Veterinary Epidemiology and Zoonosis

EPIDEMIC AND ITS TYPES

Epidemic

• An occurrence of infectious or non-infectious disease to a level in excess of the expected level (expected level means endemic level).
• Sudden unpredictable increase in the number of cases of an infectious disease in a population. 
• An increase in disease or death grater than two standard deviations above the mean.
• An extremely rapid increase in the number of cases of suggestive of common source epidemic (i.e. all animals exposed to common source at the same time), whereas a slower build up is suggestive of propagated epidemic.

Types of epidemic

• Common-source epidemic
• Propagated epidemic
• Endemic Diseases
• Sporadic  Diseases