Viral Haemorrhagic Fever: The West African Zaire Ebola Virus outbreak Dr Eleri Wilson-Davies eleridavies@nhs.net Consultant Medical Virologist West of Scotland Specialist Virology Centre
VHF are of particular public health importance because they: Can spread readily within a hospital setting Have a high case-fatality rate Are difficult to recognise and detect rapidly There is no evidence based treatment
1976 Yambuku, Democratic Republic of Congo (previously Zaire) – near Ebola river Nzara, Sudan 318 cases 280 deaths 38 serologically confirmed survivors 88% mortality rate Serum specimens were collected from persons in villages in the epidemic area if they had acute febrile illness during the epidemic period and were in contact with probable cases
Family: Filoviridae Species: Zaire ebolavirus (EBOV) Sudan ebolavirus (SUDV) Bundibugyo ebolavirus (BDBV) ------------------------------ Taï Forest ebolavirus (TAFV) Reston ebolavirus (RESTV)
Helical polymorphic Non-segmented Negative sense Single-stranded RNA viruses Variable lengths
Primary transmission Contact with the blood, secretions, organs or other bodily fluids of infected animals Fruit bats Chimpanzees Gorillas Monkeys Forest antelope Porcupines
Secondary transmission NO AEROSOL TRANSMISSION Mucous membrane protection prevents ALL transmission All VHFs enveloped viruses Easily inactivated In the UK the greatest risk to health care staff occurs BEFORE the diagnosis
West Africa Outbreak 17/11/14 CASES DEATHS Spain 1 Guinea 1919 1166 Sierra Leone 5586 1187 Senegal 1 Mali 4 3 Liberia 6878 2812 Nigeria 20 8 United States 4 1 TOTAL 14,413 5,177 CURRENT REPORTED MORTALITY 36%
Why? Poverty Travel for work Civil war Lack health infrastructure Doctors 1-2 per 100,000 of population in urban areas No/insufficient PPE HCW fail to be paid
Culture Fear Hide symptomatic family members Long-standing funeral practices that involve close contact with highly infectious corpses Distrust of government - corruption Two Nigerians have died after drinking salt water, which was rumoured to be protective
APPENDIX 7: LABORATORY PROCEDURES
Publications: BBV laboratory infections Most recent references are from 1978 - 1995 These are not representative of current health and safety practice Grist NR, Emslie JAN. Infections in British clinical laboratories, 1988–1989. J Clin Pathol 1991; 44:667–9. Extract from the abstract: "Hepatitis was not reported. The sustained low level of hepatitis is encouraging and suggests a low risk to staff of bloodborne infections such as human immunodeficiency virus."
Walker D, Campbell D. A survey of infections in United Kingdom laboratories, 1994–1995. J Clin Pathol 1999; 52:415–8. The single bloodborne virus infection reported (HCV) details in table 6, the possible laboratory infection was potentially acquired by an ancillary staff member who 'may have' cut themselves on glass, as they worked in the wash up area.
Take home message: If you protect yourself from blood-borne viruses (HIV/HBV/HCV) you are protecting yourself against VHF viruses
www.hps.scot.nhs.uk Dr Eleri Wilson-Davies eleridavies@nhs.net Consultant Medical Virologist West of Scotland Specialist Virology Centre