A California deer mouse caught in routine trapping in the Santa Ysabel area has tested positive for the potentially deadly hantavirus, the first positive testing of the virus in San Diego County in 2018. County officials are reminding people that they should always protect themselves if they find rodents living in their homes, sheds and garages. In particular, they said people should never sweep up or vacuum up rodent nests and droppings if they find them. Officials said people should use "wet cleaning" methods instead if they have to clean, to keep hantavirus from being stirred into the air where it can be inhaled. Hantavirus is not unusual in San Diego County. However, it is mainly carried by wild mice that do not live in the same spaces with people. The mouse that tested positive was trapped in Inaja Memorial Park in Santa Ysabel. Infected rodents shed hantavirus through their saliva, urine and feces. When that matter dries, it - and the virus - can be stirred into the air if swept or vacuumed, where it can be breathed in. Hantavirus can cause deadly infections in people. There is no vaccine or cure. However, people have very little chance of being exposed to the virus if they keep wild rodents out of their homes and workplaces. Seal up all external holes in homes, garages and sheds larger than a dime to keep rodents from getting in. Eliminate rodent infestations immediately. Avoid rodent-infested areas and do not stir up dust or materials that may be contaminated with rodent droppings and urine. Clean up rodent droppings and urine using the wet cleaning method described below.