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  • What is GIDEON? +

    GIDEON is a must-have resource on Infectious Diseases, with epidemiological data going back to 1348 AD. It is ideally suited to help diagnose diseases, identify pathogens, and stay up to date on the latest trends in epidemiology and treatment.

  • What does GIDEON stand for? +

    GIDEON stands for Global Infectious Disease and Epidemiology
    Online Network.

  • How do I sign up for a free trial of GIDEON? +

    Click here.

  • How do I order GIDEON? +

  • Is GIDEON an Evidence based medicine (EBM) database? +

    Yes, all sources are peer-reviewed and backed by scientific evidence – most are considered the premier scientific sources. Uncontrolled, or poorly-analyzed studies will not appear in these publications. This also holds for websites used in maintaining GIDEON. Virtually all are governmental sites. Reputable computer lists in the field are used, in a manner that fits the standards of evidence-based medicine.

    For example, although ProMED is considered THE site for new and ongoing outbreaks, many of its own sources consist of newspapers and news agencies. Therefore we cite ProMED in circumstances where this is the only information source for a given outbreak (often in underdeveloped and remote; new information sources which become available will also be included.
    In-text references in GIDEON further support GIDEON as an Evidence-Based Medicine database by allowing the user to view all source information, and to reach their own conclusions regarding the credibility of those sources if needed.

  • Can I use GIDEON when I am visiting patients away from the computer? +

    GIDEON works on all devices, anywhere where there is an Internet connection.

  • What time span does GIDEON cover? +

    GIDEON data goes back to 1348 AD!

    While most diseases are covered from the 1920s, there are smallpox graphs that start in the 1880s to 1890s (Egypt and Japan), and outbreaks are covered from as early as 1348 (plague).

    Other diseases with broad historical coverage include anthrax (1770), botulism (1793), cholera (1832), and dengue (1850).

  • How are the data in GIDEON collected? +

    The data in GIDEON are accessed and collated through a system of computer macros and dedicated source lists developed over the past 25 years. A daily search of PubMed is conducted against a listing of all GIDEON key words, and titles / abstracts of interest are reviewed. All available national Health Ministry publications [print and electronic] are scanned, as are standard publications of WHO and CDC. Relevant peer-reviewed publications (Infectious Diseases, Microbiology, Antimicrobial Agents, Tropical Medicine, etc) are continually examined for relevant articles. A partial listing of resources appears here.

  • Which scientific journals are resources for GIDEON? +

    Please refer to Resources.

  • How does GIDEON provide disease statistics from some small countries, such as countries in Africa? +

    The sources for data included in GIDEON currently include all relevant health ministry publications (electronic and print), peer review journal publications, and standard texts. A partial listing is available. The quality and frequency of data input vary widely from source to source. GIDEON is updated every day.

    A summary of newly added data is available here. When possible, data are assigned an electronically-linked reference number; and when users require further details regarding sources, they are encouraged to contact us through the feedback link.

  • Are diagnosis probabilities affected by season? +

    In most cases, rates by season will change the ranking of some diseases in the Diagnose module. Seasonal rates will change continually, depending on individual outbreaks, location by hemisphere, and distance from the Equator. At most, these changes will affect only the ranking of relevant diseases.

  • How are signs, symptoms and laboratory tests selected for inclusion in GIDEON? +

    Signs and symptoms incorporated in GIDEON are those generally used by specialists in the field.

    Most are easy to assess, and discriminative in the consideration or elimination of large groups of individual diseases. Similarly, the phenotypic tests are useful in the identification of large subgroups of bacteria, or the identification of individual major taxa.

    For example, one of our users asked, ‘Why is yellow pigment included, but not red pigment?’ The presence or absence of yellow pigment is extremely important in the identification of major human pathogens; while red color is limited to only a few minor taxa.

  • How does GIDEON collect case count data? +

    GIDEON follows over 32,000 data sets – more than 700,000 individual data points (ie. cases per year) as of mid-2018.  We haven’t found a  practical means for attributing reference for individual data.  A generic listing of references is available at

  • How do I cancel my account? +

    If you signed up for a free trial, your account will expire automatically at completion. If you wish to cancel your subscription, click on the link in your email receipt or contact us.

