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Taylor-Robinson AW. Complex transmission epidemiology of neglected Australian arboviruses: diverse non-human vertebrate hosts and competent arthropod invertebrate vectors. Front Microbiol 2024; 15:1469710. [PMID: 39296304 PMCID: PMC11408357 DOI: 10.3389/fmicb.2024.1469710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Accepted: 08/20/2024] [Indexed: 09/21/2024] Open
Abstract
More than 75 arboviruses are indigenous to Australia, of which at least 13 are known to cause disease in humans. Alphaviruses are the most common arboviruses, notably including Ross River and Barmah Forest viruses, which contribute a significant public health and economic burden in Australia. Both can cause febrile illness with arthritic symptoms. Each circulates nationally across diverse climates and environments, and has multi-host, multi-vector dynamics. Several medically important flaviviruses also circulate in Australia. Infection with Murray Valley encephalitis or Kunjin viruses is less common but is associated with brain inflammation. Key research priorities for Australian arboviruses aim to understand clinical manifestations, develop timely diagnostics, and identify transmission cycles that permit the maintenance of arboviruses. While these can now be answered for a handful of notifiable alpha- and flaviviruses there are others for which non-human vertebrate hosts and competent arthropod invertebrate vectors are still to be identified and/or whose role in transmission is not well understood. One or more of these 'neglected' arboviruses may be the causative agent of a proportion of the many thousands of fever-related illnesses reported annually in Australia that at present remain undiagnosed. Here, what is known about enzootic cycling of viruses between arthropod vectors and mammalian and avian reservoir hosts is summarised. How and to what extent these interactions influence the epidemiology of arbovirus transmission and infection is discussed.
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Affiliation(s)
- Andrew W Taylor-Robinson
- College of Health Sciences, VinUniversity, Hanoi, Vietnam
- Center for Global Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- College of Health and Human Sciences, Charles Darwin University, Casuarina, NT, Australia
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Fujii M, Ito S, Katsumata E, Chambers JK, Matsugo H, Takenaka-Uema A, Murakami S, Uchida K, Horimoto T. Japanese Encephalitis Virus and Schizophyllum commune Co-Infection in a Harbor Seal in Japan. Vet Sci 2024; 11:215. [PMID: 38787188 PMCID: PMC11125775 DOI: 10.3390/vetsci11050215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 05/09/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024] Open
Abstract
The Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, has a wide host range, extending from pigs and ardeid birds to opportunistic dead-end hosts, such as humans and horses. However, JEV encephalitis infections in aquatic mammals are rare, with only two cases in seals reported to date. Here, we report a lethal case of JEV and Schizophyllum commune co-infection in an aquarium-housed harbor seal in Japan. We isolated JEV from the brain of the dead seal and characterized its phylogeny and pathogenicity in mice. The virus isolate from the seal was classified as genotype GIb, which aligns with recent Japanese human and mosquito isolates as well as other seal viruses detected in China and Korea, and does not exhibit a unique sequence trait distinct from that of human and mosquito strains. We demonstrated that the seal isolate is pathogenic to mice and causes neuronal symptoms. These data suggest that seals should be considered a susceptible dead-end host for circulating JEV in natural settings.
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Affiliation(s)
- Marina Fujii
- Laboratory of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan; (M.F.); (H.M.); (A.T.-U.); (S.M.)
| | - Soma Ito
- Laboratory of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan; (S.I.); (J.K.C.)
| | | | - James K. Chambers
- Laboratory of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan; (S.I.); (J.K.C.)
| | - Hiromichi Matsugo
- Laboratory of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan; (M.F.); (H.M.); (A.T.-U.); (S.M.)
| | - Akiko Takenaka-Uema
- Laboratory of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan; (M.F.); (H.M.); (A.T.-U.); (S.M.)
| | - Shin Murakami
- Laboratory of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan; (M.F.); (H.M.); (A.T.-U.); (S.M.)
| | - Kazuyuki Uchida
- Laboratory of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan; (S.I.); (J.K.C.)
| | - Taisuke Horimoto
- Laboratory of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo 113-8657, Japan; (M.F.); (H.M.); (A.T.-U.); (S.M.)
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Lee E, Kim M, Kim YB. Attenuated Chimeric GI/GIII Vaccine Candidate against Japanese Encephalitis Virus. Vaccines (Basel) 2023; 11:1827. [PMID: 38140231 PMCID: PMC10747704 DOI: 10.3390/vaccines11121827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/06/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023] Open
Abstract
Japanese encephalitis (JE) is a very severe disease characterized by high fatality rates and the development of permanent behavioral, psychiatric, and neurological sequelae among survivors. Japanese encephalitis virus (JEV), a flavivirus, is responsible for JE. In Asia, Genotype I (GI) has emerged as the dominant strain, replacing Genotype III (GIII). However, no clinically approved drug is available to treat JEV infection, and currently available commercial vaccines derived from JEV GIII strains provide only partial protection against GI. Utilizing a reverse genetics system, this study attempted to produce a novel chimeric JEV strain with high efficacy against JEV GI. Accordingly, a GI/GIII intertypic recombinant strain, namely SA14-GI env, was generated by substituting the E region of the GIII SA14-14-2 strain with that of the GI strain, K05GS. The neurovirulence of the mutant virus was significantly reduced in mice. Analysis of the immunogenicity of the chimeric virus revealed that it induced neutralizing antibodies against JEV GI in mice, and the protective efficacy of SA14-GI env was higher than that of SA14-14-2. These findings suggest that SA14-GI env may be a safe and effective live-attenuated vaccine candidate against JEV GI.
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Affiliation(s)
| | | | - Young Bong Kim
- Department of Biomedical Science and Engineering, Konkuk University, Seoul 05029, Republic of Korea; (E.L.); (M.K.)
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Zhang W, Wang J, Liu Q, Gong Z. A Review of Pathogens Transmitted by the Container-Inhabiting Mosquitoes, Aedes Albopictus, A Global Public Health Threat. China CDC Wkly 2023; 5:984-990. [PMID: 38023389 PMCID: PMC10652089 DOI: 10.46234/ccdcw2023.185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 10/31/2023] [Indexed: 12/01/2023] Open
Abstract
Dengue virus (DENV), Chikungunya virus (CHIKV), and Zika virus (ZIKV) are highly pathogenic human arboviruses transmitted by the Aedes (Stegomyia) albopictus (Skuse) (Diptera: Culicidae) or Ae. Albopictus mosquito. These arboviruses are responsible for causing fever, hemorrhagic conditions, and neurological diseases in humans post-bite from an infected Aedes mosquito. Over the past 80 years, the Ae. albopictus has infested every habitable continent, bar Antarctica, thereby escalating the probability of global insect-borne infectious disease outbreaks. This research follows the global transmission pattern of Ae. albopictus and provides a summary of disease prevention and control strategies for mosquito-borne infections, as implemented by the World Health Organization (WHO) and both Asian and European countries. Consequently, this study can aid in the prevention and control of mosquito-borne diseases while acting as a basis for international collaboration on effectively managing arbovirus infection issues in public health.
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Affiliation(s)
- Wenrong Zhang
- School of Public Health, Hangzhou Medical College, Hangzhou City, Zhejiang Province, China
| | - Jinna Wang
- Institute of Infectious Disease Prevention and Control, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou City, Zhejiang Province, China
| | - Qinmei Liu
- Institute of Infectious Disease Prevention and Control, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou City, Zhejiang Province, China
| | - Zhenyu Gong
- Institute of Infectious Disease Prevention and Control, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou City, Zhejiang Province, China
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Hsu JY, Hung CC, Tsou TP, Chen WC. Epidemiology and risk factors of Japanese encephalitis in Taiwan, 2010-2022. PLoS Negl Trop Dis 2023; 17:e0011421. [PMID: 37782654 PMCID: PMC10569588 DOI: 10.1371/journal.pntd.0011421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 10/12/2023] [Accepted: 09/24/2023] [Indexed: 10/04/2023] Open
Abstract
INTRODUCTION Taiwan introduced a two-dose inactivated Japanese encephalitis (JE) mouse brain-derived (JE-MB) vaccine into routine childhood immunization in 1968, with booster vaccination implemented in 1974 and 1983. In 2017, JE-MB vaccine was replaced by a two-dose live-attenuated chimeric vaccine (JE-CV). After implementation of JE vaccination programs, JE cases have shifted from children to adults. In this study, we described the JE epidemiology and identify high-risk groups to further inform vaccine policy. METHODOLOGY/PRINCIPAL FINDINGS We extracted data from Taiwan's notifiable disease surveillance database, vital statistics, and employment statistics from 2010 to 2022. Diagnosis of JE was confirmed by JE seroconversion, a four-fold increase in virus-specific antibodies, a positive JE viral nucleic-acid test, or JE virus isolation. From 2010 to 2022, a total of 313 cases of JE were diagnosed, resulting in an overall incidence rate of 0.10 cases per 100,000 person-years and a mortality rate of 0.006 per 100,000 population per year. Among these patients, 64% were male, and the median age was 51 years (range 0-82). Compared with people born in or after 1976 (vaccinated with four doses of JE-MB vaccine or two doses of JE-CV), those born in or before 1962 (unvaccinated) and those born during 1963-1975 (vaccinated with two or three doses of JE-MB vaccine) had a 4.2-fold (95% confidence interval [CI] 3.0-5.7) and 5.9-fold (95% CI 4.3-8.1) higher risk of JE, respectively. The relative risk of working in agriculture, forestry, fishing, or animal husbandry, compared to other occupations, was 5.0 (95% CI 3.5-7.0). CONCLUSIONS/SIGNIFICANCE In Taiwan, individuals born before 1976 and those employed in agriculture, forestry, fishing, or animal husbandry had a higher risk of JE. We recommend JE vaccination for people in these high-risk groups who have not been fully vaccinated or have an unknown vaccination history.
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Affiliation(s)
- Jen-Yu Hsu
- Department of Occupational Medicine and Clinical Toxicology, Taipei Veterans General Hospital, Taipei, Taiwan
- Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chien-Ching Hung
- Department of Tropical Medicine and Parasitology, National Taiwan University College of Medicine, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
- Department of Internal Medicine, National Taiwan University Hospital Yunlin Branch, Yunlin, Taiwan
| | - Tsung-Pei Tsou
- Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan
| | - Wan-Chin Chen
- Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan
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Hernandez-Valencia JC, Muñoz-Laiton P, Gómez GF, Correa MM. A Systematic Review on the Viruses of Anopheles Mosquitoes: The Potential Importance for Public Health. Trop Med Infect Dis 2023; 8:459. [PMID: 37888587 PMCID: PMC10610971 DOI: 10.3390/tropicalmed8100459] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 09/20/2023] [Accepted: 09/21/2023] [Indexed: 10/28/2023] Open
Abstract
Anopheles mosquitoes are the vectors of Plasmodium, the etiological agent of malaria. In addition, Anopheles funestus and Anopheles gambiae are the main vectors of the O'nyong-nyong virus. However, research on the viruses carried by Anopheles is scarce; thus, the possible transmission of viruses by Anopheles is still unexplored. This systematic review was carried out to identify studies that report viruses in natural populations of Anopheles or virus infection and transmission in laboratory-reared mosquitoes. The databases reviewed were EBSCO-Host, Google Scholar, Science Direct, Scopus and PubMed. After the identification and screening of candidate articles, a total of 203 original studies were included that reported on a variety of viruses detected in Anopheles natural populations. In total, 161 viruses in 54 species from 41 countries worldwide were registered. In laboratory studies, 28 viruses in 15 Anopheles species were evaluated for mosquito viral transmission capacity or viral infection. The viruses reported in Anopheles encompassed 25 viral families and included arboviruses, probable arboviruses and Insect-Specific Viruses (ISVs). Insights after performing this review include the need for (1) a better understanding of Anopheles-viral interactions, (2) characterizing the Anopheles virome-considering the public health importance of the viruses potentially transmitted by Anopheles and the significance of finding viruses with biological control activity-and (3) performing virological surveillance in natural populations of Anopheles, especially in the current context of environmental modifications that may potentiate the expansion of the Anopheles species distribution.
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Affiliation(s)
- Juan C. Hernandez-Valencia
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia, Medellín 050010, Colombia; (J.C.H.-V.); (P.M.-L.); (G.F.G.)
| | - Paola Muñoz-Laiton
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia, Medellín 050010, Colombia; (J.C.H.-V.); (P.M.-L.); (G.F.G.)
| | - Giovan F. Gómez
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia, Medellín 050010, Colombia; (J.C.H.-V.); (P.M.-L.); (G.F.G.)
- Dirección Académica, Escuela de Pregrados, Universidad Nacional de Colombia, Sede de La Paz, La Paz 202017, Colombia
| | - Margarita M. Correa
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia, Medellín 050010, Colombia; (J.C.H.-V.); (P.M.-L.); (G.F.G.)
