Japanese encephalitis (JE) is a serious disease caused by the Japanese encephalitis virus (JEV). It is spread to humans by infected mosquitoes. Humans are not able to pass JEV to other humans.

NSW Health is monitoring the evolving situation in NSW concerning Japanese Encephalitis virus. This page will be updated weekly with the latest information on confirmed cases.

Confirmed Japanese encephalitis (JE) cases by Local Health District of residence to 4pm 15 May 2022

Local Health District (LHD)Total cases (deaths)
Murrumbidgee8 (1)
Far West2
Southern NSW
1
​Western NSW
1​
​Nepean Blue Mountains
1​
Total13 (1)

*Confirmatory testing for JE is complex and takes time, therefore day of confirmation may be well after onset of illness.

Confirmed cases have potentially been exposed in these Local Government Areas:

  • Balranald
  • Berrigan
  • Carrathool
  • Dubbo
  • Federation
  • Goulburn Mulwaree
  • Griffith
  • Lockhart
  • Temora
  • Wentworth


Mosquito Surveillance in NSW

NSW Health undertakes mosquito surveillance across NSW from November to April each year. In response to Japanese Encephalitis (JE) outbreak, NSW Heath has expanded the mosquito surveillance network around the infected piggeries and to areas where human cases have been reported. The mosquito samples (including samples collected prior to JE outbreak) are being tested for Japanese Encephalitis virus (JEV). Positive results are documented in the table below.

LocationDate CollectedDate TestedJEV ResultRisk
Forbes17 January 202227 March 2022PositiveLow*
Forbes24 January 202227 March 2022PositiveLow*
​Wagga Wagga
10 January 2022​2 April 2022​Positive​Low*​

*Recent samples have tested negative for JEV

Sentinel Chicken Surveillance in NSW

NSW Health undertakes sentinel chicken surveillance in inland areas of NSW from December to April each year. The blood samples collected from the chicken flocks during the surveillance season are being tested for Japanese Encephalitis virus (JEV). Positive results are documented in the table below.

LocationDate collectedDate testedJEV resultRisk
Deniliquin
(1 chicken out of the flock of 15)
20 February 202210 April 2022Negative Low*
28 February 20225 April 2022PositiveLow*
6 March 20225 April 2022PositiveLow*

The NSW Arbovirus Surveillance and Mosquito Monitoring Program is closing the season for 2021-22, with the week ending 14 May 2022 being the final week. The start date of the 2022-23 season will be dependent on climatic conditions in Spring. Weekly reports from the current season and past seasons can be found at Surveillance - Vector-borne diseases.

How is it spread?

JE is spread by the bite of infected Culex species mosquitoes which are commonly found in NSW.

The virus is spread when mosquitoes bite an infected animal and the mosquito then bites a human. Infected pigs and some waterbirds are the animals more likely to infect mosquitoes.

Humans cannot get infected with JEV by touching an infected animal or eating animal products including pork or poultry products.

Who is at risk?

JEV has recently been identified in commercial piggeries in locations in NSW, Queensland, Victoria and South Australia. Local infection risks in NSW are likely highest among:

  • people working at or living close to piggeries, or both, which have tested positive for JEV
  • people who engage in outdoor activities (such as camping, fishing, hiking) near significant mosquito populations, particularly near waterways.

How is it prevented?

The best way to avoid JEV is to avoid mosquito bites.

The mosquitoes that transmit JEV are most active at dawn and dusk and into the evening.

Protect yourself

  • Wear light, loose-fitting long-sleeved shirts, long pants and covered footwear and socks (to reduce skin exposure). There are insecticides (for example, permethrin) available for treating clothing for those spending extended periods outdoors.
  • Apply repellent to all areas of exposed skin, especially those that contain DEET, picaridin, or oil of lemon eucalyptus which are the most effective against mosquitoes. The strength of a repellent determines the duration of protection with the higher concentrations providing longer periods of protection. Always check the label for reapplication times.
  • Reapply repellent after swimming. The duration of protection from repellent is also reduced with perspiration, such as during strenuous activity or hot weather so it may need to be reapplied more frequently.
  • Apply the sunscreen first and then apply the repellent. Be aware that DEET-containing repellents may decrease the sun protection factor (SPF) of sunscreens so you may need to re-apply the sunscreen more frequently.
  • For children in particular - most skin repellents are safe for use on children aged 3 months and older when used according to directions, although some formulations are only recommended for children aged 12 months and older - always check the product. Infants aged less than 3 months can be protected from mosquitoes by using an infant carrier draped with mosquito netting that is secured along the edges.

Vaccination

A safe and effective vaccine for JE is available for people aged 2 months and older.

What are the symptoms?

Less than 1% of people infected with JEV will experience symptoms.

Some infected people experience an illness with fever and headache.

People with severe infection may experience:

  • neck stiffness
  • disorientation
  • tremors
  • coma
  • seizures.

If you have any of these symptoms please seek medical treatment.


Current as at: Monday 16 May 2022
Contact page owner: Communicable Diseases