Common Viral Diseases in Cats

Feline Panleukopenia Virus (FPV)

Disease: Feline infectious enteritis / feline distemper

Clinical signs: Vomiting, bloody diarrhoea, pyrexia, dehydration, leukopenia, cerebellar hypoplasia in kittens

Transmission: Faeco-oral, highly stable in environment

Diagnosis: PCR, ELISA (faeces, blood)

Vaccine: ✅ Core (effective; long duration of immunity)

Major cause of kitten mortality; re-emerging in unvaccinated cats

Feline Calicivirus (FCV)

Disease: “Cat flu” complex, stomatitis, limping syndrome

Signs: Ulcers on tongue/palate, nasal/ocular discharge, sneezing, fever, lameness

Transmission: Aerosols, direct contact, fomites

Diagnosis: PCR, virus isolation

Vaccine: ✅ Core (reduces severity but not infection)

Carrier state common; highly contagious in shelters

Feline Herpesvirus

Disease: Feline viral rhinotracheitis (cat flu)

Signs: Conjunctivitis, keratitis, nasal discharge, sneezing, corneal ulcers

Transmission: Aerosols, fomites, latent reactivation under stress

Diagnosis: PCR, virus isolation, ocular swabs

Vaccine: ✅ Core

Reactivation lifelong; cause of chronic ocular disease

Feline Leukaemia Virus (FeLV)

Disease: FeLV infection (immunosuppressive + oncogenic)

Signs: Anaemia, lymphoma, immunodeficiency, poor coat, weight loss

Transmission: Saliva, grooming, bites, vertical

Diagnosis: ELISA (antigen), PCR, IFA

Vaccine: ✅ Non-core (for outdoor/multi-cat cats)

Test & vaccinate; low UK prevalence but serious disease

Feline Immunodeficiency Virus (FIV)

Disease: Feline AIDS (progressive immune suppression)

Signs: Chronic infections, stomatitis, weight loss, lymphadenopathy

Transmission: Bite wounds (saliva), vertical (rare)

Diagnosis: ELISA (antibody), PCR

Vaccine: ❌ (not available in UK)

Common in outdoor, unneutered males; long latent phase

Feline Coronavirus (FCoV) / Feline Infectious Peritonitis (FIP)

Disease: Mild enteritis (FCoV); fatal peritonitis (FIP) if mutation occurs

Signs:

• Effusive form: Ascites, dyspnoea

• Non-effusive form: Weight loss, pyrexia, ocular/neuro signs

Transmission: Faeco-oral (shared litter trays)

Diagnosis: PCR, effusion analysis (high protein, low cells), immunostaining

Vaccine: ❌ (not recommended in UK)

Common in catteries

Cowpox Virus

Disease: Cutaneous pox lesions, respiratory disease in immunosuppressed cats

Signs: Crusted ulcers on head/limbs; pneumonia possible

Transmission: Rodent bites; zoonotic!

Diagnosis: PCR, histopathology

Vaccine: none

Zoonotic – reportable; outdoor rural cats most at risk

Rabies Virus

Disease: Fatal encephalitis

Signs: Behavioural change, aggression, paralysis, hypersalivation

Transmission: Bites/saliva

Diagnosis: DFA, PCR (post-mortem)

Vaccine: ✅ (for travel/export)

Absent in UK domestic cats; notifiable disease (APHA)

Avian Influenza (H5N1 etc.)

Disease: Respiratory/neurological illness in cats after eating infected birds

Transmission: Ingestion or contact with infected birds

Diagnosis: PCR (definitive)

Vaccine: None

Rare but zoonotic; notifiable to APHA

Feline Papillomavirus

Disease: Oral papillomas, skin plaques, possible carcinoma link

Transmission: Direct contact

Diagnosis: Histopathology, PCR

Vaccine: None

Usually benign; part of normal feline virome

Rotavirus / Astrovirus

Disease: Mild enteritis, mainly kittens

Transmission: Faeco-oral

Diagnosis: PCR

Vaccine: None

Supportive care only; typically self-limiting

Core Vaccines

FPV, FCV, FHV-1