VANCOUVER - B.C. residents are being warned to take precautions against mosquitoes that might be carrying the West Nile virus.

The BC Centre for Disease Control says the mosquito population was kept in check by the cool spring, but the arrival of summer means its numbers are growing, particularly in the Okanagan and the Fraser Valley.

There have been no positive test results for West Nile virus in B.C. so far this year, but the centre says people should take action to prevent mosquito bites, including using repellents in the evening and early morning when mosquitoes are most active.

The centre also suggests dumping out water from empty flower pots and wheelbarrows, for example, to reduce sites where mosquitoes might breed.

Eighty per cent of people who are bitten by a mosquito infected with West Nile virus don't have any symptoms but in rare cases they can become seriously ill and even die

Less than a half dozen cases of West Nile virus have been recorded in B.C. in the last two years.