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Pora W, Kasamsumran N, Tharawatcharasart K, Ampol R, Siriyasatien P, Jariyapan N. Enhancement of VGG16 model with multi-view and spatial dropout for classification of mosquito vectors. PLoS One 2023; 18:e0284330. [PMID: 37486913 PMCID: PMC10365266 DOI: 10.1371/journal.pone.0284330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 03/28/2023] [Indexed: 07/26/2023] Open
Abstract
Mosquitoes transmit pathogens that can cause numerous significant infectious diseases in humans and animals such as malaria, dengue fever, chikungunya fever, and encephalitis. Although the VGG16 model is not one of the most advanced CNN networks, it is reported that a fine-tuned VGG16 model achieves accuracy over 90% when applied to the classification of mosquitoes. The present study sets out to improve the accuracy and robustness of the VGG16 network by incorporating spatial dropout layers to regularize the network and by modifying its structure to incorporate multi-view inputs. Herein, four models are implemented: (A) early-combined, (B) middle-combined, (C) late-combined, and (D) ensemble model. Moreover, a structure for combining Models (A), (B), (C), and (D), known as the classifier, is developed. Two image datasets, including a reference dataset of mosquitoes in South Korea and a newly generated dataset of mosquitoes in Thailand, are used to evaluate our models. Regards the reference dataset, the average accuracy of ten runs improved from 83.26% to 99.77%, while the standard deviation decreased from 2.60% to 0.12%. When tested on the new dataset, the classifier's accuracy was also over 99% with a standard deviation of less than 2%. This indicates that the algorithm achieves high accuracy with low variation and is independent of a particular dataset. To evaluate the robustness of the classifier, it was applied to a small dataset consisting of mosquito images captured under various conditions. Its accuracy dropped to 86.14%, but after retraining with the small dataset, it regained its previous level of precision. This demonstrates that the classifier is resilient to variation in the dataset and can be retrained to adapt to the variation. The classifier and the new mosquito dataset could be utilized to develop an application for efficient and rapid entomological surveillance for the prevention and control of mosquito-borne diseases.
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Affiliation(s)
- Wanchalerm Pora
- Department of Electrical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand
| | - Natthakorn Kasamsumran
- Department of Electrical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand
| | - Katanyu Tharawatcharasart
- Department of Electrical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand
| | - Rinnara Ampol
- Department of Parasitology, Center of Excellence in Vector Biology and Vector-Borne Disease, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Padet Siriyasatien
- Department of Parasitology, Center of Excellence in Vector Biology and Vector-Borne Disease, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Narissara Jariyapan
- Department of Parasitology, Center of Excellence in Vector Biology and Vector-Borne Disease, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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Zhu Y, Chen S, Lurong Q, Qi Z. Recent Advances in Antivirals for Japanese Encephalitis Virus. Viruses 2023; 15:v15051033. [PMID: 37243122 DOI: 10.3390/v15051033] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/28/2023] Open
Abstract
Culex mosquitoes are the primary vectors of the Japanese encephalitis virus (JEV). Since its discovery in 1935, Japanese encephalitis (JE), caused by JEV, has posed a significant threat to human health. Despite the widespread implementation of several JEV vaccines, the transmission chain of JEV in the natural ecosystem has not changed, and the vector of transmission cannot be eradicated. Therefore, JEV is still the focus of attention for flaviviruses. At present, there is no clinically specific drug for JE treatment. JEV infection is a complex interaction between the virus and the host cell, which is the focus of drug design and development. An overview of antivirals that target JEV elements and host factors is presented in this review. In addition, drugs that balance antiviral effects and host protection by regulating innate immunity, inflammation, apoptosis, or necrosis are reviewed to treat JE effectively.
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Affiliation(s)
- Yongzhe Zhu
- Department of Microbiology, Faculty of Naval Medicine, Naval Medical University, Shanghai 200433, China
| | - Shenglin Chen
- Department of Clinic Laboratory Diagnostics, General Hospital of Tibet Military Area Command of PLA, Lhasa 850007, China
| | - Qilin Lurong
- Department of Geriatrics, General Hospital of Tibet Military Area Command of PLA, Lhasa 850007, China
| | - Zhongtian Qi
- Department of Microbiology, Faculty of Naval Medicine, Naval Medical University, Shanghai 200433, China
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Impact of temperature on infection with Japanese encephalitis virus of three potential urban vectors in Taiwan; Aedes albopictus, Armigeres subalbatus, and Culex quinquefasciatus. Acta Trop 2023; 237:106726. [DOI: 10.1016/j.actatropica.2022.106726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/17/2022] [Accepted: 10/19/2022] [Indexed: 11/19/2022]
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Isolation and Genetic Characterization of Japanese Encephalitis Virus Two Decades after Its Elimination in Singapore. Viruses 2022; 14:v14122662. [PMID: 36560666 PMCID: PMC9786948 DOI: 10.3390/v14122662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 11/30/2022] Open
Abstract
Japanese encephalitis virus (JEV) is an important arbovirus in Asia that can cause serious neurological disease. JEV is transmitted by mosquitoes in an enzootic cycle involving porcine and avian reservoirs, in which humans are accidental, dead-end hosts. JEV is currently not endemic in Singapore, after pig farming was abolished in 1992; the last known human case was reported in 2005. However, due to its location along the East-Asian Australasian Flyway (EAAF), Singapore is vulnerable to JEV re-introduction from the endemic regions. Serological and genetic evidence in the last decade suggests JEV's presence in the local fauna. In the present study, we report the genetic characterization and the first isolation of JEV from 3214 mosquito pools consisting of 41,843 Culex mosquitoes, which were trapped from April 2014 to May 2021. The findings demonstrated the presence of genotype I of JEV (n = 10), in contrast to the previous reports of the presence of genotype II of JEV in Singapore. The genetic analyses also suggested that JEV has entered Singapore on several occasions and has potentially established an enzootic cycle in the local fauna. These observations have important implications in the risk assessment and the control of Japanese encephalitis in non-endemic countries, such as Singapore, that are at risk for JEV transmission.
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Aure WE, Sayama Y, Saito-Obata M, Salazar NP, Malbas FF, Galang HO, Imamura T, Zuasula CL, Oshitani H. Japanese encephalitis virus genotype III from mosquitoes in Tarlac, Philippines. IJID REGIONS 2022; 4:59-65. [PMID: 36093364 PMCID: PMC9453045 DOI: 10.1016/j.ijregi.2022.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 05/12/2022] [Accepted: 05/12/2022] [Indexed: 11/27/2022]
Abstract
Japanese encephalitis is endemic in the Philippines. Japanese encephalitis virus genotype III was detected in Culex tritaeniorhynchus. Mosquitoes breed in inundated rice fields close to human habitation. Epidemiological surveillance and immunization of children are identified needs.
Objectives The aim of this study was to investigate the presence of Japanese encephalitis virus (JEV) in a rice-farming community in the Philippines and to determine its implications regarding the epidemiology of viral encephalitides in the Asia-Pacific Region. Methods Mosquitoes were collected monthly from animal-baited traps close to flooded rice fields in two barangays (villages) in the Municipality of San Jose, Tarlac Province in Luzon, from May 2009 to July 2010. Virus was detected by nested reverse transcription PCR. Phylogenetic analysis of the amplified virus envelope gene was done using the maximum-likelihood method. Results A total of 28 700 known vector mosquitoes were collected, namely Culex vishnui, Culex fuscocephala, Culex tritaeniorhynchus, and Culex gelidus. JEV genotype III was detected in C. tritaeniorhynchus, belonging to the same genotype but form a different clade from those reported in the 1980s and in 2020 in this country. Conclusions Japanese encephalitis is associated with rice cultivation and the presence of infected mosquitoes in Tarlac, Philippines. It remains to be seen whether the observed genetic shift of genotype III to genotype I in Asia will in time have an impact on the epidemiology of Japanese encephalitis in the Philippines. For long-term disease control, regular surveillance and Japanese encephalitis immunization in children and travelers in high risk areas are recommended.
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Putra IGAA, Adi AAAM, Astawa INM, Kardena IM, Wandia IN, Soma IG, Brotcorne F, Fuentes A. First survey on seroprevalence of Japanese encephalitis in long-tailed macaques (Macaca fascicularis) in Bali, Indonesia. Vet World 2022; 15:1341-1346. [PMID: 35765485 PMCID: PMC9210850 DOI: 10.14202/vetworld.2022.1341-1346] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 04/18/2022] [Indexed: 01/20/2023] Open
Abstract
Background and Aim: Japanese encephalitis (JE) is a zoonotic infectious inflammatory brain disease caused by the JE virus (JEV). Considerable research into the seroprevalence of JE in domestic animals has been conducted, but there have been no reports of its occurrence in wild animals, including long-tailed macaques (Macaca fascicularis). This study aimed to estimate the seroprevalence of JEV infection and its determinants in long-tailed macaques in Bali and the prevalence of mosquito vectors. Materials and Methods: Blood samples (3 mL) were collected from a population of M. fascicularis (92 heads) inhabiting a small forest with irrigated rice field nearby (wetland area) in Ubud, Gianyar, and from two populations in dryland areas with no wet rice field (Uluwatu, Badung, and Nusa Penida, Bali Province, Indonesia). The collected sera were tested for antibodies against JEV using a commercially available enzyme-linked immunosorbent assay kit (qualitative monkey JE Immunoglobulin G antibody kit). The seropositivity of the antibodies was then compared based on different variables, namely, habitat type, age, and sex. Results: The seroprevalence of the JEV antibodies in all the samples tested was found to be 41.3%. The seropositivity of the monkey serum samples collected from the wetland area was 46.4%, which was higher than the seropositivity of the sera samples collected from the dried field areas (1.25%). Monkey sera collected from the wetland areas were 6.1 times (odds ratio [OR]: 6.1; 95% confidence interval [CI]: 0.71-51.5, p>0.05) more likely to be seropositive compared to the monkey sera collected from the dried field areas. Meanwhile, female monkeys were 1.79 times (OR: 1.79; 95% CI: 0.76-4.21; p>0.05) more likely to be seropositive to JEV than males. Similarly, juvenile monkeys were 2.38 times (OR: 2.38; 95% CI: 0.98-5.79); p>0.05) more likely to be seropositive against the JEV than adult monkeys. However, none of these differences achieved statistical significance. Regarding the JEV mosquito vector collection, more Culex mosquitoes were found in the samples from the wetland areas than from the dried field areas. Conclusion: The study confirms the existence of JEV infection in long-tailed macaques in Bali. There were patterned seropositivity differences based on habitat, age, and sex of the monkeys, but these were not significant. The possibility of monkeys as a JEV reservoir and the presence of the mosquitoes as the JEV vector are suggested but require more study to confirm.
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Affiliation(s)
- I Gusti Agung Arta Putra
- Laboratory of Animal Anatomy and Physiology, Faculty of Animal Husbandry, Udayana University, Kampus Bukit, Jimbaran, Badung, Bali, Indonesia; Primate Research Center, Udayana University, Kampus Bukit, Jimbaran, Badung, Bali, Indonesia
| | - Anak Agung Ayu Mirah Adi
- Laboratory of Veterinary Pathology, Faculty of Veterinary Medicine, Udayana University, Kampus Sudirman, Jalan PB Sudirman, Denpasar, Bali, Indonesia
| | - I Nyoman Mantik Astawa
- Laboratory of Veterinary Virology, Faculty of Veterinary Medicine, Udayana University, Kampus Sudirman, Jalan PB Sudirman, Denpasar, Bali, Indonesia
| | - I Made Kardena
- Laboratory of Veterinary Pathology, Faculty of Veterinary Medicine, Udayana University, Kampus Sudirman, Jalan PB Sudirman, Denpasar, Bali, Indonesia
| | - I Nengah Wandia
- Primate Research Center, Udayana University, Kampus Bukit, Jimbaran, Badung, Bali, Indonesia
| | - I Gede Soma
- Primate Research Center, Udayana University, Kampus Bukit, Jimbaran, Badung, Bali, Indonesia
| | - Fany Brotcorne
- Research Unit SPHERES, Department of Biology, Ecology, and Evolution, University of Liege, Belgium
| | - Agustin Fuentes
- Department of Anthropology, Princeton University, 123 Aaron Burr Hall, Princeton NJ 08544, United States
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P. MNP, D. RP, G. S, K. AAP, K. SM, A. SP, P. R, V. S, Dasgupta S, Krishnan J, Ishtiaq F. Island biogeography and human practices drive ecological connectivity in mosquito species richness in the Lakshadweep Archipelago. Sci Rep 2022; 12:8060. [PMID: 35577864 PMCID: PMC9110355 DOI: 10.1038/s41598-022-11898-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 04/26/2022] [Indexed: 11/11/2022] Open
Abstract
Mosquitoes are globally distributed and adapted to a broad range of environmental conditions. As obligatory hosts of many infectious pathogens, mosquito abundance and distribution are primarily determined by the presence and quality of larval habitats. To understand the dynamics and productivity of larval habitats in changing island environments, we conducted a four-month mosquito survey across ten inhabited islands in the Lakshadweep archipelago. Using fine-resolution larval habitat mapping, we recorded 7890 mosquitoes representing 13 species and 7 genera. Of these, four species comprised 95% of the total collections—Aedes albopictus (Stegomyia) was the dominant species followed by Armigeres subalbatus, Culex quinquefasciatus and Malaya genurostris. We found larval species richness was positively associated with the island area and mosquito larval richness (Chao1 estimator) was higher in artificial habitats than in natural habitats. Furthermore, mosquito species composition did not deteriorate with distance between islands. Mosquito abundance by species was associated with microclimatic variables—pH and temperature. We detected co-existence of multiple species at a micro-habitat level with no evidence of interactions like competition or predation. Our study analyzed and identified the most productive larval habitats –discarded plastic container and plastic drums contributing to high larval indices predicting dengue epidemic across the Lakshadweep islands. Our data highlight the need to devise vector control strategies by removal of human-induced plastic pollution (household waste) which is a critical driver of disease risk.
