THERE has been a sevenfold increase in Ross River virus infection notifications in NSW in the past 12 months.
The good news is none of the identified cases have so far been linked to exposure to mosquitoes around the Georges River.
This is despite a spike in January of mosquitoes in Alfords Point that can spread Ross River and Barmah Forest viruses.
Traps along the Georges River contained record numbers of the saltmarsh mosquito Aedes vigilax after high tides.
The Public Health Unit is again warning residents and campers to avoid being outside if unprotected at dawn and dusk.
The warning comes in the lead-up to the Easter school holidays, beginning Friday, April 3.
Saltmarsh mosquitoes breed in swamps along the river but moved to surrounding suburbs following January's high tides.
The man responsible for mosquito trapping in St George and Sutherland Shire, medical entomologist Cameron Webb, said previously that autumn was a peak time of year for insects to carry the virus.
Acting Public Health Unit director Catherine Bateman-Steel said there was no specific treatment for Ross River and Barmah Forest viruses so the best way to avoid infection was not to get bitten.
"It is particularly important for people planning to take trips during the Easter holidays to be prepared with measures to prevent mosquito bites," she said.
Insect repellent containing DEET or Picardin should be applied to all exposed skin.
Gardens should be free of containers that could hold water and become mosquito breeding grounds.
There are more than 30 mosquito species in St George and the shire, some of which can travel up to 10 kilometres from wetlands.
Ross River virus symptoms include rash, fever, chills, headaches, tiredness, joint pain, stiffness and swelling.