Warning about Ross River virus as mosquitoes invade backyards

Mosquito populations are exploding across Australia, with experts warning some are carrying a debilitating virus. Here’s how to get them out of your yard.

Australians are being warned to expect an explosion in mosquito populations as we head further into summer, with wet and warm weather set to create ideal breeding conditions.

The number of mosquitoes caught in monitoring traps has already boomed, according to mosquito expert Dr Cameron Webb.

“Since we’ve started monitoring in October, we’ve seen populations in western NSW go from hundreds to thousands to tens of thousands; it’s a really dramatic increase in numbers,” Dr Webb said.

Mosquito numbers are already exploding, with warnings they’re set to skyrocket as floodwaters turn stagnant and the weather gets hotter.

The concern is particularly high in areas which have been affected by recent major flooding events, which are set to become the perfect breeding ground for pests.

“The bad news is the worse is set to come, as flood waters start to recede into stagnant pools and puddles, something that’s going to coincide with hot temperatures,” Dr Webb said

“Once those flood waters recede, it creates perfect conditions for mosquitoes to move in and start breeding; the hotter it gets the more mosquitoes can breed and multiply.”

The areas of particular concern from flooding are across inland NSW and northern Victoria, according to BOM Meteorologist Miriam Bradbury.

There are fears over what large numbers of mosquitoes will mean for the spreading of diseases such as Ross River virus.

“The most significant flood areas are across inland NSW; there’s still a lot of water in those areas because they have such slow-moving rivers; the water is taking months to move through the river system,” she said.

“Areas most likely to see both wet and warm conditions together are in western NSW, pushing into north and northwestern Victoria.

“South Australia is going to be an interesting one to keep an eye on; it depends on how fast the flood waters will move into the state.”

There are fears about a likely wave of mosquito-born viruses which will come from increased numbers of the insects.

“We’re definitely concerned about mosquito-born viruses, especially the Ross River virus; we already have indications that the virus is circulating in some populations of mosquitoes in western NSW,” Dr Webb said.

Levels of mosquitoes are expected to be highest in western NSW. Picture: Marc McCormack

“We’re mostly concerned with Japanese encephalitis virus as the outcomes can potentially be fatal.

“However, we can see more Ross River virus cases and though it’s not fatal, it can be severely debilitating.”

Ross River virus infection is spread by mosquitoes and includes symptoms such as fever, chills, head and muscle aches, stiffness or swelling, and a rash.

Japanese encephalitis is a rare but serious mosquito-born illness, with some cases potentially fatal to humans.

Experts recommend installing insect screens. Picture AAP / Carmela Roche

Some people suffer symptoms such as fever, headache and vomiting, while one in every 250 people can experience more serious symptoms such as seizures, paralysis and coma.

There are a number of ways Australians can keep safe from mosquitoes, with Dr Webb saying the easiest way to avoid mosquito-borne illness is to avoid being bitten.

He recommends installing fly screens on all windows and doors you may leave open to ensure that mosquitoes remain outdoors.

“In the backyard, it’s about reducing the available water available for mosquitoes to breed in.

“Clean your gutters and check your rainwater tank, reduce the number of stagnant water from things like pots and dog bowls.”

He also highlighted the importance of applying mosquito repellent in avoiding getting bitten.

“The most important thing to note is that mosquito repellents that you can get from the supermarket or chemist are completely safe to use, and they’re also only effective if you put them all over your exposed skin.

“A little dab here and there is not going to protect you.”