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Van den Eynde C, Sohier C, Matthijs S, De Regge N. Japanese Encephalitis Virus Interaction with Mosquitoes: A Review of Vector Competence, Vector Capacity and Mosquito Immunity. Pathogens 2022; 11:317. [PMID: 35335641 PMCID: PMC8953304 DOI: 10.3390/pathogens11030317] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 02/28/2022] [Accepted: 03/01/2022] [Indexed: 02/01/2023] Open
Abstract
Japanese encephalitis virus (JEV) is a mosquito-borne zoonotic flavivirus and a major cause of human viral encephalitis in Asia. We provide an overview of the knowledge on vector competence, vector capacity, and immunity of mosquitoes in relation to JEV. JEV has so far been detected in more than 30 mosquito species. This does not necessarily mean that these species contribute to JEV transmission under field conditions. Therefore, vector capacity, which considers vector competence, as well as environmental, behavioral, cellular, and biochemical variables, needs to be taken into account. Currently, 17 species can be considered as confirmed vectors for JEV and 10 other species as potential vectors. Culex tritaeniorhynchus and Culex annulirostris are considered primary JEV vectors in endemic regions. Culex pipiens and Aedes japonicus could be considered as potentially important vectors in the case of JEV introduction in new regions. Vector competence is determined by various factors, including vector immunity. The available knowledge on physical and physiological barriers, molecular pathways, antimicrobial peptides, and microbiome is discussed in detail. This review highlights that much remains to be studied about vector immunity against JEV in order to identify novel strategies to reduce JEV transmission by mosquitoes.
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Affiliation(s)
- Claudia Van den Eynde
- Exotic Viruses and Particular Diseases, Sciensano, Groeselenberg 99, 1180 Brussels, Belgium; (C.S.); (N.D.R.)
| | - Charlotte Sohier
- Exotic Viruses and Particular Diseases, Sciensano, Groeselenberg 99, 1180 Brussels, Belgium; (C.S.); (N.D.R.)
| | - Severine Matthijs
- Enzootic, Vector-Borne and Bee Diseases, Sciensano, Groeselenberg 99, 1180 Brussels, Belgium;
| | - Nick De Regge
- Exotic Viruses and Particular Diseases, Sciensano, Groeselenberg 99, 1180 Brussels, Belgium; (C.S.); (N.D.R.)
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15
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Xu C, Zhang W, Pan Y, Wang G, Yin Q, Fu S, Li F, He Y, Xu S, Wang Z, Liang G, Nie K, Wang H. A Bibliometric Analysis of Global Research on Japanese Encephalitis From 1934 to 2020. Front Cell Infect Microbiol 2022; 12:833701. [PMID: 35155284 PMCID: PMC8829047 DOI: 10.3389/fcimb.2022.833701] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 01/04/2022] [Indexed: 12/13/2022] Open
Abstract
Japanese encephalitis (JE) is a mosquito-borne disease caused by the Japanese encephalitis virus (JEV). The disease is mainly an epidemic in Asia and has been studied for nearly 90 years. To evaluate the research trends of JE, 3,023 English publications between 1934 and 2020 were retrieved and analyzed from the Web of Science database using indicators for publication, country or territory, citation, journal, author and affiliation, keyword co-occurrence cluster, and strongest citation bursts detection. The results of the bibliometric analysis and the visualization tools show that the number of annual publications on JE has been increasing. JE has been continuously studied in the USA and also many Asian countries, such as Japan, China, India, and South Korea; however, only a few publications have high citations. The main research groups of JE in the last 5 years were in China, Japan, and the UK. The keyword co-occurrence analysis and the strongest citation bursts detection revealed that most studies focused on the pathogenic mechanism of JEV, control of outbreaks, and immunization with JE vaccine. The research maps on JE obtained by our analysis are expected to help researchers effectively explore the disease.
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Affiliation(s)
- Chongxiao Xu
- Department of Arboviruses, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Weijia Zhang
- Department of Arboviruses, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Yuefeng Pan
- Saint John’s Preparatory School, Collegeville, MN, United States
| | - Guowei Wang
- School of Clinical Medicine, Ningxia Medical University, Yinchuan, China
| | - Qikai Yin
- Department of Arboviruses, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Shihong Fu
- Department of Arboviruses, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Fan Li
- Department of Arboviruses, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Ying He
- Department of Arboviruses, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Songtao Xu
- Department of Arboviruses, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Zhenhai Wang
- Department of Neurology, General Hospital of Ningxia Medical University, Engineering Research Center for Diagnosis and Treatment of Ningxia Nervous System Diseases, Yinchuan, China
| | - Guodong Liang
- Department of Arboviruses, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Kai Nie
- Department of Arboviruses, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, China
- *Correspondence: Huanyu Wang, ; Kai Nie,
| | - Huanyu Wang
- Department of Arboviruses, NHC Key Laboratory of Biosafety, National Institute for Viral Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, China
- Chinese Center for Disease Control and Prevention Wuhan Institute of Virology, Chinese Academy of Sciences Joint Research Center for Emerging Infectious Diseases and Biosafety, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China
- *Correspondence: Huanyu Wang, ; Kai Nie,
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16
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Effectiveness of Live-Attenuated Genotype III Japanese Encephalitis Viral Vaccine against Circulating Genotype I Viruses in Swine. Viruses 2022; 14:v14010114. [PMID: 35062317 PMCID: PMC8778556 DOI: 10.3390/v14010114] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/02/2022] [Accepted: 01/07/2022] [Indexed: 01/15/2023] Open
Abstract
Expansion of genotype I (GI) Japanese encephalitis viruses (JEV) has resulted in the replacement of the dominant genotype III (GIII) viruses, raising serious public health concerns for using GIII virus-derived vaccines to effectively control JEV epidemics. Therefore, this study used swine as the model to estimate the effectiveness of GIII live-attenuated vaccine against GI virus infection by comparing the incidence of stillbirth/abortion in gilts from vaccinated and non-vaccinated pig farms during the GI-circulation period. In total, 389 and 213 litters of gilts were recorded from four vaccinated and two non-vaccinated pig farms, respectively. All viruses detected in the aborted fetuses and mosquitoes belonged to the GI genotype during the study period. We thus estimated that the vaccine effectiveness of GIII live-attenuated vaccine against GI viruses in naive gilts based on the overall incidence of stillbirth/abortion and incidence of JEV-confirmed stillbirth/abortion was 65.5% (50.8–75.7%) and 74.7% (34.5–90.2%), respectively. In contrast to previous estimates, the GIII live-attenuated vaccine had an efficacy of 95.6% (68.3–99.4%) to prevent the incidence of stillbirth/abortion during the GIII-circulating period. These results indicate that the vaccine effectiveness of GIII live-attenuated JEV vaccine to prevent stillbirth/abortion caused by GI viruses is lower than that against GIII viruses.
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17
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Chiou SS, Chen JM, Chen YY, Chia MY, Fan YC. The feasibility of field collected pig oronasal secretions as specimens for the virologic surveillance of Japanese encephalitis virus. PLoS Negl Trop Dis 2021; 15:e0009977. [PMID: 34860839 PMCID: PMC8673640 DOI: 10.1371/journal.pntd.0009977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 12/15/2021] [Accepted: 11/05/2021] [Indexed: 11/24/2022] Open
Abstract
Virologic surveillance of Japanese encephalitis virus (JEV) relies on collecting pig blood specimens and adult mosquitoes in the past. Viral RNAs extracted from pig blood specimens suffer from low detecting positivity by reverse transcription PCR (RT-PCR). The oronasal transmission of the virus has been demonstrated in experimentally infected pigs. This observation suggested oronasal specimens could be useful source in the virus surveillance. However, the role of this unusual route of transmission remains unproven in the operational pig farm. In this study, we explore the feasibility of using pig oronasal secretions collected by chewing ropes to improve the positivity of detection in commercial pig farms. The multiplex genotype-specific RT-PCR was used in this study to determine and compare the positivity of detecting JEV viral RNAs in pig’s oronasal secretions and blood specimens, and the primary mosquito vector. Oronasal specimens had the overall positive rate of 6.0% (95% CI 1.3%–16.6%) (3/50) to 10.0% (95% CI 2.1%–26.5%) (3/30) for JEV during transmission period despite the negative results of all blood-derived specimens (n = 2442). Interestingly, pig oronasal secretions and female Culex tritaeniorhynchus mosquito samples collected from the same pig farm showed similar viral RNA positive rates, 10.0% (95% CI 2.1%–26.5%) (3/30) and 8.9% (95% CI 2.5%–21.2%) (4/45), respectively (p> 0.05). Pig oronasal secretion-based surveillance revealed the seasonality of viral activity and identified closely related genotype I virus derived from the mosquito isolates. This finding indicates oronasal secretion-based RT-PCR assay can be a non-invasive, alternative method of implementing JEV surveillance in the epidemic area prior to the circulation of virus-positive mosquitoes. Mosquito-borne Japanese encephalitis virus (JEV) has either endemic or seasonal patterns of transmission in Asia and Australia. Most hosts infected by the virus remains asymptomatic but can result in severe encephalitis in humans and horses, and abortion or stillbirth in pregnant sows. Isolation of virus in adult mosquitoes or pig seroconversion has been used as an early indicator of upcoming JE outbreak in humans. Genotype identification of the virus is important since current human and domestic animal vaccines are all genotype III (GIII) specific. GIII vaccine elicited immunity has reduced cross-protections to genotypes other than GIII. Our virologic surveillance using pig’s oronasal secretion detected higher prevalence and earlier genotype I virus activity than using pig’s blood and mosquitoes, respectively. This proposed surveillance tool might be more effective that will allow the public health agency to properly implement the preventive measures, such as implementing mosquito control, encouraging booster vaccination, and encouraging the use of mosquito repellent, to reduce the impact of upcoming outbreak. Collection of pig’s oronasal secretion is non-invasive to pigs and less technically demanding to operators. Thus we propose the use of pig’s oronasal secretions as the novel source of specimens for virologic surveillance to replace the traditional pig blood or adult mosquito specimens to monitor and control JE outbreak/epidemic in the future.
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Affiliation(s)
- Shyan-Song Chiou
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Jo-Mei Chen
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Yi-Ying Chen
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Min-Yuan Chia
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Yi-Chin Fan
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
- * E-mail:
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18
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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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19
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Agboli E, Zahouli JBZ, Badolo A, Jöst H. Mosquito-Associated Viruses and Their Related Mosquitoes in West Africa. Viruses 2021; 13:v13050891. [PMID: 34065928 PMCID: PMC8151702 DOI: 10.3390/v13050891] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 12/13/2022] Open
Abstract
Mosquito-associated viruses (MAVs), including mosquito-specific viruses (MSVs) and mosquito-borne (arbo)viruses (MBVs), are an increasing public, veterinary, and global health concern, and West Africa is projected to be the next front for arboviral diseases. As in-depth knowledge of the ecologies of both western African MAVs and related mosquitoes is still limited, we review available and comprehensive data on their diversity, abundance, and distribution. Data on MAVs’ occurrence and related mosquitoes were extracted from peer-reviewed publications. Data on MSVs, and mosquito and vertebrate host ranges are sparse. However, more data are available on MBVs (i.e., dengue, yellow fever, chikungunya, Zika, and Rift Valley fever viruses), detected in wild and domestic animals, and humans, with infections more concentrated in urban areas and areas affected by strong anthropogenic changes. Aedes aegypti, Culex quinquefasciatus, and Aedes albopictus are incriminated as key arbovirus vectors. These findings outline MAV, related mosquitoes, key knowledge gaps, and future research areas. Additionally, these data highlight the need to increase our understanding of MAVs and their impact on host mosquito ecology, to improve our knowledge of arbovirus transmission, and to develop specific strategies and capacities for arboviral disease surveillance, diagnostic, prevention, control, and outbreak responses in West Africa.
