Department of Health Acting Medical Entomologist Sue Harrington said there was an increase in the number of cases of RRV reported to the Department.

She said doctors had diagnosed RRV infections in people exposed to mosquito bites in the Peel, Perth and other areas of the South West.

“Monitoring programs in coastal areas of the South West have shown substantial breeding of mosquito species capable of carrying RRV after high tides and rainfall during September,” she said.

“The early occurrence of RRV cases suggests that there is the potential for higher than normal RRV activity this year.

“Seasonal increases in temperature and other environmental conditions will continue to favour mosquito breeding and virus activity.

“There have also been cases reported of another similar mosquito-borne virus, Barmah Forest virus (BFV), from South West regions.”

Ms Harrington said mosquito management programs by local governments and the Department of Health were already under way in several regions that have a recognised RRV risk.

“However, it is not realistic to rely on these programs to keep mosquitoes below safe levels and people need to take their own precautions to avoid mosquito bites,” she said.

Coastal communities within three kilometres of tidal salt marshes and seasonal brackish and freshwater wetlands are considered to be at greatest risk.