House Mice

house mouse

House mice are among the most troublesome rodents in the United States. Found in homes, commercial structures, open fields, and agricultural land, house mice are:

  • Small rodents with large ears and small black eyes, weighing about 1/2 oz
  • Typically brown to gray in color
  • About 5 1/2 to 7 1/2 inches long, from nose to the tip of the tail

House mice are great climbers that can run up any vertical surface, across rope or wire cables, and jump a foot down to the floor. They can spread diseases including: 

  • Salmonella (food poisoning)
  • Rat-bite fever
  • Tapeworms
  • Ringworm

House mice do not carry hantavirus. Other wild mice, like deer mice, can vector hantavirus, but are most often found in rural areas, the desert, and mountains and rarely invade inhabited human homes.

rodent droppings next to a ruler

Signs

  • Mouse droppings, usually found in sheltered areas
  • Fresh chew marks on insulation inside walls and electrical wires
  • Nests built from fine shredded paper and other fibrous materials or shredded areas

Prevention

Excluding mice from your home is the most successful and permanent form of prevention. In addition, removing food and habitat (such as trash or clutter) that attracts mice can also help to prevent mouse problems. 

Repair Openings: 

  • Seal gaps or openings larger than 1/4 in. with heavy, hard-to-chew materials such as wire hardware cloth, liquid foam, plaster, plywood, metal sheeting, or 1/8 in. galvanized steel mesh
  • Fill cracks in buildings, vents, metal, or concrete
  • Replace damaged window screens
  • Seal gaps around pipes and wires
Remove Attractants:
  • Store likely food sources in plastic or metal air-tight mouse-proof containers. House mice eat most food, especially those high in fat, protein, and sugar.
  • Eliminate water sources and quickly clean up spills
  • Do not leave dirty dishes in the sink overnight
  • Do not leave a pet's water or food dish out overnight
  • Clean food from counter tops, tables, and floors
  • Remove trash or garbage daily
  • Clear away trash, clutter, or anywhere else mice could hide. 
mouse chewing

Control

Trapping: Trapping is a good way to control mice, but keep in mind that it can take time. Traps are ideal in places where poison would be hazardous to humans and pets: homes, garages, businesses, restaurants, food storage warehouses, hospitals, schools, and nursing homes.
  • Bait traps with soft foods that cannot be removed easily, like peanut butter. Mice love it and it is cheap!
  • Set traps at the base of walls, behind objects and in dark places where mice like to travel. Set the trap perpendicular to the wall, with the trigger, the part that holds the bait, against the wall.

Repellents: Repellents rarely work well to control mouse problems. Electronic or sonic repelling devices do not work. Oils, powders, or sprays made of hot pepper, mint, or peppermint may temporarily help to keep mice from chewing on trees, shrubs, and fences, however the mice will eventually adapt. 

Chemical Rodenticides: Poison baits and other chemical rodenticides kill mice but should be used as a last resort; they rarely work well to solve the problem. When using rodenticides, be careful to follow all instructions on the label, and to keep them out of reach of children and pets. 

Questions?

  (858) 694-2888

  vector@sdcounty.ca.gov