Testing Flashcards
What must the virus be like for isolation to be possible?
Stable outside the host
What must a viral transport medium do?
Inhibit bacteria
Why is virus isolation not often done?
takes a long time
Why is EM rarely used?
Expensive, high expertise
How can you confirm a haemagglutination test?
Haemagglutination inhibition
How do you detect viral antigen?
Polyclonal or monoclonal antibodies
What are two ways you can identify a virus by incubation with antibody?
Direct detection or two antibody system
What can you label antibody with?
Fluorescein, peroxidase, colloidal gold
What can you do on an immobilisaed antigen?
Immunohistology or captures antigen
What do Rapid Immunomigration tests do for FeLV?
Use blood, saliva or tears to look for p27
How do in house test kits for FeLV-antigen or parvo work?
ELISA
What’s an advantage of PCR?
Fast
What’s a disadvantage of PCR?
False positives due to contamination
How can you get false negatives due to PCR?
Intermittent virus shedding
What does more PCR cycles mean?
Less virus present
What are the three types of antibodies?
Maternally derived (6-8 weeks), from vaccination (DIVA), from previous or current infection (rising titre or IgM)
How do you test for calicivirus or herpesvirus?
Viral isolation
What should you do if you get a positive FeLV test?
Re-test in 12 weeks, if negative could be latent infection so do bone marrow PCR
How do you diagnose FIV?
Antibody test (ELISA or RIM), confirm with PCR or Western Blot
Why is FIP hard to diagnose?
If coronavirus antibody is high this only shows exposure, and PCR cannot differentiate between FIP and enteric coronavirus
SO how should you diagnose FIP?
Do antibody titre and PCR, and diagnose if margin or error is high
Why is coronavirus isoaltion difficult?
Fragile
When can you get a false negative in bacteria?
If on antibiotics
How do you take a sample for blood culture?
In a meat broth
Where can you find anaerobes?
Abscess, endometritis, pyothorax
How long do anaerobes survive in air?
No more than 20 minutes
What happens if you refrigerate anaerobes?
Kills them
How can you determine antibiotic sensitivity?
Broth dilution MIC or agar gel diffusion
What’s the problem with sensitivity testing?
Only for aerobic bacteria and variable in vivo tissue penetration
In which species should you not use intradermal TB testing?
Ctas
When can you get false positives in intradermal TB testing in dogs?
Due to cross-reactivity
Where do you TB test dogs?
Inner pinna
Why is serology for Mycoplasma unreliable?
Cross-react
What’s the problem with bacterial isolation from biopsy?
Needs special media and techniques
Which method is not available for avian, human and bovine mycobacteria?
PCR
How do you submit swabs for yeast culture?
Bacterial transport medium
What is easier to stain for yeast than sellotape?
Smear
