The wet weather will increase stagnant water in the Sacramento region, which could lead to more bids and mosquitoes testing positive to West Nile virus, according to vector control officials.
The two days of drizzle are expected to be followed by a rapid warm-up with the possibility of 100-degree readings by the weekend in the Sacramento region.
"The excess water will increase mosquito habitats," said David Brown, Sacramento-Yolo Mosquito & Vector Control district manager. "As temperatures warm up by the end of the week, the virus will likely amplify and the risk of human transmission will increase."
There has not been as much West Nile virus activity as last year. However, Brown believes the summer will likely bring increased activity.
In Sacramento, seven dead birds and 19 mosquito samples have tested positive for West Nile virus. One case of the virus in a person has been reported to the California Department of Public Health.
In Yolo County, two dead birds and five mosquito samples have tested positive for the virus.
In response to recent findings, district crews on the ground have started fogging with insecticide.