The city of Hamilton has confirmed the first local human case of West Nile virus this season.

Hamilton’s Medical Officer of Health has moved the risk of contracting the virus from moderator to high.

The city says officials continue to see more West Nile Virus positive mosquitos in traps in the city.

“The risk of being infected with West Nile virus exists locally. Please continue to take precautions to avoid illness spread by mosquitos. This includes applying insect repellent containing DEET or Icaridin, covering up, and to also remove standing water on your property to prevent mosquito breeding,” said Dr. Bart Harvey, Public Health physician, in a news release. “The risk of West Nile virus will drop once there is a heavy frost that reduces the number of mosquitoes.”

Officials say workers are continuing larvicide treatments on city street catch basins, in addition to ongoing treatment of surface waters on public land.

Most people infected with West Nile virus have no symptoms but some others, including older adults or those with weakened immune systems, may experience West Nile fever or may develop more severe illness including inflammation of the brain or the lining of the brain.

If symptoms do occur, they usually appear two to 14 days after being bitten by an infected mosquito.