Controlling Wild Rodent Infestations

What to know

  • Rodents can carry many diseases that can spread directly or indirectly to people.
  • It's easier to control rodents before they can establish themselves in your home or building.
  • Regularly check your home for rodent droppings and gnaw marks as these are both signs of a rodent's presence.
A rat surprised to see a human so close.


Rodents, such as rats, mice, and chipmunks, are known to carry many diseases. These diseases can spread to people directly, through:

  • Handling of rodents
  • Contact with rodent droppings (poop), urine, or saliva
  • Rodent bites

Rodent droppings, urine, and saliva can spread by breathing in air or eating food that is contaminated with rodent waste.

Rodents can also carry ticks, mites, or fleas that can spread diseases. Many diseases do not cause any apparent illness in rodents. This means you cannot tell if a rodent is carrying a disease just by looking at it.

Infestation of rodents in and around the home is the main reason disease spreads from rodents to people. The best way to prevent a rodent infestation and contact with rodents is to remove:

  • Food sources
  • Water
  • Items that provide shelter for rodents

Signs that rodents are present

The first signs of rodents usually appear before you even see a rat or mouse. Regular inspection of the inside and outside of a home or business is important to identify signs of rodents. It's easier to control rodents before they have time to become established.

A drawer revealing the presence of rodents. Inside the drawer are mouse droppings. On the side are gnaw marks.
Two signs of rodent presence are rodent droppings and gnaw marks.

Rodent droppings

Rodent droppings can be found anywhere rodents have accessed. They are common in cabinets, drawers, and other areas out of plain sight. Rodent droppings are pointed at one end and often contain hair.

It can be challenging to know if there is an active rodent population just by examining droppings. One way to be sure is to safely clean the area. If droppings are present after cleaning, this indicates an active rodent presence.

Gnaw marks

Rats and mice gnaw to create better access points and keep their teeth at the proper length. Their teeth leave distinct marks and are a good sign that rodents were active in the area. Gnaw marks alone may only mean that rodents were active in the area at some point. Gnaw marks are often found in the same area as droppings.

The same clean-up techniques can be used to help determine if there is an active rodent presence.

Diseases spread by rodents

Diseases spread directly by rodents

Certain diseases can spread from rodents to people through direct contact with infected rodents. This can be through breathing in contaminated air, touching contaminated materials and then touching eyes, nose, or mouth. They can also spread by being bitten or scratched by an infected rodent, or eating food contaminated by an infected rodent.

Bacterial diseases

Viral diseases

*Argentine hemorrhagic fever, Bolivian hemorrhagic fever, Chapare Hemorrhagic Fever, Sabiá-associated hemorrhagic fever, and Venezuelan hemorrhagic fever.

Diseases spread indirectly by rodents

Certain diseases can spread from rodents to people through indirect contact. This can occur when people are bitten by ticks, mites, fleas, and mosquitos that have fed on infected rodents. Diseases can also spread to people from rodents through the consumption of an intermediate host (for example, beetles or cockroaches).

Bacterial diseases

Parasitic Diseases

Viral diseases