Tierrasanta is a planned community built mostly in the 1970s and 1980s on land that was once part of Camp Elliott, a military training area. It sits on a mesa almost completely surrounded by open space. Mission Trails Regional Park lies to the east, and canyons cut through and around the neighborhood on every side. Many streets end at a canyon rim.
That much open space changes the rodent picture. Roof rats are still common, nesting in the landscaping and climbing into attics. But homes on the rims also see deer mice, which live in brush and grassland and move into garages, sheds and storage when they can. The deer mouse is the main carrier of Sin Nombre hantavirus in California, so droppings in a closed garage or shed here call for careful wet cleanup. See rodent diseases in San Diego.
The housing is mostly single-family tract homes and townhomes with stucco walls and tile or composition roofs, plus a number of condo complexes with shared walls. After forty-plus years, garage door seals, vent screens and the gaps around utility lines are the usual weak spots. Townhome rows with shared attics let rats travel from unit to unit.
Tierrasanta Boulevard and Santo Road carry most traffic to the small commercial center in the middle of the community. Open space trails start at the ends of many streets, which brings coyotes, snakes and other wildlife close to homes along with the rodents.
If you call from Tierrasanta, say whether your home backs onto open space and whether you are finding droppings in the garage or a shed. Ask the technician to identify the mouse species before cleanup starts. Keep firewood and storage off the ground and away from walls, and trim brush near the house, as the county advises for homes near open land. The county's hantavirus brochure also suggests cutting grass and weeds within 100 feet of buildings.