  • Are the probabilities given ever tested for accuracy? +

    Links to published studies follow. Note that studies largely assessed the ranking of diseases; ie, did the disease listed first reflect the true diagnosis? GIDEON does not make such a claim. In fact, the disease listed first only carries a higher statistical probability than other diseases on the list.


  • What is GIDEON's First Case Scenario feature? +

    The diseases listed are compatible with the signs and symptoms selected but are not endemic to the chosen country. This tool was developed in consultation with the World Health Organization and is designed to identify the initial cases of known diseases in new settings; ie, SARS in Canada (2003), Monkeypox in the United States (2003) West Nile fever in the United States (1999), Japanese spotted fever in Korea (2004), etc. For an example of use, see First Case Scenario.

  • How does GIDEON circumvent the ambiguity of less accurate information, i.e. "suspected" vs "reported" vs "confirmed" cases...? +

    The reliability of the information in GIDEON is only as reliable as the primary source. As such, “suspected cases”, “reported outbreaks”, etc. are quoted as given along a reference link.

  • GIDEON is only limited to infectious diseases. Won't this mislead the clinician? +

    This problem has existed long before the creation of GIDEON. Several disclaimers in the program warn the user that non-infectious diseases may mimic infection, and that the program is not intended as a replacement for sound clinical judgment.

  • During a recent outbreak, why did newspapers report Avian Influenza in more countries than are listed by GIDEON? +

    GIDEON only reports cases after they are confirmed by WHO / Authorized reference lab. Individual countries and the media often report new cases of “bird flu”, only to retract these reports after a day or two. In some cases they report H5N1, and it later turns into H5 – not N1. Many reports are simply rumors.

  • How often is population census information updated? +

    Population data are updated once yearly, for all countries. These data are available toward the middle of the current year, while incidence figures are generally published a number of months into the next year. Thus, rates per 100,000 are automatically generated as soon as the latter becomes available.


  • Why are some Caribbean countries grouped together as "Antilles (miscellaneous)"? +

    Each of the following Island groups in the Antilles are followed as individual “countries” in GIDEON: Aruba, Anguilla, Barbados, British Virgin Islands, Cayman Islands, Cuba, Haiti, Dominican Republic, Guadeloupe, Jamaica, Martinique, Montserrat, Puerto Rico, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Trinidad and Tobago, Virgin Islands, U.S. A small number of additional islands in the region (Curacao, Saba, Saint Barthelemy, Saint-Martin, Sint Eustatius, Sint Maarten) share similar disease endemicity, but publish relatively few relevant reports on a regular basis. As such, these have been grouped together under a single rubric: Antilles (miscellaneous) Note that several of these islands represent “overseas territories” of France, the Netherlands, the United States and the United Kingdom – and are not “countries” in the political sense.

  • How is susceptibility defined in the Drugs module? Is it based on FDA approval? +

    ‘Susceptible [sensitive]’ in GIDEON is defined as >=50% of strains susceptible to therapeutic drug levels. In many cases, this material comes from journal publications. FDA approval might take years after publication. Susceptible is not defined as ‘FDA-approved’ since the process is very slow, and does not necessarily represent standards outside of the US.

  • What drugs are included in GIDEON? +

    The Drugs module in GIDEON follows every anti-infective agent which has been released in one or more countries for clinical use in humans, and for which relevant pharmacological data are published. Drugs which are currently in development, and those limited to topical use only (skin, eye, vaginal) are not included. Agents which are no longer licensed, or which have been replaced by more advanced drugs remain in the module for historical interest.

  • Is "Drug of choice" available in every country? +

    “Drug of Choice” as designated by the Sanford Guide, Medical Letter, Up to Date, etc. There are few – if any – instances where these drugs are not universally available.

  • How does GIDEON compare to Travax? +

  • What vaccines are included in GIDEON? +

    The Vaccines module in GIDEON follows all vaccine and globulin preparations which have been released in one or more countries for clinical use in humans, and for which relevant pharmacological data are published. Vaccines which are currently in development are not included. Agents which are no longer licensed, or which have been replaced by more advanced vaccines remain in the module for historical interest.

