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ASM review


ASM News 68: March 2002

CD-ROM software. Copyright 2001, Latest version: 2001-3. GIDEON Informatics [ ], $895 for 1-year subscription.

Health care workers are increasingly expected to know something about the global epidemiology of infectious disease such as the distribution of vaccine preventable infections, arthropod-borne infections (malaria and dengue), and a few well-known parasitic infections such as schistosomiasis and leishmaniasis. During the current world crisis, it would be nice to know everything there is to know about anthrax: what the disease is, where it occurs, and how it is diagnosed, treated, and prevented. Many practitioners are not involved in the care of ill returned travelers, leaving this to the infectious disease consultant and/or the expert in clinical tropical medicine. In this regard, the diagnosis of illness in returned travelers requires a knowledge of the geographic incidence of likely diseases, the likelihood of exposure to infection, and the clinical features of each disease. Unfortunately, there are few good sources in the medical literature which provide both a clinical and epidemiological approach to the patient.

The advantage of a computer program, in this case GIDEON, is that it can link the clinical aspects of disease with its epidemiology and formulate a differential diagnosis for an illness in the returned traveler. Since its release in 1991, GIDEON (Global Infectious Disease Epidemiology Network) has served as a computer program for diagnosis simulation and informatics in geographic medicine. It was designed to diagnose and simulate any infectious disease worldwide or to identify any species of bacterium or yeast. Additional modules follow the global and country-specific status of all infectious diseases as well as the pharmacology and usage of all anti-infective drugs and vaccines. GIDEON has four modules: a diagnosis module, an epidemiology module, a therapy module, and a microbiology module.

The diagnosis module generates a ranked differential diagnosis based on country of disease acquisition, signs, symptoms, patient demographics, laboratory data, exposure history, and incubation. The user may select any number of disease features or travel itinerary by mouse click. The resulting differential diagnosis is generated by a Bayesian matrix which examines both disease incidence and symptoms prevalence within each specific disease. Even though one must consider the ranking of a differential diagnosis with a critical eye, the advantage of GIDEON is the completeness of the differential diagnosis; the program often contains a few rare conditions which might not have been considered initially.

The major strength of GIDEON is its large database, which contains over 10,000 country-disease summaries. This module may be used to access data on the clinical and epidemiological profile for any one of over 230 diseases. Using the disease list, one can determine the global distribution of an infection instantaneously and the status of the infection in a particular country. A very useful option generates lists of infections based on epidemiological profiles. This is particularly helpful when one suspects the mode of acquisition of infection. For example, if a febrile patient returning from Zimbabwe gives a history of tick exposure, GIDEON will provide a list of all the tick-borne diseases or, specifically, tick-borne viral infections of Zimbabwe (or almost any other country of the world).

The therapy module provides the pharmacology and usage of vaccines and anti-infective agents, the latter by generic or proprietary name. The dosage for adults and children, adverse effects, cerebrospinal fluid penetration, dialysis adjustments, drug interactions, and spectrum are included for each agent. I was impressed by the extensive lists of proprietary and generic names which could be easily cross-referenced at the touch of a key stroke. Many travelers return with a list of proprietary named drugs which were administered overseas, and the practitioner is stuck with the task of trying to figure out what was prescribed. In reviewing the treatments recommended by GIDEON, the most up-to-date therapy is consistently provided. The vaccine module presents dosing and booster schedules, as well as contraindications and adverse reactions.

The Microbiology module can be used to identify all species of bacteria, mycobacteria, and yeasts based on phenotypic tests; or explore and compare the features of any taxon or group of taxa. This module is continually up to date, and I would estimate that at least 100 species contained in GIDEON have yet to appear in commercial systems used in American laboratories.

In summary, GIDEON is a very useful diagnostic tool for geographic medical conditions. The epidemiological module is particularly useful in formulating a differential diagnosis based on country-by-country exposure. Both of these modules, and in fact, the therapeutic module, are excellent teaching tools for trainees. This program is highly recommended for travel medicine, tropical medicine, and infectious disease practitioners, particularly those residing in teaching institutions. The current price of GIDEON includes the program plus one year of updates, and is not much more than a textbook for single users, with discounts offered for multiyear or multiuser subscriptions. If this is too dear, I would recommend its purchase by a group practice, clinic, or institution to have available for common usage. In particular, teaching institutions could avail themselves of the extraordinary diagnostic and teaching capabilities of this enormous, continuously updated database. This program does what textbooks cannot, and does it well!

Stephen Edberg
Yale University School of Medicine
New Haven, Conn.