The Centers for Disease Control and Prevention has issued epidemiologic risk factors clinicians should consider when evaluating a person for Ebola virus disease, classifying contacts or considering movement restrictions.
In the guidelines, the CDC lays out the following three categories:
1. High risk. People are at high risk for Ebola if they have experienced the following:
• Percutaneous or mucous membrane exposure to blood or body fluids of a symptomatic Ebola patient
• Exposure to blood or body fluids of a symptomatic Ebola patient without proper personal protective equipment
• Processing the blood or body fluids of a symptomatic Ebola patient without proper PPE or biosafety precautions
• Direct contact with a dead body without PPE in a country with a widespread Ebola outbreak
• Living in the immediate household or provided care to a symptomatic Ebola patient
2. Some risk. This category includes people who had close contact with a symptomatic Ebola patient in households, a healthcare facility or community. Close contact is being within about three feet of a person while he or she was showing Ebola symptoms without proper PPE.
3. Low (but not zero) risk. This category includes people who were in a country with widespread Ebola infections but with no known exposure, having brief contact with a person in early stages of Ebola virus disease or while showing symptoms, or having traveled on an airplane with a symptomatic Ebola patient.
There is also a "no identifiable risk" category.
See the full guidance here.