Intentional biological release

Intentional release of a biological organism could mimic a naturally occurring outbreak

and the recognition and response to an undeclared terrorist use of an infectious

disease agent will be much more complicated to detect than an announced biological

release, a chemical release, or terrorist bombing. Health investigators may not

immediately recognize that an infectious disease outbreak is the result of an intentional

release of germs. CDC has long recognized that the following selected illnesses may

result from nature or from terrorism: encephalitis, hemorrhagic mediastinitis,

pneumonia with abnormal liver function tests, papulopustular rash (such as smallpox),

hemorrhagic fever, descending paralysis, and nausea, vomiting, and diarrhea. The

following epidemiological attributes summarize some characteristics of outbreaks that

should suggest the possibility of intentional use of an infectious agent:

• Occurrence of a seasonal disease during the wrong time of year;

• Outbreak of a disease in an area that normally does not experience the disease;

• Outbreak of a rare disease;

• Unusual age distribution of persons involved in the outbreak;

• Unusual clinical symptoms not typically seen with a known pathogen (especially

respiratory symptoms);

• Unusual epidemiologic features of an outbreak (e.g., a typical pathogen transmitted

solely by food ingestion now found to be transmitted from person to person).