Fowl Cholera is a contagious, widely distributed disease that affects domestic and wild birds. It is usually apparent as a septicemia of sudden onset with high morbidity and mortality, but chronic and asymptomatic infections also occur. Pasteurella multocida (Pm) is the causative agent. Pm-derived bacterins are available but are effective only against homologous serotype challenge. Live vaccines of low virulence are available.