Health authorities are sounding the alarm over a looming surge in Ross River virus infections, a concerning mosquito-borne illness. The rising number of infections has prompted mosquito spraying initiatives in high-risk suburbs, such as Wooloowin, Clayfield, Gordon Park, and Hendra in the northern suburbs of Brisbane, among other areas.
Chief Health Officer John Gerrard revealed a very high number of Ross River virus detections in mosquitoes across nine different council areas stretching from Mackay to South East Queensland.
And the number of infected mosquitoes — at 31 positive traps of the 700 tested across the state — is higher than what was detected during the horror 2019-2020 summer, ultimately leading to a whopping 3381 Ross River infections for that year.
There were 699 cases of the Ross River virus in 2023. As of the end of January this year, 64 people have been infected.
Efforts to increased mosquito spraying are underway in Wooloowin and other North Brisbane areas.
About the Ross River Virus
There is no cure nor vaccine for Ross River virus, and whilst most people recover in a few weeks some people experience joint pain and fatigue months after infection.
Origin and Spread
Ross River Virus (RRV) is a mosquito-borne alphavirus that is endemic to Australia, Papua New Guinea, and the Pacific Islands. The virus primarily spreads through the bite of infected mosquitoes, notably those in the Aedes and Culex genera, which are common in these regions.
Symptoms and Treatment
RRV infection can lead to a range of symptoms, from mild to debilitating. Common symptoms include polyarthritis, rash, fever, fatigue, and muscle pain. These symptoms can significantly affect an individual’s ability to perform daily activities and, in some cases, can persist for months or even years. While there is no specific treatment for RRV, management of symptoms is possible through medication and physical therapy.
Epidemiology
The virus has shown a notable propensity for causing large outbreaks, particularly in coastal regions. The incidence of RRV infection varies seasonally and geographically, with the highest rates typically observed in areas with warmer climates and in proximity to bodies of water where mosquito populations thrive.
Prevention
Preventing RRV infection centres on controlling mosquito populations and minimising individual exposure to mosquito bites. Public health measures include community education on the use of insect repellent, the importance of wearing protective clothing, and the need to eliminate standing water around homes and communities to reduce mosquito breeding sites.
Global Health Perspective
RRV is considered a significant public health issue within its endemic regions. With climate change and increasing global travel, there is a potential for RRV to expand its geographical reach, making it a subject of interest for global health monitoring and research
Elevated Risk and Intensified Efforts
Dr Gerrard expressed concern over the significant increase in Ross River virus detections in mosquito populations early in the usual season, particularly across a wide geographical area. This surge indicates heightened virus activity.
Typically, Ross River virus infections begin to surge with the arrival of rain and warm temperatures in December, reaching their peak in February and March. Moreover, it’s common to observe a notable increase in Ross River virus cases every three to four years, indicating a potential spike in infections.
With the current high mosquito numbers and recent surveillance findings, there is an increased risk of human exposure to mosquitoes carrying the virus throughout Queensland.
Metro North Public Health Unit entomologist Jon Darbro said in the past month it had been either wet or hot which added to the extra mosquitoes around.
Mr Darbro explained that the increased rainfall this season provides mosquitoes with additional breeding sites for laying eggs and larval development, resulting in larger mosquito populations. Warmer temperatures also contribute to heightened mosquito activity, accelerating their growth and the drying process of eggs. These conditions create an ideal environment for multiple mosquito species to thrive, as observed by many.
Metro North covers areas like Wooloowin, Clayfield and Hendra, which has intensified its spraying efforts in late January 2024.
More Mosquito Spraying for Brisbane and Gold Coast
Swarms of mosquitoes have inundated nearly every suburb across South East Queensland, with wet weather and warm temperatures creating the perfect breeding grounds for the flying pests. The unwanted buzz and bites have forced Brisbane City Council to spray an extraordinary 2,400 sites a week – a 140 per cent increase on the normal mozzie spraying schedules including seven aerial attacks in the past nine weeks.
Across Brisbane, 136 of 190 suburbs have been targeted and 24 on the Gold Coast. Redland City Council have increased their aerial treatments of mosquito larvae by 60 per cent making it the biggest year on record since 2016-2017. While Logan City Council, Sunshine Coast Council and Gold Coast Coast have also increased their spraying schedules.
According to the Queensland Health notifiable notifications data, dozens of mosquito-borne disease cases have been confirmed, including 29 cases of Ross River virus and three of dengue in the first three weeks of January.
Prevention Measures Urged
Dr Gerrard reiterated that people needed to take measures to protect themselves from mosquito bites and mosquito-borne diseases.
- Any mosquito could potentially carry Ross River virus; increased bites raise the likelihood of infection.
- Mosquitoes are active throughout the day, with some species most active at dusk and dawn.
- It’s advisable to avoid outdoor activities during peak mosquito activity times.
- Preventive measures include regularly applying insect repellent containing DEET, picaridin, or oil of lemon eucalyptus.
- Wear loose, light-coloured clothing to cover up arms, legs, and feet to minimize exposure to mosquito bites.
Published 12-Feb-2024