Download Histotechnology Zaire ebolavirus Outbrea[...]

Viral Haemorrhagic Fever:
The West African Zaire Ebola
Virus outbreak
Dr Eleri Wilson-Davies
[email protected]
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)
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•
•
•
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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
Spain
Guinea
Sierra Leone
Senegal
Mali
Liberia
Nigeria
United States
1
1919
5586
1
4
6878
20
4
DEATHS
1166
1187
3
2812
8
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
[email protected]
Consultant Medical Virologist
West of Scotland Specialist Virology Centre