Surveillance Flashcards

1
Q

Define monitoring

A

Continous efforts to collect data to detect changes or trends in the occourence of disease in order to inform decisisons

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2
Q

Define passive surveillance

A

Surveillance = monitoring with the view to intervene if prevalence rises above a certain theshold

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3
Q

Define incident

A

The first isolation and all subsequent isolations of the same serovar from an animal OR epidemiologiclaly distinct group of animals on a single premises wihtin a 30d period

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4
Q

How has salmonella incidence in humans and livestock changed over recent years?

A

parallell

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5
Q

Give an example of surveillance whre the threshold is 0

A

FMD

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6
Q

What is the target level of clinical mastitis?

A

30 cases/100 cows/year

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7
Q

How may surveillance be used?

A
  • monitoring diseases deemed to be of importance
  • checking for effectiveness of control measures
  • if eradication is achieved, demonstrating freedom from infection
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8
Q

Give an example of a disease where the aim of surveillance is to prove freedom of disease

A

Brucellosis

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9
Q

What was the first animal disease to be officiallly declared eradicated

A

rinderpest

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10
Q

What do farm level surveillance systems focus on?

A
  • diseases controllable by the farmer
  • focus on productivity
  • rely on farm records
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11
Q

Give egs. of monitoring/surveillance objectives at a natinoal level

A
  • demonstrate freedom from disease (eg. brucellosis)
  • outbreak detection
  • diseas control/eradication
  • monitor zoonoses (eg. salmonella)
  • pregress of hazard reduction programmes
  • detect emerging disease
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12
Q

Give egs. of monitoring/surveillance objectives at an industrial level

A
  • freedom from disease
  • outbreaks
  • define herd health status
  • monitor production diseases
  • monitor zoonoses and food bourne pathogens
  • document acceptable risk levels
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13
Q

Give egs. of monitoring/surveillance objectives at a prodcer levle

A
  • monitor production diseases
  • outbreak detection
  • assure freedom from food safetly hazard
  • define herd/product status
  • documnet aceptable risk levels
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14
Q

Give egs. of monitoring/surveillance objectives at a wildlife levle

A

establish disease status

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15
Q

How may cases be defined?

A
  • clinical criteria: suspect cases that become confirmed following lab work (lab criteria added)
  • epidemiological criteria eg. FMD control: farms defined as potental cases on the bases of location with repect to infected farms or dangerous contact with infected farms
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16
Q

What are the varying levels of disease prevalence?

A
  • case
  • outbreak
  • epidemic
  • pandemic
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17
Q

How are incidence and prevalence different?

A
  • incidence = rate (no. new cases/ population at risk*time at risk)
  • prevalence = proportion (no. existing cases/population at risk)
18
Q

Define internal and external validity

A
  • internal : measuring what is happening on farm, valid for that farm
  • external validity: extrapolating to general population
19
Q

What is the difference between active and passice monitoring or surveillance? Which is more susceptable to bias?

A
  • passive: waiting, reliant on case reporting, awareness and motivation to report [most biased]
  • active: searching, surveys, testing
20
Q

How does systematic error differ from random error?

A
  • systematic error: error due to the design, implementation or analysis of the surveillance programme
  • random error: due to samping variation due to a random sampe of the popuation being studeied to make inferences about the whole popuation
21
Q

Give 3 types of bias

A
  • case detection: case ascertainment
  • selection bias: in surveys if participation is voluntary, if not all famrs listed in sampking frame
  • information bias: case definition, diagnositc tests
22
Q

How may underrerporting skew surveillance statistics?

A

The “clinical iceberg” means deaths, severe disease and moderate disease [likely to be admitted to hosptial] but mild disease and sub-clinical infection not often reported so no cases actually ^ than recorded.

23
Q

What is important regarding defining cases for epidemiology?

A

deifnition must be specific so that all cases are recorded correctly

24
Q

What is important following detection of a case?

A

Dissemination of information quickly and efficiently to those who require it

25
Q

How may lab tests introduce bias to results?

A

Differing sensitivity and specificity of lab tests

26
Q

How may sampling introduce bias?

A

Picking a non random group of subjects

27
Q

What are the 2 types of farm level monitoring and surveillance?

A
  • statutory eg. TB, Brucella

- coluntary industry led eg. JD, BVD

28
Q

Define a notifiable disease

A

statutory requirement to report suspicion of a clinical case of disease

29
Q

Define a reportable disease

A

statutory requirement to report a lab confirmed isolation of organisms (ie. Salmonella nad Brucella) Under Zoonoses order 1989. Report made by lab that isolated the organism from animal dervied sample.

30
Q

Who should notifiable disease be reported to?

A
  • local animal health DVM

- now APHVLA

31
Q

Give 3 purposes of disease surveillance

A
  1. monitor trends in existing diseases by comparison against a threshold
  2. monitor and ID new and emerging diseases, zoonotic infections and intoxications (often threshold = 0)
  3. inform defra and other stakeholders (potential risks/developing problems, directing policy and stategy)
32
Q

Who carries out vet disease surveillance in the UK?

A
  • animal owners and keepers
  • vets
  • livestock industry organisations
  • universities
  • abattoirs
  • diagnostic laboratories
  • VMD
  • international monitoring eg. OIE, FAO, EFSA
33
Q

What are VLA PM centres now known as?

A

Veterinary Investigation Centres

34
Q

Who pays for PME of adult sheep/pig/deer?

A

Taxpayer subsidises, farmer pays rest

35
Q

What 3 diagnostic services are available for vets in practice?

A
  1. PM of carcasses suitable for surveillance
  2. postal samples (swabs, bloods, biopsy)
  3. advice on disease diagnoses and control
36
Q

What use is the submission of a casrcasse for PME for national vet disease surveillance?

A
  1. endemic disease levels
  2. animal welfare issues (eg. flystrike)
  3. notifiable diseases eg. Newcastle disease in pheasants, swine fever suspicions
  4. novel diseases (eg shmallenburg)
  5. zoonoses (HAIRS=human and animal surveillance) (eg. E . Coli)
  6. chemical threats to food chain eg. car battery eaten by cows
  7. ABx resistance
  8. adverse reactions (eg. bluetongue vax -> abortion?)
37
Q

How is scanning surveillance within APHA standardised?

A
  • submission forms and farmfile database (single database for all pssive and active surveillance, including statutory [brucella] and emergency response [FMD, CSF] monitoring)
  • accredited lab testing facitlities to ensure quality control
  • standardised recording by code with specific diagnostic criteria
38
Q

What is another term for scanning surveillance?

A

Passive surveillance

39
Q

What is the downside to passive surveillance?

A

May miss cases - no. diagnosed cases is only the tip of the iceberg

40
Q

What is targeted surveillance and when is this used?

A
  • research into new diseases or changes in recognised diseases identified by scanning
    eg. testing notifiable diseases..
    > BSE in fallen stock over 48 months old
    > TB (low case rate, expensive, not great test, also test healthy animals)
    …and others..
    > Anthrax in all sudden cattle death
    > FMD (blood testing during and after outbreaks)
    > Brucella to assure freedom from disease
  • also import testing, ABx resistnace, novel diseases, zoonoses (salmonella, campylobacter)
41
Q

Where does national vet disease surveillance data orginiate from?

A
  • scanning surveillance
  • targeted surveillance
  • mandatory reporting (notifiable diseases and reportable disease eg. salmonella and brucella)
  • voluntary reporting (although this is underreported and inaccurate)