Rodent Illnesses in Cats

Causes, Treatment, and Prevention

Cat playing with little gerbil mouse on thetable
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Does your cat catch mice, voles, and rats—or maybe chipmunks and squirrels? Cats love to hunt rodents of all kinds and will often bring home what they catch. Unfortunately, they may also bring home rodent illnesses: infections, parasites, or toxins that they contracted from their prey, some of which can be fatal if left untreated. Recognizing the signs of these varied illnesses, which range from gastrointestinal distress to neurological problems, is critical because prompt veterinary attention may be required to save your cat's life.

What Are Rodent Illnesses?

Rodent illnesses are those infections, diseases, or toxicities carried and transmitted by rodent species. These include toxoplasmosis, plague bacteria, hantavirus, tularemia, intestinal parasites, and rodenticide toxins.

Symptoms of Rodent Illnesses in Cats

Symptoms of rat-borne illnesses in cats are sometimes severe and may affect multiple bodily systems from head to tail. Many of the following symptoms may occur with more than one illness, so knowing specific characteristics of each illness and what part(s) of the body they affect will help determine the cause and appropriate treatment.


  • Lethargy
  • Gastrointestinal problems (vomiting, diarrhea)
  • Respiratory issues (nasal drainage, sneezing, or coughing)
  • Mouth lesions
  • Weight loss
  • Fever
  • Enlarged lymph nodes in the head and neck
  • Abdominal pain
  • Jaundice (yellowing of skin, mucous membranes, and the whites of the eyes)
  • Organ failure
  • Pale gums
  • Loss of coordination
  • Seizures

Types of Rodent Illnesses in Cats

There are a few rodent illnesses that may affect cats in the United States. The most serious are bacterial diseases, contracted by eating or being bitten by rodents. Parasites are a common and treatable concern, but the presence of these pests can be challenging and time-consuming to treat if a cat frequents the outdoors. Illness due to poisoning (eating a poisoned mouse, for instance) is also concerning because it can be fatal.


Toxoplasmosis is one of the most common parasitic diseases in cats. This infection is caused by the Toxoplasma gondii parasite. Toxoplasmosis can affect many animals, including humans. However, the cat is the ideal host for Toxoplasma gondii because it is the only animal in which this microscopic parasite can complete its life cycle.

Cats become infected by Toxoplasma gondii by ingesting the cysts of this parasite. Most often, this occurs when cats eat mice or rats infected with the parasite. However, they can also ingest it during grooming after coming in contact with infected soil or feces.

Cats infected with toxoplasmosis will often show no symptoms. In rare cases, cats will develop lethargy, gastrointestinal problems, or even respiratory issues. Many cats will remain silent carriers their whole lives.

Humans can contract toxoplasmosis after handling cat litter that contains the parasite and accidentally ingesting the microscopic cysts. They can also get it after touching and ingesting contaminated meat.

Intestinal Parasites

Many rodents are infected with common intestinal parasites like tapeworms, hookworms, and roundworms. Intestinal parasites can cause diarrhea, vomiting, and weight loss. Some intestinal parasites can be passed on to other pets or humans in the home.

If your cat goes outdoors or is known to catch vermin, routine fecal testing is recommended to check for the presence of intestinal parasites. Your veterinarian can prescribe anti-parasitic medications to de-worm your cat. In addition, some monthly heartworm and flea preventive medications will de-worm your cat with each dose.

Plague Bacteria

Some rodents carry the plague, an infection caused by the bacteria Yersinia pestis. This is essentially the same bacteria responsible for causing the infamous "black plague" of the Middle Ages. Plague is often transmitted by fleas, but cats can be infected by eating the meat of infected rodents.

Cats infected with Yersinia pestis may experience lethargy, depression, loss of appetite, vomiting, diarrhea, coughing, muscle soreness, and fever. The cat may develop lymph node enlargement, lesions in the mouth, and weight loss.

Treatment involves the use of antibiotics and providing supportive care. The sooner treatment can begin, the better the odds of survival.

It is uncommon for humans to contract plague. When they do become infected, it is usually through a flea bite. Symptoms and treatment are relatively similar to those in cats.


Several types of rodents are known to carry hantavirus. Cats can be infected by hantavirus but will show no symptoms, therefore the virus is not dangerous to them. In addition, cats cannot transmit hantavirus to people.

However, humans can be exposed through contact with infected rodents. Though serious complications from hantavirus are uncommon in humans, exposure can lead to a serious condition called hantavirus pulmonary syndrome.


Tularemia is a disease caused by the Francisella tularensis bacteria carried by rodents and rabbits. Though it is uncommon in cats of North America, it can affect them—most often in late spring and summer.

Commonly called "rabbit fever," tularemia generally causes sudden high fever, large painful lymph nodes in the head and neck, abdominal pain, jaundice (yellowing of skin, mucous membranes, and the whites of the eyes), and organ failure.

Tularemia is diagnosed by laboratory tests such as a complete blood count (CBC), a blood chemistry panel, and a urinalysis. An ultrasound may be required to check for masses in a cat's internal organs.

This infection can be fatal, but cats can survive. Treatment must be early and aggressive, involving antibiotics and supportive care.

Rodenticide Toxicity

Rodenticide, or rat poison, is highly toxic to cats. This toxicity is not technically transmitted from rodents to cats; it results from contact with poisons designed to kill rodents. Cats may eat rat poison that has been placed in and around the house. More commonly, cats are exposed to poison after eating all or part of a rodent that has ingested it.

Rodenticide is dangerous to cats, even in small amounts. These poisons may cause lethargy, gastrointestinal upset, pale gums, loss of coordination, and seizures.

If you suspect your cat was exposed to rat poison, seek veterinary treatment immediately because aggressive treatment is often necessary. There are several types of rat poison, so symptoms and treatments will vary. Knowing the rodenticide your cat encountered will help determine the proper treatment.

Prognosis for Cats with Rodent Illnesses

Cats can recover from rodent-borne illnesses, but the chances of survival are best with swift and aggressive treatment that is specific to the particular ailment. Delay in treatment can result in fatalities from bacterial infections (except hantavirus) or rodenticide exposure.

How to Prevent Rodent Illnesses

If you see your cat with a dead or dying rodent, try to remove the rodent to prevent your cat from eating it.


Always wear gloves when handling rodents. As an added layer of protection against hantavirus, a mask is also recommended.

After exposure to a rodent, it's important to watch your cat closely for several days. Contact your veterinarian right away if your cat is showing any signs of illness. If your cat is a regular rodent-catcher, you may need to visit the vet more frequently to screen for diseases and parasites.

All cats should be on year-round flea prevention, but this is even more important if your cat goes outdoors and hunts. Consider tick prevention as well.

Avoid using rodenticides around your home to reduce the risk of exposure to rat poison.

One of the best things you can do to minimize exposure is to keep your cat indoors.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.
Article Sources
The Spruce Pets uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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