EPIDEMIOLOGY
İnci Başak Müştak, PhD
Ankara University Faculty of Veterinary
Medicine
Definition of Epidemiology
■ The study of disease in populations and of factors that determine its occurence.
The term as ‘Epidemiology’ ralated to studies of human populations and ‘epidemics’ is used for the outbreaks of disease in human
populations
‘Epizootiology’ ralated to studies of animal populations and
‘epizootics’ is used for the outbreaks of disease in animal
populations
The uses of Epidemiology
1. determination of the origin of a disease whose cause is known;
2. investigation and control of a disease whose cause is either unknown or poorly understood;
3. acquisition of information on the ecology and natural history of a disease;
4. planning, monitoring and assessment of disease control programmes;
5. assessment of the economic and other social effects of a disease, and
analysis of the costs and benefits of alternative control programmes.
Types of Epidemiological Investigation
1. Descriptive epidemiology 2. Analytical epidemiology
3. Experimental epidemiology
4. Theoretical epidemiology
Components of Epidemiology
■ The first stage in any investigation is the COLLECTION OF RELEVANT DATA.
■ Investigations can be either qualitative or quantitative or a combination of these two approaches.
Qualitative investigations:
The natural history of disease, Causal hypothesis testing
Quantitative investigations:
Surveys Monitoring Surveillance Modelling
Evaluation of disease control
HEALTH and DISEASE
■ Health; a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity. (WHO, 2014)
■ Disease; is the separation of the body from health or abnormal clinical symptoms.
DISEASE FACTORS
• External factors
• Internal factors
EXTERNAL FACTORS
■ Physical factors (rays, heat, electricity etc.)
■ Chemical agents (chemical substances, gases, poisons, nurtition etc.)
■ Mechanical factors (hit, impact, plunge, asphyxia etc. )
■ Biological factors – Arthropods – Helminths – Protozoan
– Fungi and Yeast – Bacteria
– Virus – Prion
INTERNAL FACTORS
■ Hormonal
■ Metabolic
■ Genetic
Reference: Veterinary Epidemiology, 4ed. Michael Thrusfield with Robert Christley, Brown H, Diggle PJ, French N, Howe K, Kelly L, O’Connor A, Sargeant J, Wood H.
