SA Health widens mosquito vaccine amid concerns of bumper mozzie season and risks of Japanese encephalitis virus

South Australia’s unusually wet spring has fuelled concerns of a big mosquito season as authorities widen a critical vaccination against a rare, but deadly, insect disease.

South Australia’s unusually wet spring has fuelled concerns of a big mosquito season as authorities widen a critical vaccination against a rare, but deadly, insect disease.

The state government will spend $1.84m to expand a free vaccine against Japanese encephalitis virus, to target thousands of River Murray locals at “greater risk” of contracting the mosquito-borne bug.

Doctors say mosquito bites spread the virus to humans through but while most people don’t experience any illness, extreme cases can cause life-threatening brain infections.

Symptoms include confusion, headaches, neck stiffness, tremors, drowsiness and seizures.

SA Health, which warned GPs about the “important rollout” this week, has this year recorded nine cases in Loxton Waikerie, Murray Bridge and Coorong councils as well as the Adelaide Hills. Two patients have died.

Residents are being urged to take precautions against mosquito-borne illnesses after a wet spring.

In the past five years one case was reported in 2020, but that patient contracted it overseas. Experts warn of a bigger mosquito season, which starts in the summer months, after a wetter than usual few months.

A third consecutive La Nina weather event has sparked “conditions which presents increased risk of mosquito-borne disease, including JEV, this year”, according to Health Minister Chris Picton.

“This is the first time we’ve seen locally acquired cases of JEV in South Australia, and we’re taking action to stop the virus spreading,” he said.

“Wet weather and high humidity have created an ideal breeding ground for mosquitoes. We’ve also had a lot of backwaters around the River Murray already filled, further giving mosquitoes somewhere to breed.

“Rolling these vaccines out quickly and expanding our surveillance programs will be vital in helping fight the bite.”

Health Minister Chris Picton has urged people around the river to get the vaccine. Picture: NCA NewsWire / Naomi Jellicoe

The new SA Health jab rollout will target residents and workers in a postcode within 5km of the River Murray, Lake Alexandrina and Lake Albert.

Residents must be older than two months of age and spend at least four hours outdoors. Rules are similar for workers but holiday homeowners or people with a second residence are not included.

More than 23,000 vaccines are available at eight SA Health pop-up clinics and seven GP facilities. Chemists are included in coming weeks.

At least 900 people in high-risk groups – including piggery workers and those with direct contact with mosquitoes – have already been vaccinated.

Deputy chief public health officer Dr Chris Lease urged repellent use, loose fitting clothing outdoors and accommodation nets or screens.