  • GIDEON sometimes references ProMED. Does this affect its status as an Evidence Based Medicine database? +

    Although ProMED often quotes news agencies, we have opted to enter these links for two reasons:
    1. These are often the only citations for a given outbreak. Since the reader can now access the source they can easily judge the credibility of the note, thus fulfilling the requirement for evidence-based material. Many of these ProMED references relate to outbreaks in underdeveloped countries and remote areas, and may never find expression in more ‘credible’ publications.
    2. Journal articles on a given event appear only after a delay of months to years. The daily counts of cases for current outbreaks of major diseases (Marburg, Avian Flu, Polio) link to ProMED citations of WHO, CDC etc.

  • How do I access information regarding malaria prophylaxis in a specific country? +

    Malaria prophylaxis advice is based on the presence or absence of chloroquine-resistant Plasmodium falciparum. Travelers to countries having resistance are advised to take either Malarone (Atovoquone-Proguanil or Mefloquine.

    Each country record in GIDEON lists malaria prophylaxis advice applicable to that country.

  • What is the definition for "disease is endemic to" a given country? +

    “Endemic” is defined by the reported occurrence of autochthonous or locally-acquired cases. In some instances, a given disease has been reported in recent years, as opposed to the continued ongoing occurrence.

    In some cases, WHO or CDC will declare that a disease has been “eradicated” or “eliminated” – but GIDEON will continue to list the condition as “endemic” for a year or two, in the name of caution. The term ‘endemic’ is also used in GIDEON’s interactive maps.

  • How is GIDEON able to provide a percent probability for diagnosis? +

    The Disease diagnosis and Microbiology identification modules in GIDEON are powered by a Bayesian matrix which calculates probability based on the formula:

    P [S/D1] X PD1
    P-D1 [given S] = —————————————————–
    P [S/D1] X PD1 + P [S/D2] X PD2 … + P [S/Dn] X PDn

    – where P=Probability S=Symptom complex D1=Disease 1 D2=Disease 2 [etc]
    In the microbiology module, PD=Organism probability and S=Phenotype complex
    Two basic spread sheets feed data into this formula:
    1) incidence of diseases vs country name
    2) likelihood of symptom vs. disease name
    In other words, when the user enters a list of symptoms and country of acquisition for a patient, GIDEON does the following:
    1- access a list of diseases for the country in question
    2- rank the diseases by relative incidence
    3- delete diseases which are not compatible with the indicated symptoms
    4- multiply each disease probability by symptom probability
    5- re-rank the diseases by the relative product size in ‘4’

  • What's the difference between "Endemic" and "Potentially endemic"? +

    For the purposes of generating GIDEON, the designation “endemic” is primarily an operational term. The Diagnosis module must be as inclusive as possible when dealing with a patient exposed in a given country, and the maps must not overlook the presence of a key disease in that country. In many cases, when only single cases of a rare disease have been reported in each of several countries (ie, Dioctophyma renale infection), those countries will be designated “endemic” Similarly, repeated reports of autochthonous transmission will be sufficient for this designation.

    Statements that a disease is “endemic” to a given country are sufficient for assignment in GIDEON if so designated by CDC, WHO, PAHO or the relevant Health Ministry. Third-party sources which claim that a disease is “endemic” are not used.

    The designation “potentially endemic” might indicate that a pathogen is currently documented in food vehicles, reservoirs or bridging vectors; asymptomatic infection (seroprevalence) is described in the population; or that cases of the disease in question have not been reported in the past year or two, but had been documented in previous years. For the purposes of differential diagnosis and generation of maps, the terms “potentially endemic” and “endemic” are equivalent.

    When ProMED withdraws / corrects an item – or if additional details are published elsewhere – GIDEON will adjust the relevant note accordingly.

    Printed and electronic data from Health Ministries are used extensively by GIDEON.

  • What are the definitions for Vehicle and Vector? +

    Vector: An arthropod or other living carrier which transports an infectious agent from an infected organism or reservoir to a susceptible individual or immediate surroundings.

    Vehicle: The mode of transmission for an infectious agent. This generally implies a passive and inanimate (i.e., non-vector) mode.

  • What is the definition for "reservoir"? +

    Infectious Diseases practitioners are primarily concerned with the site of each disease in nature (“reservoir”) and their route into the body (vehicle / vector). GIDEON is primarily designed as a practical tool for clinicians in the field of Infectious Diseases. As such, designations of “reservoir” were largely derived from those listed for each individual disease in standard textbooks. The staff of GIDEON was never concerned in verifying or “determining” the veracity of these terms, but rather in relaying published information on the natural site for each pathogen / disease. Finer points regarding pathogen biology within specific animals are extremely interesting, but beyond the scope of our project.

