Japanese encephalitis virus: an emerging and re-emerging virus in Australia
John S. Mackenzie A * and David T. Williams B
+ Author Affiliations
- Author Affiliations
A Faculty of Health Sciences, Curtin University, Unit 143, 6 Tighe Street, Jolimont, Perth, WA 6014, Australia.
B CSIRO Australian Centre for Disease Preparedness, Geelong, Vic., Australia.
John Mackenzie is an Emeritus Professor of Curtin University, and an Honorary Professor at The University of Queensland. His research has been largely concerned with vector-borne viruses, emerging zoonoses, and the One Health concept. He currently serves on WHO Emergency Committees on Polio and on COVID-19, and is a member of the FAO-UNEP-WHO-WOAH One Health High Level Expert Panel. He has been a member of the National Arbovirus and Malaria Advisory Committee since its inception. He is a former President of ASM, and Secretary-General of IUMS. |
Dr David Williams leads the Diagnosis and Mammalian Infectious Disease Research group at the CSIRO Australian Centre for Disease Preparedness in Geelong. David’s research interests include the detection, epidemiology and pathogenesis of emerging and exotic viruses that affect humans and animals. This work has focussed on mosquito-borne viruses such as Japanese encephalitis virus. David is a member of the National Arbovirus and Malaria Advisory Committee and the Public Health Laboratory Network Expert Review Panel on Japanese encephalitis. |
* Correspondence to: J.Mackenzie@curtin.edu.au
Microbiology Australia 43(4) 150-155 https://doi.org/10.1071/MA22050
Submitted: 11 October 2022 Accepted: 5 November 2022 Published: 1 December 2022
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the ASM. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)
Abstract
Japanese encephalitis virus (JEV) first emerged in the Torres Strait of north-eastern Australia in 1995, with three human cases, and widespread infection of pigs on a number of islands. The virus was shown to belong to genotype II. Further cases occurred in 1998, including the first case on mainland Australia on Cape York. A second genotype of JEV, genotype Ia, was reported in mosquitoes and pigs in 2000–04, possibly displacing genotype II. JEV re-emerged in Australia with a fatal human case on the Tiwi Islands, Northern Territory, in 2021, and shown to belong to genotype IV. This case was followed about a year later by a large outbreak of JE; first detected in piggeries in four states, Queensland, New South Wales, Victoria, and South Australia, resulting in reproductive losses affecting 80 piggeries and 42 human cases, with seven fatal cases. The wide geographic spread of cases suggested that the virus had been circulating for a number of months or even years prior to detection, and has led to significant concern that the virus will become endemic to Australia, in a similar ecology to Murray Valley encephalitis virus. Known competent mosquito vectors and ardeid birds, as maintenance hosts, occur in Australia, and it is probable that feral pigs will provide an additional wildlife reservoir of virus. Little is known of the properties of genotype IV, but it is expected to have a similar ecology and pathogenesis to other JEV genotypes.
Keywords: ardeid birds, Culex sp. mosquitoes, domestic piggeries, feral pigs, flaviviruses, Japanese encephalitis, Japanese encephalitis virus, JEV genotype IV, malformed and stillborn pigs, Torres Strait.
References
[1] Campbell, GL et al.. (2011) Estimated global incidence of Japanese encephalitis: a systematic review. Bull World Health Organ 89, 766–774E.| Estimated global incidence of Japanese encephalitis: a systematic review.Crossref | GoogleScholarGoogle Scholar |
[2] Mackenzie JS et al. (2007) Japanese encephalitis virus: the geographic distribution, incidence, and spread of a virus with a propensity to emerge in new areas. In Emerging Viruses in Human Populations (Tabor E, ed.). pp. 201–268. Elsevier.
