Three Armadale residents have contracted Ross River virus (RRV) during the 2025-26 mosquito breeding season, according to Armadale Mayor Ruth Butterfield.
In a Facebook post on January 20, the City of Armadale confirmed the virus had been detected in mosquitoes at Piara Nature Reserve.
However, Ms Butterfield said she did not believe the recent human cases were acquired within the city.
Ms Butterfield said mosquito management was a year-round process, with increased surveillance and treatment during warmer months when mosquito activity typically rises.
“We’re continuing to carry out targeted treatment in known breeding areas, and we’re asking residents to assist by reducing standing water around their homes and taking simple precautions to avoid mosquito bites,” she said.
According to the city’s management plan, preventative larval treatment was undertaken in identified breeding sites including wetlands, drainage areas and natural reserves.
Ms Butterfield said treatment locations were determined through ongoing surveillance and environmental assessments.
“Larval control is the most effective and environmentally responsible way to reduce mosquito numbers before they become adults,” she said.
Residents are being urged to remove or empty water-holding containers around their homes and gardens, such as unused swimming pools, pot plant saucers and other items that can collect water to help limit mosquito breeding.
The city is also encouraging simple personal protection measures, including wearing long, loose-fitting clothing outdoors, particularly at dawn and dusk as well as using effective mosquito repellent.
The Examiner asked the Department of Health (DOH) how many RRV cases had been recorded between 2021 and 2025.
DOH chief health officer Andrew Robertson did not provide a yearly breakdown but said six cases had been detected in Serpentine Jarrahdale, eight in Armadale, six in Gosnells and five in Canning throughout the 2021-25 period.
“RRV is always present across WA, with case numbers varying from year to year,” Dr Robertson said.
