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Fever in Cats

If your cat is running a fever it may indicate an underlying health problem that requires urgent treatment. Today, our Harrisburg vets explain some of the causes and symptoms of fevers in cats and what to do if your cat has a fever.

Fever in Cats

Cats, like humans, frequently develop fevers when their immune systems are fighting off an infection or disease. Cats have a normal body temperature of 100.4o to 102.5o Fahrenheit. In cats, a fever is defined as a temperature of more than 102.5o F.

If your feline friend shows any of the signs of fever below it is essential to seek veterinary care. Cats that develop a fever higher than 106º F are at serious risk of damage to their vital organs. 

Signs of Fever in Cats

Depending on the underlying cause, symptoms of fever in cats include: 

  • Lack of appetite
  • Weakness or lethargy
  • Shivering 
  • Rapid heart rate
  • Decreased activity 
  • Decreased drinking
  • Dehydration 
  • Poor grooming
  • Vomiting
  • Diarrhea 

How To Take Your Cat's Temperature

Taking your cat's temperature is fairly straightforward. Simply use a digital thermometer aimed at your cat’s ear, or use a pediatric rectal thermometer for a more accurate reading. Never use an older-style mercury thermometer when taking your pet's temperature! If the thermometer breaks it can be very harmful to your kitty's health.

A pediatric rectal thermometer is the best way to accurately measure your pet's temperature and determine whether your cat has a fever. Lubricate the thermometer with petroleum jelly before inserting it gently. It's important not to go too far as it could damage your cat's delicate rectal tissue. You may require the assistance of another person to calmly restrain your cat while inserting the thermometer. To get an accurate reading, leave the thermometer in place for at least two minutes.

If you think that your cat may have a fever but you are uncomfortable taking its temperature, contact your veterinarian right away to book an appointment. Your vet will be able to quickly assess your kitty's temperature and overall state of health.

Causes of Fever in Cats

Fevers generally occur in cats when their immune system is activated by conditions such as:

  • Bacterial and viral infections
  • Fungal infection
  • Internal injury
  • Trauma
  • Parasites
  • Autoimmune disease
  • Certain medications
  • A tumor
  • Immune-mediated inflammatory disease
  • Poisoning
  • Metabolic disorders
  • Endocrine disorders

Conditions that Can Cause Fever in Cats

Outdoor cats are at the highest risk for exposure to diseases than indoor cats. Several serious conditions can cause fever in cats, including:

Bobcat Fever in Cats (Cytauxzoonosis) 

Also known as Tick fever, Bobcat fever in cats is an acute, sometimes fatal disease in cats caused by the bite of a tick infected with the Cytauxzoon Felis parasite. This condition often strikes healthy, young adult cats that spend time outdoors. Symptoms of Bobcat fever in cats are lethargy, lack of appetite, fever, anemia (pale gums), jaundice, and difficulty breathing.

Valley Fever (Coccidioidomycosis) 

Valley fever in cats is caused by the inhalation of the soil fungus Coccidioides immitis found in desert regions of the Southwestern United States. Symptoms of valley fever in cats include fever, lethargy, poor appetite, and coughing, but can progress to severe joint and back pain, seizures, and blindness.


Haemobartonellosis is an antibiotic-resistant bacterial blood infection seen in cats. This condition often leads to urinary tract infections and pneumonia which are very hard to treat.


Ehrlichiosis is a tick-borne disease that causes fever in cats. Fever, swollen lymph nodes, lethargy, decreased appetite, unusual bruising or bleeding, and eye inflammation are all symptoms of Ehrlichiosis in cats.

Milk Fever (Eclampsia) 

Eclampsia typically occurs in cats approximately 4 weeks after giving birth to kittens. Early signs of milk fever in cats include a stiff walk, restlessness, and excessive panting.

Cat Scratch Fever (Bartonellosis) 

This condition can be transmitted between animals and from animals to humans. In cats, the disease is typically spread through contact with flea feces. Symptoms of cat scratch fever in cats include fever, swollen glands, lethargy, decreased appetite, and in some cases reproductive difficulties. 


One of the most prevalent parasitic diseases. Toxoplasmosis in cats can cause symptoms such as fever, diarrhea, coughing, difficulty breathing, jaundice, and seizures, and it can be fatal in severe cases.

What To Do If Your Cat Has a Fever

It is important to NEVER give your cat human medications without the explicit advice of a veterinarian! Many human medications, such as acetaminophen, can be extremely toxic to cats.

Make sure your cat stays hydrated by ensuring that they have easy access to fresh clean water and make sure they have a comfortable place to relax. 

If your cat has a fever that lasts longer than 24 hours or goes above 106º F contact your veterinarian to book an urgent appointment or visit your local emergency animal hospital right away.

Your veterinarian will perform a thorough examination of your cat to determine the cause of the fever and prescribe the best treatment to help restore your cat's health. Even after a thorough veterinary examination, the cause of your cat's fever may be unknown in some cases, and your cat may be diagnosed with a fever of unknown origin (FUO). If your cat is dehydrated to a moderate or severe degree, intravenous fluids may be administered to help him feel better and fight off illness.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding people or pets. Always follow your doctor's advice regarding asthma or other allergy symptoms. 

If your cat requires urgent care, contact us right away. We'll do everything we can to try and fit you and your cat into our schedule.

New Patients Welcome

Colonial Park Animal Clinic is accepting new patients! Our experienced vets are passionate about the health of companion animals. Get in touch today to book your pet's first appointment.

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(717) 540-7140