A panzootic (from Greek παν pan all + ζόιον zoion animal) is an epizootic (an outbreak of an infectious disease of animals) that spreads across a large region (for example a continent), or even worldwide. The equivalent in human populations is called a pandemic. A panzootic (from Greek παν pan all + ζόιον zoion animal) is an epizootic (an outbreak of an infectious disease of animals) that spreads across a large region (for example a continent), or even worldwide. The equivalent in human populations is called a pandemic.