Recurrent Fever
🔥 Recurrent Fever in Cats with FIP
Overview
Recurrent fever is one of the most common early signs of feline infectious peritonitis (FIP). Affected cats often experience fluctuating body temperatures that temporarily respond to antibiotics or anti-inflammatory medications but quickly return once treatment stops.
Unlike bacterial infections, this fever is driven by an abnormal immune response triggered by mutated feline coronavirus, not by active bacterial growth.
Typical Characteristics
Cats with FIP-related fever may show:
🌡️ Persistent or recurring high temperature (often above 39.5°C / 103°F)
🔁 Temporary improvement followed by relapse
💊 Poor or no response to antibiotics
😿 Lethargy, reduced appetite, and decreased activity
📉 Gradual weight loss over time
The fever may fluctuate daily and appear intermittent, which can delay diagnosis.
Why FIP Causes Recurrent Fever
FIP causes widespread inflammation of blood vessels and tissues. The immune system releases inflammatory mediators that continuously stimulate the body’s temperature regulation system, resulting in prolonged or recurring fever even without bacterial infection.
This immune-mediated fever is a hallmark feature of both wet and dry forms of FIP.
When to Seek Veterinary Care
Veterinary evaluation is recommended if a cat has:
Fever lasting more than 2–3 days
Fever that repeatedly returns after medication
Fever accompanied by weight loss, abdominal swelling, neurologic signs, or eye changes
Poor appetite or progressive weakness
Early diagnosis improves treatment planning and monitoring.
Diagnostic Considerations
Veterinarians may evaluate:
Complete blood count (CBC)
Total protein and A/G ratio
Inflammation markers
Imaging (ultrasound / X-ray)
Clinical trend monitoring
Recurrent fever alone does not confirm FIP, but it is an important clinical indicator when combined with other findings.
Trusted Medical References
Information is based on guidance from:
Cornell University College of Veterinary Medicine
Merck Veterinary Manual
VCA Animal Hospitals
International Society of Feline Medicine (ISFM)
American Association of Feline Practitioners (AAFP)
⚠ Medical Disclaimer
This content is provided for educational purposes only and does not replace professional veterinary diagnosis or treatment. Always consult a licensed veterinarian.
