Ross River fever: Mosquito-borne virus causes spike in disease numbers

There has been a spike in the number of cases of Ross River fever spread by North Queensland’s bush mosquito population.

There have been 133 cases of Ross River fever, caused by the mosquito-borne Ross River virus, recorded in the Townsville Health and Hospital Service district so far this year.

There has been a spike in the number of cases of Ross River fever spread by North Queensland’s bush mosquito population.

There have been 133 cases of the disease, caused by the mosquito-borne Ross River virus, recorded in the Townsville Health and Hospital Service district so far this year.

The number of cases of the potentially debilitating disease are well up on the year-to-date mean average of 45 for the 2019-2023 period.

That compares to just 58 cases in the Cairns and Hinterland Health and Hospital Service and 61 cases in the Mackay HHS.

Dr Steven Donohue, director of the Townsville Public Health Unit, said it was too early to call the spike on previous years an “outbreak”, as it was being described in south-east Queensland.

The Sunshine Coast, for example, has recorded 284 cases this year.

“We’re not calling it as an outbreak as the numbers are quite low, but it is more than we’ve had for a few years,” Dr Steven Donohue said.

He said Ross River virus was an “animal disease” that infected a range of mammals, for wildlife to domesticated animals such as cows.

“What can happen is in certain years when it’s in larger numbers in animals, then it spills over into humans.”

Dr Steven Donohue, director of the Townsville Public Health Unit, said it was too early to call the spike in Ross River fever cases an “outbreak”, as it was being described as such in south-east Queensland. Picture: Supplied

Dr Donohue said that unlike Dengue fever that was spread by the Aedes aegypti mosquito that tended to inhabit areas close to human habitation, Ross River virus was spread by a multitude of “bush and swamp mosquitos”.

“It’s been a good year for mosquitos, there’s been plenty of rain, and that’s probably coinciding with larger than normal numbers in some of the wild animals,” he said.

“So it’s not surprising that we’re seeing more of a spill over to humans than we have had in recent years.”

Dr Donohue said the advice to avoid infection was to cover-up and to don insect repellent, particularly around mornings and evenings when mosquitos were most active.

“The good news is that it is generally not severe or fatal.”

He said symptoms began to occur a week after being bitten, and ranged from not feeling a thing, to fever, headaches, feeling unwell and rashes.

“But what is a bit more prominent with Ross River … is that it can cause quite a nasty pain in the joints, including quite small joints like those in the wrist and the hand,” he said.

“It can go on for months and can be quite disabling.”

Dr Donohue said the only treatment was anti-inflammatories.

He said he was currently more concerned about influenza and trying to get people vaccinated.

Townsville City Council said it’s year-round mosquito management program targeted larval-stage mosquitoes in ponded water.

A spokesperson said that as part of this program, it surveyed mosquito-breeding areas and treated those sites through both ground and aerial operations.

“Community members should apply personal repellent, wear loose, light-coloured clothing, avoid being outside during dawn and dusk and screen the windows of their homes as mosquito prevention measures,” she said.

“Council also encourages community members to participate in mosquito control by removing any potential breeding sites like water-filled containers in or around their homes.”

Originally published as Ross River fever: Mosquito-borne virus causes spike in disease numbers