Mice and rats can spread disease through their saliva, feces, or urine. They also often host mites, fleas, and other parasites that can transmit diseases to people.

Luckily, mice aren’t aggressive and usually only bite people when they feel threatened or cornered. Unless you’re handling them, you’re very unlikely to get bitten.

Mice bites usually aren’t serious, but it’s still a good idea to see a doctor if you get bitten. The main threat of rodent bites is the risk of infection. Mice carry bacteria and viruses that can lead to potentially lethal conditions.

Let’s take a look at what mice bites look like and the potential risks.

Mice have strong front teeth that can break your skin if they bite you. Their bite can cause a sharp pinching sensation and draw blood. Usually, their bite causes a single puncture wound.

You’re most likely to get bitten by a mouse if you’re handling it. However, in rare circumstances, a mouse may bite you if it feels threatened, even if it’s unintentional.

A 2018 Canadian news story describes a woman getting bit on the leg by an unprovoked mouse in a theater. After getting bitten, the woman looked under her seat and saw three mice living there.

Most of the risks of mouse bites come from potential bacterial or viral infections. Mouse bites can also cause allergic reactions in some people.

According to the Centers for Disease Control and Prevention (CDC), small rodents including mice and rats almost never carry rabies.

Allergic reactions

A 2014 case study describes an animal caretaker who had an allergic reaction after being bitten by a lab mouse.

The 55-year-old man received a bite on his middle finger. Within 10 minutes his whole body became itchy and he developed a rash on his arms. Five minutes later, he developed swollen lips and he became dizzy.

The man’s symptoms subsided within 8 hours after admittance to a hospital.

Rat-bite fever (RBF)

Rat-bite fever is a type of infection carried by bacteria that live on some rodents. It can be transmitted through bites or by consuming food and water contaminated with rodent feces or urine.

Symptoms usually begin within 3 to 10 days of contact. In some cases, it may be delayed up to 21 days. It causes symptoms such as:

  • fever
  • vomiting
  • headache
  • muscle pain
  • joint swelling or pain (about 50 percent of the time)
  • rash (about 75 percent of the time)

Antibiotics are highly effective at curing rate-bite fever if it’s treated quickly. If not treated, the mortality rate is more than 10 percent.

Hantavirus

Hantavirus is a rare but potentially lethal disease spread by deer mice and white-footed mice. It has a mortality rate of 38 percent. Early symptoms of this viral infection include:

  • fever
  • fatigue
  • muscle aches
  • dizziness
  • chills
  • nausea
  • vomiting
  • diarrhea
  • abdominal pain

Four to 10 days after infection, some people develop symptoms like:

  • shortness of breath
  • coughing
  • a feeling of a band tightening around your chest
  • fluid in lungs

Hantavirus can be spread through mouse saliva, urine, or feces. Transmission through mouse bites is rare. Usually, people develop it through airborne transmission.

Lymphocytic choriomeningitis

Lymphocytic choriomeningitis is a viral disease carried by rodents. It’s estimated that 5 percent of house mice in the United States carry lymphocytic choriomeningitis. It can be transmitted to humans through saliva, blood, feces, or urine.

Symptoms usually onset within 8 to 13 days of exposure.

Early symptoms often include:

  • fever
  • a general feeling of unwellness
  • loss of appetite
  • headache
  • vomiting

If the infection spreads, it can lead to more serious conditions like meningitis. Meningitis is an infection of the tissue that lines your spinal cord and brain.

Pet mice may bite you when you handle them. You can minimize your chances of getting bitten by wearing gloves when you put your hands in their cage or when you pick them up.

The CDC doesn’t recommend that families with children under 5 years old, pregnant women, or people with weakened immune systems keep pet rodents since they have the potential to carry disease. Like other mice, pet mice can spread diseases through their saliva, feces, or urine.

Some diseases like lymphocytic choriomeningitis are more common in wild mice but have also been reported from pet mice.

If you’re bitten or scratched by a rodent, you should immediately clean your wound with warm water and soap. After you clean the area, you can dry it with a fresh towel and apply an antibiotic cream and bandage.

It’s a good idea to see a doctor any time you’re bitten by a rodent. Even though the wound might not look serious, rodents can carry bacteria and viruses in their saliva that can cause potentially life-threatening diseases.

There currently aren’t any laboratory tests that can tell whether a mouse is carrying the bacteria that causes rat-bite fever, so a doctor may provide you with antibiotics before an infection develops.

Mice rarely bite but may do so if they feel cornered or threatened. If you’re bitten by a mouse, it’s a good idea to immediately wash the wound with soapy water and see a doctor. Most infections caused by rodent bites have a good outlook when treated quickly.