11 Diseases You Can Get From Mice and Rats

Mice and rats are the most common rodents to break into homes. These pests aren’t just disgusting to have around. They carry many pathogens and can spread diseases to humans and pets. Some of these diseases are potentially fatal so it is paramount that you address the rodent problem as soon as possible.

Rodents can transmit diseases in two ways; directly and indirectly. Direct infection occurs when humans come into contact with rodents, droppings, urine, and animal carcasses. Indirect infection happens through other side-effects of the rodents, most commonly ticks and fleas.

Diseases Spread Directly by Rodents

1. Plague


Rodent carriers: Wild rodents including wood rats, ground, fox, and wood squirrels, chipmunks

Plague Column in Vienna

Plague is perhaps the most recognizable disease spread by rats and is infamous for its devastation of Europe in the middle Ages. Cases of the plague are very rare today and mostly occur in rural areas in the western United States. It is worth noting that other rodents including squirrels and chipmunks can spread the plague, usually through contact with a dead infected animal. Rodents may also spread bubonic plague indirectly through infected ticks.

The most common types of plague include pneumonic, bubonic, and speticemic.

Common symptoms: Pneumonic plague symptoms include fever, weakness, headache, shortness of breath, rapidly developing pneumonia, and bloody mucus. Bubonic plague symptoms include headache, fever, weakness, painful and tender lymph nodes. Septicemic plague symptoms include chills, fever, abdominal pain, extreme weakness, and shock.

Treatment: Plague is treatable with commonly available antibiotics.

2. Rat-Bite Fever


Rodent carriers: Rats and mice

Rat-bite fever (RBF) is caused by the bacteria Streptobacillus moniliformis. The disease is spread to humans by consuming food or water that is contaminated by rat/mice feces or by a scratch or bite from an infected rodent. You can also contract rat-bite fever by handling a dead rodent. Rat-bite fever is a serious disease and is potentially fatal if not treated.

Children under 5 years are especially at risk of contracting RBF because their immune systems are not fully developed. Other at-risk individuals include adults older than 65, pregnant women, and people with compromised immunity such as HIV/AIDS and cancer patients.

Common symptoms: Muscle pain, fever, headache, vomiting, joint pain and/or swelling, and rash. Symptoms typically take 3-10 days to appear.

Treatment: Antibiotics are very effective in the treatment of rat-bite fever.

3. Hantavirus Pulmonary Syndrome


Rodent carriers: Cotton rat, deer mouse, white footed-mouse, rice rat

Hantavirus Pulmonary Syndrome (HPS) is common throughout most of North and South America and is spread through inhaling dust or debris that is contaminated with rodent feces or urine. People can also contract the virus by direct contact with rodent droppings or urine or by contact with an infected rodent. Although rare, it is also possible to get infected from a scratch or bite inflicted by rodents.

Microbiologists at the Centers of Disease Control suiting up. They work with viral hemorrhagic fevers including HPS.

The primary risk of infection comes from having rodents in and around the home. There have been no reported cases of person-to-person transmission in the United States. HOS has a mortality rate of about 38% so it is potentially fatal if not addressed quickly. Experts believe that symptoms may develop between 1-8 weeks after exposure although the data on incubation time is not precise.

Common Symptoms: Early symptoms include muscle aches, fever, fatigue, dizziness, headaches, chills, nausea, vomiting, abdominal pain, and vomiting. Late symptoms include shortness of breath, coughing, and difficulty breathing.

Treatment: There is no treatment specific to Hantavirus and most infected patients are treated in the intensive care unit. Treatment for HPS is more successful with an early diagnosis so be sure to inform your doctor that you have been in contact with rodents if you develop any of the aforementioned symptoms.

4. Leptospirosis


Rodent carriers: Most kinds of rodents

Leptospirosis is mostly spread by ingesting food or water that is contaminated with animal urine. Other animals that may carry the bacterium include horses, pigs, dogs, cattle, and wild animals. Infected animals do not show any symptoms.