[3] Mackenzie, JS et al.. (2002) Japanese encephalitis as an emerging virus: the emergence and spread of Japanese encephalitis virus in Australasia. Curr Top Microbiol Immunol 267, 49–73.
| Japanese encephalitis as an emerging virus: the emergence and spread of Japanese encephalitis virus in Australasia.Crossref | GoogleScholarGoogle Scholar |
[4] Vaughn, DW and Hoke Jr, CH (1992) The epidemiology of Japanese encephalitis: prospects for prevention. Epidemiol Rev 14, 197–221.
| The epidemiology of Japanese encephalitis: prospects for prevention.Crossref | GoogleScholarGoogle Scholar |
[5] Mansfield, KL et al.. (2017) Japanese encephalitis virus infection, diagnosis and control in domestic animals. Vet Microbiol 201, 85–92.
| Japanese encephalitis virus infection, diagnosis and control in domestic animals.Crossref | GoogleScholarGoogle Scholar |
[6] Ricklin, ME et al.. (2016) Vector-free transmission and persistence of Japanese encephalitis virus in pigs. Nat Commun 7, 10832.
| Vector-free transmission and persistence of Japanese encephalitis virus in pigs.Crossref | GoogleScholarGoogle Scholar |
[7] Solomon, T and Vaughn, DW (2002) Pathogenesis and clinical features of Japanese encephalitis and West Nile virus infections. Curr Top Microbiol Immunol 267, 171–194.
| Pathogenesis and clinical features of Japanese encephalitis and West Nile virus infections.Crossref | GoogleScholarGoogle Scholar |
[8] Solomon, T et al.. (2003) Origin and evolution of Japanese encephalitis virus in southeast Asia. J Virol 77, 3091–3098.
| Origin and evolution of Japanese encephalitis virus in southeast Asia.Crossref | GoogleScholarGoogle Scholar |
[9] Gao, X et al.. (2015) Insights into the evolutionary history of Japanese encephalitis virus (JEV) based on whole-genome sequences comprising the five genotypes. Virol J 12, 43.
| Insights into the evolutionary history of Japanese encephalitis virus (JEV) based on whole-genome sequences comprising the five genotypes.Crossref | GoogleScholarGoogle Scholar |
[10] Chen, W-R et al.. (1990) Genetic variation of Japanese encephalitis virus in nature. J Gen Virol 71, 2915–2922.
| Genetic variation of Japanese encephalitis virus in nature.Crossref | GoogleScholarGoogle Scholar |
[11] Chen, W-R et al.. (1992) A new genotype of Japanese encephalitis virus from Indonesia. Am J Trop Med Hyg 47, 61–69.
| A new genotype of Japanese encephalitis virus from Indonesia.Crossref | GoogleScholarGoogle Scholar |
[12] Uchil, PD and Satchidanandam, V (2001) Phylogenetic analysis of Japanese encephalitis virus: envelope gene-based analysis reveals a fifth genotype, geographic clustering, and multiple introductions of the virus into the Indian subcontinent. Am J Trop Med Hyg 65, 242–251.
| Phylogenetic analysis of Japanese encephalitis virus: envelope gene-based analysis reveals a fifth genotype, geographic clustering, and multiple introductions of the virus into the Indian subcontinent.Crossref | GoogleScholarGoogle Scholar |
[13] Schuh, AJ et al.. (2014) Dynamics of the emergence and establishment of a newly dominant genotype of Japanese encephalitis virus throughout Asia. J Virol 88, 4522–4532.
| Dynamics of the emergence and establishment of a newly dominant genotype of Japanese encephalitis virus throughout Asia.Crossref | GoogleScholarGoogle Scholar |
[14] Schuh, AJ et al.. (2013) Phylogeography of Japanese encephalitis virus: genotype is associated with climate. PLoS Negl Trop Dis 7, e2411.
| Phylogeography of Japanese encephalitis virus: genotype is associated with climate.Crossref | GoogleScholarGoogle Scholar |
[15] Gao, X et al.. (2019) Changing geographic distribution of Japanese encephalitis virus genotypes, 1935–2017. Vector Borne Zoonotic Dis 19, 35–44.
| Changing geographic distribution of Japanese encephalitis virus genotypes, 1935–2017.Crossref | GoogleScholarGoogle Scholar |
[16] Pan, XL et al.. (2011) Emergence of genotype I of Japanese encephalitis virus as the dominant genotype in Asia. J Virol 85, 9847–9853.
| Emergence of genotype I of Japanese encephalitis virus as the dominant genotype in Asia.Crossref | GoogleScholarGoogle Scholar |
[17] Li, MH et al.. (2011) Genotype V Japanese encephalitis virus is emerging. PLoS Negl Trop Dis 5, e1231.
