FIP Flashcards
(22 cards)
What type of virus causes feline coronavirus infection and feline infectious peritonitis (FIP)?
Feline coronavirus infection and feline infectious peritonitis (FIP) are caused by large enveloped single-stranded RNA viruses of the coronavirus family, characterised by large surface spikes.
How does feline coronavirus (FCoV) typically spread and survive in the environment?
FCoV is transmitted primarily via the faeco-oral route, with contaminated litter trays and fomites being key sources. It survives 24-48 hours at room temperature and up to 7 weeks in dry environments. It is readily inactivated by disinfectants.
What is the prevalence of FCoV infection and FIP in different cat populations?
FCoV infection is very common: in multi-cat households with >6 cats, 50-100% are infected. FIP is rare: ~1 in 5000 cats in small households; 5-10% in catteries. Infection may be persistent, leading to chronic shedding.
Which cats are at increased risk of developing FIP?
Kittens and young adults (<12 months) are commonly affected; a second peak occurs in cats >10 years. Increased risk exists in multi-cat households, pedigree cats, and siblings of affected cats. Environmental stress is a significant factor.
What is the internal mutation hypothesis in the pathogenesis of FIP?
The ‘internal mutation hypothesis’ proposes that FCoV infects gastrointestinal cells, then mutates within macrophages to allow systemic replication, causing FIP. These mutated strains lose gut replication ability and are not easily transmitted between cats.
What are the two forms of FIP and how are they distinguished?
FIP has two forms: Effusive (wet), associated with poor cell-mediated immunity causing vasculitis and effusions; and Non-effusive (dry), associated with partial immunity causing pyogranulomatous inflammation in organs like the kidneys, liver, CNS, eyes, etc.
What are the clinical signs associated with effusive (wet) FIP?
Common signs include ascites, pleural and pericardial effusions, pyrexia non-responsive to antibiotics, lethargy, inappetence, dyspnoea, tachypnoea, and mild icterus.
What are the clinical signs of non-effusive (dry) FIP?
Non-effusive FIP presents with variable signs depending on organ involvement: neurological signs (seizures, ataxia), ocular signs (uveitis, retinal detachment), GI granulomas, organomegaly (mesenteric lymph nodes, liver, kidneys), and testicular enlargement in males.
What is the definitive diagnostic method for FIP?
Definitive diagnosis requires histopathological identification of pyogranulomatous lesions with immunostaining for FCoV antigen within macrophages (immunofluorescence or immunohistochemistry).
What are the common haematological and biochemical findings in cats with FIP?
Mild non-regenerative anaemia (~66% cases), mature neutrophilia, lymphopenia, eosinopenia, monocytosis. Biochemically: mild increased liver enzymes, bilirubin, increased globulins (polyclonal gamma globulinaemia), low albumin, albumin:globulin ratio <0.4 strongly suggests FIP.
What are the typical characteristics of effusion fluid in wet FIP?
Effusion fluid is clear, straw/yellow coloured, viscous, sterile, low cellularity (<5x10⁹/l), non-degenerate neutrophils and macrophages, protein content >35g/L. Rivalta’s test may support diagnosis but has limited specificity.
What role does serology play in diagnosing FIP and what are its limitations?
High FCoV antibody titres (>1:1600) are supportive but not diagnostic as they cannot differentiate FIP strains. False negatives can occur early/late in disease, and false positives from maternal antibodies in kittens.
How can PCR be used in FIP diagnosis and what are the limitations of current PCR tests?
PCR on effusion, blood, tissue detects FCoV RNA but cannot distinguish between enteric or mutated FIP strains. The FIP RealPCR (spike protein mutation detection) has poor specificity and may miss strains due to variability.
What is the role of immunostaining in diagnosing FIP?
Immunostaining detects FCoV antigen inside macrophages and is considered the gold standard. Only FIP cases have sufficient intracellular viral antigen for detection. False negatives can occur with low macrophage counts or high antibody levels.
What supportive therapies are used for cats with suspected or confirmed FIP?
Supportive care includes anti-inflammatories (prednisolone 0.5 mg/kg BID), appetite stimulants (mirtazapine), vitamin B12, antioxidants (SAMe), and fluid therapy.
Describe the mechanism and efficacy of GC376 in treating FIP.
GC376 is a protease inhibitor preventing viral polymerase cleavage, essential for replication. Trials showed high success in experimental and natural cases (6/8 experimental cats survived; 19/20 natural cases responded).
Describe the mechanism and clinical use of GS-441524 and remdesivir for FIP.
GS-441524 (nucleoside analogue) and its prodrug remdesivir act as RNA chain terminators. GS-441524 had remarkable outcomes: all experimental cats survived; 25/31 naturally infected cats sustained remission. UK access via BOVA.
What is the protocol for using GS-441524 or remdesivir based on clinical presentation?
Dosing is based on clinical presentation: 6–10 mg/kg q12h orally for GS-441524; 10–20 mg/kg q24h IV for remdesivir. Duration is at least 84 days; dose adjusted if neurological/ocular signs or poor response occur.
What are the considerations when monitoring response to GS-441524 or remdesivir treatment?
Initial clinical improvement should occur within 2–5 days. Monitor weight, effusions, lymphocyte counts, globulin, albumin levels. Enlarged lymph nodes may persist but don’t indicate relapse. TDM (Edinburgh) can guide dosage.
What is the current recommendation regarding the use of the intranasal FIP vaccine?
The intranasal vaccine (Felocell FIP) is controversial and not recommended. It shows variable efficacy and must be used only in seronegative kittens ≥16 weeks old. It is not a core vaccine.
What measures can breeders and cat owners take to reduce FCoV transmission and prevent FIP outbreaks?
Minimise stress, keep small groups, good litter hygiene, separate food/litter areas, isolate queens before parturition, avoid breeding from parents of affected kittens. Use faecal PCR to identify chronic shedders.
Is there a zoonotic risk from feline coronavirus or FIP?
No. There is no zoonotic risk from FCoV or FIP. Related coronaviruses (SARS, COVID-19) do affect humans, but FIP is unique to felines.
