Veterinary Epidemiology and Zoonosis

INTRODUCTION

• Epidemiology is a very old science, but it has gained importance only after “germ theory” of disease causation was established in 1800.
• Then epidemiology has become a more holistic discipline, and many factors in addition to the specific agent are being investigated to determine their role as potential causes of disease.
• Epidemiology is the study of how often diseases occur in different groups of people and why.
• Like the clinical findings and pathology, the epidemiology of a disease is an integral part of its basic description.
• Clinical observations determine decisions about individuals. Epidemiological observations may also guide decisions about individuals, but they relate primarily to groups of people.
• The unit of concern in epidemiologic studies is not the individuals but rather groups or categories of individuals such as pen, herd or flock.
• It gives information about what animals are affected and where and when a disease occurs - often suggestive of the cause of disease.
• Subsequently it will be necessary to identify the determinants (cause) of the disease (i.e., to explain why the disease occurs - with the objective to reduce the severity or frequency of occurrence).
• Epidemiology has its special techniques of data collection and interpretation, and its necessary jargon for technical terms.
• A key feature of epidemiology is the measurement of disease outcomes in relation to a population at risk.
• The population at risk is the group of people, healthy or sick, who would be counted as cases if they had the disease being studied.
• Epidemiological information is used to plan and evaluate strategies to prevent illness and as a guide to the management of patients in whom disease has already developed.
• Veterinary epidemiology additionally includes investigation and assessment of other health related events particularly productivity. Epidemiology thrives on heterogeneity