Epidemiology/Epizootiology Branch of medicine that describes the occurrence, distribution and types of disease in a population of animals (medical aspects of ecology). History – Fish health management –

Important terms Disease – Any deviation from normal or good health Infection – Presence of pathogen in a host Communicable disease – Transmission of causative agent to other hosts Epizootic (epidemic) – Disease outbreak in specified area (> normal infection rates) Enzootic (endemic) – Continued presence of a causative organism in a localized area

Epidemiology Seasonal trends – Factors of disease development –

Epidemiology Sources of Infection – Mode of transmission – Portal of entry –

Epidemiology Virulence – Natural Resistance –

Epidemiology Degree of infection – Acute – Subacute – Chronic – Latent –

Epidemiology Primary infection – Secondary –