Health Hazards of Mice: Why Prevention Matters

Health Hazards of Mice: Why Prevention Matters

Mice have been causing problems for as long as anyone can remember. Perhaps that’s why the US Patent Office has granted over 4,400 mousetrap patents — more than any other invention — since its establishment in 1838, and more are coming every year.

They are small, they are resourceful, and they are dangerous.

We’ve talked plenty about the costly damage mice can do to your vehicle, but the consequences go far beyond chewed wires and upholstery. Mice carry potentially deadly diseases that pose serious threats to you and your loved ones. Their droppings, urine, and nesting materials harbor dangerous pathogens that can spread through airborne particles, contaminated surfaces, and direct contact.

But what can you do to protect yourself?

In this article, we’ll look at why mice invade our vehicles, discuss what threats we should be aware of, and learn how to avoid them.

Mouse sitting in the dirt

How Mice Infest Vehicles

A mouse will make a home out of your vehicle for the simple reason that your vehicle makes a great home. It provides shelter from the elements, protection from predators, potential sources of food, and ample materials with which to make a cozy nest. This is especially true for vehicles in long-term storage, as a parked car, RV, or camper offers even greater security.

How Mice Enter Vehicles

It doesn’t take much of an opening for a mouse to invade your vehicle. Common points of entry include:

  • Engine compartments: By crawling up through the undercarriage or wheel wells, mice can quickly gain access to the warmth of the engine.
  • Air vents and HVAC systems: Uncovered vents or ducts are easily exploited by small rodents.
  • Gaps and cracks: Damaged door seals, weather stripping, or rust holes can create a large enough opening for a mouse to sneak through.

Signs of a Mice Infestation

It’s important to spot and eliminate a mice infestation as quick as possible. Here are four common signs that mice are living in your vehicle.

  • Droppings: The unpleasant discovery of small, dark, pellet-shaped mouse droppings is surefire evidence of an infestation.  
  • Strange smells: Mouse urine and droppings can leave a musky, ammonia-like smell. If a pungent odor emerges when you turn on the air conditioning, it may mean a mouse has nested in your vents.
  • Odd noises: Scratching, scurrying, or rattling sounds in the dashboard or air vents may signal mouse activity.
  • Mechanical failures: Chewed wiring can cause malfunctions to your dashboard lights, electric windows, and other mechanical systems.

How Diseases Spread Within a Vehicle

Mice are dirty guests. The mess they leave behind — droppings, urine, nesting material, and saliva — contain unhealthy bacteria. Contained within the small confines of a vehicle, these contaminants can become even more risky.  Here’s how they can spread quickly to you and your passengers:

  • Ventilation system: Your HVAC system is a favorite nesting ground for mice. When you turn on your heater or air conditioning, contaminated particles are blown into the cabin to be inhaled.
  • Surfaces: As mice move through your vehicle, scurrying over seats and dashboards and floor mats, they leave behind contaminants you may easily come into contact with.
  • Stored items: It should come as no surprise that food stores will attract mice from far and wide. Hidden snacks, groceries, water, and more can become contaminated. If consumed, you can develop painful gastrointestinal infections.
  • Physical contact: Purposefully handling mice is always a bad idea. But even accidental interactions can be dangerous. A surprise bite or brush with nesting materials can expose you directly to harmful bacteria and viruses.
Two mice outside

Diseases and Viruses Transmitted by Mice

Mice and other small rodents carry bacteria and germs that can spread to humans in close proximity. Here are five diseases and viruses transmitted by mice that you should be aware of:

Hantavirus

Most common in the western United States, Hantavirus is often carried by deer mice. When inhaled, it can cause hantavirus pulmonary syndrome (HPS) and hemorrhagic fever with renal syndrome (HRFS), two potentially life-threatening diseases.

  • Symptoms: Early signs of HPS include fever, fatigue, muscle aches, and other flu-like symptoms. If left untreated, late-stage HPS can cause the lungs to fill, potentially resulting in death. According to the CDC, 38 percent of those who develop respiratory symptoms may die from the disease.
  • Transmission: The virus is most-often passed to humans when cleaning mice droppings or nests. The disturbed particles become airborne and are then breathed in.

Lymphocytic Choriomeningitis (LCM)

One of the more common ailments, LCM is carried by the common house mouse and has affected upwards of 5 percent of all people living in urban areas, according to the CDC. And while most healthy adults will recover just fine, pregnant women and those with weakened immune systems should be extremely cautious. Fetuses may develop terminal birth defects and the immunocompromised are at severe risk of deadly complications.

  • Symptoms: The first week of an LCM infection will resemble normal flu-like symptoms, including headaches, nausea, and vomiting. But for some, the illness may work its way into the brain, causing neurological issues such as confusion, deafness, and even the inability to move.
  • Transmission: Like Hantavirus, LCM is most often contracted through waste particles. Dispose of mouse droppings and nests with gloves and a mask. 

Plague

No, the plague is not old news. While widespread outbreaks are largely a concern of the past, you’ll normally find a handful of stories each year about the plague resurfacing somewhere in the western United States. There are multiple versions of the plague — Septicemic, Pneumonic, and Bubonic — each of which is caused by the same bacterium, Yersinia pestis. Fortunately, the plague is rare and treatable enough not to cause too much concern — but it wouldn't be right to talk about rodents and disease without talking about the plague.

  • Symptoms: The symptoms of the plague depend on which of the three versions you contract, as each affects a different part of your body. Cases will often begin with flu-like symptoms before escalating to far more serious concerns, such as respiratory failure and septic shock.
  • Transmission: Unlike the Europeans from the Middle Ages, we now know that the plague is transmitted through the fleas and ticks that pray on rodents and not the rodents themselves. When a rodent dies, those fleas and ticks will jump to the nearest food source, passing the disease along.

Salmonella

A common cause of food recalls, salmonella is a fairly well-known illness. Unsurprisingly, the bacteria that causes it can be carried within mice and other rodents, putting your food stores at risk. 

  • Symptoms: Severe stomach cramps, diarrhea, vomiting, and overall gastrointestinal distress.
  • Transmission: Direct contact between mice and food stores or beverages left in your vehicle. RVs and campers with cupboards of non-perishables are at particular risk.  

Rat-Bite Fever (RBF)

Despite the name, rat-bite fever is a bacterial disease that can be spread through mice as well as rats. While it is fairly uncommon in the United States, RBF is still a potentially fatal disease anyone in contact with rodents should be aware of.

  • Symptoms: As with the other illnesses, early symptoms resemble the flu, but many will experience rashes and swelling as well. In more serious cases, the infection can spread to other major organs, resulting in serious and even deadly complications. Antibiotics should have you feeling better quickly.
  • Transmission: RBF is most-commonly transferred through direct contact with rodents, including scratches and bites. According to the CDC, symptoms could begin to show themselves anywhere between two and 21 days after contact.
Man cleaning car from rodent debris

Prevention Tips for Protecting Your Health

  • Address infestations promptly: Keep an eye out for signs of an infestation and resolve the problem as soon as possible.
  • Wear protection when cleaning mouse debris: Many of these diseases are contracted through airborne pathogens that can be inhaled after disturbing mouse droppings or nests. Wear gloves and a mask.
  • Keep food and water out of vehicles: Not only is food and water likely to attract rodents to your vehicle, but they can easily become contaminated by infected mice.
  • Use a Box-Kat mouse barrier: The best way to avoid a mice infestation is to never allow them near your vehicle in the first place. Our patented Box-Kat mouse barrier prevents mice and other small rodents from climbing over or crawling under. Install around your vehicle, and store your RV, camper, or daily driver without worry.
Back to blog