Humans may also get infected through broken skin or mucous membranes such as the mouth, nose, and eyes. Infection is more likely during floods or while kayaking, swimming, or wading in contaminated rivers and lakes. Although leptospirosis occurs all over the world, the disease is most prevalent in tropical and temperate climates.  

Common symptoms: Headache, high fever, muscle aches, chills, red eyes, vomiting, jaundice, abdominal pain, rash, and diarrhea.

Treatment: Leptospirosis is treated with antibiotics, usually penicillin and doxycycline

5. Salmonellosis


Rodent carriers: Rats and mice

Salmonellosis is typically spread by consuming food or water that is contaminated by rat droppings. It is worth noting that Salmonella refers to the group of bacteria that causes Salmonellosis, which is the disease.

Animals can carry the disease without showing any symptoms. Although anyone can get sick from salmonella, infants and children under 5 years, people with compromised immune systems, and adults older than 65 are at the highest risk.

Salmonella may also be spread by a wide range of animals including reptiles, poultry, amphibians, small mammals, dogs, cats, farm animals, and horses.

Common symptoms: fever, vomiting, diarrhea, and abdominal cramps

Treatment: Most cases of salmonella infections resolve on their own within 5-7 days. It is necessary to drink plenty of fluids to stay hydrated. People with severe diarrhea may need intravenous fluids and medical attention.

6. Lymphocytic Chorio-meningitis (LCMV)


Rodent carriers: House mouse

There are three main ways that humans contract Lymphocytic Chorio-meningitis. The first is by inhaling dust that is contaminated with rodent droppings or urine. The second cause of infection is from direct contact with infected rodents including touching their feces or urine. Although rare, you may also catch LCMV from bites or scratches from infected rodents.

Experts believe that at least 5% of house mice in the United States carry LCMV. The infected mice do not typically show any symptoms of illness and are capable of transmitting the disease to humans at any point throughout their life.   

Common symptoms: fever, lack of appetite, malaise, nausea, headache, and vomiting. LCMV may cause meningitis, acute hydrocephalus, and encephalitis.

Treatment: Lymphocytic Chorio-meningitis requires medical intervention and is treated according to severity.

Diseases Transmitted Indirectly By Rodents

Rodents including mice and rats spread diseases to humans and pets through vectors. The most common vectors, in this case, are fleas and ticks and are known as ectoparasites or external parasites.

These external parasites are often seasonal but it’s a good idea to exercise tick control all year long and understand all of the methods on how to prevent tickborne diseases.

7. Human Granulocytic Anaplasmosis


Rodent carriers: white-footed mouse, dusky-footed woodrat, deer mouse, Mexican woodrat

Vectors: Ticks

Human Granulocytic Anaplasmosis is spread to humans by bites from infected ticks. The western blacklegged tick and blacklegged ticks are typically responsible for the spread of this disease. Anaplasmosis is most common in Midwestern and Northeastern states. Mortality from the disease is low and reported at about 1% of infections.

Common Symptoms: early signs include severe headache, fever, muscle aches, chills, diarrhea, nausea, vomiting, and loss of appetite. Late symptoms include bleeding problems, respiratory failure, organ failure, and death.

Treatment: Anaplasmosis is typically treated with doxycycline which is an antibiotic.  Early treatment is necessary to prevent severe illness and even death.

8. Lyme Disease


Rodent carriers: white-footed mouse, tree squirrel

Vectors: Ticks

Lyme disease is transmitted to humans via bites from infected blacklegged ticks and is the most common vector-borne disease in America. Recent statistics suggest that around 300,000 people are infected with Lyme disease every year in the United States. The disease is caused by the bacterium Borrelia burgdorferi.

Rash from tick bite

The north-central and the northeastern United States report the highest number of Lyme diseases cases. Only blacklegged ticks can transmit the disease so getting bitten by a tick especially outside of the aforementioned regions does not automatically mean that you will get infected. Removing the tick immediately after getting bitten may reduce the chances of contracting Lyme disease.

