HealthLinkBC File #37, February 2013

Getting Rid of Rodents (Rats and Mice)

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• What harm can rodents cause?
• Is it easy to find rodents?
• How can I get rid of rodents?
• How can I prevent rodents from living on my property?
• Can I use poison to get rid of rodents?
• How can I clean up areas where rodents have been?
• For more information

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Although there are more than 20 types of rodents in British Columbia, only 3 cause common domestic or farmyard problems:

• The house mouse;
• The Norway rat; and
• The black rat.

What harm can rodents cause?

Rodents (rats and mice) can pose a threat to human health and damage property. They eat a variety of foods, including food you might have stored in your cupboards or pantry. They can contaminate the food they leave behind, which can lead to food poisoning. They can also cause damage to buildings by chewing on insulation, sidings, and wallboard.

All 3 types of rodents can also spread diseases. Diseases can be spread by their bite, urine, or droppings. Hantavirus Pulmonary Syndrome (HPS) has been associated with the inhalation of dried mouse droppings from the wild deer mouse. For more information see HealthLinkBC File #36 Hantavirus Pulmonary Syndrome (HPS). Ticks and fleas carried by rodents can also spread diseases. For more information on tick bites, see HealthLinkBC File #01 Tick Bites and Disease.

Is it easy to find rodents?

Rats and mice are easy to detect and leave plenty of evidence. They chew cereal boxes or dried foods in plastic bags, leaving a mess. Chewing marks on woodwork and plumbing pipes are other signs of a rodent infestation. Dark brown droppings are also commonly found where rodents eat and in other areas. Rats and mice often hide in between walls, in the ground, under sheds, garages, and foundations. It is possible to hear them moving around or even chewing when your house is quiet.

How can I get rid of rodents?

Rats and mice have babies often, so it is important to find and get rid of them quickly and efficiently. Even if you do not see an actual rodent, the size of the droppings can tell you if there is a mouse or rat. Mouse droppings are approximately 6 mm (¼ inch) long, and rat droppings measure up to 19 mm (¾ inch) long.

The best way to get rid of rats or mice is by using traps. Buy several of the appropriate spring loaded traps and bait them with dried fruit, peanut butter mixed with oats, or cheese. Be sure the bait is securely attached to the trip pedal; otherwise the trap may not spring when the food is removed.

Set the traps at 'right angles' (90 degrees) to the walls where the rodents are known to travel, with the bait side of the trap toward the wall.

Once you capture a rodent, make sure not to touch it with your bare hands. Wear gloves or use a plastic bag when disposing of a trapped rodent. Dispose of the rodent in sealed, double plastic garbage bags. Bury garbage bags in a 0.5 - 1 metre deep hole, burn them or put them in the trash according to local by-laws. After the dead rodents are removed from the traps, disinfect the traps with a mixture of 1 part bleach and 10 parts water.

How can I prevent rodents from living on my property?

There are steps you can take to prevent rodents on your property.

1. Eliminate food and water sources:

• Keep all garbage in metal containers with tight fitting lids.
• Compost kitchen waste in rodent-resistant containers. Do not throw meat, bones, grease, fish or other food scraps into the compost.
• Ensure the compost is away from the house. Properly maintain the compost by stirring and adding lime every few months.
• Remove fallen fruit and nuts from your yard.
• Remove pet food right after feeding and do not leave it outside overnight. Clean out waste and food from pet pens and enclosures.
• Equip bird feeders with trays and clean spilled seeds often.
• Repair any plumbing leaks to remove collected water. Cover pools and whirlpools when not in use.

2. Eliminate hiding and living places:

• Do not plant shrubs or flowers close to buildings. Keep a space clear between buildings and plants and allow 15 cm to 20 cm (6 to 8 inches) under plants. Trim grass and ditch areas.
• Remove unused piles of lumber, old sheds, or buildings.
• Do not store old cars or furniture outside.
• Store lumber and firewood on stands 30 cm to 45 cm (12 to 18 inches) off the ground.

3. Protect buildings:

• Cover crawl spaces, fresh air and attic vents with 6mm (¼ inch) metal screening or steel mesh.
• Repair cracks in cement footings and foundations.
• Build sheds on concrete slabs.
• Install 6mm (¼ inch) hardware cloth inside your compost.

Can I use poison to get rid of rodents?

It is not a good idea to use poison or baits to control rodents. Poisoned rodents can crawl away and die, and their bodies can be hard to find and breeding grounds for disease. Poisons can also accidentally harm pets, wild animals, or even children.

Ultrasound repellers, although initially effective, are expensive and do not have long-term success at eliminating rodents.

If after taking preventive measures, a rodent problem still exists on your property and you want to try rat poison, there are certain things you should consider:

• Set out non-poisoned food for a few days prior to baiting, so the rodent starts feeding in the area.
• Read and follow the directions on the label carefully.
• Set bait in areas where there is no access to children or pets.
• If there are children or pets around, place baits in protected and locked boxes.
• Place bait deep in burrows, tunnels or holes.
• Change bait frequently and before it starts to smell.
• Remove dead rodents and all baits once pest control has been completed.

If you are unable to remove the rodents on your own, contact a licensed company with certified staff to help you.

How can I clean up areas where rodents have been?

Prevent stirring up dust when you are cleaning areas where mice have lived. This includes ventilating any enclosed area for 30 minutes and wetting down the area with household disinfectant before you start. Most general purpose disinfectants and household detergents are effective. A mixture of 1 part bleach and 10 parts water can also be used. Pour mixture carefully onto the area to avoid disturbing any virus present - do not use a sprayer.

Wipe up droppings, nesting materials and other waste with a paper towel and place in a plastic garbage bag. Do not sweep or vacuum.

Double bag the contents, seal the bags, and then bury, burn, or place the bags in the trash, according to local by-laws.

Clean floors, carpets, clothing and bedding, and disinfect counter-tops, cabinets and drawers that have been in contact with mice.

Wash rubber gloves with disinfectant or soap and water before removing them. Wash your hands with soap and water after removing gloves.

During clean-up, make sure to wear an appropriate, well-fitting filter mask, rubber gloves and goggles. For more information on appropriate masks contact your local public health unit or environmental health officer.

For more information

For more information, visit the BC Ministry of Environment website at www.gov.bc.ca/env/, or contact your local environmental health officer.

For more HealthLinkBC File topics, visit www.HealthLinkBC.ca/healthfiles/ or your local public health unit. Click on www.HealthLinkBC.ca or call 8-1-1 for non-emergency health information and services in B.C. For deaf and hearing-impaired assistance, call 7-1-1 in B.C. Translation services are available in more than 130 languages on request.