Lecture 9: Feline Viruses 2 Flashcards
What is the agent causing FIP in cats? What type of virus is it?
Agent: Feline Infectious Peritonitis virus (mutated feline coronavirus)
- (+)ssRNA, enveloped
What is the pathogenesis of FIP? And how does that impact virus detection?
- Feline enteric coronavirus replicate in GI epithelium and may mutate to FIPV (spike protein mutation)
o Can be in body for month/years sub clinically - FIPV target macrophages (= systemic infection)
o No viral antigens expressed by infected macrophages = low immune response - Short viremia (7d peak) = difficult to dx via seeing in blood (RT-PCR)
How are the agent(s) impacting FIP transmitted
Transmit:
* FeCoV type 1: Shed 2-3d post infection in feces
1. Transient shedding for 2-3 mo
2. 10-15% carriers = persistent shedding
* FeCoV type 2: canine + feline coronavirus combination
1. Shed for 2 weeks, no carrier
* FIPV not transmissible between cats (must contract FeCoV and have it mutate)
What are the 4 outcomes of feline coronavirus infection
- Resistance: 5-10%
- Transient infection: 70%
- Persistant infection /carrier: 10-15%
- FIP: 1-3% (rare outcome)
What are the clinical signs of feline coronavirus infection
Clinically (FeCoV): sub clinical (rare = enteritis)
What are the clinical signs of feline infectious peritonitis virus infection
Clinically (FIPV):
* Wet: abdominal distension/ascites with proteinaceous fluid (granulocytes) + ophthalmic signs (lesions/uveitis)
* Dry: ophthalmic signs (lesions/uveitis), numerous distributed pyogranulomas (lung/kidney/intestine)
How to diagnose FIP
Dx: not easy:
* Use medical hx (young/multi-cat house/stress/pedigree)
* Clinical exam findings
* Diagnostic tests
o mRNA PCR – analyzing blood for viral replication in the blood (but high false + rate)
o RealPCR (via IDEXX) – identify the mutation, require biopsy granulomas
How to treat FIP? Is it effective?
Tx: ramdicovir
Prognosis: 80% survival with tx (100% mortality w/o)
What are the virus features of Lentivirus?
Feline Lentivirus
* RNA retrovirus
How does feline lentivirus interact with host receptors? What cells do they replicate in?
o Receptor (CD134) on activated CD4 T cells
o Uses same co-receptors as HIV (CXCR4/CCR5)
o Can replicate in B cells/astrocytes/CD4/CD8
What are risk factors common to FIV and FeLV
o Risk factors: stress/shelter/intact males/age/outdoor/previously sick
How is FIV transmitted
- Transmit: sexual, blood-blood
o low transmission between +female to offspring
What are the clinical signs of FIV
- Clinically: acute mild febrile/slow progression + Feline AIDS
o Chronic gingivostomatitis/rhinitis
o Lymphadenopathy
o Immune mediated glomerulonephritis – nephrotic syndrome (proteinuria/ascites/hypoproteinemia/dyspnea/peripheral edema)
o Weight loss
o Concurrent infection (virus/bacteria/fungi/parasite)
o Similar lifespan of FIV vs non-FIV cat
How is FIV controlled
- Tx: FIV vaccine discontinued
What is a viral feature shared by FIV and FeLV
retroviruses
What agent causes FeLV
gamma-retrovirus
How is FeLV transmitted
- Transmit: saliva, nasal secretions, blood, feces, maternal milk
What are 2 pathways of infection of FeLV
- Transient viremia: >6mo old (older) = virus removal (fast Ig response before genome integration)
- Latency and lifelong infection: <6mo old = long term viremia = future leukemia
How to diagnose FeLV? How to differentiate between the type of infection?
- Dx: antigen SNAP test: uses antigen to differentiate between the transient state and latent/leukemia state
How does FeLV subgroup impact clinical outcome
- Subgroups: 4 groups (A, B, C, T)
o B/C/T are derivatives of type A
o More pathogenicity when they recombine – ex. FeLV B = increased frequency of neoplasia/higher virus load
How to protect/control against FeLV? What are the potential concerns?
- Control: vaccine: not 100% protective – only recommended for outdoor cats, associated with feline injection site sarcoma (associated with adjuvant - alum)
o Should use non-adjuvanted/modified-live/recombinant vaccine (no modified live vaccine for FeLV)
