Israel Medical Association Journal

The appearance of “new” infectious diseases, the reemergence of “old” infectious diseases, and the deliberate introduction of infectious diseases through bioterrorism has highlighted the need for improved and innovative infectious disease surveillance systems. A review of publications reveals that traditional current surveillance systems are generally based on the recognition of a clear increase in diagnosed cases before an outbreak can be identified. For early detection of bioterrorist-initiated outbreaks, the sensitivity and timeliness of the systems need to be improved. Systems based on syndromic surveillance are being developed using technologies such as electronic reporting and the internet. The reporting sources include community physicians, public health laboratories, emergency rooms, intensive care units, district health offices, and hospital admission and discharge systems. The acid test of any system will be the ability to provide analyses and interpretations of the data that will serve the goals of the system. Such analytical methods are still in the early stages of development.

Because of its high case-fatality rate, its very high transmission potential, and the worldwide shortage of effective vaccine, smallpox tops international lists of over a dozen possible bioterror and biologic warfare agents. In a scenario involving aerosol variola virus release, tens to hundreds of first-generation cases would ensue, as would hundreds to thousands of subsequent cases resulting from person-to-person transmission. A smallpox outbreak in Israel must not be regarded as a doomsday event: the methods of smallpox outbreak control are known and will be implemented. The rapidity with which organized outbreak control measures are competently executed will determine how many generations of cases occur before the outbreak is brought under control. Planning, vaccine stockpiling, laboratory expansion, professional training and public education, all carried out well in advance of an epidemic, will minimize the number of casualties. The reinstitution of routine smallpox vaccination in Israel, as in other countries, must be given serious consideration, since it has the potential for eliminating the threat of smallpox as a bioterror agent.

Background: The large number of cases of West Nile fever diagnosed in Israel in 2000 once again brought into focus the confusion that frequently accompanies the use of the term “epidemic”.

Objective: To examine the different definitions of the term “epidemic” and to propose ways in which it can be used to both improve communication among professionals and provide the public with a better sense of the associated risks.

Methods: The literature wes reviewed for the various definitions of the terms “epidemic” and “outbreak”. Sources included popular and medical dictionaries, ancient documents, epidemiology texts, legal texts, and the medical literature.

Result: The term epidemic is variously defined. The broad definition given by epidemiologists - namely, more disease the is anticipated by previous experience - is less meaningful to the general public. In some ways it conflicts with the definitions found in the popular literature, which generally imply danger to the public and a very large number of victims.

Conclusions: The interpretation of the term epidemic may vary according to the context in which it is used. For risk communication, we suggest that every effort be made to add descriptive terms that characterize the epidemic.