VETERNIARY EPIDEMIOLOGY AND ECONOMICS
Lecture 1.1 - introduction to the course
Epidemiology of animals diseases; try to reduce societal burden of animal diseases, since
negative impact of a disease on a community
- Animal health
- Economics
- Animal welfare
- Public health (zoonosis + antimicrobial resistance)
- Environmental health
- Amount and quality of animal products
- Satisfaction of the animal owner
Learning outcomes course:
1. Several aspects of health and disease
2. Examples of eradication, control and prevention of animal diseases
3. Design basic epidemiological studies
4. Calculate epidemiological parameters and interpret the outcomes
5. Understand and apply basic economic methods for decision making regarding animals
health problems
6. understand eradication and/or prevent based on epidemiological and economic criteria
quiz notes
- Health is a relative concept, so not even an expert can easily determine a disease.
- Subclinical disease: no signs of a disease while being diseased, so symptomless.
- Clinical disease: symptoms are present.
However, expertise does play a role here: someone who specializes in a particular
disease is more likely to notice the symptoms
- Health is a dynamic balance
- Homeostasis: adaptive capacity of an individual. Can be temporary or permanent
anatomical, physiological or behavioral change of the organism to reduce or overcome
health-threatening influences.
- Specific: e.g. environmental
temperature
- aspecific: stress, non- specific
reaction to a stimulus/ stressor
- stress reaction is the body’s response to
any stimulus and allows the animal to
live with suboptimal conditions.
- In general, the risk of disease in highly
productive animals is higher. High
production affects the adaptive capacity
in a negative way.
Clinical health characteristics:
- Body temperature - Digestion
- Respiration - Behavior - Odor
- Gait and posture - Body condition - Skin, hair and feathers
- Circulation - Mucous membrane - Production
, VETERNIARY EPIDEMIOLOGY AND ECONOMICS
- Serological testing is testing by means of blood, is relatively fast and cheap testing.
Animals with detectable antibody titres are seropositive, otherwise seronegative
- To confirm the probability of a disease you can test; serological, secreta/ excreta, pH,
blood in urine, autopsy.
3 ways of determining a disease:
1. Product of a pathogen (antigen), best proof of a current infection
2. Antibodies, which is evidence of current and previous infection
3. Blood composition (e.g. enzymes, leucocyte count, blood cell ratio, minerals,
hormones)
What to do when false determined?
- False positive +: vaccination, cross- reaction, infection gone but antibodies still present
- False negative-: latency time, tolerance
Who is responsible for animal health:
1. Owners (adequate hygiene, alert to symptoms, report suspected animals diseases to
NVWA, comply requirements when importing animals outside the EU, vaccinate the
animals)
2. Government in case if a disease is exceptionally infectious or dangerous.
3. Role of vets: assist with prevention, diagnose diseases, treatment, monitor and
surveillance to prevent outbreaks and safeguard public health.
Done by the GD in the Netherlands (animals health service), collects signals of
new signs of diseases. Overall claim to detect and tackle new and existing infectious
diseases quickly.
- Animal health monitoring is vital for animal health and welfare, food safety and the
export position of the Netherlands.
- Zoonosis: an infectious disease that can be transmitted from animals to humans.
- Around 60% of the human diseases originates from animals
- Besides economic importance, there are also non- monetary burdens (public health,
animal welfare, quality products and environmental factors) to pay attention to
diseases.
- The proportion of replacements for sows is approximately 45% per year, the most
important cause for the culling of sows is a health disorder (70% times the case).
- In the Netherlands, 10-15% of the calves born die within 3 months. And 10-15% of the
piglets die in the suckling period. From these percentages 70-80% die from infectious
diseases.
Epidemiologists are often involved in research into the causes of death and health
disorders.
- Veterinarians in NL only need to register notifiable diseases in animals.
