Public health officials in Ottawa say they are investigating three more probable cases of West Nile Virus, bringing the total number of cases to five this summer.

The first case went public two weeks ago but it has not been confirmed. If any case is confirmed, that would be the first human case in Ottawa since 2006.

West Nile is transferred through mosquitoes that carry the virus, but officials say most individuals who are exposed show no symptoms.

Recommended preventive measures include:

  • Using mosquito repellent with DEET.
  • Wearing long-sleeved light-coloured shirts and pants.
  • Make sure that door and window screens fit tightly and have no holes that may allow mosquitoes indoors

Roughly 20 per cent of people who are infected may show some flu-like symptoms such as headaches, muscle aches and pain.

Medical Officer of Health Isra Levy said Ottawa's worst tally was seven or eight years ago, when there were three confirmed cases.

Levy said people should replace water in bird baths, circulate it in fish ponds and poke holes in outdoor containers so water drains.

Last month, the city confirmed the presence of West Nile in the mosquito population.

Health officials across Ontario and in several other provinces have warned about an increase in mosquitoes carrying the virus.