In short:
Feline infectious peritonitis (PIF) is a serious viral disease caused by the mutation of a feline coronavirus, causing internal granulomas without massive fluid effusion.
- Clinical incidence: FIP represents between 0.3% and 1.4% of feline deaths in veterinary clinics.
- Population at risk: Young cats under 2 years old and seniors over 10 are the most exposed.
- Key biological marker: An albumin/globulin (A:G) ratio less than 0.4 indicates strong suspicion of dry PIF.
- Official confirmation: The histopathology with immunohistochemistry (IHC) constitutes the reference examination with specificity close to 100%.
Feline infectious peritonitis (PIF) is a chronic granulomatous and pyogranulomatous vasculitis caused by a feline coronavirus mutation (FCOV), characterized by the absence of significant deflection and the development of nodular lesions granulomatous focused on several internal organs (liver, kidneys, central nervous system, eyes).
What does the PIF dries and how does it develop?
The dry form of feline infectious peritonitis is distinguished from the wet form by the near-absence fluid outbreak in the abdomen or the thorax. According to the guidance from the Advisory Board on Cat Diseases (ABCD), about 5% to 10% of cats infected with the feline enteric coronavirus (FCOV) develop a PIF following an internal viral mutation in the host. The clinical incubation period varies from a few weeks to several months.
This pathology preferentially affects individuals with an immature or weakened immune system. The guidelines published by the American Association of Feline Practitioners (AAFP) and the Everycat Health Foundation in 2022 specify that the disease represents 0.3% to 1.4% of the overall feline mortality observed in veterinary structures, the cases Concentrating mainly on cats under 2 years old and cats over 10 years old.
What are the clinical symptoms of the dry form?
In the absence of easily detectable liquid accumulation, dry PIF symptoms depend on the location of granulomas. In addition to clear general signs such as lethargy, progressive weight loss or persistent antibiotic resistant fever, the disease frequently attacks the ophthalmic and neurological spheres.
Ophthalmological and neurological manifestations listed by LAAFP (2022) include:
- Eye damage: Anterior uveitis, presence of keratic precipitates, effusion in the anterior chamber of the eye or retinitis.
- Neurological damage: Ataxia (loss of coordination), myosis or asymmetric mydriasis, nystagmus (involuntary movements of the eyes), convulsions and paraparesis.
How to establish the biological and histological diagnosis?
The diagnosis of dry PIF remains complex and requires a combination of blood tests, imaging and molecular tests. An isolated anti-FCoV antibody serology has a low diagnostic value, because it does not make the difference between the benign enteric coronavirus and the mutated virus responsible for PIF (ABCD, 2021).
The blood test frequently reveals hyperglobulinemia associated with non-regenerative anemia and lymphopenia. The plasma protein assay provides a valuable indicator: an albumin/globulin (A:G) ratio below 0.4 points to a high suspicion of PIF, while a ratio above 0.8 generally excludes disease (AAFP, 2022).
| Medical examination | Diagnostic value / performance | Recommendations (AAFP / ABCD) |
|---|---|---|
| Albumin/globulin ratio (A:G) | Strong suspicion if 0.8 | First-line blood test |
| RT-PCR on blood or plasma | Low sensitivity (30% to 50%) in the dry form | negative result does not exclude the disease |
| RT-PCR on biopsy/puncture | High specificity on mutated FCoV RNA | Targeted sampling on granuloma required |
| Histopathology + Immunohistochemistry (IHC) | Specificity close to 100% (Gold Standard) | Final confirmation on tissue biopsy |
To obtain absolute confirmation, histopathology coupled with immunohistochemistry (IHC) on tissue biopsy remains the reference examination (“Gold Standard”). LIHC offers a specificity close to 100% to identify the FCoV virus at the heart of granulomatous lesions. Nevertheless, LABCD points out that LIHC’s sensitivity to blind biopsies remains variable, due to the risk of taking uninjured tissue.
Legal framework and guarantees in France
In France, feline infectious peritonitis is included in the legal framework of redhibitory defects for the purchase of a cat. According to the rural and maritime fishing code, the buyer has a legal period of suspicion of 21 days from the delivery of the animal to have a certificate of suspicion drawn up by a veterinarian.
If the suspicion is confirmed, the legal deadline for taking legal action (action for redhibition) is set at 30 days from the date of delivery of the animal. The overall cost of a complete diagnostic assessment (including blood tests, ultrasound and targeted samples) varies according to the rates charged by the veterinary clinics and the complexity of the examinations required.
Frequently Asked Questions about the Cat’s Dry Pif
What is the most telling blood test for dry PIF?
The albumin/globulin ratio (A:G) is the most significant marker. A ratio of less than 0.4 indicates a strong suspicion of PIF, while a result greater than 0.8 generally allows this pathology to be excluded according to LAAFP guidelines.
Why is blood RT-PCR sometimes negative in case of dry PIF?
RT-PCR performed on blood or plasma has low sensitivity, between 30% and 50% in the dry form. The virus being concentrated in the granulomas of the organs, a negative blood test does not allow the diagnosis to be discarded.
What is the legal deadline for declaring a crippling defect linked to the PIF?
In accordance with the French rural and maritime fishing code, the legal time for suspicion for the PIF is 21 days after the delivery of the cat. Lacquereur then has 30 days in total to take legal action.
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