Australian health authorities are sounding the alarm about a potential surge in Ross River virus infections due to a significant increase in the detection of mosquitoes carrying this debilitating virus.
Recent data from the National Notifiable Disease Surveillance System reveals that there have been 206 notifications of Ross River virus across the country between January 1 and February 15.
The majority of cases have been reported in Queensland (135), followed by Western Australia (29), New South Wales (21), the Northern Territory (10), Victoria (eight), and Tasmania (one). Interestingly, the Australian Capital Territory (ACT) has reported zero cases so far this year.
Ross River virus is not the only mosquito-borne disease circulating in Australia this summer. As of 2024, the National Notifiable Disease Surveillance System has recorded 125 cases of Dengue virus, 54 cases of malaria, 28 cases of Barmah Forest virus, seven cases of Chikungunya virus, and one case of Flavivirus (unspecified).
While there have been no reported cases of the potentially deadly Japanese encephalitis and Murray Valley encephalitis in Australia this year, virus activity has been identified in some parts of the country.
Dr. John Gerrard, Queensland's chief health officer, reports a concerning increase in Ross River virus detections in mosquitoes across nine different local government areas from Mackay down to southeast Queensland.
"Queensland Health, along with local government partners, regularly collects mosquito samples and tests them for Ross River virus infection. This season, we have tested more than 700 mosquito trap collections for Ross River virus," Dr. Gerrard said.
"We have been notified of 31 positive mosquito traps across the state so far, which exceeds the total number we saw over the 2019-20 summer months when there was a significant outbreak of Ross River virus. In 2020, we recorded 3,381 cases of Ross River virus."
Symptoms of Ross River virus may include fever, swollen and painful joints, and rash. Treatment focuses on managing symptoms, and while most people recover within a few weeks, some may experience joint pain and fatigue for months and may require specialist treatment.
Mosquitoes transmit the virus by biting an infected animal and then transferring the virus to humans through biting. It's important to note that the virus cannot spread from person to person.
Associate Professor Cameron Webb from the University of Sydney's Medical Entomology department at NSW Health Pathology warns of an impending spike in Ross River virus cases in Australia this year.
"One of the reasons why we're concerned about Ross River virus is that we typically see major outbreaks every two or three years," Professor Webb explained.
"On the east coast of Australia, the last significant outbreak was in 2020, and we're now a few seasons past without any major activity. This raises concerns about the potential for increased virus transmission."
Professor Webb emphasizes that the period of greatest risk for Ross River virus and other mosquito-borne diseases is typically between February and March.
"It's during these months that the risk is highest," he said. "GPs play a crucial role in managing mosquito-borne diseases by identifying and treating cases and emphasizing prevention."
He advises GPs to remain vigilant about Ross River virus and other mosquito-borne diseases, especially for patients returning from areas with increased mosquito activity.
"It's important for patients living and working in regions with a high risk of mosquito-borne diseases to be aware of preventive measures and, when necessary, the availability of vaccines," Professor Webb concluded.