West Nile virus activity is on the rise in some northern California counties, according to the Sacramento-Yolo Mosquito and Vector Control District. Three dead birds and 13 mosquito samples tested positive for the virus on Aug. 13, “the highest number of positive results reported in a single day this year,” the agency said in a news release.

Northern California's first human West Nile virus case of the year has been confirmed in Butte County, according to local health officials.

We are now in the peak time for transmission of mosquito-borne disease to people and it is important for people to know that so they can take steps to protect themselves.” The post The risk for West Nile virus is now high in 10 Mass.