Australia disease surveillance

Murray Valley encephalitis in Australia, 2025-2026 surveillance data

Mosticare tracks Murray Valley encephalitis in Australia through South Australia's weekly notifications and New South Wales mosquito surveillance; the rest of Australia is not included. In the 8 weeks from 30 August to 24 October 2026, South Australia recorded no Murray Valley encephalitis notifications, according to SA Health. In the 2025-26 season, New South Wales sentinel chicken flocks recorded no Murray Valley encephalitis seroconversions.

Last updated · 27 October 2026 · CC BY 4.0

Murray Valley encephalitis in Australia

South Australia notifications

Weekly Report - Last 8 Weeks, reporting period 2026-08-30 to 2026-10-24, SA Health, Communicable Disease Control Branch. Weekly counts of notifications to the South Australian Notifiable Condition System, by week ending. SA Health extracts them weekly and states they are subject to change, so the newest report replaces earlier figures for the same week. The report does not say whether a case was acquired locally or overseas and does not name a vector. South Australia only. Source: SA Health, CC BY 4.0.
Week endingNotifications
5 September 20260
12 September 20260
19 September 20260
26 September 20260
3 October 20260
10 October 20260
17 October 20260
24 October 20260
8 weeks0

New South Wales mosquito surveillance, 2025-26 season

Sentinel chicken flocks recorded no Murray Valley encephalitis seroconversions.

A mosquito virus detection means virus was found in at least one mosquito of a trapped sample; a sentinel chicken positive means one or more chickens in a flock tested positive for antibodies to that virus for the first time. Neither is a human case, and high mosquito numbers do not always mean more human cases. Site coordinates are the mid-point of a broader location, not the exact trap. Trapping runs from around October to April. New South Wales only; seasons here run 1 July to 30 June. Source: NSW Health, CC BY 3.0 AU.

Vector species records

Presence-only and effort-biased: points show where mosquitoes were recorded, not where they are absent or how abundant they are. Species-level records only. 8,521 CC BY-NC records were excluded at retrieval, so a missing species is 'no openly licensed record', not confirmed absence. A specimen published by two datasets counts once: a compilation, sequence repository or mirror counts only the records beyond what the first-hand publisher holds for the same species, point and year, so the counts are a lower bound on distinct records. Records stacked on a country or state centroid, a placeholder rather than a place, are dropped. Coordinates are rounded to 0.01 degrees. States are assigned from Natural Earth 1:50m polygons; a record off the generalised coastline (within 0.25 degrees) or on an island (within 2.0 degrees) is placed in the nearest state, and a record whose stated coordinate uncertainty reaches past its state's boundary counts for Australia only. Source: GBIF, CC0 1.0 and CC BY 4.0.
SpeciesRecordsWhere recordedYears
Culex annulirostris2,049Queensland 1,186, Northern Territory 349, Western Australia 190, New South Wales 141, Victoria 129, Australian Capital Territory 7, South Australia 3, uncertain location 441913 to 2024

Australia: coverage by state and all sources

About Murray Valley encephalitis

Murray Valley encephalitis virus is the most serious of the endemic arboviruses in Australia. Most infections cause no symptoms; clinical encephalitis develops in about 1 in 150 to 1 in 1,000 infections. Encephalitic disease has a case fatality rate of 15 to 30%, and 30 to 50% of survivors have lasting neurological effects. The virus is maintained in the north of Western Australia and the Top End of the Northern Territory, mainly in a cycle between water birds and Culex annulirostris mosquitoes (Selvey et al., PLOS Neglected Tropical Diseases, 2014). There is no vaccine (NSW Health).

Frequently asked questions

How many Murray Valley encephalitis notifications has South Australia reported recently?

SA Health recorded no Murray Valley encephalitis notifications in South Australia in the 8 weeks from 30 August to 24 October 2026. Counts are by week of notification, locally and overseas acquired cases are combined, and the counts are subject to change. South Australia only. The rest of Australia is not included.

Has Murray Valley encephalitis been found in New South Wales mosquito surveillance?

In the 2025-26 season, New South Wales sentinel chicken flocks recorded no Murray Valley encephalitis seroconversions. A seroconversion means a sentinel chicken tested positive for antibodies to the virus for the first time. It is not a human case.

Which mosquito spreads Murray Valley encephalitis?

Culex annulirostris. Selvey et al. (PLOS Neglected Tropical Diseases, 2014) describe the virus as maintained mainly in a cycle between water birds and Culex annulirostris mosquitoes in the north of Western Australia and the Top End of the Northern Territory.

How large was the 2011 Murray Valley encephalitis outbreak?

Selvey et al. (2014) report 17 confirmed cases across Australia in the 2011 outbreak, 3 of whom died, a crude case fatality rate of 18%.