Only diseases that expand quickly, cause serious damage, cannot be prevented,
cause economic damage
Lecture 1.2 – disease prevention
Epidemiology is the study of the emergence and spread of diseases Basis of disease
Aetiology is the study of the cause of the (spread in) disease prevention and
control
The main categories of disease:
1. Genetic disorders
2. Infectious diseases ( bacteria, viruses, protozoa etc. )
Environment roles
3. Non- infectious diseases (metabolic, deficiencies, intoxications, trauma)
, VETERNIARY EPIDEMIOLOGY AND ECONOMICS
Multifactorial disease is a disease that depends on the presence of several factors for its
induction, so infectious agent(s) with a further factor(s) from the environment.
- The most common diseases in animals are multifactorial
Stressors that impact health:
- Malnutrition - poor ventilation - dampness, rain, wet, chilled
- Parasitism - ammonia fumes - new humans
- Overcrowding` - lack of colostrum
- Dust - transportation and shipping
- Predators - introduction of new animals
Disadvantages of medication:
- Pathogens becoming resistant to antimicrobials
- Toxic in case of overdose
- Residues in animals products; waiting period for slaughter, milk, etc.
- Reduction of colonization resistance (due to the negative effect on normal microbiota)
categories of transmission:
I. Horizontal transmission: infection from one individual to another
II. Vertical transmission: infection from one generation to the next by infection of the
embryo/fetus
How disease spread:
- Indirect contact: surfaces, airborne, flies, mice, birds, equipment, feed, water, clothing,
botos, etc.
- Direct contact: carrier or sick animals or discharge
vaccination strategies:
- Routine vaccination (at regular intervals):
to prevent pathogens to enter in free
areas
- Emergency vaccination: to prevent further
spread of disease when epidemics occur.
Quiz notes
Abnormalities that can be seen immediately at birth do not necessarily have to be hereditary
defects
- Correct
- Already during pregnancy, the environment can affect the unborn individual
Control of a disease is not the same as eradication of the disease
- Correct
- Control is the management of a disease
to a locally acceptable level, while
eradication is the complete, global, and
permanent elimination of a disease
Lecture 1.1 - introduction to the course
Epidemiology of animals diseases; try to reduce societal burden of animal diseases, since
negative impact of a disease on a community
- Animal health
- Economics
- Animal welfare
- Public health (zoonosis + antimicrobial resistance)
- Environmental health
- Amount and quality of animal products
- Satisfaction of the animal owner
Learning outcomes course:
1. Several aspects of health and disease
2. Examples of eradication, control and prevention of animal diseases
3. Design basic epidemiological studies
4. Calculate epidemiological parameters and interpret the outcomes
5. Understand and apply basic economic methods for decision making regarding animals
health problems
6. understand eradication and/or prevent based on epidemiological and economic criteria
quiz notes
- Health is a relative concept, so not even an expert can easily determine a disease.
- Subclinical disease: no signs of a disease while being diseased, so symptomless.
- Clinical disease: symptoms are present.
However, expertise does play a role here: someone who specializes in a particular
disease is more likely to notice the symptoms
- Health is a dynamic balance
- Homeostasis: adaptive capacity of an individual. Can be temporary or permanent
anatomical, physiological or behavioral change of the organism to reduce or overcome
health-threatening influences.
- Specific: e.g. environmental
temperature
- aspecific: stress, non- specific
reaction to a stimulus/ stressor
- stress reaction is the body’s response to
any stimulus and allows the animal to
live with suboptimal conditions.
- In general, the risk of disease in highly
productive animals is higher. High
production affects the adaptive capacity
in a negative way.
Clinical health characteristics:
- Body temperature - Digestion
- Respiration - Behavior - Odor
- Gait and posture - Body condition - Skin, hair and feathers
- Circulation - Mucous membrane - Production
, VETERNIARY EPIDEMIOLOGY AND ECONOMICS
- Serological testing is testing by means of blood, is relatively fast and cheap testing.
