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

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

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

4. 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 1EHF begins in first patient 16Local 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

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

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

7. 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

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

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

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

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

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

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

14. Ebola Hemorrhagic Fever in DR Congo (Zaire), 1976 Risk Factors Associated with Person to Person Spread Person to Person Family Contacts (non-infected) Risk FactorCases % YesCases % 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 86 58 74 84 86 71 68 58 9 ns p<0.001

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

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

17. Distribution of Ebola Hemorrhagic Fever Cases by Transmission Type, Yambuku, DR Congo (Zaire), 1976 Injection Person-to-person Both possible Unknown Neonatal Cases No. 85 149 43 30 11 318 % 27 47 14 9 3 100 Survivor s No. 0 30 4 0 38 % 0 79 11 0 101 Transmission History Ebola Hemorrhagic Fever in DR Congo (Zaire), 1976

18. 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

19. 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

20. Ebola Hemorrhagic Fever, DR Congo (Zaire), 1977 Case DefinitionsInfection: IFA titer  1:64 with no symptoms/signs August 15- November 19, 1976 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

21. 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

22. 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