“Don’t Get Bitten”: The Japanese “Mosquito” Disease Explained

By: Michael Crooks

A new virus is not exactly what anyone wants to hear about right now, but while the “mosquito” disease has arrived in Australia there are two important things to note: it is not human-to-human transmissible and prevention is key. 

Two Australians have now died from the mosquito-borne virus, Japanese encephalitis (JEV).  NSW Health reported that a man in his 70s died from the virus in a Sydney hospital on February 13. And in Victoria, authorities confirmed a man in his 60s had died from JEV on February 28.

What is it?

JEV is a virus that is transmitted to humans via mosquitos. According to the World Health Organization (WHO), the virus comes from the same family of diseases as dengue, yellow fever and West Nile viruses. There are an estimated 68,000 clinical cases every year in Asia.

JEV comes from the same family of diseases as dengue, yellow fever and West Nile viruses. It was first identified in Australia in pigs in late February.

JEV comes from the same family of diseases as dengue, yellow fever and West Nile viruses.


While most people who contract JEV will experience no symptoms, some will suffer fever, headache and vomiting. More extreme symptoms include coma, and more rarely, neurological damage or death.

Approximately one in 250 infections results in severe clinical illness. Authorities urge those who think they may have been infected with JEV to seek medical assistance.

Is it transmissible between humans?

No. According to the Australian Government’s health advice, JEV cannot be transmitted from human to human. It is also not transmitted by eating meat from an infected animal. But a person can contract the virus indirectly via the bite of a mosquito.

JEV is spread through mosquito bites “and is more common in areas of increased mosquito activity”, reports health.gov.au.


Griffith University’s Dr Ali Zaid, an expert in the impact of mosquito-borne viruses, advises that to avoid JEV people should protect themselves from mosquito bites.

“This is currently the best ‘population-scale’ approach,” he said. “Prevention is always better than a cure”.

“The use of effective mosquito repellents – that contain DEET [diethyltoluamide] or Picaridin, for instance – is highly recommended, and avoiding outdoor areas during dusk and dawn.”


While there is no cure for JEV, people can relieve their symptoms through the normal means: rest, fluids and pain relief medication. In rare cases, hospitalisation is required.


There is a vaccine available, but authorities aren’t urging people to get jabbed just yet.  Dr Zaid says that it’s more important for those who are likely to come in contact with the virus to get vaccinated.

“This means people who live in areas where the mosquito species that carries the virus is known to be quite abundant,” Dr Zaid said.

“In the context of recent events, I would expect people who work in and/or around piggeries to be offered the vaccine, since they are exposed to both mosquitoes and pigs who act as amplifying hosts.”

Dr Zaid said it’s worth remembering that transmission of JEV “requires a mosquito and an amplifying host, like pigs, or water birds”, he said.

“For example human-mosquito-human is unlikely to result in effective transmission, but pig-mosquito-human is.”


According to WHO, major outbreaks of JEV occur every two to 15 years.

“JEV transmission intensifies during the rainy season,” a WHO statement read, referring to the breeding of mosquitos.

Still, according to WHO, “there has not yet been evidence of increased JEV transmission following major floods or tsunamis. The spread of JEV in new areas has been correlated with agricultural development”.

For more information visit the NSW Health JEV info page.

Article supplied with thanks to Hope Media.

About the Author: Michael is a journalist contributor at radio station Hope 103.2.

Feature image: Photo by Shardar Tarikul Islam on Unsplash  

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