| Genotype V Japanese encephalitis virus is emerging.Crossref | GoogleScholarGoogle Scholar |
[18] Takhampunya, R et al.. (2011) Emergence of Japanese encephalitis virus genotype V in the Republic of Korea. Virol J 8, 449.
| Emergence of Japanese encephalitis virus genotype V in the Republic of Korea.Crossref | GoogleScholarGoogle Scholar |
[19] Schuh, AJ et al.. (2013) Genetic diversity of Japanese encephalitis virus isolates obtained from the Indonesian archipelago between 1974 and 1987. Vector Borne Zoonotic Dis 13, 479–488.
| Genetic diversity of Japanese encephalitis virus isolates obtained from the Indonesian archipelago between 1974 and 1987.Crossref | GoogleScholarGoogle Scholar |
[20] Kuwata, R et al.. (2020) Distribution of Japanese encephalitis virus, Japan and Southeast Asia, 2016–2018. Emerg Infect Dis 26, 125–128.
| Distribution of Japanese encephalitis virus, Japan and Southeast Asia, 2016–2018.Crossref | GoogleScholarGoogle Scholar |
[21] Faizah, AN et al.. (2021) Identification and isolation of Japanese encephalitis virus Genotype IV from Culex vishnui collected in Bali, Indonesia in 2019. Am J Trop Med Hyg 105, 813–817.
| Identification and isolation of Japanese encephalitis virus Genotype IV from Culex vishnui collected in Bali, Indonesia in 2019.Crossref | GoogleScholarGoogle Scholar |
[22] Pyke, AT et al.. (2020) A case of Japanese encephalitis with a fatal outcome in an Australian who traveled from Bali in 2019. Trop Med Infect Dis 5, 133.
| A case of Japanese encephalitis with a fatal outcome in an Australian who traveled from Bali in 2019.Crossref | GoogleScholarGoogle Scholar |
[23] Mackenzie JS et al. (2006) Japanese encephalitis virus: an example of a virus with a propensity to emerge and spread in new geographic areas. In Emerging Viruses in Human Populations. Perspectives in Medical Virology (Tabor E, ed.). Vol. 16, pp. 201–268. Elsevier, Amsterdam.
| Crossref |
[24] Platonov, AE et al.. (2012) Does the Japanese encephalitis virus (JEV) represent a threat for human health in Europe? Detection of JEV RNA sequences in birds collected in Italy. Euro Surveill 17, 20241.
| Does the Japanese encephalitis virus (JEV) represent a threat for human health in Europe? Detection of JEV RNA sequences in birds collected in Italy.Crossref | GoogleScholarGoogle Scholar |
[25] Ravanini, P et al.. (2012) Japanese encephalitis virus RNA detected in Culex pipiens mosquitoes in Italy. Euro Surveill 17, 20221.
| Japanese encephalitis virus RNA detected in Culex pipiens mosquitoes in Italy.Crossref | GoogleScholarGoogle Scholar |
[26] Simon-Loriere, E et al.. (2017) Autochthonous Japanese encephalitis with yellow fever coinfection in Africa. N Engl J Med 376, 1483–1485.
| Autochthonous Japanese encephalitis with yellow fever coinfection in Africa.Crossref | GoogleScholarGoogle Scholar |
[27] European Centre for Disease Prevention and Control. Factsheet about Japanese encephalitis. https://www.ecdc.europa.eu/en/japanese-encephalitis/facts
[28] Oliveira, ARS et al.. (2020) Perspectives regarding the risk of introduction of the Japanese encephalitis virus (JEV) in the United States. Front Vet Sci 7, 48.
| Perspectives regarding the risk of introduction of the Japanese encephalitis virus (JEV) in the United States.Crossref | GoogleScholarGoogle Scholar |
[29] Hanna, JN et al.. (1996) An outbreak of Japanese encephalitis in the Torres Strait, Australia, 1995. Med J Aust 165, 256–260.
| An outbreak of Japanese encephalitis in the Torres Strait, Australia, 1995.Crossref | GoogleScholarGoogle Scholar |
[30] Ritchie, SA et al.. (1997) Isolation of Japanese encephalitis virus from Culex annulirostris in Australia. Am J Trop Med Hyg 56, 80–84.