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Affiliation(s)
- Eric Agboli
- Molecular Biology and Immunology Department, Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany;
- Department of Epidemiology and Biostatistics, School of Public Health, University of Health and Allied Sciences, Ho PMB 31, Ghana
| | - Julien B. Z. Zahouli
- Centre d’Entomologie Médicale et Vétérinaire, Université Alassane Ouattara, Bouake, 27 BP 529 Abidjan 27, Cote D’Ivoire;
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Département de Recherche et Développement, 01 BP 1303 Abidjan 01, Cote D’Ivoire
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland
| | - Athanase Badolo
- Laboratory of Fundamental and Applied Entomology, Universitée Joseph Ki-Zerbo, Ouagadougou 03 BP 7021, Burkina Faso;
| | - Hanna Jöst
- Bernhard Nocht Institute for Tropical Medicine, WHO Collaborating Centre for Arbovirus and Hemorrhagic Fever Reference and Research, 20359 Hamburg, Germany
- Correspondence:
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20
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Thongsripong P, Chandler JA, Kittayapong P, Wilcox BA, Kapan DD, Bennett SN. Metagenomic shotgun sequencing reveals host species as an important driver of virome composition in mosquitoes. Sci Rep 2021; 11:8448. [PMID: 33875673 PMCID: PMC8055903 DOI: 10.1038/s41598-021-87122-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 03/18/2021] [Indexed: 02/02/2023] Open
Abstract
High-throughput nucleic acid sequencing has greatly accelerated the discovery of viruses in the environment. Mosquitoes, because of their public health importance, are among those organisms whose viromes are being intensively characterized. Despite the deluge of sequence information, our understanding of the major drivers influencing the ecology of mosquito viromes remains limited. Using methods to increase the relative proportion of microbial RNA coupled with RNA-seq we characterize RNA viruses and other symbionts of three mosquito species collected along a rural to urban habitat gradient in Thailand. The full factorial study design allows us to explicitly investigate the relative importance of host species and habitat in structuring viral communities. We found that the pattern of virus presence was defined primarily by host species rather than by geographic locations or habitats. Our result suggests that insect-associated viruses display relatively narrow host ranges but are capable of spreading through a mosquito population at the geographical scale of our study. We also detected various single-celled and multicellular microorganisms such as bacteria, alveolates, fungi, and nematodes. Our study emphasizes the importance of including ecological information in viromic studies in order to gain further insights into viral ecology in systems where host specificity is driving both viral ecology and evolution.
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Affiliation(s)
- Panpim Thongsripong
- Department of Microbiology, Institute for Biodiversity Science and Sustainability, California Academy of Sciences, San Francisco, CA, USA.
| | - James Angus Chandler
- Department of Microbiology, Institute for Biodiversity Science and Sustainability, California Academy of Sciences, San Francisco, CA, USA
| | - Pattamaporn Kittayapong
- Center of Excellence for Vectors and Vector-Borne Diseases, Faculty of Science, Mahidol University At Salaya, Nakhon Pathom, Thailand
| | - Bruce A Wilcox
- Global Health Group International, ASEAN Institute for Health Development, Mahidol University At Salaya, Nakhon Pathom, Thailand
| | - Durrell D Kapan
- Department of Entomology and Center for Comparative Genomics, Institute for Biodiversity Sciences and Sustainability, California Academy of Sciences, San Francisco, CA, USA
- Center for Conservation and Research Training, Pacific Biosciences Research Center, University of Hawai'i At Manoa, Honolulu, HI, USA
| | - Shannon N Bennett
- Department of Microbiology, Institute for Biodiversity Science and Sustainability, California Academy of Sciences, San Francisco, CA, USA
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21
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Bourke BP, Wilkerson RC, Linton YM. Molecular species delimitation reveals high diversity in the mosquito Anopheles tessellatus Theobald, 1901 (Diptera, Culicidae) across its range. Acta Trop 2021; 215:105799. [PMID: 33358735 DOI: 10.1016/j.actatropica.2020.105799] [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: 10/30/2020] [Revised: 12/11/2020] [Accepted: 12/15/2020] [Indexed: 10/22/2022]
Abstract
Anopheles tessellatus is a potentially important vector found across South, East and Southeast Asia. While it was formerly considered a formidable vector of human Plasmodium and filarial parasites in the Maldives, and of lesser importance as a vector of human Plasmodium in Sri Lanka and parts of Indonesia, it is currently of little or unknown health importance in many other parts of its range. This study describes the genetic diversity and evolutionary relationships among An. tessellatus populations in nine Asian countries at the COI gene using maximum-likelihood and Bayesian phylogenetic inference tree and cluster-based species delimitation approaches. These analyses reveal exceptional levels of genetic diversity in An. tessellatus populations across its known range, and identify up to six putative species in the newly determined Tessellatus Complex. The existence of such cryptic diversity has potentially important consequences for vector management and disease control. Differences in the ecologies and life histories among these species may have considerable impact on vectorial capacity and may go some way towards explaining why An. tessellatus s.l. has such varying degrees of public health importance across its range.
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22
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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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23
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Li S, Jiang F, Lu H, Kang X, Wang Y, Zou Z, Wen D, Zheng A, Liu C, Liu Q, Kang L, Xia Q, Cui F. Mosquito Diversity and Population Genetic Structure of Six Mosquito Species From Hainan Island. Front Genet 2020; 11:602863. [PMID: 33193749 PMCID: PMC7658394 DOI: 10.3389/fgene.2020.602863] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 10/12/2020] [Indexed: 11/13/2022] Open
Abstract
Hainan is a tropical island in southern China with abundant mosquito species, putting Hainan at risk of mosquito-borne virus disease outbreaks. The population genetic diversity of most mosquito species on Hainan Island remains elusive. In this study, we report the diversity of mosquito species and the genetic diversity of the predominant species on Hainan. Field populations of adults or larvae were collected from 12 regions of Hainan Island in 2018 and 2019. A fragment of the mitochondrial cytochrome c oxidase subunit I (coxI) gene was sequenced from 1,228 mosquito samples and used for species identification and genetic diversity analysis. Twenty-three known mosquito species from the genera Aedes, Armigeres, Culex, Mansonia, and Anopheles and nine unconfirmed mosquito species were identified. Aedes albopictus, Armigeres subalbatus, and Culex pipiens quinquefasciatus were the most prevalent mosquito species on Hainan. The regions north of Danzhou, Tunchang, and Qionghai exhibited high mosquito diversity (26 species). The order of the total haplotype diversity and nucleotide diversity of the populations from high to low was as follows: Culex tritaeniorhynchus, Ar. subalbatus, Culex pallidothorax, Culex gelidus, Ae. albopictus, and C. p. quinquefasciatus. Tajima's D and Fu's F s tests showed that Ae. albopictus, C. p. quinquefasciatus, C. tritaeniorhynchus, and C. gelidus had experienced population expansion, while the Ar. subalbatus and C. pallidothorax populations were in genetic equilibrium. Significant genetic differentiation existed in the overall populations of Ae. albopictus, Ar. subalbatus, C. p. quinquefasciatus, and C. pallidothorax. The Ae. albopictus populations on Hainan were characterized by frequent gene exchange with populations from Guangdong and four other tropical countries, raising the risk of viral disease outbreaks in these regions. Two subgroups were reported in the Ar. subalbatus populations for the first time. Our findings may have important implications for vector control on Hainan Island.
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Affiliation(s)
- Siping Li
- Key Laboratory of Tropical Translational Medicine of Ministry of Education and School of Tropical Medicine and Laboratory Medicine, Hainan Medical University, Haikou, China
| | - Feng Jiang
- Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China
| | - Hong Lu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xun Kang
- Key Laboratory of Tropical Translational Medicine of Ministry of Education and School of Tropical Medicine and Laboratory Medicine, Hainan Medical University, Haikou, China
| | - Yanhong Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Zhen Zou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Dan Wen
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Aihua Zheng
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Chunxiang Liu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Qiyong Liu
- State Key Laboratory of Infectious Diseases Prevention and Control, WHO Collaborating Centre for Vector Surveillance and Management, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Le Kang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China
| | - Qianfeng Xia
- Key Laboratory of Tropical Translational Medicine of Ministry of Education and School of Tropical Medicine and Laboratory Medicine, Hainan Medical University, Haikou, China
| | - Feng Cui
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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Hameed M, Khan S, Xu J, Zhang J, Wang X, Di D, Chen Z, Naveed Anwar M, Wahaab A, Ma X, Nawaz M, Liu K, Li B, Shao D, Qiu Y, Wei J, Ma Z. Detection of Japanese encephalitis virus in mosquitoes from Xinjiang during next-generation sequencing arboviral surveillance. Transbound Emerg Dis 2020; 68:467-476. [PMID: 32614516 DOI: 10.1111/tbed.13697] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 06/14/2020] [Accepted: 06/16/2020] [Indexed: 01/10/2023]
Abstract
A total of 548 mosquitoes were collected from different animal farms located near to highly populated cities in Xinjiang and were subjected to metagenomic next-generation sequencing (mNGS). The mNGS data demonstrated that 18,842 (XJ1 strain) and 1,077 (XJ2 strain) of Japanese encephalitis virus (JEV)-related reads were detected in XJ1 and XJ2 mosquito samples collected from Wushi and Wensu counties of Aksu area, which accounted for 0.032% and 0.006% of the total clean reads generated from XJ1 and XJ2 samples, respectively. The Bayesian molecular phylogenetic analysis suggested that XJ1 and XJ2 strains belonged to JEV genotype III and were clustered with JEV strains isolated in China. Notably, Bayesian molecular time line phylogeny revealed that XJ1 strain shared its MRCA with JEV GSS strain about 67 YA, suggesting that XJ1 strain likely originated from linages closely related to GSS strain and spread to Xinjiang later. Overall, these findings suggest that Xinjiang was probably not free from JEV, and thus, a further surveillance of JEV is required in Xinjiang.
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Affiliation(s)
- Muddassar Hameed
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Sawar Khan
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Jinpeng Xu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Junjie Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Xin Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Di Di
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Zheng Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, PR China
| | - Muhammad Naveed Anwar
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Abdul Wahaab
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Xiaochun Ma
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Mohsin Nawaz
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Ke Liu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Beibei Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Donghua Shao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Yafeng Qiu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Jianchao Wei
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Zhiyong Ma
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
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Chapman GE, Sherlock K, Hesson JC, Blagrove MSC, Lycett GJ, Archer D, Solomon T, Baylis M. Laboratory transmission potential of British mosquitoes for equine arboviruses. Parasit Vectors 2020; 13:413. [PMID: 32787904 PMCID: PMC7425075 DOI: 10.1186/s13071-020-04285-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 08/03/2020] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND There has been no evidence of transmission of mosquito-borne arboviruses of equine or human health concern to date in the UK. However, in recent years there have been a number of outbreaks of viral diseases spread by vectors in Europe. These events, in conjunction with increasing rates of globalisation and climate change, have led to concern over the future risk of mosquito-borne viral disease outbreaks in northern Europe and have highlighted the importance of being prepared for potential disease outbreaks. Here we assess several UK mosquito species for their potential to transmit arboviruses important for both equine and human health, as measured by the presence of viral RNA in saliva at different time points after taking an infective blood meal. RESULTS The following wild-caught British mosquitoes were evaluated for their potential as vectors of zoonotic equine arboviruses: Ochlerotatus detritus for Venezuelan equine encephalitis virus (VEEV) and Ross River virus (RRV), and Culiseta annulata and Culex pipiens for Japanese encephalitis virus (JEV). Production of RNA in saliva was demonstrated at varying efficiencies for all mosquito-virus pairs. Ochlerotatus detritus was more permissive for production of RRV RNA in saliva than VEEV RNA. For RRV, 27.3% of mosquitoes expectorated viral RNA at 7 days post-infection when incubated at 21 °C and 50% at 24 °C. Strikingly, 72% of Cx. pipiens produced JEV RNA in saliva after 21 days at 18 °C. For some mosquito-virus pairs, infection and salivary RNA titres reduced over time, suggesting unstable infection dynamics. CONCLUSIONS This study adds to the number of Palaearctic mosquito species that demonstrate expectoration of viral RNA, for arboviruses of importance to human and equine health. This work adds to evidence that native mosquito species should be investigated further for their potential to vector zoonotic mosquito-borne arboviral disease of equines in northern Europe. The evidence that Cx. pipiens is potentially an efficient laboratory vector of JEV at temperatures as low as 18 °C warrants further investigation, as this mosquito is abundant in cooler regions of Europe and is considered an important vector for West Nile Virus, which has a comparable transmission ecology.
