"The risk for human cases of West Nile Virus infection increases at this time of year," said Hamilton's medical officer of health Elizabeth Richardson. "This is why it is important to protect yourself and family members against mosquito bites," she stressed.

Mosquitoes get the virus when they feed on the blood of infected birds. It is passed on to humans when infected mosquitoes bite them.

While most people infected with WNV have no symptoms, some experience a very mild illness with fever. A small proportion develops a more serious illness from the bite, developing inflammation of the brain, the lining of the brain or the spinal cord. If symptoms occur, they appear two to 14 days after being bitten.

To date this year, there have not been any reported human cases of WNV in Hamilton. However, two adult mosquito traps, one in lower Stoney Creek and the other in lower east Hamilton, tested positive last Wednesday.

Last year, a woman in her mid-sixties was the only reported WNV case in Hamilton. There were three positive mosquito pools and six positive dead birds. In 2006, Hamilton had three human cases and six dead birds tested positive.

Hamilton's worst year occurred in 2002 when 19 dead birds were confirmed to have the virus and there were 16 human cases resulting in one death.

The City of Hamilton continually assesses the risk for human illness and has a comprehensive surveillance and protection program. As part of its prevention program, the city began its fourth and final round of larviciding treatments on city catch basins last Wednesday. Green dots on the catch basins indicate that treatment has been completed.

Surface waters on public land are also being treated and will continue to be into the fall.

To help prevent mosquitoes from laying their eggs in shallow water, residents are encouraged to remove standing water from eaves trough, wading pools and yards at least once a week. Given the record amounts of rainfall in the Hamilton area in recent weeks, it isn't practical to expect rural Flamborough residents to remove large bodies of standing water from their fields, Rob Hall, the city's director of health protection, acknowledged this week. But everyone, regardless of where they live, needs to take personal protection measures, he said.

The most effective way to avoid being bitten by mosquitoes is to use a repellent containing DEET. When using mosquito repellent, manufacturer's instructions should be followed.

Another effective preventive measure is to wear a light-coloured, long-sleeved shirt and pants outdoors when frequenting known mosquito areas such as wooded areas, golf courses or gardens, especially at dawn and dusk when mosquitoes are most active.

For additional information on WNV or to report a dead bird, please call the West Nile Virus line at 905-546-3575 during business hours or go online to make a report or view positive results from past seasons at www.hamilton.ca/westnile.