On March 28th and 29th, District staff, in conjunction with the California Department of Public Health, trapped and tested rodents for Sin Nombre hantavirus at San Bruno Mountain State & County Park. Each rodent was anesthetized, then measured and checked for parasites. Laboratory staff then drew blood for the hantavirus antibody test. After recovering from anesthesia, each rodent was carefully released at the exact location where it was trapped. Staff tested a total of 15 mice.