| Isolation of Japanese encephalitis virus from Culex annulirostris in Australia.Crossref | GoogleScholarGoogle Scholar |
[31] Hanna, J et al.. (1996) Vaccination against Japanese encephalitis in the Torres Strait. Comm Dis Intell 20, 188–191.
| Vaccination against Japanese encephalitis in the Torres Strait.Crossref | GoogleScholarGoogle Scholar |
[32] Johansen, CA et al.. (2000) Isolation of Japanese encephalitis virus from mosquitoes (Diptera: Culicidae) collected in the Western Province of Papua New Guinea, 1997–1998. Am J Trop Med Hyg 62, 631–638.
| Isolation of Japanese encephalitis virus from mosquitoes (Diptera: Culicidae) collected in the Western Province of Papua New Guinea, 1997–1998.Crossref | GoogleScholarGoogle Scholar |
[33] Mackenzie JS, et al. (2002) Japanese encephalitis as an emerging virus: the emergence and spread of Japanese encephalitis virus in Australasia. In Japanese Encephalitis and West Nile Viruses. Current Topics in Microbiology and Immunology (Mackenzie JS et al., eds). Vol. 267, pp. 49–73. Springer, Berlin, Heidelberg.
| Crossref |
[34] Hanson, JP et al.. (2004) Japanese encephalitis acquired near Port Moresby: implications for residents and travellers to Papua New Guinea. Med J Aust 181, 282.
| Japanese encephalitis acquired near Port Moresby: implications for residents and travellers to Papua New Guinea.Crossref | GoogleScholarGoogle Scholar |
[35] Spicer, PE (1997) Japanese Encephalitis in Western Irian Jaya. J Travel Med 4, 146–147.
| Japanese Encephalitis in Western Irian Jaya.Crossref | GoogleScholarGoogle Scholar |
[36] Spicer, PE et al.. (1999) Antibodies to Japanese encephalitis virus in human sera collected from Irian Jaya. Follow-up of a previously reported case of Japanese encephalitis in that region. Trans R Soc Trop Med Hyg 93, 511–514.
| Antibodies to Japanese encephalitis virus in human sera collected from Irian Jaya. Follow-up of a previously reported case of Japanese encephalitis in that region.Crossref | GoogleScholarGoogle Scholar |
[37] Hanna, JN et al.. (1999) Japanese encephalitis in north Queensland, Australia, 1998. Med J Aust 170, 533–536.
| Japanese encephalitis in north Queensland, Australia, 1998.Crossref | GoogleScholarGoogle Scholar |
[38] van den Hurk, AF et al.. (2019) Japanese encephalitis virus in Australia: from known known to known unknown. Trop Med Infect Dis 4, 38.
| Japanese encephalitis virus in Australia: from known known to known unknown.Crossref | GoogleScholarGoogle Scholar |
[39] Pyke, AT et al.. (2001) The appearance of a second genotype of Japanese encephalitis virus in the Australasian region. Am J Trop Med Hyg 65, 747–753.
| The appearance of a second genotype of Japanese encephalitis virus in the Australasian region.Crossref | GoogleScholarGoogle Scholar |
[40] Ritchie, SA and Rochester, W (2001) Wind-blown mosquitoes and introduction of Japanese encephalitis into Australia. Emerg Infect Dis 7, 900–903.
| Wind-blown mosquitoes and introduction of Japanese encephalitis into Australia.Crossref | GoogleScholarGoogle Scholar |
[41] Johansen, CA et al.. (2004) Flavivirus isolations from mosquitoes collected from Saibai Island in the Torres Strait, Australia, during an incursion of Japanese encephalitis virus. Med Vet Entomol 18, 281–287.
| Flavivirus isolations from mosquitoes collected from Saibai Island in the Torres Strait, Australia, during an incursion of Japanese encephalitis virus.Crossref | GoogleScholarGoogle Scholar |
[42] Van Den Hurk, AF et al.. (2006) Short report: the first isolation of Japanese encephalitis virus from mosquitoes collected from mainland Australia. Am J Trop Med Hyg 75, 21–25.
