Filovirus disease outbreak toolbox

Updated | July 2026

Key reference documents

Ebola disease information page (WHO)
Ebola virus disease fact sheet (WHO, 2025)
Marburg virus disease fact sheet (WHO, 2026)
Surveillance, case investigation and contact tracing in filovirus disease outbreaks (WHO, 2026)
Infection prevention and control guideline for Ebola and Marburg diseases (WHO, 2026)
Public health advice on multisectoral action for social and economic protection of communities during Ebola disease outbreaks (WHO, 2026)
Ebola and Marburg virus disease epidemics: preparedness, alert, control and evaluation: Interim manual Version 1.2 (WHO, 2014)
Map - Geographic distribution of Marburg virus disease outbreaks and bats of Pteropodidae family (WHO, 2023)

Ongoing Bundibugyo virus disease outbreak

Ongoing outbreak in the Democratic republic of Congo (AFRO, 2026)
Ebola - The Democratic Republic of Congo, 2026 (WHO. 2026)

Case definitions

Routine surveillance case definition

Filovirus disease case definition to be used by health care professionals	Suspected case
	a. Any individual presenting with fever or history of fever and no response to treatment of usual causes of fever in the area, AND - haemorrhage, including bloody diarrhoea, bleeding from gums, bleeding into skin (purpura), bleeding into eyes or urine; OR - at least two of the following symptoms: severe headache, weakness, joint pain, muscle pain, diarrhoea, vomiting, nausea, conjunctivitis, hiccups, irritability/fussiness (in children under the age of 2) AND recent history of visiting mines/ caves; exposure to sick or dead wild animals; being in contact with sick individuals with similar symptoms. OR b. Any individual who died after bleeding.
Confirmed case	a. A suspected case with laboratory confirmation*
Examples of events to be reported through community-based surveillance (not exhaustive)	Two or more persons presenting with similar severe illnesses in the same setting within two weeks. Two or more persons dying in the same community within two weeks. Any human illness or death after exposure to animals and raw animal products (such as fluids and raw meat). Cluster of illness or nontraumatic death from human or wild animal (likely to be reported by a health care facility). Cluster of illness or deaths among HCWs after attending to a similarly ill patient.

* The preferred assay to confirm a filovirus infection is nucleic acid amplification test; in certain circumstances genomic sequencing or serology (convalescent patients) may be used.

Case definitions to be used during a filovirus disease outbreak

Filovirus disease case definition to be used for community-based surveillance (for example, by a community health worker)	Signal suggestive of a suspected case (alert)
	a. Any individual presenting with fever or recent history of fever and no response to treatment of usual causes of fever in the area; AND - at least two of the following symptoms: severe headache, weakness, joint pain, muscle pain, diarrhoea, vomiting, nausea, red eyes/conjunctivitis, hiccups; OR - bleeding, including bloody diarrhoea, bleeding from gums, bleeding into skin (purpura), blood in urine. b. Any sudden death (except for deaths following injury or violence). Any such situation should be immediately reported to a surveillance team or to the closest health care facility.
Case definitions to be used by HCWs	Suspected case a. Any person, alive or dead, with fever or history of fever and no response to usual causes of fever in the area; AND - is a filovirus disease case contact person, a dead or sick animal contact person, or a laboratory contact person; OR - had travel history in an affected area[1] in the past 21 days (to be used in countries, territories or areas where there is no active filovirus outbreak). OR b. Any person with fever or history of fever and at least three of the following symptoms: severe headache, weakness, joint pain, muscle pain, diarrhoea, vomiting, nausea, red eyes/conjunctivitis, hiccups, irritability/fussiness (in children under the age of 2). OR c. Any person with inexplicable bleeding. OR d. Any sudden, inexplicable death. Note: if laboratory specimens are collected in due time during or after the illness, the preceding categories are reclassified as laboratory confirmed cases or non cases. Probable case Any suspected case, alive or deceased, for whom laboratory results were not available, but who has an epidemiological link to a confirmed case or to a recognized transmission chain containing a confirmed case. Note: if laboratory specimens are collected in due time during or after the illness, the preceding categories are reclassified as laboratory confirmed cases or non cases. Confirmed case Any suspected or probable case with a positive laboratory result. Non case* Any suspected or probable case with a negative laboratory result³. Negative results include the absence of detectable RNA of, antigens or antibodies to a filovirus, assuming sample was collected in the right time frame.

Filovirus disease case definition to be used for community-based surveillance (for example, by a community health worker)

Signal suggestive of a suspected case (alert)

a. Any individual presenting with fever or recent history of fever and no response to treatment of usual causes of fever in the area; AND
- at least two of the following symptoms: severe headache, weakness, joint pain, muscle pain, diarrhoea, vomiting, nausea, red eyes/conjunctivitis, hiccups; OR
- bleeding, including bloody diarrhoea, bleeding from gums, bleeding into skin (purpura), blood in urine.
b. Any sudden death (except for deaths following injury or violence).
Any such situation should be immediately reported to a surveillance team or to the closest health care facility.

Case definitions to be used by HCWs

Suspected case
a. Any person, alive or dead, with fever or history of fever and no response to usual causes of fever in the area; AND
- is a filovirus disease case contact person, a dead or sick animal contact person, or a laboratory contact person; OR
- had travel history in an affected area[1] in the past 21 days (to be used in countries, territories or areas where there is no active filovirus outbreak).
OR
b. Any person with fever or history of fever and at least three of the following symptoms: severe headache, weakness, joint pain, muscle pain, diarrhoea, vomiting, nausea, red eyes/conjunctivitis, hiccups, irritability/fussiness (in children under the age of 2).
OR
c. Any person with inexplicable bleeding.
OR
d. Any sudden, inexplicable death.
Note: if laboratory specimens are collected in due time during or after the illness, the preceding categories are reclassified as laboratory confirmed cases or non cases.

Probable case
Any suspected case, alive or deceased, for whom laboratory results were not available, but who has an epidemiological link to a confirmed case or to a recognized transmission chain containing a confirmed case.
Note: if laboratory specimens are collected in due time during or after the illness, the preceding categories are reclassified as laboratory confirmed cases or non cases.

Confirmed case
Any suspected or probable case with a positive laboratory result*.

Non case
Any suspected or probable case with a negative laboratory result³. Negative results include the absence of detectable RNA of, antigens or antibodies to a filovirus, assuming sample was collected in the right time frame.

[1] Affected areas should be defined as precisely as possible at the smallest administrative level to improve the case definition sensitivity.