One great way to try to prevent squirrels from nesting in your home is to keep brush and trees trimmed back at least 3 feet from your home’s exterior. This will make it more difficult for the rodents to get access and they’ll likely look elsewhere for shelter.

Common symptoms: Early symptoms of Lyme disease include rash, fever, headache, chills, muscle and joint aches, and fatigue. Later symptoms of the disease include neck stiffness and severe headaches, arthritis, dizziness, facial palsy, inflammation of the brain and spinal cord, numbness, and nerve pain.

Treatment: Lyme disease is usually treated with antibiotics including amoxicillin, doxycycline, and cefuroxime axetil.

9. Babesiosis


Rodent carriers: Deer mice, white-footed mice, and voles

Vectors: Tick

Babesiosis is spread to humans by bites from infected blacklegged and deer ticks. Infections tend to be seasonal, peaking during the warm months. Cases of Babesiosis are most prevalent in the upper Midwest and Northeast United States.

Most people infected with Babesiosis do not show symptoms and the parasites cannot be transmitted from person-to-person. The parasite is mostly transmitted by ticks in the nymph stage.

Common symptoms: Most people do not show symptoms while the ones who do may develop headache, fever, loss of appetite, body aches, fatigue, and nausea.

Treatment: Most people do not need treatment for Babesiosis particularly if they do not show any symptoms. Effective treatments are available for those who do show symptoms.

10. Murine Typhus


Rodent carriers: Rats

Vectors: Fleas

Humans contract Murine Typhus from infected fleas. The fleas get the bacteria (Rickettsia typhi) from infected rats.

Chest Xray of patient suffering from acute respiratory distress syndrome caused by murine typhus

When the infected flea bites a human, the broken skin is exposed to infection by the insect’s feces. It is also possible to breathe in infected flea dirt or rub the dirt in mucous membranes such as the eyes.

Flea-borne typhus is generally rare in the United States and most cases have been reported in Texas, Hawaii, and California.

Common symptoms: Fever, loss of appetite, body aches, nausea, stomach pain, rash, vomiting, and muscle pain. Symptoms may begin to appear 2 weeks after exposure.

Treatment: Flea-borne typhus is treated with antibiotics, usually doxycycline.

11. Rocky Mountain Spotted Fever (RMSF)


Rodent carriers: Bushy-tailed woodrat, deer mouse, chipmunk, ground squirrel

Vectors: Ticks

Rocky Mountain spotted fever is spread to humans through the bite of an infected tick. This is a serious disease and is potentially fatal if not treated early. The disease is typically spread by Rocky Mountain wood tick, American dog tick, and brown dog tick.

Cases of RMSF have been reported all over the United States but are most prevalent in Oklahoma, Arkansas, Tennessee, Carolina, and Missouri.

Common symptoms: Headache, fever, muscle pain, nausea, rash, vomiting, lack of appetite, and stomach pain.

Pocket Pets and Diseases

Pet rodents can also spread diseases

Outdoor rats and mice breaking into your home aren’t the only pathogen-carrying rodents you need to be worried about. Sometimes the danger lies with your own pets. Pocket pets such as guinea pigs, hamsters, rats, mice, ferrets, and rabbits can also harbor dangerous diseases.

This usually happens when your pets come into contact with infected wildlife and outdoor rodents where they contract these diseases. The pets can then transmit the disease to their human owners.

The most common diseases that may be transmitted to humans by their pocket pets include:

  • Lymphocytic chorio-meningitis (LCMV)
  • Salmonellosis
  • Leptospirosis
  • Rat-bite fever
  • Plague

Instances of people contracting these diseases from pocket pets are relatively rare especially if your pets do not typically leave the house. Extra precautions may be necessary for these pets especially to protect them from Salmonellosis, the most common disease to afflict small mammals.

It is always a good idea to schedule regular visits to the vet to ensure that your pets stay healthy and that any infections are spotted and treated early. Also, wash your hands thoroughly after handling the pets, including their droppings, urine, and bedding. Help your children to wash their hands and discourage them from kissing their pets.

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Written by Ben Cannon

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