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Affiliation(s)
- Gail E. Chapman
- Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Ken Sherlock
- Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Jenny C. Hesson
- Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Marcus S. C. Blagrove
- Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Gareth J. Lycett
- Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Debra Archer
- Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - Tom Solomon
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
- Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK
- Walton Centre NHS Foundation Trust, Liverpool, UK
| | - Matthew Baylis
- Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
- Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK
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Li CX, Guo XX, Deng YQ, Liu QM, Xing D, Sun AJ, Wu Q, Dong YD, Zhang YM, Zhang HD, Cao WC, Qin CF, Zhao TY. Susceptibility of Armigeres subalbatus Coquillett (Diptera: Culicidae) to Zika virus through oral and urine infection. PLoS Negl Trop Dis 2020; 14:e0008450. [PMID: 32628662 PMCID: PMC7402514 DOI: 10.1371/journal.pntd.0008450] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 08/04/2020] [Accepted: 06/03/2020] [Indexed: 12/28/2022] Open
Abstract
Background Zika virus (ZIKV) disease outbreaks have been occurring in South America since 2015, and has spread to North America. Because birth defects and cases of Guillain Barré have been associated with infection with ZIKV, this has drawn global attention. ZIKV is generally considered an Aedes-transmitted pathogen. The transmission of ZIKV through blood by Aedes mosquito bites has been recognized as the major transmission route. However, it is not clear whether there are other transmission routes that can cause viral infection in mosquitos. The aim of the present study is to describe the susceptibility of Armigeres subalbatus, which often develop in human waste lagoons, to ZIKV, through oral infection in adult mosquitoes and urine infection in larvae. Methodology/Principal findings Five-day-old female Ar. subalbatus ingested infectious blood meals containing ZIKV. After 4, 7, and 10 days of ingesting infectious blood meals, ZIKV could be detected in the midguts, salivary glands, ovaries, and collected saliva of mosquitoes. The ZIKV infection rate (IR) on day 10 reached 40% in salivary glands and 13% in saliva, indicating that these mosquitoes were able to transmit ZIKV. In addition, ZIKV infection was also discovered in mosquito ovaries, suggesting the possibility of vertical transmission of virus. Moreover, Ar. subalbatus transmitted ZIKV to infant mice bitten by infectious mosquitoes. In a second experiment, 1st-instar larvae of Ar. subalbatus were reared in water containing ZIKV and human urine. After pupation, pupae were placed in clean water and transferred to a mosquito cage for emergence. Although ZIKV RNA was detected in all of the larvae tested, ZIKV was not detected in the saliva of any adult Ar. subalbatus. Considering that there are more uncontrollable factors in nature than in the laboratory environment, the possibility that the virus is transmitted to adult mosquitoes via larvae is very small period. Conclusions/Significance Adult Ar. subalbatus could be infected with ZIKV and transmit ZIKV through mosquito bites. Therefore, in many rural areas in China and in undeveloped areas of other Asian countries, the management of human waste lagoons in the prevention and control of Zika disease should be considered. Corresponding adjustments and modifications should also be made in prevention and control strategies against ZIKV. Zika is a serious threat to global health since the outbreak in Brazil in 2015. Zika virus (ZIKV) is generally considered as an Aedes-transmitted pathogen. The transmission of ZIKV by mosquito bite has been recognized as the major transmission route. However, it is possible that some important potential vectors may not yet have been examined. Armigeres subalbatus is one of primary mosquito species in China, which could develop in human waste lagoons. In the study, through oral infection experiments, it was found that Ar. subalbatus could be infected with ZIKV and transmit ZIKV through mosquito bites. Therefore, in many rural areas in China and in undeveloped areas of other Asian countries, it is valid to consider that this mosquito species should be given enough attention in the prevention and control of Zika epidemic.
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Affiliation(s)
- Chun-xiao Li
- Department of Vector Biology and Control, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Xiao-xia Guo
- Department of Vector Biology and Control, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Yong-qiang Deng
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Qin-mei Liu
- Department of Vector Biology and Control, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Dan Xing
- Department of Vector Biology and Control, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Ai-juan Sun
- Department of Vector Biology and Control, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Qun Wu
- Department of Vector Biology and Control, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Yan-de Dong
- Department of Vector Biology and Control, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Ying-mei Zhang
- Department of Vector Biology and Control, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Heng-duan Zhang
- Department of Vector Biology and Control, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
| | - Wu-chun Cao
- Department of Epidemiology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
- * E-mail: (WCC); (CFQ); (TYZ)
| | - Cheng-feng Qin
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
- * E-mail: (WCC); (CFQ); (TYZ)
| | - Tong-yan Zhao
- Department of Vector Biology and Control, State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Beijing, China
- * E-mail: (WCC); (CFQ); (TYZ)
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Peng SH, Su CL, Chang MC, Hu HC, Yang SL, Shu PY. Genome Analysis of a Novel Tembusu Virus in Taiwan. Viruses 2020; 12:v12050567. [PMID: 32455871 PMCID: PMC7290467 DOI: 10.3390/v12050567] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/20/2020] [Accepted: 05/20/2020] [Indexed: 12/25/2022] Open
Abstract
We identified and isolated a novel Tembusu virus (TMUV) strain TP1906 (TMUV-TP1906) from a Culexannulus mosquito pool collected from the northern part of Taiwan in 2019. The TMUV-TP1906 genome is a 10,990-nucleotide-long, positive-sense, single-stranded RNA, consisting of a single open reading frame (ORF) encoding a polyprotein of 3425 amino acids, with 5′ and 3′ untranslated regions (UTRs) of 94 and 618 nucleotides, respectively. The nucleotide sequence of the TMUV-TP1906 of ORF exhibited 93.71% and 91.27% similarity with Sitiawan virus (STWV) and the TMUV prototype strain MM1775, respectively. The 3′-UTR variable region of TMUV-TP1906 showed nucleotide sequence divergence with other TMUV strains. Phylogenetic analysis of the complete ORF and polyprotein sequences revealed that TMUV-TP1906 is most closely related to STWV which causes encephalitis and retarded growth in chickens. We found that the TMUV-TP1906 caused a cytopathic effect (CPE) in the DF-1 chicken fibroblast cell line, while no apparent CPE was observed in Vero and C6/36 cells. In this study, we first identified and isolated a novel TMUV strain in Taiwan. In addition, to our knowledge, it is the first time that the TMUV strain was isolated from the Cx. annulus mosquitoes. Further study is warranted to investigate the host range and virulence of TMUV-TP1906.
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28
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Chang YH, Chiao DJ, Hsu YL, Lin CC, Wu HL, Shu PY, Chang SF, Chang JH, Kuo SC. Mosquito Cell-Derived Japanese Encephalitis Virus-Like Particles Induce Specific Humoral and Cellular Immune Responses in Mice. Viruses 2020; 12:v12030336. [PMID: 32204533 PMCID: PMC7150764 DOI: 10.3390/v12030336] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 03/12/2020] [Accepted: 03/18/2020] [Indexed: 12/13/2022] Open
Abstract
The Japanese encephalitis virus (JEV) is the major cause of an acute encephalitis syndrome in many Asian countries, despite the fact that an effective vaccine has been developed. Virus-like particles (VLPs) are self-assembled multi-subunit protein structures which possess specific epitope antigenicities related to corresponding native viruses. These properties mean that VLPs are considered safe antigens that can be used in clinical applications. In this study, we developed a novel baculovirus/mosquito (BacMos) expression system which potentially enables the scalable production of JEV genotype III (GIII) VLPs (which are secreted from mosquito cells). The mosquito-cell-derived JEV VLPs comprised 30-nm spherical particles as well as precursor membrane protein (prM) and envelope (E) proteins with densities that ranged from 30% to 55% across a sucrose gradient. We used IgM antibody-capture enzyme-linked immunosorbent assays to assess the resemblance between VLPs and authentic virions and thereby characterized the epitope specific antigenicity of VLPs. VLP immunization was found to elicit a specific immune response toward a balanced IgG2a/IgG1 ratio. This response effectively neutralized both JEV GI and GIII and elicited a mixed Th1/Th2 response in mice. This study supports the development of mosquito cell-derived JEV VLPs to serve as candidate vaccines against JEV.
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MESH Headings
- Animals
- Antibodies, Neutralizing/immunology
- Antibodies, Viral/immunology
- Cell Line
- Culicidae/virology
- Cytokines/metabolism
- Disease Models, Animal
- Encephalitis Virus, Japanese/immunology
- Encephalitis Virus, Japanese/ultrastructure
- Encephalitis, Japanese/immunology
- Encephalitis, Japanese/virology
- Enzyme-Linked Immunosorbent Assay
- Epitopes/immunology
- Fluorescent Antibody Technique
- Immunity, Cellular
- Immunity, Humoral
- Mice
- Neutralization Tests
- Vaccines, Virus-Like Particle/immunology
- Virion
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Affiliation(s)
- Yu-Hsiu Chang
- Institute of Preventive Medicine, National Defense Medical Center, Taipei 11490, Taiwan; (Y.-H.C.); (D.-J.C.); (Y.-L.H.); (C.-C.L.); (H.-L.W.); (J.-H.C.)
| | - Der-Jiang Chiao
- Institute of Preventive Medicine, National Defense Medical Center, Taipei 11490, Taiwan; (Y.-H.C.); (D.-J.C.); (Y.-L.H.); (C.-C.L.); (H.-L.W.); (J.-H.C.)
| | - Yu-Lin Hsu
- Institute of Preventive Medicine, National Defense Medical Center, Taipei 11490, Taiwan; (Y.-H.C.); (D.-J.C.); (Y.-L.H.); (C.-C.L.); (H.-L.W.); (J.-H.C.)
| | - Chang-Chi Lin
- Institute of Preventive Medicine, National Defense Medical Center, Taipei 11490, Taiwan; (Y.-H.C.); (D.-J.C.); (Y.-L.H.); (C.-C.L.); (H.-L.W.); (J.-H.C.)
- Department and Graduate Institute of Microbiology and Immunology, National Defense Medical Center, Taipei 11490, Taiwan
| | - Hsueh-Ling Wu
- Institute of Preventive Medicine, National Defense Medical Center, Taipei 11490, Taiwan; (Y.-H.C.); (D.-J.C.); (Y.-L.H.); (C.-C.L.); (H.-L.W.); (J.-H.C.)
| | - Pei-Yun Shu
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei 11561, Taiwan; (P.-Y.S.); (S.-F.C.)
| | - Shu-Fen Chang
- Center for Diagnostics and Vaccine Development, Centers for Disease Control, Ministry of Health and Welfare, Taipei 11561, Taiwan; (P.-Y.S.); (S.-F.C.)
| | - Jui-Huan Chang
- Institute of Preventive Medicine, National Defense Medical Center, Taipei 11490, Taiwan; (Y.-H.C.); (D.-J.C.); (Y.-L.H.); (C.-C.L.); (H.-L.W.); (J.-H.C.)
| | - Szu-Cheng Kuo
- Institute of Preventive Medicine, National Defense Medical Center, Taipei 11490, Taiwan; (Y.-H.C.); (D.-J.C.); (Y.-L.H.); (C.-C.L.); (H.-L.W.); (J.-H.C.)
- Department and Graduate Institute of Microbiology and Immunology, National Defense Medical Center, Taipei 11490, Taiwan
- Correspondence: ; Tel.: +886-2-8177-7038 (ext. 19946)
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Wang X, Guo S, Hameed M, Zhang J, Pang L, Li B, Qiu Y, Liu K, Shao D, Ma Z, Zhong D, Wei J, Li P. Rapid differential detection of genotype I and III Japanese encephalitis virus from clinical samples by a novel duplex TaqMan probe-based RT-qPCR assay. J Virol Methods 2020; 279:113841. [PMID: 32105753 DOI: 10.1016/j.jviromet.2020.113841] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/19/2020] [Accepted: 02/23/2020] [Indexed: 11/26/2022]
Abstract
Japanese Encephalitis (JE) is an acute infectious disease that threatens both human and pig populations throughout Asia. JE is caused by the Japanese Encephalitis Virus (JEV), of which genotype III (GIII) had been the most prevalent strain throughout Asia, but recent studies have shown that genotype I (GI) has replaced GIII as the predominant version. Pigs and mosquitoes play a primary role in JEV transmission. However, a method for the rapid differentiation between JEV G I and G III remains unavailable. This study aimed to establish a rapid JEV genotyping method using novel duplex TaqMan RT-qPCR assay.specific primer and probes located in the PrM/M gene that were able to specifically differentiate GI and GIII JEV, was selected as the duplex TaqMan RT-qPCR target.The specificity, sensitivity and reproducibility test of this assay were validated. The sensitivity of the assay was 10 genomic RNA copies for both GI and GIII JEV in field mosquito and pig samples,and more sensitive than the current methods. In addition, the novel assay can be completed in less than 1 h. Therefore, This duplex TaqMan RT-qPCR assay is a promising tool for rapid differential detection and epidemiology of GI and GIII JEV strains in China. The results showed that co-circulation of GI and GIII infections with GI infection being more prevalent in pigs or mosquitoes in eastern China.
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Affiliation(s)
- Xin Wang
- Yangtze University, Jingzhou, 434000, People's Republic of China; Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, People's Republic of China
| | - Shuang Guo
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, People's Republic of China
| | - Muddassar Hameed
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, People's Republic of China
| | - Junjie Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, People's Republic of China
| | - Linlin Pang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, People's Republic of China
| | - Beibei Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, People's Republic of China
| | - Yafeng Qiu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, People's Republic of China
| | - Ke Liu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, People's Republic of China
| | - Donghua Shao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, People's Republic of China
| | - Zhiyong Ma
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, People's Republic of China
| | - Dengke Zhong
- Shanghai Vocational and Technical College of Agriculture and Forestry, Shanghai, 201600, People's Republic of China.
| | - Jianchao Wei
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, People's Republic of China.
| | - Peng Li
- Yangtze University, Jingzhou, 434000, People's Republic of China.
