Infectious Disease Control Tools Flashcards
How can test and cull be implemented? Which disease is this useful for?
> individual
- bTB
- Johnes disease
- PI BVD
herd level
- FMD (so infectious)
- BSE
sensitivity and specificity of the test
local level (surrounded farms and neighbouring herds)
- FMD
- outside in v inside out (where do you start culling? more infectious start outside in, debatable)
country level
- not really
- depopulating whole country not really viable
probabilities of spread within herd or area and costs, want to eradicate dz to allow trading
Was burning FMD carcasses necessary ?
Probs not, bad image for sector, lactic acid build up in dead muscle tissues should have killed virus
How can chickens be killed?
- co2
- electrocute
- on site kill units (difficult multi levels)
Who pays for test and cull?
- endemic : farmer
- epidemic : government
- zoonotic : farmer/government (eg. TB)
> if you choose to eradicate the disease you dictate the rules (eg. Aujeskys in PIGS)
Use of vaccination to control infectious disease? Considerations?
> timing
- seasonal disease (eg. Lepto Spring dogs so Weils disease not contracted when splashing in water in summer)
strategically
- buffer (FMD) NB. Will have to kill vax animals eventually - worth it in the long run?
- whole country (BTV spread by flying vector)
- depend on threat (NCD waxing and waning prevalence)
Aim of vax?
Reduce affected animals to R0
How effective is vaccination in an endemic situiation?
Depends on vax > BVD and Leptospira - poor - need to get rid of PIs > salmonella - mediocre > IBR/clostridium - good
Why are movement restrictions useful?
- minimise spread (animal hosts best media to transport disease over a long period in time and long distance) IMMEDIATE otherwise everyone moves animals quickly
- C&D (cleaning disinfection)
- 72 HR standstill (FMD, CSF)
- bovine TB and brucella abortus standstill on farm only
Why may movement restrictions be put on? What else is included in this sometimes?
- buy time to assess situation
- horses or other species included (minimise illegal trailer use)
- by foot movement as well
- conflict with trade and farmers poss
What is zoning
Regionalisation or compartmentalisation
- lift movement restriction in non affected areas
TB testing in Wales and southwest?
Minimally 1 test per year
Where is TB free?
Scotland ? Maybe?
If buying in animals to an infected area (eg. With TB) should you buy affected or naive animals?
- non-infected to dilute disease burden in the infected area
- ask about this - by bringing naive animals in do you risk ^ active infection? Or do we just not care about this because trying to eradicate disease?)
What is surveillance?
Repeated measurement, recording and review of data related to occourence of events such as disease
> need to act on this
- improve dz control (farmers only pay for data collection if they perceive an economic benefit in doing so)
What are the 3 principles of disease control ?
> find it - surveillance > fix it - vax, movement restriction, compartmentalisation > kill it - test and cull > KEEP IT OUT!!
