viral haemorrhagic fever: the west african zaire ebola virus outbreak dr eleri wilson-davies...

Viral Haemorrhagic Fever: The West African Zaire Ebola

Virus outbreak

Dr Eleri Wilson-Davieseleridavies@nhs.net

Consultant Medical VirologistWest 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)

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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 DEATHSSpain 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 - 1995These 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