Vaccines and diagnostics - companion animals and horses Flashcards
Describe an ideal vaccine
- protection against all strain
- prevents infection and shedding
- provides rapid and long lived immunity after single dose
- induces immunological memory so minimal boosters required
Outline passive immunisation
= administering Ab
- natural via colostrum
- administration of antiserum
Describe active immunisation
= administration of Ag + adjuvant
- MLV
- killed
- toxoids
- subunit
- recombinant
Outline vaccine delivery
- most systemic (SC, IM, ID) –> good systemic immunity
- altering route can influence immune response (IN much better at generating IgA response for mucosal protection)
Outline vaccin eprotocls
- primary courses often to young animals (MDA interference, can persist for 12-14 weeks, after this generally MLV only require single dose, inactivated/subunit require at least 2 doses, 2-3 weeks apart, booster q6mo-3 years depending on manufacturer)
Describe vaccination of dogs/cats
WSAVA GUIDELINES
- core (recommended) and non-core (risk assessed)
- dog core DHP (rabies if endemic), non-core: L, Pi
- cat core CHP (rabies if endemic), non-core FeLV
- primary course at 8, 12 adn 16 weeks
- post-vaccine serology recommened in dogs
- booster at 1 yo
- boost no more frequently than 3y intervals
- serology in dogs to determine if booster required?
- these recommendations can conflict with datasheet (8, 10 wk primary course but may cause more vaccine failures)
T/F: immunologically speaking, you don’t need to start the primary course again if booster lapses
True
T/F: there is a therapeutic DNA vaccine (human tyrosinase) for tx of canine malignant melanoma
True
Adverse effects - vaccination
- rare
- often mild (1 in 10,000)
- transient pyrexia and lethargy
- allergic reactions (IgE mediated): facial pruritus and oedema
- link b.w some adjuvanted vaccines (FeLV and rabies) and FISS
- non-adjuvanted vaccines (canarypox vector) available to avoid this
Name 2 vaccines of rabbites
- myxomatosis
- viral haemorrhagic disease
Outline vaccination of horses
PASSIVE IMMUNISATION: - hyperimmune equine plasma for FPT - tetanus antitoxin - rotavirus of pregnant mare for MDA transfer to foal ACTIVE IMMUNISATION: - equine influenza - tetanus toxoid (immediate protection) - EHV-1, EHV-4 - others: WNV, EVA, strangles
What is a new companion animal vaccine protocol?
- 1st dose at 6-8wks
- 2nd dose at 9-10 wks
- MDA interference at this younger age increases risk failure
- allows earlier socialisation
- ideally 3rd dose at 16 wks
What is CaniLeish?
- Leishmania infantum
- PETS
- 3 doses as primary course
- boost annually
- 4 times reduced risk of infection
Reasons for vaccine failure
- strains/serotype in vaccine don’t protect against that in population (feline calicivirus, Leptospira serovars)
- vaccine not stored properly or expired
- vaccine not administered properly
- animal too young/old –> immature/senescent immune system
- interference by MDA
- prior exposure to pathogen (FeLV, herpes)
- animal immunosuppressed / immunocompromised
- animal genetically programmed to generate inappropriate response (e.g. MHC genes in rottweilers may predispose to vaccine failure)
What feline vaccines are available in the USA?
- FIV vaccine (Fel-O-Vax): 2 FIV strains but 70% effective at preventing infection
- ‘FIP’ vaccine: given IN for IgA against enteric coronavirus (which causes FIP), protect against initial infection to prevent persistence and mutation, kittens often exposed before vaccination
Outline serological testing for response to vaccination in companion animals
- DHP for dogs
- CHP for cats
- rabies under PETSs scheme (FAVN test, must reach threshold of 0.5IU/ml to be considered protected, vaccinate and test 3-4 weeks later, rottweilers are poor responders, since Jan 2012, testing is not mandatory but still recommended)
- only AHVLA or BioBest lab
- remember LAG PHASE thus Ab negative doesn’t necesarily mean pathogen negative. Requires 2 consecutive negative samples with period of isolation in between to be more conclusive
Describe acute and convalescent sera
- sample 2-3 wks apart
- if timing correct, first sample often hits LAG/LOG PHASE, then PLATEAU PHASE of Ab response subsequently and show rise in titre b/w the 2 points
What does antigen-specific IgM > IgG normally indicate?
- recent exposure
- often ties in with onset of CS
What tests are performed for serology?
- ELISA
- Rapid immune-migration assay (RIM)
- indirect IFAT
- VNA
- HA/HAI assay
Is rabisin (Merial) or Nobivac Rabies better at generating Ab response?
Rabisin (Merial) better
What serological tests area available for dogs?
- distemper
- parvovirus
- adenovirus
- herpes
- coronavirus
- PI
What tests for dogs with neurologicla signs, myositis or PUO
- T. gondii (IgM and IgG)
- Neospora caninum
What serological tests for dogs with acute kidney dz?
- leptospira
- this is a microscopic agglutination test (MAT)
What serology can be done for fungal rhinitis?
- Aspergillus
- Cryptococcous
T/F: scabies serology can be used to aid diagnosis of sarcoptic mange
True
What serologicla tests are available for cats?
- FIV
- toxoplasma/ neospora
- cat flu: feline calicivirus, herpes, chlamydophila
- FIP (care when interpreting coronavirus serology)
Why do you ned to take serology carefully with coronavirus/ FIP?
- serology doesn’t differentiate exposure to enteric coronavirus and progression to FIP
- dx should be based on combination of typical CS and lab findings
- coronavirus titre > 640 would be consistent with dz in cat presenting with consistent CS
What serological tests are available for equines?
- EHV-1, -4 (equine abortion, respiratory and neurological dz)
- EHV-3 for coital exanthema
- Respiratory dz (influenza, adenovirus, rhinovirus)
When might serological tests be required for horses?
import/ export/ pre-breeding an dsales. usually EVA and EIA. Animals might also need to be demonstrated as Ab negative to other pathogens when importing from some countries (vesicular stomatitis, dourine, glanders)