[43] Waller, C et al.. (2022) Japanese encephalitis in Australia — a sentinel case. N Engl J Med 387, 661–662.
| Japanese encephalitis in Australia — a sentinel case.Crossref | GoogleScholarGoogle Scholar |
[44] Sikazwe, C et al.. (2022) Molecular detection and characterisation of the first Japanese encephalitis virus belonging to genotype IV in Australia. PLoS Negl Trop Dis , .
[45] Australian Department of Agriculture, Fisheries, and Forestry (2022) Japanese encephalitis detected in eastern Australia. 1 March. https://www.awe.gov.au/about/news/media-releases/japanese-encephalitis-virus (accessed 30 September 2022)
[46] Australian Department of Health and Aged Care (2022) Japanese encephalitis virus situation declared a Communicable Disease Incident of National Significance. 4 March. https://www.health.gov.au/news/japanese-encephalitis-virus-situation-declared-a-communicable-disease-incident-of-national-significance (accessed 1 October 2022)
[47] Australian Department of Agriculture, Fisheries and Forestry (2022) Japanese encephalitis. Updated 29 July. https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/animal/japanese-encephalitis (accessed 1 October 2022)
[48] Australian Department of Health and Aged Care (2022) Japanese encephalitis virus (JEV). Current status, 19 July. Japanese encephalitis virus (JEV) | Australian Government Department of Health and Aged Care (accessed 1 October 2022)
[49] Northern Territory Government (2022) Japanese encephalitis in animals. Updated 19 July. https://nt.gov.au/industry/agriculture/livestock/animal-health-and-diseases/japanese-encephalitis-in-animals#:~:text=Northern% 20Territory,and% 20Cox% 2DDaly% 20unincorporated% 20areas (accessed 30 September 2022)
[50] National Feral Pig Action Plan. Japanese encephalitis virus (JEV) Action Plan Fact Sheet. https://feralpigs.com.au/wp-content/uploads/2022/06/JEV-Factsheet-27-June-2022.pdf (accessed 10 October 2022)
[51] South Australia Arid Lands Landscape Board. Notifiable diseases detected in feral pigs. Across the Outback, 2022, Issue 97, October, p. 11. https://www.landscape.sa.gov.au/saal/news-resources/publications (accessed 10 October 2022)
[52] Appaiahgari, MB and Vrati, S (2012) Clinical development of IMOJEV®—a recombinant Japanese encephalitis chimeric vaccine (JE-CV). Expert Opin Biol Ther 12, 1251–1263.
| Clinical development of IMOJEV®—a recombinant Japanese encephalitis chimeric vaccine (JE-CV).Crossref | GoogleScholarGoogle Scholar |
[53] Firbas, C and Jilma, B (2015) Product review on the JE vaccine IXIARO. Hum Vaccin Immunother 11, 411–420.
| Product review on the JE vaccine IXIARO.Crossref | GoogleScholarGoogle Scholar |
[54] Igarashi, A (2002) Control of Japanese encephalitis in Japan: immunization of humans and animals, and vector control. Curr Top Microbiol Immunol 267, 139–152.
| Control of Japanese encephalitis in Japan: immunization of humans and animals, and vector control.Crossref | GoogleScholarGoogle Scholar |
[55] van den Hurk, AF et al.. (2022) The emergence of Japanese encephalitis virus in Australia in 2022: existing knowledge of mosquito vectors. Viruses 14, 1208.
| The emergence of Japanese encephalitis virus in Australia in 2022: existing knowledge of mosquito vectors.Crossref | GoogleScholarGoogle Scholar |
[56] Daniels P et al. (2000) Assessment of the potential of Australian fauna as maintenance or amplifying hosts of Japanese encephalitis (JE) virus. In Report to the Northern Australian Quarantine Strategy. CSIRO Animal Health Laboratory, Geelong, Australia. pp. 1–3.
[57] New South Wales Health Department. Summary of NSW Japanese encephalitis virus serosurvey results. https://www.health.nsw.gov.au/environment/pests/vector/Documents/jev-serosurvey-report.pdf (accessed 5 November 2022)
[58] Pham, D et al.. (2022) Emergence of Japanese encephalitis in Australia: a diagnostic perspective. Pathology 54, 669–677.
| Emergence of Japanese encephalitis in Australia: a diagnostic perspective.Crossref | GoogleScholarGoogle Scholar |