Sources

  • SA Health, Weekly Report - Last 8 Weeks (notifiable conditions, South Australia)Source: SA Health, Weekly Report - Last 8 Weeks, CC BY 4.0. Extracted and reformatted by Mosticare. CC BY 4.0
  • NSW Arbovirus Surveillance and Mosquito Monitoring Program, arbovirus data (Data.NSW)© State of New South Wales NSW Ministry of Health. For current information go to www.health.nsw.gov.au. Arbovirus data, Data.NSW, CC BY 3.0 AU. Reformatted by Mosticare. CC BY 3.0 AU
  • GBIF occurrence records, mosquitoes (Culicidae) in Australia, CC0 1.0 and CC BY 4.0 onlyGBIF.org occurrence data. Dataset publishers are credited per dataset. CC0 1.0 and CC BY 4.0
    32 GBIF datasets
    • Walter Reed Biosystematics Unit, Smithsonian Institution. Mosquito Occurrence Dataset. Occurrence dataset https://doi.org/10.15468/tw2y9b accessed via GBIF.org on 2026-10-27. CC BY 4.0, 8,959 records
    • Queensland Museum (2026). Queensland Museum provider for OZCAM. Occurrence dataset https://doi.org/10.15468/lotsye accessed via GBIF.org on 2026-10-27. CC BY 4.0, 6,897 records
    • Commonwealth Scientific and Industrial Research Organisation (2026). Australian National Insect Collection. Occurrence dataset https://doi.org/10.15468/s1hm8r accessed via GBIF.org on 2026-10-27. CC BY 4.0, 2,299 records
    • Museums Victoria (2026). Museums Victoria provider for OZCAM. Occurrence dataset https://doi.org/10.15468/lp1ctu accessed via GBIF.org on 2026-10-27. CC0 1.0, 1,423 records
    • European Bioinformatics Institute (EMBL-EBI), GBIF Helpdesk (2026). INSDC Sequences. Version 1.190. European Nucleotide Archive (EMBL-EBI). Occurrence dataset https://doi.org/10.15468/sbmztx accessed via GBIF.org on 2026-10-27. CC BY 4.0, 1,073 records
    • iNaturalist contributors, iNaturalist (2026). iNaturalist Research-grade Observations. iNaturalist.org. Occurrence dataset https://doi.org/10.15468/ab3s5x accessed via GBIF.org on 2026-10-27. CC BY 4.0, CC0 1.0, 980 records
    • The International Barcode of Life Consortium (2026). International Barcode of Life project (iBOL). Occurrence dataset https://doi.org/10.15468/inygc6 accessed via GBIF.org on 2026-10-27. CC BY 4.0, 662 records
    • NSW Department of planning, industry and environment (2026). NSW BioNet Atlas. Occurrence dataset https://doi.org/10.15468/14jd9g accessed via GBIF.org on 2026-10-27. CC BY 4.0, 383 records
    • Atlas of Living Australia (2026). Dandjoo. Occurrence dataset https://doi.org/10.15468/4vq6up accessed via GBIF.org on 2026-10-27. CC BY 4.0, 361 records
    • Australian Museum (2026). Australian Museum provider for OZCAM. Occurrence dataset https://doi.org/10.15468/e7susi accessed via GBIF.org on 2026-10-27. CC BY 4.0, 305 records
    • Kraemer M U G, Sinka M E, Duda K A, Mylne A, Shearer F M, Brady O J, Messina J P, Barker C M, Moore C G, Carvalho R G, Coelho G E, Van Bortel W, Hendrickx G, Schaffner F, Wint G R W, Elyazar I R F, Teng H, Hay S I, Page R D M. Global compendium of Aedes aegypti occurrence. Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow. Occurrence dataset https://doi.org/10.15468/bgmqmr accessed via GBIF.org on 2026-10-27. CC0 1.0, 290 records
    • European Molecular Biology Laboratory Australia (2019). European Molecular Biology Laboratory Australian Mirror. Occurrence dataset https://doi.org/10.15468/ypsvix accessed via GBIF.org on 2026-10-27. CC BY 4.0, 212 records
    • Victorian Department of Energy, Environment and Climate Action (2026). Victorian Biodiversity Atlas. Occurrence dataset https://doi.org/10.15468/khlfs3 accessed via GBIF.org on 2026-10-27. CC BY 4.0, 89 records
    • Ciliberti P, Creuwels J (2026). Naturalis Biodiversity Center (NL) - Diptera. Naturalis Biodiversity Center. Occurrence dataset https://doi.org/10.15468/cl6p3l accessed via GBIF.org on 2026-10-27. CC0 1.0, 40 records
    • NatureMap (2019). Carnarvon Basin Wetland Invertebrate Survey. Occurrence dataset https://doi.org/10.15468/gpgvgr accessed via GBIF.org on 2026-10-27. CC BY 4.0, 38 records
    • NatureMap (2019). Carnarvon Basin (Aquatic Projects) - Invertebrates. Occurrence dataset https://doi.org/10.15468/6vptrw accessed via GBIF.org on 2026-10-27. CC BY 4.0, 38 records
    • NSW Department of Primary Industries (2026). NSW DPI Biosecurity Collections. Occurrence dataset https://doi.org/10.15468/7k7b25 accessed via GBIF.org on 2026-10-27. CC BY 4.0, 30 records
