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Japanese Encephalitis - reducing your risk

Friday, 22 April 2022

Japanese encephalitis (JE) is a virus that is spread to humans through mosquito bites and may cause a rare and potentially life-threatening infection of the brain.

Mosquito-borne disease transmission is affected by both rainfall and temperature. Recent significant rainfall events are likely to have played a role in the emergence of Japanese Encephalitis in southern Australia because the disease spread relies on mosquitoes, and mosquito numbers are known to increase after significant rainfall events.

There will continue to be an increased risk of mosquito-borne disease transmission following extreme rainfall events; however, it is not known what impact other weather conditions (e.g. drought conditions) may have on the spread of mosquito-borne diseases.

Currently, Japanese encephalitis cases in Victoria have been concentrated around the Murray river region.

As the virus is currently circulating in pig and mosquito populations, it is likely to continue spreading to humans in affected areas. This will be reduced by the introduction of the JEV vaccination program and other control measures such as mosquito control.

At this stage, there is no indication that the virus is circulating in pigs or mosquitoes in Greater Geelong or Surf Coast.

Transmission is likely to decrease in the winter months as mosquito numbers significantly decrease during this time.

Victoria has an extensive and effective mosquito surveillance program. This program monitors the levels of key mosquito species, as well as the presence of key mosquito-borne diseases in Victoria.

Most JE virus infections are asymptomatic, however those with severe infection (less than one per cent) may develop encephalitis (inflammation of the brain) which may lead to death or permanent disability. Usually, symptoms develop 6 to 16 days after being bitten by an infected mosquito.

- JE virus is spread to humans through the bite of an infected mosquito.
- JE virus cannot be spread directly from person to person.
- JE virus cannot be caught through eating pork or pig products.

There are two ways to protect yourself and your family: avoiding mosquito bites and vaccination.

Steps to protect yourself and your family against mosquito-borne diseases include:

- Wearing long, loose fitting clothes outdoors.
- Using mosquito repellents containing picaridin or DEET on all exposed skin.
- Limiting outdoor activity if lots of mosquitoes are about.
- Using ‘knockdown’ fly sprays and plug-in repellent devices indoors.
- Using mosquito coils in small outdoor areas where you gather to sit or eat.
- Making sure your accommodation is mosquito-proof.
- Sleeping under mosquito nets treated with insecticides if you don’t have flywire screens on windows on your home or are sleeping in an untreated tent or out in the open.
- Making sure there is no stagnant water around your home.

For more information on Japanese encephalitis click here.