Health officials in B.C. are urging residents to take precautions against the West Nile virus. (Canadian Press)

The B.C. Centre for Disease Control says breeding conditions for mosquitoes in the province are perfect — and officials are on heightened alert for West Nile virus.

The centre says the hot weather combined with standing pools of water from recent flooding will increase populations this month.

"When we see flooding and we see seepage around rivers and ditches and areas, that's a prime breeding ground for mosquitoes," says Dr. Bonnie Henry.

She says the Okanagan and Fraser Valley are the most at-risk areas of the province.

"We have not had any positive mosquitoes or any human cases yet in B.C. but with the increasing numbers of mosquitoes, that's when the risk increases," says Henry.

"Between now and the end of August, we know that the risk is going to increase. We know that we've had West Nile virus in B.C. in the last couple of years and there have been a few people infected."

Last year, there were no reports of anyone contracting the virus in B.C., largely due to cool weather suppressing mosquito populations. One person in B.C. was infected in 2010, as were two people in 2009.

Henry is advising British Columbians to take precautions.

"The mosquitoes that can carry West Nile virus tend to be more active in the evening, through the night and into the morning," she says.

"So if you are out at that period of time and there's mosquitoes around, the most effective protective measure is to use mosquito repellants and the ones that contain DEET are the most effective."

Only about one in five infected people get sick. One in 150 infected people will develop severe symptoms including neck stiffness, disorientation, coma and paralysis.