Signs of Rodent Infestations

Signs of Rodent Infestations

As Fall approaches and temperatures begin to dip, the risk of rodent incursion into schools and commercial facilities increases dramatically.

Signs of Rodent Infestations

Rodent Awareness Week

Rodent Awareness Week is observed nationally between October 16th through the 22nd.

This year the National Pest Management Association (NPMA) advises schools and businesses to exercise extreme vigilance in preventing costly rodent infestations before they take hold in stores, offices, and classrooms.

According to several sources, typical mouse extermination services cost between $200 - $600 per visit and can range as high as $6K for large infestations requiring fumigation services.

Worldwide, rodent infestations have resulted in the destruction of tens of millions of tons of food worth an estimated $30B U.S.

In the United States, rat infestations are alleged to result in more than $19B in damages, marking them the most destructive invasive species in the country.

According to a 2013 study published by the University of South Florida;

Because urban rats and mice exhibit high reproductive rates, have the capacity to spread diseases, and a propensity to destroy structures and consumer goods, they remain viable threats to human health and commerce.

Initial estimates by the United Nations in 1982 reported that rats destroyed > 42 million tons of food worldwide that was worth $30 billion dollars.

In the US, the economic cost of rat damage was estimated at $19 billion/year; many times greater than any other invasive animal species.

The Economic Impact of Commensal Rodents on Small Businesses in Manhattan’s Chinatown: trends and possible causes

This is in addition to the costs of removing rodent infestations and repairing the damage left in their wake.

According to the U.S. Centers for Disease Control and Prevention (CDC), rodents transmit illness in two ways:

  • Directly by touching the rodent itself, breathing contaminated air, getting bitten or scratched, or handling material contaminated by the rodent, and;
  • Indirectly by being bitten or accidentally consuming an insect or pest contaminated by a rodent, such as fleas, ticks, lice, mites, and mosquitos.

Diseases associated with direct contact with a contaminated rodent include:

  • Hantavirus, including Hantavirus Pulmonary Syndrome, and Hemorrhagic Fever with Renal Syndrome.
  • Lassa Fever.
  • Leptospirosis.
  • Lujo Hemorrhagic Fever.
  • Lymphocytic Choriomeningitis (LCM).
  • Monkeypox.
  • Omsk Hemorrhagic Fever.
  • Rat-Bite Fever.
  • Salmonellosis.
  • South American Arenaviruses, including Argentine hemorrhagic fever, Bolivian hemorrhagic fever, Chapare Hemorrhagic Fever, Sabiá-associated hemorrhagic fever, and Venezuelan hemorrhagic fever, and;
  • Sylvatic Typhus.

Diseases spread via indirect contact include:

  • Anaplasmosis.
  • Angiostrongylus.
  • Babesiosis.
  • Borreliosis.
  • Colorado tick fever.
  • Cutaneous leishmaniasis.
  • Eastern equine encephalitis.
  • Flea-borne (Murine) Typhus.
  • Hymenolepis diminuta.
  • La Crosse virus.
  • Moniliformis moniliformis.
  • Plague.
  • Powassan virus.
  • Rickettsialpox.
  • Scrub typhus.
  • Tick-borne Relapsing Fever.
  • Tularemia, and;
  • West Nile virus.


Identifying Signs of Rodent Infestations

Established rodent infestations are often determined by the signs left by mouse or rat activity, including:

  • Droppings - Typically where food is stored and along travel paths.
  • Gnaw marks - Usually found on furniture, walls, wires, boxes, conduit, and plumbing.
  • Nests - Commonly made of shredded paper, construction material, cotton, packing materials, insulation, and fabrics.
  • Tracks - Rodents often follow established paths left through scent trails resulting in tracks left in the dust that settles in undisturbed facility areas.
  • Strange noises - The sound of scratching in the walls is often the first sign of a rodent infestation, and;
  • Sightings - Visually sighting a rodent within a facility doesn't mean there is necessarily an infestation, but it is a very strong indicator.

Prevent Rodent Infestations

Preventing rodent infestations is significantly more cost-effective than removing and cleaning up after discovering a nest and damage.

  • The first step is to prevent access into the facility by repairing all holes inside and out.
  • Next, remove any potential nesting sites and materials, such as leaf piles around the property or piles of cardboard indoors.
  • Additionally, professionally clean in and around the facility daily, especially in areas where food is prepared, stored, consumed, or thrown out, and;
  • Ensure garbage bins are tightly sealed to prevent access.

If rodent droppings, urine, nests, or corpses are discovered:

  • Ensure service personnel are wearing appropriate PPE, including face masks, goggles, and rubber gloves.
  • When and where possible, allow the contaminated area to ventilate for a minimum of 30 minutes.
  • Saturate the contaminated spot or corpse with a general-purpose disinfectant or bleach mixture and allow it to soak in for at least 5 minutes.
  • Remove the waste, material, or rodent body and place it in a sealable garbage bag.
  • Remove and replace contaminated insulation.
  • Clean and then disinfect the contaminated and surrounding spaces using a commercial-grade soap-based detergent and EPA-registered general-purpose disinfectant.
  • Professionally shampoo any contaminated rugs, carpets, and furniture.
  • Dispose of all waste materials in a sealed bin.
  • Wash gloved hands with warm soap and water for a minimum of 20 seconds.
  • Remove and dispose of the gloves.
  • Wash ungloved hands with soap and water for an additional 20+ seconds.


References & Resources



Rodent infestations carry the burden of short and long-term financial and health challenges that are easily mitigated when combined with enhanced cleaning services and the right integrated pest control and management solutions.

Onboarding the requisite labor and material resources necessary to ensure the highest standards of cleanliness and safety are maintained can prove cost-prohibitive.

Outsourcing is a proven method for onboarding highly in-demand cleaning and disinfection services and experience for a fraction of the price of maintaining a similar service in-house.

If you would like more information regarding the effectiveness of high-performance infection prevention and control measures, or if you would like to schedule a free, no-obligation on-site assessment of your facility's custodial needs, contact us today for a free quote!

In Bakersfield, CA, call (661) 437-3253

In Fresno, CA, call (559) 206-1059

In Valencia, CA, or Santa Clarita, CA, call (661) 437-3253

In Palmdale, CA, or Lancaster, CA, call (661) 371-4756

Vanguard Cleaning Systems of the Southern Valley

Vanguard Cleaning Systems of the Southern Valley