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30
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Saxena SK, Kumar S, Haikerwal A. Animal Flaviviruses. EMERGING AND TRANSBOUNDARY ANIMAL VIRUSES 2020. [DOI: 10.1007/978-981-15-0402-0_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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31
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Functional Correlation between Subcellular Localizations of Japanese Encephalitis Virus Capsid Protein and Virus Production. J Virol 2019; 93:JVI.00612-19. [PMID: 31315991 DOI: 10.1128/jvi.00612-19] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/07/2019] [Indexed: 01/16/2023] Open
Abstract
The flavivirus capsid protein is considered to be essential for the formation of nucleocapsid complexes with viral genomic RNA at the viral replication organelle that appears on the endoplasmic reticulum (ER), as well as for incorporation into virus particles. However, this protein is also detected at the lipid droplet (LD) and nucleolus, and physiological roles of these off-site localizations are still unclear. In this study, we made a series of alanine substitution mutants of Japanese encephalitis virus (JEV) capsid protein that cover all polar and hydrophobic amino acid residues to identify the molecular surfaces required for virus particle formation and for localization at the LD and nucleolus. Five mutants exhibited a defect in the formation of infectious particles, and two of these mutants failed to be incorporated into the subviral particles (SVP). Three mutants lost the ability to localize to the nucleolus, and only a single mutant, with mutations at α2, was unable to localize to the LD. Unlike the cytoplasmic capsid protein, the nucleolar capsid protein was resistant to detergent treatment, and the α2 mutant was hypersensitive to detergent treatment. To scrutinize the relationship between these localizations and viral particle formation, we made eight additional alanine substitution mutants and found that all the mutants that did not localize at the LD or nucleolus failed to form normal viral particles. These results support the functional correlation between LD or nucleolus localization of the flaviviral capsid protein and the formation of infectious viral particles.IMPORTANCE This study is the first to report the comprehensive mutagenesis of a flavivirus capsid protein. We assessed the requirement of each molecular surface for infectious viral particle formation as well as for LD and nucleolar localization and found functional relationships between the subcellular localization of the virus capsid protein and infectious virus particle formation. We developed a system to independently assess the packaging of viral RNA and that of the capsid protein and found a molecular surface of the capsid protein that is crucial for packaging of viral RNA but not for packaging of the capsid protein itself. We also characterized the biochemical properties of capsid protein mutants and found that the capsid protein localizes at the nucleolus in a different manner than for its localization to the LD. Our comprehensive alanine-scanning mutagenesis study will aid in the development of antiflavivirus small molecules that can target the flavivirus capsid protein.
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Hameed M, Liu K, Anwar MN, Wahaab A, Safdar A, Di D, Boruah P, Xu J, Wang X, Li B, Zhu H, Nawaz M, Shao D, Qiu Y, Wei J, Ma Z. The emerged genotype I of Japanese encephalitis virus shows an infectivity similar to genotype III in Culex pipiens mosquitoes from China. PLoS Negl Trop Dis 2019; 13:e0007716. [PMID: 31557156 PMCID: PMC6762057 DOI: 10.1371/journal.pntd.0007716] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/16/2019] [Indexed: 12/14/2022] Open
Abstract
Japanese Encephalitis virus (JEV) is a zoonotic flavivirus that represents the most significant etiology of childhood viral neurological infections throughout the Asia. During the last 20 years, JEV genotype dominance has shifted from genotype III (GIII) to genotype I (GI). To date, the exact mechanism of this displacement is still not known. Culex (Cx.) mosquitoes are the most common species in China and play an essential role in maintaining JEV enzootic transmission cycle. In this study, we used Cx. pipiens mosquitoes from China as an in vivo mosquito model to explore if mosquitoes played a potential role in JEV genotype shift. We exposed female Cx. pipiens mosquitoes orally to either GI or GIII JEV strains. Midgut, whole mosquitoes, secondary organs, and salivary glands of JEV-infected mosquitoes were collected at 7 and 14 days of post infection (dpi) and subjected to measure the infection rate, replication kinetics, dissemination rate and transmission potential of the infected JEV strains in Cx. pipiens mosquitoes by 50% tissue culture infective dose assay. We found that Cx. pipiens mosquito was competent vector for both GI and GIII JEV infection, with similar infection rates and growth kinetics. After the establishment of infection, Cx. pipiens mosquitoes disseminated both JEV genotypes to secondary organs at similar rates of dissemination. A few GI-infected mosquito salivary glands (16.2%) were positive for GI virus, whereas GIII virus was undetectable in GIII-infected mosquito salivary glands at 7 dpi. However, 29.4% (5/17) and 36.3% (8/22) were positive for GI- and GIII-infected mosquito salivary glands at 14 dpi, respectively, showing an increase in JEV positive rate. No statistical difference in the transmission rate between GI- and GIII-infected mosquitoes was detected. Our experiment data demonstrated that GI and GIII viruses have similar infectivity in Cx. pipiens mosquitoes, suggesting that Cx. pipiens mosquitoes from China may not play a critical role in JEV genotype shift. Although the current data were obtained solely from Cx. pipiens mosquitoes, it is likely that the conclusion drawn could be extrapolated to the role of mosquitoes in JEV genotype shift.
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Affiliation(s)
- Muddassar Hameed
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Ke Liu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Muhammad Naveed Anwar
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Abdul Wahaab
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Anum Safdar
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Di Di
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Prerona Boruah
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Jinpeng Xu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Xin Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Beibei Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Huaimin Zhu
- Department of Pathogen biology, Second Military Medical University, Shanghai, PR China
| | - Mohsin Nawaz
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Donghua Shao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Yafeng Qiu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Jianchao Wei
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
| | - Zhiyong Ma
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, PR China
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Esser HJ, Mögling R, Cleton NB, van der Jeugd H, Sprong H, Stroo A, Koopmans MPG, de Boer WF, Reusken CBEM. Risk factors associated with sustained circulation of six zoonotic arboviruses: a systematic review for selection of surveillance sites in non-endemic areas. Parasit Vectors 2019; 12:265. [PMID: 31133059 PMCID: PMC6537422 DOI: 10.1186/s13071-019-3515-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 05/19/2019] [Indexed: 12/30/2022] Open
Abstract
Arboviruses represent a significant burden to public health and local economies due to their ability to cause unpredictable and widespread epidemics. To maximize early detection of arbovirus emergence in non-endemic areas, surveillance efforts should target areas where circulation is most likely. However, identifying such hotspots of potential emergence is a major challenge. The ecological conditions leading to arbovirus outbreaks are shaped by complex interactions between the virus, its vertebrate hosts, arthropod vector, and abiotic environment that are often poorly understood. Here, we systematically review the ecological risk factors associated with the circulation of six arboviruses that are of considerable concern to northwestern Europe. These include three mosquito-borne viruses (Japanese encephalitis virus, West Nile virus, Rift Valley fever virus) and three tick-borne viruses (Crimean-Congo hemorrhagic fever virus, tick-borne encephalitis virus, and louping-ill virus). We consider both intrinsic (e.g. vector and reservoir host competence) and extrinsic (e.g. temperature, precipitation, host densities, land use) risk factors, identify current knowledge gaps, and discuss future directions. Our systematic review provides baseline information for the identification of regions and habitats that have suitable ecological conditions for endemic circulation, and therefore may be used to target early warning surveillance programs aimed at detecting multi-virus and/or arbovirus emergence.
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Affiliation(s)
- Helen J Esser
- Resource Ecology Group, Wageningen University & Research, Wageningen, The Netherlands. .,Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands.
| | - Ramona Mögling
- Department of Viroscience, WHO CC for arbovirus and viral hemorrhagic fever reference and research, Erasmus University Medical Centre, Rotterdam, The Netherlands
| | - Natalie B Cleton
- Department of Viroscience, WHO CC for arbovirus and viral hemorrhagic fever reference and research, Erasmus University Medical Centre, Rotterdam, The Netherlands.,Centre for Infectious Disease Control, National Institute for Public Health and Environment (RIVM), Bilthoven, The Netherlands
| | - Henk van der Jeugd
- Vogeltrekstation-Dutch Centre for Avian Migration and Demography, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
| | - Hein Sprong
- Centre for Infectious Disease Control, National Institute for Public Health and Environment (RIVM), Bilthoven, The Netherlands
| | - Arjan Stroo
- Centre for Monitoring of Vectors (CMV), National Reference Centre (NRC), Netherlands Food and Consumer Product Safety Authority (NVWA), Ministry of Economic Affairs, Wageningen, The Netherlands
| | - Marion P G Koopmans
- Department of Viroscience, WHO CC for arbovirus and viral hemorrhagic fever reference and research, Erasmus University Medical Centre, Rotterdam, The Netherlands
| | - Willem F de Boer
- Resource Ecology Group, Wageningen University & Research, Wageningen, The Netherlands
| | - Chantal B E M Reusken
- Department of Viroscience, WHO CC for arbovirus and viral hemorrhagic fever reference and research, Erasmus University Medical Centre, Rotterdam, The Netherlands.,Centre for Infectious Disease Control, National Institute for Public Health and Environment (RIVM), Bilthoven, The Netherlands
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Interaction of RNA viruses of the natural virome with the African malaria vector, Anopheles coluzzii. Sci Rep 2019; 9:6319. [PMID: 31004099 PMCID: PMC6474895 DOI: 10.1038/s41598-019-42825-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 04/10/2019] [Indexed: 11/08/2022] Open
Abstract
Mosquitoes are colonized by a little-studied natural virome. Like the bacterial microbiome, the virome also probably influences the biology and immunity of mosquito vector populations, but tractable experimental models are lacking. We recently discovered two novel viruses in the virome of wild Anopheles and in colonies of the malaria vector Anopheles coluzzii: Anopheles C virus and Anopheles cypovirus. Here, we describe biological interactions between these two viruses and An. coluzzii mosquitoes. Viral abundance varies reproducibly during mosquito development. DNA forms of these viruses were not detected, and thus viral persistence is likely based on vertical transmission of RNA genomes. At least Anopheles C virus is vertically transmitted by an intraembryonic route. Relative abundance of the two viruses is inversely correlated in individual mosquitoes. One possible mechanism for this could be interactions with host immunity, and functional genomic analysis indicated differential influence of at least the Toll and JAK/STAT immune signaling pathways upon the viruses. The nonrandom distributions and interactions with host immunity suggest that these and other members of the natural virome may constitute a source of unrecognized heterogeneity in mosquito vector populations.
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Early Events in Japanese Encephalitis Virus Infection: Viral Entry. Pathogens 2018; 7:pathogens7030068. [PMID: 30104482 PMCID: PMC6161159 DOI: 10.3390/pathogens7030068] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/31/2018] [Accepted: 08/06/2018] [Indexed: 12/15/2022] Open
Abstract
Japanese encephalitis virus (JEV), a mosquito-borne zoonotic flavivirus, is an enveloped positive-strand RNA virus that can cause a spectrum of clinical manifestations, ranging from mild febrile illness to severe neuroinvasive disease. Today, several killed and live vaccines are available in different parts of the globe for use in humans to prevent JEV-induced diseases, yet no antivirals are available to treat JEV-associated diseases. Despite the progress made in vaccine research and development, JEV is still a major public health problem in southern, eastern, and southeastern Asia, as well as northern Oceania, with the potential to become an emerging global pathogen. In viral replication, the entry of JEV into the cell is the first step in a cascade of complex interactions between the virus and target cells that is required for the initiation, dissemination, and maintenance of infection. Because this step determines cell/tissue tropism and pathogenesis, it is a promising target for antiviral therapy. JEV entry is mediated by the viral glycoprotein E, which binds virions to the cell surface (attachment), delivers them to endosomes (endocytosis), and catalyzes the fusion between the viral and endosomal membranes (membrane fusion), followed by the release of the viral genome into the cytoplasm (uncoating). In this multistep process, a collection of host factors are involved. In this review, we summarize the current knowledge on the viral and cellular components involved in JEV entry into host cells, with an emphasis on the initial virus-host cell interactions on the cell surface.
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Oliveira AR, Strathe E, Etcheverry L, Cohnstaedt LW, McVey DS, Piaggio J, Cernicchiaro N. Assessment of data on vector and host competence for Japanese encephalitis virus: A systematic review of the literature. Prev Vet Med 2018; 154:71-89. [DOI: 10.1016/j.prevetmed.2018.03.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/19/2018] [Accepted: 03/20/2018] [Indexed: 12/15/2022]
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Pearce JC, Learoyd TP, Langendorf BJ, Logan JG. Japanese encephalitis: the vectors, ecology and potential for expansion. J Travel Med 2018; 25:S16-S26. [PMID: 29718435 DOI: 10.1093/jtm/tay009] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 02/20/2018] [Indexed: 01/09/2023]
Abstract
BACKGROUND Japanese encephalitis (JE) is a viral disease predominantly located in South East Asia and commonly associated with transmission between amplifying hosts, such as pigs, and the mosquito Culex tritaeniorhynchus, where human infection represents a dead end in the life cycle of the virus. The expansion of JE beyond an Asiatic confine is dependent on a multitude of complex factors that stem back to genetic subtype variation. A complex interplay of the genetic variation and vector competencies combine with variables such as geography, climate change and urbanization. METHODS Our understanding of JE is still at an early stage with long-term longitudinal vector surveillance necessary to better understand the dynamics of JE transmission and to characterize the role of potential secondary vectors such as Cx. pipiens and Cx. bitaeniorhynchus. The authors review the vectors indicated in transmission and the ecological, genetic and anthropological factors that affect the disease's range and epidemiology. CONCLUSION Monitoring for the presence of JE virus in mosquitoes in general can be used to estimate levels of potential JE exposure, intensity of viral activity and genetic variation of JEV throughout surveyed areas. Increased surveillance and diagnosis of viral encephalitis caused by genotype 5 JE virus is required in particular, with the expansion in epidemiology and disease prevalence in new geographic areas an issue of great concern. Additional studies that measure the impact of vectors (e.g. bionomics and vector competence) in the transmission of JEV and that incorporate environmental factors (e.g. weekly rainfall) are needed to define the roles of Culex species in the viral pathogenesis during outbreak and non-outbreak years.
