Course Access
Dengue fever
What is it?
Dengue fever is a viral infection that is transmitted through the bite of infected mosquitos, and is prevalent in tropical and subtropical regions worldwide1. Most areas of Australia do not have the types of mosquitos that carry the dengue virus, however outbreaks can still occur in North Queensland each year when someone becomes infected overseas and is bitten by a mosquito in Australia, that mosquito can then spread the virus to others.
In 2023 the World Health Organization reported the highest number of dengue cases recorded, more than 6.5 million cases and 7300 deaths were reported in over 80 countries1. During this time period Australia recorded 1117 cases, with most cases occurring in Queensland (53%) followed by New South Wales (16.5%)2.
In 2011, the World Mosquito Program began releasing Aedes aegypti mosquitos infected with the Wolbachia bacteria in parts of Queensland3. The Wolbachia bacteria spreads through mosquito populations and works to supress population growth and block virus replication inside mosquitos, reducing their ability to transmit viruses including dengue, yellow fever and Zika3. Since then, local dengue transmission has effectively disappeared in Queensland3.
However, following this successful elimination program, in January 2025 Townsville recorded its first locally acquired case of dengue fever in five years4. And in May 2025, the Cairns and Hinterland Hospital confirmed the first locally acquired case of dengue fever in seven years, this case was in a person who has had no recent travel outside the region5. Despite these local cases, the risk to the public remains low.
Signs and Symptoms
Dengue fever is categorised into two groups by the World Health Organization (WHO), classic/uncomplicated or severe. Classic or uncomplicated dengue can present with a mild fever lasting around 3-5 days, or with a sudden onset high fever, severe headache, orbital pain, myalgia or rash2,6. While severe dengue fever can be life threatening and include haemorrhage and thrombocytopenia2.
The incubation period for dengue fever is 3 – 14 days after being bitten by the infected mosquito6.
How is it transmitted?
Dengue fever is caused by one of 4 dengue viruses, which are primarily carried and spread by the Aedes aegypti and Aedes albopictus mosquitos7. Dengue is not transmitted from person-to-person.
Mosquitos become infected by biting people who are infected with the dengue virus, that can then be spread through bites to other people1. The mosquito remains infective for the rest of its life, and can continue to spread the virus every time it bites someone6.
At risk groups?
People are at risk of dengue fever when travelling to a dengue-affected area, including tropical and sub-tropical regions of Asia, Africa and South America8.
While the risk to the public in Australia is considered to be low, people are urged to be alert to the symptoms of Dengue fever.
Prevention?
Dengue fever can be prevented through measures to control mosquitos, personal protection through wearing long, loose fitting and light coloured clothing, using personal mosquito repellents, and avoiding mosquito prone areas6.
References
1. World Health Organization. Dengue and severe dengue WHO. https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue
2. Silburn A, Arndell J. The impact of dengue viruses: Surveillance, response, and public health implications in Queensland, Australia. Public Health in Practice. 2024/12/01/ 2024;8:100529. doi:https://doi.org/10.1016/j.puhip.2024.100529
3. World Mosquito Program. Wolbachia mosquitos block dengue across Australia’s far north. Monash University, . https://www.worldmosquitoprogram.org/en/news-stories/media-releases/wolbachia-mosquitoes-block-dengue-across-australias-far-north
4. Chomicki C. Mosquito-norne dengue fever, Japanese encephalitis detected in Queensland. ABC News. https://www.abc.net.au/news/2025-01-17/mosquito-dengue-fever-japanese-encephalitis-cases-queensland/104828632
5. Strohfeldt. C. Cairns records locally caught case of dengue amid global surge. Sydney Morning Herald. Updated May 14 2025. https://www.smh.com.au/national/queensland/cairns-records-locally-caught-case-of-dengue-amid-global-surge-20250514-p5lz05.html
6. Victorian Department of Health. Dengue virus disease. Victorian Department of Health. https://www.health.vic.gov.au/infectious-diseases/dengue-virus-disease
7. Health direct. Dengue fever. https://www.healthdirect.gov.au/dengue-fever
8. NSW Health. Dengue fact sheet. NSW Government. Updated 18 April 2024. https://www.health.nsw.gov.au/Infectious/factsheets/Pages/dengue.aspx