What Diseases Do Rats Carry?

Key Points

• Serious Health Risks: Rats and mice can transmit over 35 different diseases to humans.

• Modes of Transmission: Diseases are spread directly through urine, feces, or bites or indirectly via fleas, ticks, and mites.

• Common Illnesses: Diseases commonly transmitted by Hantavirus, Leptospirosis, Salmonella, and Rat-Bite Fever.

• Prevention is Key: Proper sanitation and sealing entry points are the best defense against rodent-borne illness.

Rats are more than just a nuisance that goes bump in the night; they are vehicles for dangerous pathogens. Understanding what these rodents carry is the first step in protecting your home and family. Here is a breakdown of the pathology behind the pests.

How Do Rats Spread Disease?

You don't have to be bitten by a rat to get sick. In fact, most transmission happens without you ever seeing the rodent. Diseases generally fall into two categories:

Direct Transmission

This occurs when you come into direct contact with the rat or its waste.

• Inhalation: Breathing in dust contaminated with dried urine or droppings.

• Ingestion: Eating food or water that has been contaminated by a rodent.

• Physical Contact: Touching a dead rodent, their urine, or nesting materials.

• Bites/Scratches: While less common today, a cornered rat will defend itself.

Indirect Transmission

Indirect transmission is a bit sneakier. It involves a "middleman" passing the disease from an infected rat to you. Think of parasites like fleas, ticks, and mites. They'll feed on a sick rat, pick up the disease, and then pass it along to you with their next bite.

Common Diseases Transmitted by Rats

While not every rat carries every disease, the risk profile is high enough that you should never handle a wild rodent without professional protection.

Hantavirus

Hantavirus Pulmonary Syndrome is a rare but extremely serious viral infection that primarily attacks the lungs. This disease causes the lungs to fill with fluid, leading to severe respiratory distress, and can be fatal if not treated promptly.

• Carriers: Commonly spread by the deer mouse, white-footed mouse, rice rat, and cotton rat.

• Transmission: It is airborne. When fresh rodent urine, droppings, or nesting materials are stirred up, viruses get into the air and are inhaled.

• Symptoms: Starts with flu-like symptoms (fever, muscle aches) but can rapidly escalate to severe difficulty breathing.

Leptospirosis

Leptospirosis is a bacterial infection that can affect both humans and animals. It is caused by bacteria of the genus Leptospira and is commonly found in water or soil contaminated by animal urine. Symptoms can range from mild flu-like illness to serious complications if left untreated.

• Transmission: Usually contracted by coming into contact with water or soil contaminated by the urine of infected animals.

• Risk Factors: If you have an infestation in a basement, crawlspace, or garage where dampness occurs, the risk increases.

• Complications: Without treatment, it can lead to kidney damage, liver failure, and respiratory distress.

Salmonellosis

Salmonellosis is an infection caused by Salmonella bacteria, which is one of the most common culprits behind food poisoning. These bacteria can spread when food or surfaces become contaminated, often through contact with rodents.

• Transmission: Rats walk through filth and then track bacteria across your kitchen counters, pantries, and food preparation surfaces.

• Symptoms: Diarrhea, fever, and abdominal cramps.

Rat-Bite Fever (RBF)

Rat-Bite Fever is an infectious disease that people can contract after being bitten or scratched by rodents, particularly rats. The infection is caused by bacteria that live in the mouths of these animals and can lead to serious complications if left untreated.

• Transmission: Can be spread by a bite, scratch, or even contact with a dead rodent.

• Symptoms: Fever, vomiting, headache, and rash.

Lymphocytic Choriomeningitis (LCMV)

Lymphocytic Choriomeningitis is a viral infection primarily transmitted by rodents, especially the common house mouse. The disease can cause flu-like symptoms and, in more serious cases, lead to inflammation of the brain and nervous system, posing significant risks to pregnant women and individuals with weakened immune systems.

• Carriers: The common house mouse is the primary culprit here.

• Transmission: Exposure to fresh urine, droppings, saliva, or nesting materials.

• Risks: While some experience only temporary discomfort, it can cause severe neurological problems, particularly in pregnant women and immunocompromised individuals.

The Plague

The Plague, caused by the bacterium Yersinia pestis, is one of history's most notorious infectious diseases. It was responsible for the Black Death in the Middle Ages, which wiped out millions across Europe. While today it is extremely rare in the U.S., the disease still serves as a reminder of the dangers posed by rodents.

• Transmission: Spread indirectly by fleas that have fed on infected rats.

• Context: While rare in the U.S. today, it serves as a reminder of the historical impact of rodent infestations.

Allergies & Asthma from Rats

Even if a rat is disease-free, it can still ruin your day. Rodent dander, shedding hair, and droppings are potent allergens. For many homeowners, a hidden infestation manifests as persistent sneezing, watery eyes, or asthma attacks that just won't go away.

A Closer Look: The Science of Rodent Diseases

At Orkin, we believe in using science to help protect your home. The video below details the specific risks associated with different species, including the differences between House Mice and Norway Rats, and dives deeper into Hantavirus prevention.

Watch: Diseases Carried by Rats and Mice

More Resources on Rats

How to Get Rid of Rats

Rats can be controlled by sealing entry gaps larger than ¼ inch and removing attractants like unsecured food and clutter, while traps placed along walls help eliminate active infestations.

Can You Spray for Rats?

Effective rat control requires eliminating food, water, and shelter sources, sealing entry points as small as a quarter, and maintaining clean, well‑kept surroundings.

Do Rat Pellets and Traps Work?

Rat pellets offer limited effectiveness, while snap traps are considered the most reliable method once rats gain entry. Long‑term control still depends on sealing access points and preventing attractants.

My Carpet Has Been Chewed by Rats

Carpet damage near small holes and outdoor soil disturbances is often caused by rats

Do Ultrasonic Rodent Repellers Really Work?

Ultrasonic repellents aren’t considered effective because their sound doesn’t travel far and rodents quickly adapt to it.

Does Brodifacoum and Warfrin Rat and Mouse Poison Make Rodents Thirsty?

Because brodifacoum and warfarin cause internal bleeding rather than thirst, there’s no way to predict where a rodent will die, making these poisons risky and best handled by professionals.