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Preventing Diseases from Insects & Rodents

Animals or insects such as rats, mosquitoes and ticks that can transmit diseases to humans are called vectors. To obtain more information on prevention of diseases from vectors, call the Orange County Vector Control District at (714) 971-2421 or check the OCVCD web site.



Mosquitoes can carry diseases such as West Nile Virus, encephalitis and malaria. Mosquitoes need water to complete their life cycle. To prevent mosquitoes from breeding, you should:

  • Empty standing water in containers after running the sprinklers or after a rain.
  • Remove and dispose of any containers that may collect water such as buckets, cans, old tires, etc. Usable containers should be stored upside down so they do not collect water.
  • Keep swimming pools and ornamental ponds clean and equipment in working order. Chlorine will not kill mosquito eggs.
  • Report standing water sources such as ditches and street gutters or other problems with mosquitoes to the Orange County Vector Control District at (714) 971-2421.
  • Repair or replace damaged window or door screens.

To avoid mosquito bites:

  • Avoid exposure to mosquitoes during hours of biting (dusk and dawn)
  • Use mosquito "candles" which emit a smell that keeps mosquitoes away



Ticks can carry Lyme disease, Rocky Mountain Spotted Fever and other diseases. Although these diseases are seen rarely in Orange County, it is important to reduce exposure to ticks when entering areas where ticks are likely to be found.

To reduce exposure:

  • Walk on clear trails. Avoid trail margins, brush and grassy areas while hiking.
  • Wear long-sleeved shirts, long pants and closed-toe shoes.
  • Tuck your pants into your boots or socks and your shirt into your pants.
  • Wear light-colored clothing so ticks can be seen easily. Check yourself and your children frequently.
  • Apply insect repellent effective against ticks. Permethrin-containing repellents are approved for use on clothing only. DEET repellents can be used on skin and clothing, but be sure to follow the label directions. Remove the repellent by washing after coming indoors.

Ticks found on the body should be removed promptly. Grasp the tick with tweezers as close as possible to the skin. Remove the tick by gently pulling the tick straight out without twisting or squeezing the body. Ticks can be taken to the Orange County Vector Control District for identification.



Rodents such as mice and rats may carry disease agents such as certain bacteria, or may have fleas, which can carry plague or typhus. To prevent rodents from entering your home:

  • Store and cover food (including pet food) and water in rodent-proof metal or thick plastic containers with tight-fitting lids. Store garbage in similar containers
  • Do not leave pet food outside in feeding dishes
  • Wash dishes and cooking utensils immediately after use and remove spilled food
  • Dispose of trash and clutter
  • Use steel wool or cement to seal, screen, or otherwise cover all building openings that have a diameter of ¼ inch or larger
  • When possible, place woodpiles 100 feet or more from the house, and elevate wood at least 12 inches off the ground
  • Trim vegetation away from the roof, walls, fences and trees
  • Use weather-stripping on bottoms of doors
  • Use raised cement foundations in new construction of sheds, barn, outbuildings, or woodpiles

To clean rodent contaminated areas:

  • Never touch a rodent, its droppings, or its urine with bare hands. Wear rubber or plastic gloves to handle rodent materials
  • Spray rodents, rodent nests, droppings or other items that have been contaminated by rodents with disinfectant. Soak the material thoroughly and then wipe up and place in a plastic bag. Place plastic bag in a second plastic bag and dispose in the regular trash. DO NOT sweep or vacuum materials which may create dust.
  • Before removal of gloves, wash gloved hands in a disinfectant and then soap and water. Thoroughly wash your hands after removing your gloves.
  • Disinfectants that can be used include a commercial disinfectant or a fresh solution of 3 tablespoons of household bleach in 1 gallon of water
  • Wash potentially contaminated bedding and clothing with detergent and water as hot as the fabric will allow. Use gloves when handling contaminated laundry. Machine dry on a high temperature setting or allow to air dry in the sun.