Lecture 4 - Disease control Flashcards
WHY DO WE NEED DISEASE CONTROL?
Disease control can be achieved by: (2)
treating the sick animals (reduces dz prevalence)
or through prevention of the dz
(reduces both incidence and prevalence)
The term eradiaction has 4 meanings in the context of disease control.
- Extinction of an infectious agent. Eradication has not been completed if a single infectious agent survives antwhere in the nature
- Reduction of inf. dz prevalence in a specified area to a level at which transmission does not occur
- Reduction of inf. dz to a level at which the dz ceases to be a major health problem, although some transmission may still occur
- Regional extinction of an infectious agent
PRRS
Porcine Reproductive and Respiratory Syndrome
a viral disease affetcing pigs
The term elimination means what in the context of disease control.
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.
The meaning of the term biosecurity in the context of disease control.
Management-practice activities that reduce the opportunities for infectious agents to gain access to, or spread within, a food animal production unit.
/
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
Categorization of inf. Dz’s according to globally implemented prevention and control strategies.
Higly infectious and notifiable dz’s belong to what category
Eradication
Categorization of inf. Dz’s according to globally implemented prevention and control strategies.
Other notifiable animal dz’z and zoonoses
belong to what category
Control
Categorization of inf. Dz’s according to globally implemented prevention and control strategies.
Endemic dz’s belong to what category
Prevention
Eradication -category for disease control strategies covers what types of diseases
Higly infectious and notifiable dz’s
Control -category for disease control strategies covers what types of diseases
Prevention -category for disease control strategies covers what types of diseases
Endemic diseases
Chain of infection (epidemic/epizootic process) (6)
- Pathological agent
- Reservoir
- Path from reservoir
- Mode of transmission
- Path of entry
- Susceptible host
Primary prevention does what
Modifies determinants to prevent or postpone new cases of disease and therefore reduces incidence
Secondary prevention does what
Detects and treats dz promptly to shorten dz duration or to prolong life
Tertiary prevention does what
Treatment of long-term cases to reduce dysfunction or to prolong life (i.e., to make outcome less severe)
3 ways to influence disease prevention
- Microbial exposure
- total exclusion from exposure – eradication
- partial exclusion from exposure – prevention - Animal resistance
- Methods of transmission
Modes of transmission from herd to herd in order of significance
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
Properties of the host to influence infection in the population (3)
Susceptibility
Infectiousness
Immunity
Properties of the agent to influence infection in the population (4)
Pathogenicity
Virulence
Contagiousness
Stability
Environmental conditions that influence infection in the population (3)
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
General measures for the control of infectious disease in a farm
Biosecurity program
- Prevent introduction of the agent to the herd
- Cleaning and desinfection
- Reduce effective contact
Resilience and resistance in animals
Specific measures for the control of infectious disease in a farm
Measures implemented to resist a certain inf. dz
- Vaccination
- Treating the sick
- Culling of the sick and infected animals
Prophylactic quarantine for new animals should be
21-30 days
2 measures in order to Reduce effective contacts:
Grouping by age
All in – all out system
4 methods of reducing infection burden
Cleaning and disinfection
Isolation and culling the shedders
Treatment – ABs
Vaccination
4 methods of ensuring animal resistance to infection
Good housing conditions – temperature, humidity, ventilation…
Stress free environment
Proper feeding – balanced, good quality feed; probiotics?
Vaccination
meaning of SPF in disease control context
specific pathogen-free animals
In estonia, diseases are categorized as (2)
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