Animals with detectable antibody titres are seropositive, otherwise seronegative
- To confirm the probability of a disease you can test; serological, secreta/ excreta, pH,
blood in urine, autopsy.
3 ways of determining a disease:
1. Product of a pathogen (antigen), best proof of a current infection
2. Antibodies, which is evidence of current and previous infection
3. Blood composition (e.g. enzymes, leucocyte count, blood cell ratio, minerals,
hormones)
What to do when false determined?
- False positive +: vaccination, cross- reaction, infection gone but antibodies still present
- False negative-: latency time, tolerance
Who is responsible for animal health:
1. Owners (adequate hygiene, alert to symptoms, report suspected animals diseases to
NVWA, comply requirements when importing animals outside the EU, vaccinate the
animals)
2. Government in case if a disease is exceptionally infectious or dangerous.
3. Role of vets: assist with prevention, diagnose diseases, treatment, monitor and
surveillance to prevent outbreaks and safeguard public health.
Done by the GD in the Netherlands (animals health service), collects signals of
new signs of diseases. Overall claim to detect and tackle new and existing infectious
diseases quickly.
- Animal health monitoring is vital for animal health and welfare, food safety and the
export position of the Netherlands.
- Zoonosis: an infectious disease that can be transmitted from animals to humans.
- Around 60% of the human diseases originates from animals
- Besides economic importance, there are also non- monetary burdens (public health,
animal welfare, quality products and environmental factors) to pay attention to
diseases.
- The proportion of replacements for sows is approximately 45% per year, the most
important cause for the culling of sows is a health disorder (70% times the case).
- In the Netherlands, 10-15% of the calves born die within 3 months. And 10-15% of the
piglets die in the suckling period. From these percentages 70-80% die from infectious
diseases.
Epidemiologists are often involved in research into the causes of death and health
disorders.
- Veterinarians in NL only need to register notifiable diseases in animals.
Only diseases that expand quickly, cause serious damage, cannot be prevented,
cause economic damage
Lecture 1.2 – disease prevention
Epidemiology is the study of the emergence and spread of diseases Basis of disease
Aetiology is the study of the cause of the (spread in) disease prevention and
control
The main categories of disease:
1. Genetic disorders
2. Infectious diseases ( bacteria, viruses, protozoa etc. )
Environment roles
3. Non- infectious diseases (metabolic, deficiencies, intoxications, trauma)
, VETERNIARY EPIDEMIOLOGY AND ECONOMICS
Multifactorial disease is a disease that depends on the presence of several factors for its
induction, so infectious agent(s) with a further factor(s) from the environment.
- The most common diseases in animals are multifactorial
Stressors that impact health:
- Malnutrition - poor ventilation - dampness, rain, wet, chilled
- Parasitism - ammonia fumes - new humans
- Overcrowding` - lack of colostrum
- Dust - transportation and shipping
- Predators - introduction of new animals
Disadvantages of medication:
- Pathogens becoming resistant to antimicrobials
- Toxic in case of overdose
- Residues in animals products; waiting period for slaughter, milk, etc.
- Reduction of colonization resistance (due to the negative effect on normal microbiota)
categories of transmission:
I. Horizontal transmission: infection from one individual to another
II. Vertical transmission: infection from one generation to the next by infection of the
embryo/fetus
How disease spread:
- Indirect contact: surfaces, airborne, flies, mice, birds, equipment, feed, water, clothing,
botos, etc.
- Direct contact: carrier or sick animals or discharge
vaccination strategies:
- Routine vaccination (at regular intervals):
to prevent pathogens to enter in free
areas
- Emergency vaccination: to prevent further
spread of disease when epidemics occur.
Quiz notes
Abnormalities that can be seen immediately at birth do not necessarily have to be hereditary
defects
- Correct
- Already during pregnancy, the environment can affect the unborn individual
Control of a disease is not the same as eradication of the disease
- Correct
- Control is the management of a disease
to a locally acceptable level, while
eradication is the complete, global, and
permanent elimination of a disease
