West Nile virus has been found in Ottawa's mosquito population, public health officials have confirmed.

The infections can be spread by mosquitoes and could possibly cause serious illness, but most people show no symptoms.

Ottawa Public Health says elderly people and those people who have weakened immune systems could experience flu-like symptoms.

That means people should take precautions such as reducing the time they are near standing water sites such as birdbaths and swimming pool covers.

Everyone should also apply an approved mosquito repellent and avoid being outside in the hours between dusk and dawn when mosquitoes are most active.

The Ottawa area has not seen a human case of West Nile virus since 2006.

Public health officials test standing water sites such as ditches. Officials also treat city-owned storm sewers with chemicals.