Generate a Differential Diagnosis

Differential Diagnosis

One of the most important initial steps when investigating an outbreak of unknown respiratory illness is generating the “differential diagnosis.” The differential diagnosis is a list of the most likely infectious causes or etiologies of an outbreak. Differential diagnosis also refers to the process of comparing how likely one pathogen caused the disease versus another.

Generating a differential diagnosis enables investigators to use time and resources most efficiently and effectively to determine an outbreak’s etiology. The process helps focus questionnaire development, specimen collection, laboratory testing, empiric treatment regimens, and targeted urgent public health interventions. Also, a thoughtful differential diagnosis ensures investigators consider all likely etiologies early in an outbreak investigation. This process makes it less likely that investigators miss or overlook an etiology.

Differential Diagnosis Spreadsheets

The spreadsheets below summarize information on the principle pathogens or groups of infectious agents known to cause respiratory illness.

• Demographic and Epidemiologic Data [2 pages]
  This spreadsheet summarizes information about host demographics and epidemiologic features of infection (e.g. incubation period and case fatality rate).
• Clinical Information [2 pages]
  This spreadsheet highlights information on clinical features of infection for multiple pathogens. Clinical features include unique laboratory findings and unique pathology findings.
• Risk Factors for Disease [2 pages]
  This spreadsheet includes information about known factors of disease, like specific occupations at increased risk or group settings that are often affected.

Persons with disabilities having problems accessing the above files may call 1-800-CDC-INFO (1-800-232-4636) for assistance.