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Affiliation(s)
- James C Pearce
- ARCTEC, Keppel Street, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Tristan P Learoyd
- Valneva UK Ltd, Centaur House, Ancells Business Park, Ancells Road, Fleet, Hampshire GU51 2UJ, UK
| | - Benjamin J Langendorf
- ARCTEC, Keppel Street, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - James G Logan
- ARCTEC, Keppel Street, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.,Department of Disease Control, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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38
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Lindquist L. Recent and historical trends in the epidemiology of Japanese encephalitis and its implication for risk assessment in travellers. J Travel Med 2018; 25:S3-S9. [PMID: 29718434 DOI: 10.1093/jtm/tay006] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 01/17/2018] [Indexed: 01/30/2023]
Abstract
Japanese encephalitis is a major disease in many countries in Asia often visited by both leisure and non-leisure travellers. Although reported cases of Japanese apoptosis (JE) in travellers are relatively few, there are indications that both the number of cases might be underreported and that changes in the epidemiological situation in these parts of Asia may increase the risk, especially non-leisure travellers. Although JE mainly is considered a rural disease urban cases are seen the large economic growth and urbanization of previously rural areas in many for JE high-endemic areas may further add to the risk for JE, especially for business travellers, when visiting newly established peri-urban areas. This review will address these dynamic and unpredictable risks for JE and discuss its possible implications for the traveller.
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Affiliation(s)
- Lars Lindquist
- Karolinska Institutet, Karolinska University Hospital, SE 141 86 Huddinge, Sweden; Clinic for Infectious Diseases Huddinge I63; SE 141 86 Huddinge, Sweden
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A Systematic Review of the Natural Virome of Anopheles Mosquitoes. Viruses 2018; 10:v10050222. [PMID: 29695682 PMCID: PMC5977215 DOI: 10.3390/v10050222] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 04/20/2018] [Accepted: 04/21/2018] [Indexed: 12/15/2022] Open
Abstract
Anopheles mosquitoes are vectors of human malaria, but they also harbor viruses, collectively termed the virome. The Anopheles virome is relatively poorly studied, and the number and function of viruses are unknown. Only the o’nyong-nyong arbovirus (ONNV) is known to be consistently transmitted to vertebrates by Anopheles mosquitoes. A systematic literature review searched four databases: PubMed, Web of Science, Scopus, and Lissa. In addition, online and print resources were searched manually. The searches yielded 259 records. After screening for eligibility criteria, we found at least 51 viruses reported in Anopheles, including viruses with potential to cause febrile disease if transmitted to humans or other vertebrates. Studies to date have not provided evidence that Anopheles consistently transmit and maintain arboviruses other than ONNV. However, anthropophilic Anopheles vectors of malaria are constantly exposed to arboviruses in human bloodmeals. It is possible that in malaria-endemic zones, febrile symptoms may be commonly misdiagnosed. It is also possible that anophelines may be inherently less competent arbovirus vectors than culicines, but if true, the biological basis would warrant further study. This systematic review contributes a context to characterize the biology, knowledge gaps, and potential public health risk of Anopheles viruses.
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Lin CL, Chang HL, Lin CY, Chen KT. Seasonal Patterns of Japanese Encephalitis and Associated Meteorological Factors in Taiwan. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:E1317. [PMID: 29109371 PMCID: PMC5707956 DOI: 10.3390/ijerph14111317] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 10/25/2017] [Accepted: 10/27/2017] [Indexed: 11/16/2022]
Abstract
The persistent transmission of Japanese encephalitis virus (JEV) in Taiwan necessitates exploring the risk factors of occurrence of Japanese encephalitis (JE). The purpose of this study was to assess the relationship between meteorological factors and the incidence of JE in Taiwan. We collected data for cases of JE reported to the Taiwan Centers for Disease Control (Taiwan CDC) from 2000 to 2014. Meteorological data were obtained from the Taiwan Central Weather Bureau. The relationships between weather variability and the incidence of JE in Taiwan were determined via Poisson regression analysis and a case-crossover methodology. During the 15-year study period, a total of 379 cases of JE were reported. The incidence of JE showed significant seasonality, with the majority of cases occurring in summertime (for oscillation, p < 0.001). The number of JE cases started to increase at temperatures of 22 °C (r² = 0.88, p < 0.001). Similarly, the number of JE cases began to increase at a relative humidity of 70-74% (r² = 0.75, p < 0.005). The number of JE cases was positively associated with mean temperature and relative humidity in the period preceding the infection. In conclusion, the occurrence of JE is significantly associated with increasing temperature and relative humidity in Taiwan. Therefore, these factors could be regarded as warning signals indicating the need to implement preventive measures.
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Affiliation(s)
- Che-Liang Lin
- Internal Medicine Chest Division, Chi-Mei Medical Center, Liouying, Tainan 736, Taiwan.
| | - Hsiao-Ling Chang
- Division of Infection Control and Biosafety, Centers for Disease Control, Ministry of Health and Welfare, Taipei 104, Taiwan.
- School of Public Health, National Defense Medical Center, National Defense University, Taipei 117, Taiwan.
| | - Chuan-Yao Lin
- Research Center for Environmental Changes, Academia Sinica, 115, Taiwan.
| | - Kow-Tong Chen
- Department of Occupational Medicine, Tainan Municipal Hospital (Managed by Show Chwan Medical Care Corporation), Tainan 701, Taiwan.
- Department of Public Health, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan.
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Wu YH, Chen JM, Su CY. Occurrence of old age Japanese Encephalitis: Current situation in Taiwan. J Formos Med Assoc 2017; 116:915-916. [PMID: 28528139 DOI: 10.1016/j.jfma.2017.04.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 04/09/2017] [Accepted: 04/17/2017] [Indexed: 12/01/2022] Open
Affiliation(s)
- Ying-Hui Wu
- Department of Family Medicine, Renai Branch, Taipei City Hospital, Taipei City, Taiwan, ROC
| | - Jer-Min Chen
- Department of Family Medicine, Renai Branch, Taipei City Hospital, Taipei City, Taiwan, ROC
| | - Chen-Yi Su
- Department of Internal Medicine, Renai Branch, Taipei City Hospital, Taipei City, Taiwan, ROC.
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Longbottom J, Browne AJ, Pigott DM, Sinka ME, Golding N, Hay SI, Moyes CL, Shearer FM. Mapping the spatial distribution of the Japanese encephalitis vector, Culex tritaeniorhynchus Giles, 1901 (Diptera: Culicidae) within areas of Japanese encephalitis risk. Parasit Vectors 2017; 10:148. [PMID: 28302156 PMCID: PMC5356256 DOI: 10.1186/s13071-017-2086-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/10/2017] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Japanese encephalitis (JE) is one of the most significant aetiological agents of viral encephalitis in Asia. This medically important arbovirus is primarily spread from vertebrate hosts to humans by the mosquito vector Culex tritaeniorhynchus. Knowledge of the contemporary distribution of this vector species is lacking, and efforts to define areas of disease risk greatly depend on a thorough understanding of the variation in this mosquito's geographical distribution. RESULTS We assembled a contemporary database of Cx. tritaeniorhynchus presence records within Japanese encephalitis risk areas from formal literature and other relevant resources, resulting in 1,045 geo-referenced, spatially and temporally unique presence records spanning from 1928 to 2014 (71.9% of records obtained between 2001 and 2014). These presence data were combined with a background dataset capturing sample bias in our presence dataset, along with environmental and socio-economic covariates, to inform a boosted regression tree model predicting environmental suitability for Cx. tritaeniorhynchus at each 5 × 5 km gridded cell within areas of JE risk. The resulting fine-scale map highlights areas of high environmental suitability for this species across India, Nepal and China that coincide with areas of high JE incidence, emphasising the role of this vector in disease transmission and the utility of the map generated. CONCLUSIONS Our map contributes towards efforts determining the spatial heterogeneity in Cx. tritaeniorhynchus distribution within the limits of JE transmission. Specifically, this map can be used to inform vector control programs and can be used to identify key areas where the prevention of Cx. tritaeniorhynchus establishment should be a priority.
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Affiliation(s)
- Joshua Longbottom
- Spatial Ecology & Epidemiology Group, Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Annie J. Browne
- Spatial Ecology & Epidemiology Group, Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - David M. Pigott
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA USA
| | - Marianne E. Sinka
- Oxford Long Term Ecology Laboratory, Department of Zoology, University of Oxford, Oxford, UK
| | - Nick Golding
- Quantitative & Applied Ecology Group, School of BioSciences, University of Melbourne, Parkville, VIC Australia
| | - Simon I. Hay
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA USA
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Catherine L. Moyes
- Spatial Ecology & Epidemiology Group, Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Freya M. Shearer
- Spatial Ecology & Epidemiology Group, Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
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European Aedes albopictus and Culex pipiens Are Competent Vectors for Japanese Encephalitis Virus. PLoS Negl Trop Dis 2017; 11:e0005294. [PMID: 28085881 PMCID: PMC5268654 DOI: 10.1371/journal.pntd.0005294] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 01/26/2017] [Accepted: 01/02/2017] [Indexed: 11/19/2022] Open
Abstract
Background Japanese encephalitis virus (JEV) is the causative agent of Japanese encephalitis, the leading cause of viral encephalitis in Asia. JEV transmission cycle involves mosquitoes and vertebrate hosts. The detection of JEV RNA in a pool of Culex pipiens caught in 2010 in Italy raised the concern of a putative emergence of the virus in Europe. We aimed to study the vector competence of European mosquito populations, such as Cx. pipiens and Aedes albopictus for JEV genotypes 3 and 5. Findings After oral feeding on an infectious blood meal, mosquitoes were dissected at various times post-virus exposure. We found that the peak for JEV infection and transmission was between 11 and 13 days post-virus exposure. We observed a faster dissemination of both JEV genotypes in Ae. albopictus mosquitoes, when compared with Cx. pipiens mosquitoes. We also dissected salivary glands and collected saliva from infected mosquitoes and showed that Ae. albopictus mosquitoes transmitted JEV earlier than Cx. pipiens. The virus collected from Ae. albopictus and Cx. pipiens saliva was competent at causing pathogenesis in a mouse model for JEV infection. Using this model, we found that mosquito saliva or salivary glands did not enhance the severity of the disease. Conclusions In this study, we demonstrated that European populations of Ae. albopictus and Cx. pipiens were efficient vectors for JEV transmission. Susceptible vertebrate species that develop high viremia are an obligatory part of the JEV transmission cycle. This study highlights the need to investigate the susceptibility of potential JEV reservoir hosts in Europe, notably amongst swine populations and local water birds. Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis in Asia. JEV is maintained in a cycle involving mosquitoes and vertebrate hosts, mainly pigs and wading birds. Humans can be infected when bitten by an infected mosquito. Culex tritaeniorhynchus is the main vector of the disease in tropical and subtropical areas. The recent detection of JEV in birds and mosquitoes collected in Northern Italy has led us to evaluate the putative emergence of this arboviral disease in Europe. For this purpose, we have tested the competence of European populations of Cx. pipiens and Aedes albopictus to transmit this virus in a laboratory setting. We showed that these local mosquitoes could be infected and were capable of transmitting a pathogenic virus to mice. It is thus urgent to evaluate the risks of JEV emergence in European regions displaying a favorable environment for mosquito vectors, susceptible pigs and wading birds.
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Diseases of the Nervous System. Vet Med (Auckl) 2017. [PMCID: PMC7322266 DOI: 10.1016/b978-0-7020-5246-0.00014-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Chang YK, Chang HL, Wu HS, Chen KT. Epidemiological Features of Japanese Encephalitis in Taiwan from 2000 to 2014. Am J Trop Med Hyg 2016; 96:382-388. [PMID: 27821699 DOI: 10.4269/ajtmh.16-0330] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 09/20/2016] [Indexed: 11/07/2022] Open
Abstract
The incidence of Japanese encephalitis (JE) decreased sharply after the national vaccination program was implemented in Taiwan in 1968. However, cases of JE still occur. The purpose of this study was to assess the epidemiology and vaccination policy for JE in Taiwan. We analyzed the data on JE cases reported to the Taiwan Centers for Disease Control (Taiwan CDC) between 2000 and 2014. During the 15-year study period, a total of 4,474 cases were reported to the Taiwan CDC. Of these, 379 (8.5%) were classified as confirmed cases, and 4,095 (91.5%) were classified as suspected cases. The incidence of JE ranged from 0.59 to 1.61 per 1,000,000 people and peaked in 2007. Men had a higher incidence of JE than women (1.37 versus 0.84 per 1,000,000; P = 0.03). Patients who were 40-59 years of age had a higher incidence than did patients younger than 20 years (1.82 versus 0.23; P < 0.001). Patients who lived in the eastern region of Taiwan had the highest incidence rate of JE (P < 0.001). Compared with those who were not vaccinated with the JE vaccine, patients who received four doses of JE vaccine had a lower risk of suffering from death and/or hospitalization (adjusted odds ratio: 0.26; 95% confidence interval: 0.08-0.90; P = 0.04). JE is still a public health problem in Taiwan, and monitoring JE via diagnostic testing to determine the best vaccination program along with enforcing JE vaccine boosters for adults is necessary to eliminate JE in Taiwan.
