Foreign Animal Diseases. Important transmissible livestock or poultry diseases that are largely absent from the United States and its territories and that have the potential to cause significant health or economic impact should the causative agent be introduced. Foreign animal diseases discussed in this chapter include:

• Exotic Newcastle disease (END)

• Foot-and-mouth disease (FMD)

Recently Emergent Diseases. Infectious diseases for which the risk in animals has increased in the past two decades or threatens to increase in the near future. These diseases include:

1. New infections resulting from changes or evolution of existing organisms or newly infectious particles (such as prions)

2. Known infections spreading to new geographic areas or populations

3. Previously unrecognized infections emerging in new geographic areas and human populations due to changing technologies and behaviors

4. Old infections reemerging as a result of antimicrobial resistance in known agents or breakdowns in animal disease control measures.

The recently emergent diseases addressed in this chapter are:

• Monkeypox

• Bovine spongiform encephalopathy (BSE)

Previously Unknown Agents. Pathogens previously unrecognized that have recently (within the past decade) been transmitted from animals to humans. Included for discussion in this chapter:

• Severe acute respiratory syndrome (SARS) coronavirus