Feline infectious peritonitis

What type of virus causes Feline infectious peritonitis

Alphacoronovirus (FCoV)

Describe coronaviruses

RNA genome inside lipid envelope

• dies in environment

• RNA means constantly evolving

Surface proteins

What are the two biotypes of feline corona viruses

FIPV - feline infectious peritonitis virus

FECoV - feline enteric coronavirus

Do all cats with FECoV develop FIV? WHY

no.

depends on :

• virus biotype / strain

• dose of virus

• immune status of cat

Describe pathogenesis of FeCoV

oronasal infection

grows and proliferates in tonsils, URT, and intestinal epithelium

in some cases, sporadically mutates into FIPV.

Describe pathogenesis of FIPV and how this infection occurs

cat infected with FeCoV → sporadic mutation of virus → FIPV.

FIPV is an immune complex disease.

• Immune complexes deposit in walls of small blood vessels leading to vasculitis

• Antibody binding to virus enhances uptake by macrophages

• Cats that do not have antiviral antibodies do not develop FIP

three possible outcomes

• good cell mediated immunity = recovery

• partial cell mediated immunity = dry FIP

• poor cell mediated immunity = wet FIP

How does antibody enhancement affect FIP treatments / prevention?

FIP is an immune complex disease. Cannot give Abs for treatment, Abs in vaccine will cause more damage.

Immune complexes deposit in walls of small blood vessels leading to vasculitis. Antibody binding to virus enhances uptake by macrophages, Cats that do not have antiviral antibodies do not develop FIP

Where does FeCoV replicate?

Where does FIPV replicate?

enterocytes

enterocytes and macrophages.

What are the symptoms of wet FIP

Invariably fatal

accumulation of fluid within body cavities

• depression

• lethargy

• weight loss

• abdominal swelling

• jaundice

• hepatomelargy

• dyspnoea

• muffles heart sounds

• fluctuating unresponsive fever

Dry FIP symptoms

Invariably fatal.

• fluctuating unresponsive fever

• anorexia

• depression

• lethargy

• jaundice

• ataxia

• paresis

• behavioral changes

• iritis

• uveitis

• signs are dependent on organ involved.

How can you diagnose FIP

• definitive - histopathology + post mortem

• pre-mortem - clinical signs, fluid examination, clinical pathology and FeCov serology

What would you see in the haematology / blood biochemistry in cat with FIP

Hyperproteinaemia – raised globulins

Albumin/globulin ratio decreases

Increased liver enzymes, bilirubin and urea

What does FIP fluid look like and contain?

viscous, straw coloured fluid.

froths when shaken, clots on standing.

high protein content IgG>IgA

What is a limitation of PCR for diagnosis?

cannot differentiate between FIPV and FeCov

How can you test for FCOV in serology

limitations?

Immunofluorescence, ELISA

not differenciative between FIP / FCOV

How is FeCoV transmited?

shed in faeces and saliva

cats infected by ingestion of virus

(can also have transplacental spread)