Ebola virus outbreak toolbox

Ebola virus outbreak toolbox

Updated | August 2024

Welcome to the Ebola virus Outbreak toolbox

Case definitions

These case definitions are taken from the Integrated disease surveillance and response technical guidelines: Booklet Two: sections 1, 2, and 3, 3rd ed (page 18).

Surveillance case definition

Suspected case

  • any person presenting with onset of fever and no response to usual causes of fever in the area, AND at least one of the following signs: bloody diarrhoea, bleeding from gums, bleeding into skin (purpura), bleeding into eyes and urine.

Confirmed case

  • a suspected case-patient with laboratory confirmation (positive IgM antibody, positive PCR or viral isolation), OR epidemiological link to confirmed cases or outbreak. 

Alert case (community-based surveillance) 

  • any person presenting with onset of fever and no response to treatment of usual causes of fever in the area; OR 
  • at least one of the following signs: bleeding, bloody diarrhoea, bleeding into urine; OR 
  • any sudden death. 

Outbreak case definitions

Suspected case

  • any person, alive or dead, suffering or having suffered from sudden onset of high fever, and had contact with a suspected, probable, or confirmed Ebola case, or a dead or sick animal; OR
  • any person with sudden onset of high fever, AND at least three of the following symptoms: headache, lethargy, anorexia/loss of appetite, aching muscles or joints, stomach pain, difficulty swallowing, vomiting, difficulty breathing, diarrhoea, hiccups; OR
  • any person with inexplicable bleeding; OR
  • any sudden, inexplicable death.

Probable case

  • any suspected case-patient evaluated by a clinician, OR
  • any deceased suspected case-patient (where it has not been possible to collect specimens for laboratory confirmation) having an epidemiological link with a confirmed case.

Confirmed case

  • any suspected or probable case-patient with a positive laboratory result (detection of Ebola virus by reverse transcription polymerase chain reaction (RT-PCR), or detection of Immunoglobulin M (IgM) antibodies directed against Ebola viruses).

Non case 

  • any suspected or probable case-patient with a negative laboratory result (showing no specific antibodies, ribonucleic acid (RNA) or specific detectable antigens) more than 72 hours after symptom onset.

Contact person definition

  • any person having had direct physical contact with the bodily fluids of a sick or deceased person or indirect contact through contaminated surfaces, material, or equipment, such as needles or soiled clothes, within the past 21 day.

Case definitions are highly context dependant and may vary from on outbreak to the other.

Dead or sick animal contacts

  • Any person having been exposed to a sick or dead animal, less than 21 days before the identification as a contact by surveillance teams, in at least one of the following ways:
    • direct physical contact with the animal
    • direct contact with the animal’s blood or body fluids (including through the carving up the animal, or consumption of raw bush meat)

Laboratory contacts

  • Any person having been exposed to biological material in a laboratory, less than 21 days before the identification as a contact by surveillance teams, in at least one of the following ways:
    • has had direct contact with specimens collected from suspected patients
    • has had direct contact with specimens collected from suspected animal cases

 

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