  • How are Outbreaks defined in GIDEON? +

    In GIDEON, the designation “outbreak” may appear for one of four reasons.
    1. An event is specifically reported as “an outbreak” in source literature.
    2. In general, any grouping of cases – including family clusters and epidemics – will be listed as an “outbreak” for purpose of consistency. The term “outbreak” is generic here, and much will depend on the nature of the disease itself as there is no numerical cutoff.
    3. Citations of animal disease are denoted as “outbreaks” – even when only one animal is involved – in keeping with OIE definitions. Thus, a report of anthrax in a single goat is considered an outbreak in their reporting system.

  • How are Notable Outbreaks defined? +

    “Notable” is defined as “Noted” in every available journal, book, Health Ministry (etc) publication.

  • Are there mortality rates for each disease? +

    Mortality rates for individual diseases are incorporated in the Diagnosis matrix and stated in the Clinical tab for individual diseases. Assigning a specific mortality rate is problematic, since these will vary by country, patient age, patient category, underlying diseases (pregnant women, cancer patients, etc) For example, the death rate among MERS cases in the Korean outbreak was 16%, vs. a 45% mortality rate in Saudi Arabia to date. The mortality rate for tetanus among African patients is much higher than those in Western Europe, etc.

  • Does the GIDEON Diagnosis module work for animal diseases? Is GIDEON adaptable to the use of veterinarians? +

    GIDEON is designed specifically for human disease, and we are unaware of a parallel program for animals. The existing program could not be used for diagnosis of veterinary disease for several reasons:
    1. the data base does not include most of the necessary diseases
    2. the Bayesian statistical matrix is based on human incidence and prevalence data;
    3. the diagnostic data base is limited to signs/symptoms relevant to human disease.
    In theory, a similar program could be designed for veterinary use, but would require a complete set of data bases and spread sheets for each individual species, each set tied to relevant signs and symptoms for that particular species, in turn tied to additional data sets for each of over 200 countries (It’s taken us over 20 years to design, test and bring-to-market a system useful for only one species – Homo sapiens).

  • The Bioterrorism simulator appears to be giving information on past potential terrorism events; but, what does the tool simulate? +

    The Bioterrorism module generates a ranked differential diagnosis list of Infectious Diseases having potential use as Bioterror agents – based on signs, symptoms, incubation period [ie, time from exposure], laboratory tests, etc. (The concept of ‘Country of acquisition’ is not relevant).

    The Bayesian matrix employed in GIDEON is based on published prevalence of clinical features for each disease X prior probability of disease occurrence. There are no numbers for the latter (ie, what is the numerical “probability” plague will be used as a bioterror agent) As such, we assigned an arbitrary weight to each based on intuitive assessment. For example, if a given set of signs and symptoms is compatible with both Anthrax and Argentine hemorrhagic fever, GIDEON will rank the former higher in the Differential Diagnosis list – given its previous use in Bioterror, ease of delivery and storage, etc.

    * The key point here is that the diseases which are listed will not change – only the ranking of these diseases. The specificity of the list will ultimately depend on comprehensive entry of all signs, symptoms, laboratory data, etc.

    Also see Why is the differential diagnosis list for a Bioterrorism scenario not Bayesian?

  • Why is the differential diagnosis list for a Bioterrorism scenario not Bayesian? +

    The standard GIDEON diagnosis matrix is Bayesian; ie, based on the product of disease incidence X symptom/sign probability. In contrast, the Bioterror module is non-Bayesian – ie, relative disease incidence (prior probability) is not factored into ranking of the differential diagnosis list. Although we may intuitively assume that Anthrax and Smallpox carry higher ‘probability’ for use in Bioterror, vs. Marburg disease or Argentine hemorrhagic fever, precise numbers are lacking. Associated Epidemiology notes stress the history and relevance of individual diseases to Bioterrorism. The number of people who develop smallpox from a “smallpox-bomb” may be the same as the number who develop Ebola from an “Ebola-bomb.” For this reason, if there is a possibility of bioterror, GIDEON ranks the diseases only on the basis of the chance for symptoms in each disease.

