Most people think wildlife infestations are “just a nuisance” — annoying noises in the attic, scratching behind the walls, a smell that’s hard to ignore.
But the reality is that wildlife inside or around your home can lead to serious and often overlooked health risks.
Not every infestation becomes a medical emergency, of course.
Still, wildlife brings bacteria, parasites, and air-quality issues that can quietly harm your home and your family over time.
Here’s what every homeowner should know about the hidden health dangers of unwanted wildlife guests — and why early prevention or removal matters.
1. Air-Quality Problems Caused by Wildlife Droppings & Urine
One of the biggest issues with wildlife infestations isn’t what you see — it’s what you breathe.
Animal droppings and urine release:
-
Ammonia
-
Bacteria
-
Fungal spores
-
Toxic particles
-
Microscopic organic dust
These linger in insulation, wood, and HVAC systems and can spread throughout the home.
Common symptoms of wildlife-related air contamination include:
-
Persistent coughing
-
Allergy-like symptoms
-
Headaches
-
Burning eyes or throat
-
Nausea
-
Fatigue
-
Worsening asthma
People with allergies or respiratory conditions (especially children and elderly residents) are more susceptible.
Animals that commonly cause air-quality problems:
-
Rats & mice — high ammonia levels from urine
-
Bats — droppings can lead to fungal growth
-
Raccoons — large droppings that contaminate insulation
-
Birds — droppings near vents or AC units
-
Squirrels — nesting materials + waste in attics
An attic contaminated for months or years can quietly lower indoor air quality without homeowners realizing why.
2. Mold & Fungal Growth: A Silent, Spreading Danger
Droppings + moisture = the perfect recipe for harmful fungal growth.
One of the most well-known examples is histoplasmosis, a respiratory disease caused by fungal spores found in bat and bird droppings.
When disturbed, these spores can become airborne and inhaled.
Symptoms of histoplasmosis can include:
-
Fever
-
Chest pain
-
Coughing
-
Fatigue
-
Flu-like illness
Most cases are mild — but in severe situations, it can become a long-term or dangerous respiratory infection.
Infested attics, crawlspaces, and old barns are common hotspots.
3. Parasites That Hitchhike Into Your Home
Where wildlife goes, parasites follow.
Animals often carry:
-
Fleas
-
Ticks
-
Mites
-
Roundworms
-
Tapeworms
Even if the animal leaves or dies, the parasites can remain — seeking new hosts, like pets or humans.
Examples:
-
Raccoon Roundworm (Baylisascaris) can survive in raccoon droppings for years and is dangerous if accidentally ingested or inhaled.
-
Ticks from mice or squirrels can transmit diseases like Lyme, ehrlichiosis, or Rocky Mountain spotted fever.
-
Fleas can multiply rapidly in attics or crawlspaces once introduced.
You don’t have to touch or see wildlife to be exposed — often the parasites do the traveling for them.
4. Zoonotic Diseases: What You Need to Know
Zoonotic diseases are illnesses that can transfer from animals to humans.
This doesn’t mean every wildlife encounter is risky, but infestations create prolonged, close exposure — which increases the chance.
Common zoonotic diseases linked to wildlife:
Rats & Mice
-
Leptospirosis
-
Hantavirus
-
Salmonella
-
Lymphocytic choriomeningitis virus (LCMV)
Droppings, saliva, and urine are major carriers.
Raccoons
-
Raccoon roundworm
-
Salmonella
-
Leptospirosis
Raccoons also leave large quantities of waste in “latrine sites,” which are highly contaminated.
Bats
-
Rabies (rare but serious)
-
Histoplasmosis (from droppings)
Attics with long-term colonies can accumulate dangerous levels of guano.
Birds
-
Histoplasmosis
-
Cryptococcosis
-
Psittacosis (in parrots, pigeons, and other birds)
Bird debris in vents or AC units increases risk.
Squirrels
While squirrels carry fewer severe zoonotic diseases than rodents or raccoons, they still carry:
-
Salmonella
-
Ticks
-
Fleas
-
Mites
Skunks
-
Rabies
-
Leptospirosis
-
Roundworms
While not common inside homes, their dens beneath porches or decks bring risks.
5. Structural Damage That Leads to Secondary Hazards
Beyond disease, wildlife can damage key home structures — which creates indirect health dangers.
Examples include:
-
Chewed electrical wires → fire risk
-
Damaged insulation → extreme temperature fluctuations, mold
-
Contaminated HVAC ducts → spreads odors, spores, and bacteria
-
Damaged wood beams → structural integrity issues
Many infestations remain hidden for months, and by the time a homeowner notices, damage is already widespread.
6. When Wildlife Dies Inside the Home
One overlooked health risk:
sometimes the animal never leaves.
Dead wildlife in walls, attics, or crawlspaces causes:
-
Strong, lingering odors
-
Maggots and flies
-
Airborne bacteria
-
Secondary infestations (insects, other scavengers)
Decomposition gases can circulate through HVAC systems, affecting the entire home.
7. Pets Are at Even Higher Risk
Pets can inhale, ingest, or physically contact wildlife waste far more easily than humans.
Dogs and cats may:
-
Chase wildlife
-
Play in contaminated areas
-
Ingest droppings
-
Pick up ticks or fleas
-
Get scratched or bitten
This can lead to:
-
Parasite infestations
-
Infections
-
Allergic reactions
-
Illnesses like leptospirosis or roundworms
A wildlife control plan protects pets just as much as humans.
8. Why Early Wildlife Removal Matters
Not every infestation causes serious harm —
but the ones that do can be devastating, expensive, and difficult to clean up if ignored.
Early removal helps avoid:
-
Air contamination
-
Spread of parasites
-
Damage to insulation and wiring
-
Odors and decomposition
-
Mold and fungal growth
-
Disease exposure
-
Expensive repairs later
Remediation is always easier (and safer) when the problem is caught early.
Final Thoughts
Wildlife is a beautiful and essential part of nature — but inside the home, it creates health and safety risks that most homeowners never consider until it's too late.
Being aware of the air-quality issues, parasites, and zoonotic diseases linked to infestations helps homeowners make informed decisions that protect:
-
Their families
-
Their pets
-
Their home’s long-term condition
Understanding the hidden risks is the first step toward safer, healthier living.
Got Wildlife or Pests?
If you think that you have a wildlife or pest infestation problem, don't hesitate to reach out to us by calling 855-WILDLIFE or by visiting www.wildlifexteam.com for more information.
Thanks!
-Wildlife x Team International