Feline Retroviruses

Question 1

FeLV (feline leukaemia virus) disease (5)

Answer 1

• infectious lymphoma
• disease only in persistently infected cats
• disease only once it infiltrates into BM (oropharynx –> Regional LN –> BM –> other organs –> salivary glands
• infection remains in BM for a very long time (up to 140 weeks) where it appears apparently latent (tests negative) but it is replicating within the BM
• can be a transient or persistent infection
• transmission by licking/grooming (love virus)

Question 2

FeLV

• pathogenesis (3)
• Diseases it causes (5)
• Anaemia causes (3)

Answer 2

retroviral lifecyle allows mutation (to FeLV subgroup C–> FeSV [feline sarcoma virus]), recombination ( to subgroup C) or insertion into genes (apoptosis/ oncogenesis)

• immunosuppression, anaemia, neoplasia (leukaemia/lymphoma), glomerulonphritis, infertility
• causes of anaemia: immunosuppression, mutation to FeLV-C (pure red cell aplasia), neoplasia (myelphithis, haemorrhage, renal lymphoma)

Question 3

FeLV

• immunity (3)
• Dx (5)
• Tx (healthy vs sick cat)
• vaccines

Answer 3

• FeLV neutralising antibodies (prevent reoccurance but don’t fight off disease), cytotoxic T cells (fight off infection), Nh cell, complement
• RIM assay, CITE assay, ELISA, virus isolation, immunoflorescence
• healthy: isolate and rescreen in 12 weeks, vaccinate all other cats in house hold
• euthanasia
• inactivates, subunit (dilutes A efficacy), recombinant surface proteins, recombinant viral vectors

Question 4

FIV (feline immunodeficiency virus)

• virus facts (4)
• pathogenesis
• stages of human infection (5)

Answer 4

• no recovery from infection; slow progression
• lentivirus
• cell-to-cell transmission e.g. biting
• long incubation period
• persistently infected
• initial viraemia –> persistently infected but virus is kept in check by immune system –> decreases in immunity and increase in disease after many years
• PNL (pyrexia, neutrophlia, lymphopenia), latency, PGL (persistent, generalised lymphodenopathy), ARC (AIDS related complex), AIDS

Question 5

FIV

• disease association
• Dx (4)
• Tx (5)

Answer 5

• increase in risk of tumours, neurological disorders, lymphodenopathy, lymphopenia, pyrexia, wasting
• Dx: RIM assay, antigen ELISA, immunoblotting, virus isolation
• Tx: ABs (to clear up concurrent problems), short course of corticosteroids (to control inflammation), anti HIV drugs (AZT, PMEA, ddI/ddC, euthanasia, good housing

Question 6

Feline infectious anaemia

• bacterias
• disease
• haematological findings (4)
• DDX (3)
• Dx (1)
• predisposing factors (3)
• Tx (2)

Answer 6

-mycoplasma haemofelis (large)/ haemominutum (small)
- IMHA –> regenerative anaemia
-anaemia (increase in MCV with time), increase in reticulocytes, jaundice, positive coombs test
-DDx: IMHA, onion poisoning, heinz body anaemia
Dx: difficult: PcPc takes 1-2 weeks (will be dead/better by then)
-FeLV, stress, neoplasia
-Tx: tetracyclines will induce a temporary (3 week) remission, prednisilone initially