Patient with Ebola Hemorrhagic Fever, Bumba Zone, Equateur Province, DR Congo (Zaire), October 1976

Active Surveillance for EHF Cases, Equateur Province, DR Congo (Zaire), November-December 1976

Investigations of EHF Cases in Villages, Equateur Province, DR Congo (Zaire), October-December 1976 Dr. M. Mbuyi & Nurse Sukato interviewing mourning family member

Ebola Hemorrhagic Fever in Democratic Republic of the Congo (Zaire), 1976-1977 Selected Events Aug 26 First patient presents with fever in Yambuku, Equateur Province, receives chloroquine injection; fever resolves in 4 days Sept 1 EHF begins in first patient 16 Local clinician reviews 17 patients; reports unknown disease to Kinshasa 23-25 First medical team visit from Kinshasa; typhoid fever suspected, vaccination; evacuation of Belgian nun to capital 30 Yambuku hospital closed, 11 of 17 staff members dead Sept 30/ Oct 20 Three nurses die in Kinshasa

Ebola Hemorrhagic Fever in Democratic Republic of the Congo (Zaire), 1976-1977 Selected Events Oct 2-6 Second medical visit from Kinshasa; specimens collected 3 Health zone quarantined by Minister 8-12 Transmission occurring in Kinshasa hospital 13-14 Filovirus seen on EM in Belgium, UK and USA 14 New virus (Ebola) identified at CDC 18 International Commission formed 19-27 Survey team to Yambuku; reports active cases in 8 villages 30 Airlift of surveillance teams to NE DR Congo, covers DRC-Sudan frontier

EHF in DR Congo (Zaire), 1976-1977 Selected Events (cont’d) Nov 2 Plasmapheresis program begins with convalescent patients 4 Widespread surveillance in epidemic zone 5 Last case dies 16 Surveillance, research and clinical care support arrives in Yambuku Dec 16 Emergency officially over Jan 28 Plasmapheresis program ends

International Commission Discoveries Ebola Hemorrhagic Fever in Democratic Republic of the Congo (Zaire), 1976-1977 International Commission Discoveries Virology Isolation and characterization of Ebola virus Differentiation from Marburg virus Immunology

International Commission Discoveries Ebola Hemorrhagic Fever in Democratic Republic of the Congo (Zaire), 1976-1977 International Commission Discoveries Clinical Described symptoms and signs including Hemorrhagic manifestations Pancreatitis Incubation period

International Commission Discoveries Patient Management and Control Ebola Hemorrhagic Fever in Democratic Republic of the Congo (Zaire), 1976-1977 International Commission Discoveries Patient Management and Control Isolation of patients effective Surveillance of households, villages Plasmapheresis of convalescents

International Commission Discoveries Ebola Hemorrhagic Fever in Democratic Republic of the Congo (Zaire), 1976-1977 International Commission Discoveries Epidemiology Mode of transmission Risk groups Attack rates; individuals, families, villages Geographic distribution and spread

International Commission Discoveries Ebola Hemorrhagic Fever in Democratic Republic of the Congo (Zaire), 1976-1977 International Commission Discoveries Immunology Developed IFA test for Ebola Found evidence of previous infection

Epidemic in northern DR Congo (Zaire) Ebola Hemorrhagic Fever in Democratic Republic of the Congo (Zaire), 1976-1977 Initial Information Epidemic in northern DR Congo (Zaire) 100% of villages affected 100% of persons in villages affected 100% of affected persons in villages dead

Ebola Hemorrhagic Fever in Democratic Republic of the Congo (Zaire), 1976-1977 Initial Information Cause? Typhoid Lassa fever Yellow fever Sources of Information International plantation manager (confidential) World Health Organization (limited) US Embassy (limited) Scientists in Belgium and France

Ebola Hemorrhagic Fever in DR Congo (Zaire), 1976 Risk Factors Associated with Person to Person Spread Person to Person Family Contacts (non-infected) Risk Factor Cases % Yes Cases % Yes P Touched cases Attended burial Cared for case Slept in same room Prepared cadaver Aided in delivery of child from sick patient 126 119 116 104 86 71 69 59 18 91 98 84 58 74 68 9 ns p<0.001

Distribution of Cases in Villages Ebola Hemorrhagic Fever in DR Congo (Zaire), 1976 Distribution of Cases in Villages Cases Number of Villages % of Villages Cumulative % 1 2-5 6-9 10-14 15-19 20-29  30 17 18 12 4 1 2 55 31 64 86 93 95 97 101 31 33 22 7 2 4

Ebola Hemorrhagic Fever in DR Congo (Zaire), 1976 Family Contact Attack Rate by Generation of Illness No. of Subsequent Cases 38 20 3 1 62 No. of Family Exposures 496 459 117 29 1103 No. of Families of Cases 61 62 18 5 146 Attack Rate (%) 7.5 4.4 2.6 3.4 5.6 Generation 1* 2 3 4 Total * persons acquiring disease by injection

Ebola Hemorrhagic Fever in DR Congo (Zaire), 1976 Distribution of Ebola Hemorrhagic Fever Cases by Transmission Type, Yambuku, DR Congo (Zaire), 1976 Cases Survivors Transmission History No. 85 149 43 30 11 318 % 27 47 14 9 3 100 No. 30 4 38 % 79 11 101 Injection Person-to-person Both possible Unknown Neonatal

Ebola Hemorrhagic Fever, DR Congo (Zaire), 1977 Case Definitions Probable: Living in epidemic area Died after  1 days with  2 of the following: headache, fever, abdominal pain, nausea/vomiting, bleeding With 3 preceding weeks received an injection or had contact with a probable or proven case No other diagnosis

Ebola Hemorrhagic Fever, DR Congo (Zaire), 1977 Case Definitions Proven: Ebola virus isolated or shown by EM Or IFA titer of  1:64 after 3 weeks of symptom onset

Ebola Hemorrhagic Fever, DR Congo (Zaire), 1977 Infection: IFA titer  1:64 with no symptoms/signs August 15- November 19, 1976 Case Definitions Possible: Headache and/or fever for  24 hours with or without other signs/symptoms Contact with a probable or proven case, within 3 weeks Treated with antimalarials, antibiotics, antipyretics Bled and checked for antibodies Any case of fever and bleeding anywhere in DR Congo Neonatal: Newborns of probable cases if died within 28 days

Ebola Hemorrhagic Fever, DR Congo (Zaire), 1977 Case Definitions Primary Contact: Face to face contact with a probable or proven case Between 2 days before symptom onset and death or recovery Surveillance 21 days from last contact Secondary Contact: Face to face contact with primary contact

Ebola Hemorrhagic Fever, DR Congo (Zaire), 1976-77 Major Gaps and Challenges Natural history undefined Surveillance and response weak No specific treatment or precaution Limited application of modern technologies Few laboratories involved Filovirus and other “orphan” diseases receive low priority