immunology

Feline calicivirus

  • Calciviridae: + SS RNA virus

  • Transmitted through Oral & nasal secretions.

  • Oral & URT disease: lesions on margins of tongue with mild respiratory disease.

  • Limping syndrome: Acute transient lameness following oral signs.

  • Feline stomatitis (rare): Progressive necrosis of oral mucosa (bilateral in caudal area). Extract teeth.

  • Virulent systemic feline calicivirus (high mortality mutation): Widespread subcutaneous oedema & lesions (esp. mouth, ears, nose & paw pad)

  • Very resistant in environment

  • Recovered cats can become carriers (1 month to life)

  • Hard to grow in cell culture

 

Feline enteric coronavirus

  • Coronaviridae: +SS RNA virus

  • Faecal-oral

  • Often subclinical

  • transient, mild gastrointestinal illness in kittens, 15% of cats shed indefinitely (all shed for first 10 months).

  • High potential for spillover

  • No vaccine

 

Feline infectious peritonitis

  • Coronaviridae: +SS RNA virus        

  • Mutation of FECoV (1-5%)

  • High mortality (quicker in kittens & with wet form)

  • Key sign – Persistent but undulating fever that is unresponsive to antibiotics

  • Wet (effusive): Accumulation of fluid in abdomen or chest, which cause breathing difficulties.

  • Dry: No accumulation of fluid, and more likely to show ocular and neurological signs

  • No vaccine

 

Feline panleukopenia virus

  • Parvoviridae: SS DNA virus

  • Transmitted through all secretions

  • Malabsorption diarrhoea

  • Last 2 weeks of pregnancy to last 2 weeks of life = Lesions in external granular layer of cerebellum

  • Very resistant in environment

  • Maternal antibodies passed on

  • Replicate in actively dividing cells (esp. haematopoietic, lymphocyte and intestinal mucosa precursors)

  • More severe in neonate

 

 

Felid alpha 1 herpes virus

  • Herpesviridae: DS DNA virus

  • Transmission = Respiratory

  • Viral rhinotracheitis – upper respiratory infection (with eye conditions)

  • Frequently co-infected with caliciviruses.

  • Latency and persistency

  • Can cross placenta

  • Latent in ganglionic neurons

 

 

Feline immunodeficiency (FIV)

  • Retroviridae: Diploid, 2 ssRNA viruses

  • Saliva (fighting)

  • converted into dsDNA via reverse transcriptase

  • High mutation rate

  • Viral DNA is integrated into host genome – hence, it is persistent and hard to target

  • Exogenous virus = horizontal transmission (clinically important).

  • PCR is not effective due to asymptomatic phase (low levels of viremia).

  • Progressive depletion of CD4 T cells = immunodeficiency

  • 3 stages – primary, asymptomatic & secondary (associated with increased infections)

  • Vax & prevent exposure        , No cure (infected for life).

  • Increased risk of blood cancers.

 

 

Feline leukaemia virus (FeLV)

  • Transmission = Only FeLV A: Oronasal contact w. saliva or urine, Vertical (transplacental & -mammary).

  • Immunosuppression – increased risk of blood cancer and persistent/recurrent infections.

  • RAT test

  • No cure (infected for life).

  • FeLV A (original): Only horizontally transmissible form

  • FeLV B:  frequency of cancer

  • FeLV C: erythroid hypoplasia

  • FeLV T: destroys T lymphocytes

  • enFeLV: In most cats (vertical)