JEV: Deadly virus could spread after floods, warns QIMR scientists

Queensland’s top scientists are concerned that the deadly Japanese encephalitis virus will spread to coastal areas following the floods and the anticipated explosion of mosquitoes.

The recent extreme weather event has created ideal conditions for mosquito breeding.

Queensland’s top scientists are concerned that the deadly Japanese encephalitis virus will spread to coastal areas following the floods and the anticipated explosion of mosquitoes.

QIMR Berghofer’s Mosquito Control Laboratory’s Brian Johnson said: “While JEV has been circulating in the Darling Downs and Murrumbidgee region, the large flooding resulting from Cyclone Alfred may increase the risk of its spread to new areas.”

Five cases of Japanese encephalitis were reported in Queensland in 2022, resulting in one death and there has been none until this year with one case recorded in the Darling Downs and one in Townsville.

The QIMR expert warns that the recent extreme weather event has created ideal conditions for mosquito breeding, raising concerns about potential outbreaks of Japanese encephalitis and Ross River virus.

Dr Johnson said that warm seasonal temperatures, combined with large areas of standing water created by the heavy rains and coastal flooding from Cyclone Alfred, provide the perfect environment for the spread of disease.

“Residents should expect a significant increase in mosquito numbers beginning in one or two weeks after the cessation of rain and the settling of flood waters. Elevated mosquito populations are likely to persist for several weeks until floodwaters recede,” he said.

While there is a vaccine available for Japanese encephalitis, there are no treatments for arboviruses readily available for humans.

Researchers at QIMR Berghofer are currently working to uncover new treatments for Japanese encephalitis.

Daniel Rawle, from QIMR Berghofer’s Emerging Viral Diseases laboratory, said that while only one in 250 people infected with Japanese encephalitis develops symptoms, the disease can be severe for those who do. Among symptomatic cases, one-third will die from the illness, while another third will become seriously ill, requiring long-term hospital care and potentially experiencing prolonged or permanent disability.

“We are trying to understand why Japanese encephalitis causes mild symptoms in some people but leads to severe illness or even death in others. Our research focuses on how this virus infects neurons and affects the brain in different ways, helping us find better ways to treat and prevent the disease,” Dr Rawle said.

HOW TO PROTECT YOURSELF

* Wear long sleeves and long trousers when outdoors, particularly at dawn and dusk when mosquitoes are most active

* Apply mosquito repellent to any exposed skin

* Use traditional repellents containing DEET or Picaridin for best results

* Consider natural repellents with lemon eucalyptus oil, but reapply every couple of hours

* Empty water reservoirs around the home including pot plant saucers, clogged rain gutters and pet bowls