseases Branch, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - Yi-Ling Lin
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Shyan-Song Chiou
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
- * E-mail:
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Review of Emerging Japanese Encephalitis Virus: New Aspects and Concepts about Entry into the Brain and Inter-Cellular Spreading. Pathogens 2019; 8:pathogens8030111. [PMID: 31357540 PMCID: PMC6789543 DOI: 10.3390/pathogens8030111] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 07/17/2019] [Accepted: 07/22/2019] [Indexed: 12/12/2022] Open
Abstract
Japanese encephalitis virus (JEV) is an emerging flavivirus of the Asia-Pacific region. More than two billion people live in endemic or epidemic areas and are at risk of infection. Recently, the first autochthonous human case was recorded in Africa, and infected birds have been found in Europe. JEV may spread even further to other continents. The first section of this review covers established and new information about the epidemiology of JEV. The subsequent sections focus on the impact of JEV on humans, including the natural course and immunity. Furthermore, new concepts are discussed about JEV’s entry into the brain. Finally, interactions of JEV and host cells are covered, as well as how JEV may spread in the body through latently infected immune cells and cell-to-cell transmission of virions or via other infectious material, including JEV genomic RNA.
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