    • Data Management A (2026). ALA species sightings and OzAtlas. Atlas of Living Australia. Occurrence dataset https://doi.org/10.15468/jayxmn accessed via GBIF.org on 2026-10-27. CC BY 4.0, 26 records
    • NatureMapr (2026). NatureMapr. Occurrence dataset https://doi.org/10.15468/uye32x accessed via GBIF.org on 2026-10-27. CC BY 4.0, 24 records
    • Murray-Darling Basin Authority (2019). MDFRC macroinvertebrate survey. Occurrence dataset https://doi.org/10.15468/paioao accessed via GBIF.org on 2026-10-27. CC BY 4.0, 8 records
    • Kraemer M U G, Sinka M E, Duda K A, Mylne A, Shearer F M, Brady O J, Messina J P, Barker C M, Moore C G, Carvalho R G, Coelho G E, Van Bortel W, Hendrickx G, Schaffner F, Wint G R W, Elyazar I R F, Teng H, Hay S I, Page R D M. Global compendium of Aedes albopictus occurrence. Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow. Occurrence dataset https://doi.org/10.15468/7apj8n accessed via GBIF.org on 2026-10-27. CC0 1.0, 5 records
    • Kelly T, Cooyou E, Murphy A, Cooyou J, Lewis Y, Barnes P, Andrews J, Brown J, Gudge S, Suominen S, Provoost P, Gillard E, Douvere F, Appeltans W (2026). UNESCO eDNA expedition in Ningaloo Coast (Australia): May 2023. Version 2.1. OBIS Secretariat. Occurrence dataset https://doi.org/10.25607/290ncx accessed via GBIF.org on 2026-10-27. CC0 1.0, 5 records
    • Tasmanian Museum and Art Gallery (2026). Tasmanian Museum and Art Gallery provider for OZCAM. Occurrence dataset https://doi.org/10.15468/ijp8p9 accessed via GBIF.org on 2026-10-27. CC BY 4.0, 4 records
    • Atlas of Living Australia (2024). Kangaroo Island Insect Collection. Occurrence dataset https://doi.org/10.15468/rhwnkz accessed via GBIF.org on 2026-10-27. CC BY 4.0, 3 records
    • Grinter C, Fong J (2026). CAS Entomology (ENT). Version 6.389. California Academy of Sciences. Occurrence dataset https://doi.org/10.15468/3ibpmo accessed via GBIF.org on 2026-10-27. CC0 1.0, 2 records
    • Wild A (2026). University of Texas, Biodiversity Center, Entomology Collection (UTIC). Version 1.338. University of Texas at Austin, Biodiversity Collections. Occurrence dataset https://doi.org/10.15468/sanyq7 accessed via GBIF.org on 2026-10-27. CC0 1.0, 2 records
    • South Australian Museum (2025). South Australian Museum Adelaide provider for OZCAM. Occurrence dataset https://doi.org/10.15468/wz4rrh accessed via GBIF.org on 2026-10-27. CC BY 4.0, 2 records
    • North Sydney Council (2026). Wildlife Watch NSC. Occurrence dataset https://doi.org/10.15468/4x6bze accessed via GBIF.org on 2026-10-27. CC BY 4.0, 1 record
    • Hubley B (2024). Royal Ontario Museum - Entomology Collection. Version 2.0. Royal Ontario Museum. Occurrence dataset https://doi.org/10.5886/p69k4g accessed via GBIF.org on 2026-10-27. CC BY 4.0, 1 record
    • Western Australian Museum (2024). Western Australian Museum provider for OZCAM. Occurrence dataset https://doi.org/10.15468/5qt0dm accessed via GBIF.org on 2026-10-27. CC BY 4.0, 1 record
    • Orrell T, Informatics and Data Science Center - Digital Stewardship (2026). NMNH Extant Specimen Records (USNM, US). Version 1.113. National Museum of Natural History, Smithsonian Institution. Occurrence dataset https://doi.org/10.15468/hnhrg3 accessed via GBIF.org on 2026-10-27. CC0 1.0, 1 record
    • Gilligan J, Wood C, DiBattista J, Jain F, Suominen S, Provoost P, Gillard E, Douvere F, Appeltans W (2026). UNESCO eDNA expedition in Lord Howe Island Group (Australia): January 2023. Version 1.1. OBIS Secretariat. Occurrence dataset https://doi.org/10.15468/mpevs2 accessed via GBIF.org on 2026-10-27. CC0 1.0, 1 record

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About this data

Mosticare aggregates and re-publishes vector-borne disease surveillance from ECDC, EFSA, national and state ministries of health, and GBIF. Mosticare is an aggregator, not a primary surveillance authority, every figure on this page cites the originating source and is independently verifiable. This is a partial aggregation; for the complete EU/EEA totals, ECDC is the primary source.

The incidence records and weekly notification counts are published as free, machine-readable feeds under CC BY 4.0, the point-in-time incidence snapshot at /threat-map/feed.json (JSON Schema) and the multi-year trends at /threat-map/feed/trends.json (JSON Schema). The mosquito surveillance and species records on this page are not in the feeds. See the Global Mosquito Threat Map and the full data room.