Lecture 4 - Disease control

Question 1

WHY DO WE NEED DISEASE CONTROL?

Answer 1

Question 2

Disease control can be achieved by: (2)

Answer 2

treating the sick animals (reduces dz prevalence)

or through prevention of the dz
(reduces both incidence and prevalence)

Question 3

The term eradiaction has 4 meanings in the context of disease control.

Answer 3

1. Extinction of an infectious agent. Eradication has not been completed if a single infectious agent survives antwhere in the nature
2. Reduction of inf. dz prevalence in a specified area to a level at which transmission does not occur
3. Reduction of inf. dz to a level at which the dz ceases to be a major health problem, although some transmission may still occur
4. Regional extinction of an infectious agent

Question 4

PRRS

Answer 4

Porcine Reproductive and Respiratory Syndrome

a viral disease affetcing pigs

Question 5

The term elimination means what in the context of disease control.

Answer 5

Reduction in the incidence of inf. dz below the level achieved by control, so that either very few or no cases occur.

Infectious agent may be allowed to persist.

Question 6

The meaning of the term biosecurity in the context of disease control.

Answer 6

Management-practice activities that reduce the opportunities for infectious agents to gain access to, or spread within, a food animal production unit.

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a set of protocols or precautions used to minimize the risk of introducing an infectious disease into an animal population, and to prevent the spread of disease within that population

Question 7

Categorization of inf. Dz’s according to globally implemented prevention and control strategies.

Higly infectious and notifiable dz’s belong to what category

Answer 7

Eradication

Question 8

Categorization of inf. Dz’s according to globally implemented prevention and control strategies.

Other notifiable animal dz’z and zoonoses
belong to what category

Answer 8

Control

Question 9

Categorization of inf. Dz’s according to globally implemented prevention and control strategies.

Endemic dz’s belong to what category

Answer 9

Prevention

Question 10

Eradication -category for disease control strategies covers what types of diseases

Answer 10

Higly infectious and notifiable dz’s

Question 11

Control -category for disease control strategies covers what types of diseases

Answer 11

Question 12

Prevention -category for disease control strategies covers what types of diseases

Answer 12

Endemic diseases

Question 13

Chain of infection (epidemic/epizootic process) (6)

Answer 13

1. Pathological agent
2. Reservoir
3. Path from reservoir
4. Mode of transmission
5. Path of entry
6. Susceptible host

Question 14

Primary prevention does what

Answer 14

Modifies determinants to prevent or postpone new cases of disease and therefore reduces incidence

Question 15

Secondary prevention does what

Answer 15

Detects and treats dz promptly to shorten dz duration or to prolong life

Question 16

Tertiary prevention does what

Answer 16

Treatment of long-term cases to reduce dysfunction or to prolong life (i.e., to make outcome less severe)

Question 17

3 ways to influence disease prevention

Answer 17

1. Microbial exposure
   - total exclusion from exposure – eradication
   - partial exclusion from exposure – prevention
2. Animal resistance
3. Methods of transmission

Question 18

Modes of transmission from herd to herd in order of significance

Answer 18

Infected animals that show no clinical signs
Vehicles
Feed and water
Fomites
Vectors
Contact with wild animals (birds, rodents etc.)
Carcassess that has not been properly disposed of
Sperm, embryos
Wind

Question 19

Properties of the host to influence infection in the population (3)

Answer 19

Susceptibility
Infectiousness
Immunity

Question 20

Properties of the agent to influence infection in the population (4)

Answer 20

Pathogenicity
Virulence
Contagiousness
Stability

Question 21

Environmental conditions that influence infection in the population (3)

Answer 21

environmental Effect on general condition of the host

environmental Influence on presence and abundance of the agent

environment’s Effect on portal of entry of the pathogen

Question 22

General measures for the control of infectious disease in a farm

Answer 22

Biosecurity program
- Prevent introduction of the agent to the herd
- Cleaning and desinfection
- Reduce effective contact

Resilience and resistance in animals

Question 23

Specific measures for the control of infectious disease in a farm

Answer 23

Measures implemented to resist a certain inf. dz
- Vaccination
- Treating the sick
- Culling of the sick and infected animals

Question 24

Prophylactic quarantine for new animals should be

Answer 24

21-30 days

Question 25

2 measures in order to Reduce effective contacts:

Answer 25

Grouping by age
All in – all out system

Question 26

4 methods of reducing infection burden

Answer 26

Cleaning and disinfection
Isolation and culling the shedders
Treatment – ABs
Vaccination

Question 27

4 methods of ensuring animal resistance to infection

Answer 27

Good housing conditions – temperature, humidity, ventilation…

Stress free environment

Proper feeding – balanced, good quality feed; probiotics?

Vaccination

Question 28

meaning of SPF in disease control context

Answer 28

specific pathogen-free animals

Question 29

In estonia, diseases are categorized as (2)

Answer 29

Notifiable animal diseases

(Highly contagious and notifiable diseases diagnosed in Estonia:
1982 – Foot and mouth disease (FMD)
1994 – Classical swine fever (CSF)
2007 – Newcastle disease
2014 – African swine fever (ASF))

Reportable diseases