Four more cases of Japanese encephalitis virus have been confirmed in SA residents, bringing the number to eight - including one death.
The Department for Health and Wellbeing's health protection and licensing services executive director Chris Lease said they had been investigating several cases of encephalitis in SA, to see if they were linked with the spread of JE.
"We can confirm that one of the additional cases includes the person who we previously reported had sadly passed away earlier this month," he said.
"Of our eight total JEV cases in SA, five remain in hospital and two have since been discharged.
"Two people in hospital with encephalitis remain under investigation."
Dr Lease said it was "crucial" that all SA residents continue to take extra precautions against mosquitoes.
"People planning activities around the River Murray are warned to be especially vigilant, particularly between dusk and dawn when mosquitoes are most active," he said.
Most people who are infected with flaviviruses such as JEV, Kokobera virus, West Nile virus, and Murray Valley encephalitis virus are asymptomatic or develop a mild febrile illness.
A small proportion of infected people will develop encephalitis, which may be fatal or cause long-term neurological damage.
Symptoms of encephalitis may include confusion, headaches, neck stiffness, tremors, drowsiness and seizures.
Families with young children should be especially mindful of mosquito bites, as children under five years-of-age have a higher risk of developing encephalitis if infected with JEV.
Dr Lease said while there were some vaccines available for flaviviruses, personal and household protective measures remained the first line of defence in avoiding mosquito bites and other mosquito-borne diseases such as Ross River virus infection.
"If you are outside, apply an insect repellent containing DEET or picaridin, and try to stop mosquitoes coming indoors," Dr Lease said.
"Cover up with long, loose fitting and light-coloured clothing. Mosquitoes can bite through tight clothing such as jeans or leggings.
"Mosquito coils can also be useful when outside but do not leave them burning unattended and always remember to extinguish them carefully by breaking the smouldering end off, immersing it in water and storing it away from the house to completely cool."
Dr Lease said it was important that people remained vigilant in protecting themselves against mosquito bites, particularly during periods of warmer weather when mosquito activity was high."
The Department of Primary Industries and Regions is undertaking surveillance measures within SA to monitor for JEV and continues to work closely with the Department for Health and Wellbeing.
The normal lifecycle of JEV is between waterbirds and mosquitoes, which may then accidently spill over to pigs and horses, and owners are reminded to remain vigilant.
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