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Affiliation(s)
- Yu-Kang Chang
- Department of Radiology, Liouying Campus, Chi-Mei Medical Center, Tainan, Taiwan
| | - Hsiao-Ling Chang
- Division of Infection Control and Biosafety, Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan.,School Public Health, National Defense Medical Center, National Defense University, Taipei, Taiwan
| | - Ho-Sheng Wu
- Hsinchu Blood Center, Taiwan Blood Services Foundation, Hsinchu, Taiwan.,School of Medical Laboratory Science and Biotechnology, Taipei Medical University, Taipei, Taiwan
| | - Kow-Tong Chen
- Department of Occupational Medicine, Tainan Municipal Hospital, Tainan, Taiwan. .,Department of Public Health, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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Differential Infectivities among Different Japanese Encephalitis Virus Genotypes in Culex quinquefasciatus Mosquitoes. PLoS Negl Trop Dis 2016; 10:e0005038. [PMID: 27706157 PMCID: PMC5051684 DOI: 10.1371/journal.pntd.0005038] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 09/13/2016] [Indexed: 12/29/2022] Open
Abstract
During the last 20 years, the epidemiology of Japanese encephalitis virus (JEV) has changed significantly in its endemic regions due to the gradual displacement of the previously dominant genotype III (GIII) with clade b of GI (GI-b). Whilst there is only limited genetic difference distinguishing the two GI clades (GI-a and GI-b), GI-b has shown a significantly wider and more rapid dispersal pattern in several regions in Asia than the GI-a clade, which remains restricted in its geographic distribution since its emergence. Although previously published molecular epidemiological evidence has shown distinct phylodynamic patterns, characterization of the two GI clades has only been limited to in vitro studies. In this study, Culex quinquefasciatus, a known competent JEV mosquito vector species, was orally challenged with three JEV strains each representing GI-a, GI-b, and GIII, respectively. Infection and dissemination were determined based on the detection of infectious viruses in homogenized mosquitoes. Detection of JEV RNA in mosquito saliva at 14 days post infection indicated that Cx. quinquefasciatus can be a competent vector species for both GI and GIII strains. Significantly higher infection rates in mosquitoes exposed to the GI-b and GIII strains than the GI-a strain suggest infectivity in arthropod vectors may lead to the selective advantage of previously and currently dominant genotypes. It could thus play a role in enzootic transmission cycles for the maintenance of JEV if this virus were ever to be introduced into North America. Japanese encephalitis virus (JEV) is a zoonotic flavivirus, which is primarily transmitted by Culex species mosquitoes and a leading cause of pediatric encephalitis in Asia. JEV is also an important public health threat to countries outside the endemic region because collections of Cx. quinquefasciatus from around the world have demonstrated competence for the transmission of JEV and are capable of establishing enzootic transmission cycles between viremic avian and swine species. In the last two decades, the dominantly circulating genotype of JEV in endemic regions has experienced a significant shift (genotype III to Genotype I). It is unclear if the newly dominant circulating G1-b genotype can still be vectored by Cx. quinquefasciatus. In this study, Cx. quinquefasciatus collected from North America was demonstrated to be competent for the transmission of the newly dominant genotype. Different infectivities observed between the endemic strains and non-endemic strain provides the mechanistic knowledge of the selection and emergence of endemic genotypes after continuous viral evolution.
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Sero-Molecular Epidemiology of Japanese Encephalitis in Zhejiang, an Eastern Province of China. PLoS Negl Trop Dis 2016; 10:e0004936. [PMID: 27560360 PMCID: PMC4999095 DOI: 10.1371/journal.pntd.0004936] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/01/2016] [Indexed: 11/19/2022] Open
Abstract
Background Sporadic Japanese encephalitis (JE) cases still have been reported in Zhejiang Province in recent years, and concerns about vaccine cross-protection and population-level immunity have been raised off and on within the public health sphere. Genotype I (GI) has replaced GIII as the dominant genotype in Asian countries during the past few decades, which caused considerable concerns about the potential change of epidemiology characteristics and the vaccine effectiveness. The aim of this study was to investigate the prevalence of JE neutralizing antibody and its waning antibody trend after live attenuated JE vaccine immunization. Additionally, this study analyzed the molecular characteristics of the E gene of Zhejiang Japanese encephalitis virus (JEV) strains, and established genetic relationships with other JEV strains. Methodology/Principal Findings A total of 570 serum specimens were sampled from community population aged from 0 to 92 years old in Xianju county of Zhejiang Province in 2013–2014. Microseroneutralization test results were analyzed to estimate the population immunity and to observe antibody dynamics in vaccinated children. E genes of 28 JEV strains isolated in Zhejiang Province were sequenced for phylogenetic tree construction and molecular characteristics analysis with other selected strains. Positive JE neutralizing antibody rates were higher in residents ≥35 years old (81%~98%) and lower in residents <35 years old (0~57%). 7 or 8 years after the 2nd live attenuated vaccine dose, the antibodies against for 4 different strains with microseroneutralization test were decreased by 55%~73% on seropositive rates and by 25%~38% on GMTs respectively. JEV strains isolated in recent years were all grouped into GI, while those isolated in the 1980s belonged to GIII. On important amino acid sites related to antigenicity, there was no divergence between the Zhejiang JE virus strains and the vaccine strain (SA14-14-2). Conclusion/Significances JE neutralizing antibody positive rates increase in age ≥10 years old population, likely reflecting natural infection or natural boosting of immunity through exposure to wild virus. JE seropositivity rates were quite low in <35 years old age groups in Zhejiang Province. Waning of neutralizing antibody after live attenuated vaccine immunization was observed, but the clinical significance should be further investigated. Both the peripheral antibody response and genetic characterization indicate that current live attenuated JE vaccine conferred equal neutralizing potency against GI or GIII of wild strains. GI has replaced GIII as the dominant genotype in Zhejiang in the past few decades. Although the chance of exposure to wild JE virus has reduced, the virus still circulates in nature; therefore, it is necessary to implement immunization program for children continually and to conduct surveillance activity periodically. Japanese encephalitis (JE) remains one of the most significant public health problems in Asia and the Western Pacific region. A JE viral infection can cause death and severe sequelae. Vaccination is the most effective method for preventing JE currently. After decades of routine vaccination, the number of JE cases declined considerably in Zhejiang Province, China. However, emergence of genotype I of JE as the most common genotype in China in recent decades has become a major public health problem. As all the currently available vaccines are derived from genotype III strains, the circulations of another genotype have caused considerable concerns about vaccine effectiveness. In this study, we found that population immunity against JE was quite low in children and adolescents. Waning of JE neutralizing antibody after JE immunization was observed. Therefore, issues about duration of protection and booster dose necessity need further research. On the bright side, evidence shows that the JE vaccine currently used is effective for both genotype I and III of wild viruses. Although clinical JE cases have reduced, the virus is still spreading in nature; therefore, we encourage children and other high-risk groups to adhere to the immunization program continuously.
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Yoshikawa A, Nabeshima T, Inoue S, Agoh M, Morita K. Molecular and serological epidemiology of Japanese encephalitis virus (JEV) in a remote island of western Japan: an implication of JEV migration over the East China Sea. Trop Med Health 2016; 44:8. [PMID: 27433127 PMCID: PMC4940834 DOI: 10.1186/s41182-016-0010-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 01/14/2016] [Indexed: 12/13/2022] Open
Abstract
Background Japanese encephalitis (JE) is a mosquito-borne infectious disease caused by Japanese encephalitis virus (JEV). About 1–10 cases with severe central nervous system symptoms have been constantly reported every year in Japan. To clarify the mechanism of maintenance of JEV, the present study surveyed pigs for serological evidence of JEV infection and isolated JEV strains from pigs and mosquitoes in Isahaya City (Isahaya) and Goto City (Goto) in the islets of Goto in Nagasaki Prefecture from 2008 to 2014. Results The serological survey of pigs showed the increase of IgM sero-positivity against JEV in July or August, and it was maintained until October or November in both Isahaya and Goto every year. There were 47 JEV strains isolated in Nagasaki from 2001 to 2014 including the isolates in this study, and they belonged to genotype 1. Thirty four of the isolated strains were from pigs in Isahaya and were classified under six subclusters (1-A-1, 1-A-2, 1-A-3, 1-A-4, 1-A-5, and 1-A-9). Thirteen strains were isolated from pigs and mosquitoes in Goto and were classified into three subclusters (1-A-5 (2008); 1-A-1 (2009); and 1-A-2). In the subcluster 1-A-2, three different monophyletic subgroups, 1-A-2-2 (2010), 1-A-2-3 (2011), and 1-A-2-1 (2013, 2014), appeared in Goto. Conclusions These data strongly suggested that JEV appearance in Goto seems to depend on the frequent introduction of JEV from outside of the island and this pattern is different from what has been observed in subtropical islands in the East China Sea such as Okinawa and Taiwan, where the same populations of JEV (1-A-7 (1998–2008) in Okinawa; genotype 3 (until 2012) in Taiwan) have been maintained for a long period.
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Affiliation(s)
- Akira Yoshikawa
- Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523 Japan ; Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523 Japan ; Department of Public Health, Nagasaki Prefectural Institute for Environmental Research and Public Health, 2-1306-11 Ikeda, Omura, Nagasaki 856-0026 Japan
| | - Takeshi Nabeshima
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523 Japan
| | - Shingo Inoue
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523 Japan
| | - Masanobu Agoh
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523 Japan
| | - Kouichi Morita
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523 Japan
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Qian P, Zhi X, Wang B, Zhang H, Chen H, Li X. Construction and immune efficacy of recombinant pseudorabies virus expressing PrM-E proteins of Japanese encephalitis virus genotype І. Virol J 2015; 12:214. [PMID: 26651827 PMCID: PMC4676090 DOI: 10.1186/s12985-015-0449-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 12/04/2015] [Indexed: 01/24/2023] Open
Abstract
Background Japanese encephalitis (JE) is an arboviral disease with high case fatality rates and neurologic or psychiatric sequelae among survivors in Asia, western Pacific countries and northern Australia. Japanese encephalitis virus (JEV) is the cause of JE and the emergence of genotype І (GI) JEV has displaced genotype III (GIII) as the dominant strains circulating in some Asian regions. The currently available JE vaccines are safe and effective in preventing this disease, but they are developed based on the GIII JEV strains. Methods The recombinant virus PRV TK−/gE−/PrM-E+ which expressed the premembrane (prM) and envelope (E) proteins of JEV SX09S-01 strain (genotype I, GI) was constructed by homologous recombination between the genome of PRV TK−/gE−/LacZ+ digested with EcoRI and plasmid pIE-CAG-PrM-E-BGH. Expression of JEV PrM and E proteins was analyzed by Western blot analysis. Immune efficacy of PRV TK−/gE−/PrM-E+ was further evaluated in mouse model. Results A recombinant pseudorabies virus (PRV TK−/gE−/PrM-E+) was successfully constructed. Mice experiments showed that PRV TK−/gE−/PrM-E+ could induce a high level of ELISA antibodies against PRV and JEV, as well as high titer of PRV neutralizing antibodies. After challenge with 1 × 107 PFU virulent JEV SX09S-01 strain, the time of death was delayed and the survival rate was improved in PRV TK−/gE−/PrM-E+ vaccinated mice. Conclusions PRV TK−/gE−/PrM-E+ is a potential vaccine candidate against PRV and JEV GI infection in the future.
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Affiliation(s)
- Ping Qian
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China. .,Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, P.R. China. .,Key Laboratory of development of veterinary diagnostic products, Ministry of Agriculture, Wuhan, 430070, P.R China.
| | - Xianwei Zhi
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China. .,Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, P.R. China.
| | - Bo Wang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China. .,Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, P.R. China.
| | - Huawei Zhang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China. .,Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, P.R. China.
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China. .,Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, P.R. China. .,Key Laboratory of development of veterinary diagnostic products, Ministry of Agriculture, Wuhan, 430070, P.R China.
| | - Xiangmin Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P.R. China. .,Laboratory of Animal Virology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, P.R. China. .,Key Laboratory of development of veterinary diagnostic products, Ministry of Agriculture, Wuhan, 430070, P.R China.
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Erra EO, Kantele A. The Vero cell-derived, inactivated, SA14-14-2 strain-based vaccine (Ixiaro) for prevention of Japanese encephalitis. Expert Rev Vaccines 2015; 14:1167-79. [PMID: 26162529 DOI: 10.1586/14760584.2015.1061939] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
With an estimated 68,000 cases each year, Japanese encephalitis (JE) is the leading cause of viral encephalitis in Asia. Vaccination against the disease is recommended for endemic populations and also for travelers at risk. Recently, a Vero cell-derived, inactivated, SA14-14-2 strain-based JE vaccine (JE-VC) became available for travelers from non-endemic regions, replacing the traditional mouse brain-derived vaccines. First licensed in 2009, JE-VC is currently available in Europe, the USA, Canada, Australia and several other countries. In 2013, the vaccine was approved by the European Medicines Agency and the US Food and Drug Administration for use in children. This review summarizes current data on the immunogenicity, safety and clinical use of JE-VC.
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Affiliation(s)
- Elina O Erra
- Haartman Institute, University of Helsinki, Helsinki, Finland
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