Epornithic is:

EPORNITHIC: It is an outbreak (epidemic) of disease in a bird population. EPIZOOTIC: It is an epidemic of disease in an animal population (often with the implication that it may also affect human populations). Only a few zoonotic agents cause major epidemics. Examples are anthrax, brucellosis, rabies, influenza, Rift valley fever, Japanese encephalitis and equine encephalitis. ENZOOTIC: It is an endemic occurring in animals. Examples include anthrax, rabies, brucellosis, bovine tuberculosis, endemic typhus. Ref: Park 21st edition, page 89.