  • Why can't I find details on the management of endocarditis in GIDEON ? +

    Entire books are written on the treatment of endocarditis, meningitis, urinary tract infection, bacterial pneumonia and other generic infections. This is well beyond the scope of GIDEON. The best source for this type of material has always been standard texts and review articles. The Clinical Notes in GIDEON do provide links to major journal reviews, including diagnosis and treatment of endocarditis, etc.

  • How does GIDEON identify organisms in the Microbiology module? +

    GIDEON generates a ranked ID list for bacteria based on the occurrence of phenotypic tests times the likelihood for each relative taxon in clinical material [“prior prevalence”]. Phenotypic data used for ID are taken from Bergey’s Manual and other standard tests, J Clin Microbiol. Int J Syst Evolut Microbiol, and other relevant journals.
    To generate a listing of phenotypic tests used by GIDEON for any taxa, click Bacteria, Mycobacteria or Yeasts tab, scroll to the taxon of interest, click on it’s name, and click on phenotype. In the comparison module, blank spaces for any given reaction indicate lack of data.

  • Why would I use GIDEON if I already use Maldi-Tof? +

    Because GIDEON:
    1. contains hundreds of organisms that are not identified by Maldi-Tof
    2. is updated almost daily – thus organisms which were published a week ago will be in Gideon, but will not be identifiable in Maldi-Tof for many months
    3. follows parasites, viruses etc – of interest to the laboratory, but not identifiable in Maldi-Tof
    4. follows descriptive info on every organism (ecology, disease association, drug susceptibility), and a compare function which is invaluable for teaching.

  • Why is the Bacillus Simplex not included in GIDEON? +

    GIDEON includes only taxa found in humans / clinical material.

  • How do I cite GIDEON in a paper that I'm writing? +

    “[cited material] In GIDEON online. Retrieved from on [access date]”. If required: ISSN 1938-6508.

  • Is GIDEON available in languages other than English? +

    GIDEON’s source language is English. Some of the synonyms for diseases, countries and drugs are in other languages. Using Chrome enables support for multiple languages.

  • How does the Infectious Diseases module compare to Johns Hopkins ABX guide? +

  • How does the Microbiology module compare to Bergey's manual? +

  • Questions for a paper at school +

    1. Why was GIDEON developed and who developed it?
    GIDEON was developed by Steve Berger and Uri Blackman to help doctors make better decisions and health professionals diagnose infectious diseases

    2. How many topics does this application contain? a rough estimate?

    3. How frequently do you update the topics?
    Every few days

    4. Do you provide references for the topic information?

    5. Is this mobile application information peer reviewed?
    There are many reviews of the app.

    6. What is the evidence source (text books or created internally, systematic reviews, etc)?
    See resources

    7. What method of evidence collection do you use to obtain this information?
    See EBM

Technical requirements

  • What do I need to access GIDEON? +

    You need an internet connection and a web browser on your computer or device.

    For the best possible user experience, we recommend using GIDEON with the latest browser version.

    Please note: the new GIDEON application does not run on the Internet Explorer browser, which is currently being phased out by Microsoft and stopped receiving security updates in November 2020. We recommend upgrading to the latest Microsoft Edge browser.

  • Does GIDEON work on a Mac or on Linux? +

    Yes. GIDEON application works with any operating system: Windows, Mac, Linux, iOS, and Android (see “What do I need to access GIDEON?” above).

    Please note: the new GIDEON application does not run on the Internet Explorer browser, which is currently being phased out by Microsoft and stopped receiving security updates in November 2020. We recommend upgrading to the latest Microsoft Edge browser.

  • Does GIDEON work on a mobile device? +

    Yes. You can access GIDEON from anywhere you have reception using your phone or mobile device.

  • How can I configure GIDEON to work with EZproxy? +

    Please use the following configuration with EZproxy for GIDEON (config.txt/ezproxy.cfg):

    Title GIDEON Online
    Find ‘’
    Replace ‘^^’

    Please don’t use this if authenticating via Ovid.


  • How can I transfer the ebook I downloaded on my computer to my reading device (iPhone, Kindle, Nook etc)? +

    For Kindle, use the MOBI ebook format.

    For other e-readers, such as Apple books on iPhone or Google Books on Android use the EPUB format.

    PDF is best used on larger screen device – desktop or larger tablet.

    Step by step instructions are provided to transfer files for various devices: