Download Presentation on Ebola

16th October 2014
Ebola virus disease: current
epidemiology
Dr Chris J Williams
Insert name of presentation on Master
Consultant
Epidemiologist, Public Health Wales
Slide
Outline
• Aims
• What is Ebola virus?
• Current Situation: W. Africa, US &
EU, forward look
• What is the role of LRF
• Guidance
Ebola epidemiology
Aims and objectives
Aims
1. Early case-finding, with appropriate
management of cases
2. Avoid inappropriate responses
Objectives:
1. Increase awareness in staff
2. Promote knowledge of guidelines and
participation in exercises
Ebola epidemiology
Main message
• There are currently no infectious cases of
Ebola in the UK
• We are concerned about people who are
ill (mainly fever), who have travelled to
Guinea, Liberia or Sierra Leone in the
past 21 days
• All other people have effectively zero
risk*
*Exceptions: imported blood specimens, bush meat, nurses from Spain or Texas, late-identified
source outside the affected area
Ebola epidemiology
Ebola virus disease
• Filovirus
• Infects wide variety of cells
including those lining blood vessels
• Lymph nodes, liver, adrenal
• Immune cascade
• Multi-organ failure and death
Ebola epidemiology
Course
• Symptoms: 8-12 days after exposure
(range 2-21 days)
• Early: Fever (87%), chills, myalgia,
malaise
• 5 days later: diarrhoea (66%), nausea,
vomiting (68%) and abdominal pain
• Also red eyes, chest pain, short of breath
• Death 6-16 days (7.5 days current)
Ebola epidemiology
Ebola history
• First outbreaks in 1976, East Africa
• Gap 1979-1994
• Always localised and controlled
through straightforward measures
– Safe healthcare/PPE
– Appropriate burial practices
– Isolation of cases and contact tracing
Ebola epidemiology
Past outbreaks
Outbreaks Ebola (CDC)
3.5
3
2.5
2
1.5
1
0.5
0
Ebola epidemiology
Transmission: FROM
• Sources of virus
–
–
–
–
–
Blood
Blood-stained bodily fluids
Saliva, tears
Semen
Sweat (NO)
• From: Live human; dead body; live or dead
animal (bat, monkey)
Ebola epidemiology
Transmission: VIA
•
•
•
•
•
•
Fomites
Environment
Meat/carcasses
Blood samples
Blood/tissue donations
Medical equipment
Ebola epidemiology
Transmission: TO
• Direct inoculation – through skin,
mucous membranes
• Self-inoculation (via hands, PPE)
• Sexual contact (semen)
• Blood transfusion
• Needles/medical equipment
Ebola epidemiology
Transmission: main points
• Not infectious until symptomatic
• Viral load increases after first
symptoms, highest near death
• Virus can persist on surfaces BUT
• Only isolated from visibly bloodstained items in environment
Ebola epidemiology
Main routes (Africa)
• Community, through contact with an
infected person or contaminated
fomites
• Burials, due to touching dead bodies
• Nosocomial, via lack of infection
control measures within healthcare
facilities
Ebola epidemiology
Control
• Simple infection control measures to
prevent direct contact with body
fluids, and appropriate quarantining
of ill patients, have been sufficient
to contain past outbreaks (Bennett
& Brown 1995).
Ebola epidemiology
Household risks
(DRC, Uganda)
•
•
•
•
DRC: 27 households with cases, 28/173 household contacts became ill
None of the 78 household members who had no physical contact with
the case during the clinical illness were infected (upper 95% CI, 4%).
Additional risk in adults, touching cadaver, exposure in late hospital
phase.
Uganda: 73 contacts; highest risk caring at home in late stages, more
than one type of direct contact. Sharing hut, sleeping mat indirect risks.
EVD is transmitted principally by direct physical contact
with an ill person or their body fluids during the later
stages of illness.
Ebola epidemiology
Current Situation, W Africa
Ebola epidemiology
Economics
Country
Population
(m)
GDP/Capita
2013 (USD)
Health spending per
capita, 2012 (USD)
Guinea
12
527
32
Liberia
4
454
65
Nigeria
173
3 006
94
6
809
96
64
39 337
3 647
Sierra Leone
UK
Ebola epidemiology
Distribution of cases of EVD by week of reporting in Guinea, Sierra Leone,
Liberia, Nigeria and Senegal, weeks 48/2013 to 42/2014*, n= 8 994
Epidemiology: descriptive
•
•
•
•
The incubation period was estimated to be 11.4 days with serial interval
of 15.3 days.
The case-fatality rate in in Guinea, Liberia and Sierra Leone was 70.8%
(95% CI: 68.6–72.8%) with no noticeable difference between the
countries
As of 12 October 2014, WHO reported 425 healthcare workers infected
with EVD of whom 236 died [10].
HCW account for around 5% of the cases in West Africa
Ebola epidemiology
Ebola epidemiology
Imported cases of EVD
Case of Ebola treated outside W Africa
+
gave rise to secondary case(s)
+
+
31
32
33
34
35
35
36
37
38
39
40
Week number (2014)
Countries: USA 6, Germany 3,
France 1, Spain 2, Norway 1, UK 1
41
Date of
evacuation
Source
country
Recipient
country
02-Aug-14
Liberia
USA
05-Aug-14
Liberia
USA
06-Aug-14
Liberia
Spain
24-Aug-14
Sierra Leone
UK
27-Aug-14
Sierra Leone
Germany
04-Sep-14
09-Sep-14
Monrovia,
Liberia
Kenema, Sierra
Leone
Outcome
Nationality
Discharged
US
Discharged
US
Death
Spanish
Stable
British
Epidemiologist
Recovered
Senegalese
USA
Physician
(obstetrician)
stable
US
USA
Physician
stable
US
Discharged
French
Death
Spanish
stable
Uganda
Stable
US
not known
Norway
not known
Sudan
Death
Liberia
19-Sep-14
Liberia
France
22-Sep-14
Sierra Leone
Spain
02-Oct-14
Sierra Leone
Germany
02-Oct-14
Liberia
USA
06-Oct-14
Sierra Leone
Norway
08-Oct-14
Liberia
Germany
20/09/2014
Liberia
USA
Ebola epidemiology
Profession
Healthcare
worker
Healthcare
worker
Healthcare
worker
Healthcare
worker
Healthcare
worker
Healthcare
worker
Healthcare
worker
Cameraman
Healthcare
worker
Laboratory
worker
Non-HCW
Secondary
cases
0
0
0
0
0
0
0
0
1
0
0
0
0
2
Controlling imported Ebola
• Challenges and successes
Ebola epidemiology
Potential problems in controlling imported EVD
Thomas Duncan
• Flew on 20/9; onset 24/9
• First H/C contact 25/9 - Discharged (sinusitis); travel
history not passed on. Fever, abdo pain, headache.
• Second contact 28/9 – isolated
• 76 hospital contacts
– 2 cases among these
– Contact pre-diagnosis thought to play a role
• 48 community contacts
– 0 cases to date
• Reported difficulties with PPE
Ebola epidemiology
Spain
• HCW infected despite PPE
• Occupational health slow to respond
to reported symptoms
• Confidence in healthcare system,
PPE and procedures
Ebola epidemiology
Imported cases VHF to 2012:
No evidence flight transmission
Year
Countries
Contacts
–All
ContactsHigh risk
Secondary
cases
Flight
exposure?
2008
Netherlands
ex Uganda
130
64
0
?
2008
US ex Uganda 260
?
0
?
1975
S. Africa ex
Zimbabwe
35
-
2
?
2009
Germany ex
Cote d’Ivoire
232
30
1 (serol)
Y (3 hours)
2009
UK ex Nigeria
328
0
0
Y (ill)
2009
UK ex Mali
125
7
0
Y (ill)
2005
UK ex Sierra
Leone
125
0
0
?
Ebola epidemiology
Nigerian experience
• 20 cases from 1 index (cared for sibling in Liberia who died; 20/7/2014)
• Longest chain of transmission was 3 persons
• 62% of cases were in healthcare workers (HCW)
• Secondary cases in household contacts of infected HCW
Lessons learned
• Vigorous management with appropriate resources
• EOC had units for case management; epi/contacts; travel/ports;
management; community mobilisation
• 150 contact tracers; 12 epidemiologists for 850 contacts
• Incident management system
• Rumour (salt water protects against Ebola)
Nigeria declared Ebola free on 17/10/2014
Ebola epidemiology
Fever>38 degrees C
Scenario (a)
• Collapsed man (A) of Afro-Caribbean
ethnicity in Cardiff city centre
• Sweating, bloodshot eyes
• Man B (passing by) tries to rouse man A
– flags down a passing police officer for help
• What should the police officer do now?
Ebola epidemiology
Two days later
• Partner of man B calls ambulance
• One of her children has a fever
• Asks why man B has not been
isolated and demands care for her
child
Ebola epidemiology
Scenario (b)
• Returned healthcare worker from
Liberia living in Merthyr Tydfil
• Studying in public library
• Member of public calls
environmental health concerned
about risks to other library users
Ebola epidemiology
Learning points
• Not infectious until ill
• Most Afro-Caribbean men in Cardiff
have not come from West Africa in
the last 21 days
• Immediate contacts are not a risk to
anyone unless they are carrying
bodily fluids of an infectious case
Ebola epidemiology
What can we do?
• Know who is at risk
• Know how to assess them and
pathways for referral
• Know the appropriate PPE
• Sources of advice
• Lines of communication
Ebola epidemiology
Initial PPE for assessing those with
Symptoms + travel to affected area
•
•
•
•
•
Non-physical contact (e.g. interviewing people) – no PPE
required;
Physical contact with mildly symptomatic cases (e.g. with fever)
- Standard precautions apply: Hand hygiene, gloves, forensic
suit;
Physical contact with overtly symptomatic cases: Hand hygiene,
gloves, forensic suit, fluid repellent surgical facemask, eye
protection
Physical contact with severely symptomatic patients e.g. those
with extensive bruising and/or active bleeding and/or
uncontrolled diarrhoea and/or uncontrolled vomiting: Hand
hygiene, double gloves, fluid repellent disposable gown/suit, eye
protection, FFP3 respirator.
From Ebola risk assessment at custody suites
Ebola epidemiology
Initial assessment:
commonsense approach
• Keep distance (2m)
• Avoid contact with body fluids
• Speak to person to assess travel
history and symptoms
• Then seek healthcare advice (if
appropriate)
Ebola epidemiology
Ebola preparedness: general briefing
•
•
•
•
•
•
•
•
•
•
Ebola virus disease is a severe infection caused by the Ebola virus. It has caused a number of cases and
outbreaks in Africa since 1976, and there are current outbreaks in the three West African countries Guinea
(capital Conakry, not Guinea-Bissau or equatorial Guinea), Liberia and Sierra Leone. Two other West African
countries with case(s), Senegal and Nigeria, have controlled the spread and are not now included in the list of
risk countries, but a further imported case has now been reported in Mali with subsequent contact tracing.
The disease is severe, with up to 70% of those infected dying, and is causing great hardship in the affected
countries. However, it is not as easy to catch as infections such as influenza or measles, and only direct
contact with an infected case who is ill, or some body fluids from such a case, can cause infection.
Healthcare workers caring for affected patients have the highest risk of infection, as cases are most infectious
when they are most ill.
Across Wales the risk of Ebola to the general population is low. To date there have been no persons infected
with Ebola in Wales.
However, as the situation in West Africa is escalating there is a possibility of infected persons returning to live
or work in Wales. The NHS has been preparing for potential cases.
In Wales we are asking anyone who becomes unwell with a fever within 21 days of leaving the affected areas
to contact NHS Direct Wales (dial 0845 46 47) and tell them their travel history.
The current affected areas (as of 17/10/2014 ) are Sierra Leone, Guinea and Liberia.
NHS Direct Wales will discuss your symptoms and if your symptoms are thought to require further
assessment they will organise for an ambulance to transport you safely to hospital where staff will be
prepared to assess you in an appropriate room.
Individuals phoning a GP practice for an appointment because they are unwell should be asked if they have
travelled to the affected areas of West Africa in the last 3 weeks and if so they can speak to GP on the phone.
If an individual attends a GP practice or A&E because they are unwell they should be asked if they have
travelled to the affected areas of West Africa in the last 3 weeks, if so they should be directed to a room (with
no other patients, which may be easily cleaned) and the GP present communicate preferable by phone with
the individual to make an assessment of the patient’s condition and their risk of Ebola.
Any concerns relating to a possible case of Ebola presenting to or calling primary care should be discussed
with the local health protection team and local infection doctor.
Ebola epidemiology
Mid & West Wales
Telephone number
Local Authority/Local
Health Board area
01792 607387
Carmarthenshire, Ceredigion,
Pembrokeshire, Powys
Swansea
Bridgend, Neath Port Talbot,
Swansea
Cardiff
029 2040 2478
Cardiff, Merthyr Tydfil,
Rhondda Cynon Taf, Vale of
Glamorgan
Gwent
01495 332219
Blaenau Gwent, Caerphilly,
Monmouthshire, Newport,
Torfaen
North Wales
01352 803234
Anglesey, Conwy,
Denbighshire, Flintshire,
Gwynedd, Wrexham
Out of hours please contact Public Health On-call by phoning the following Ambulance Control Centres and requesting the
public health doctor on-call.
North Wales:
Mid & West Wales:
South East Wales:
01248 689123
01267 229476
01633 626118
Ebola epidemiology
Guidance
• www.publichealthwales.org/
ebola
Ebola epidemiology
Response
•
•
•
•
•
•
Early case finding
Appropriate case management
Infection control- universal and specific
Contact tracing –community and HCW
Information management (epi/surv)
Communication (incl. Community)
Ebola epidemiology
References
•
•
•
•
•
•
•
•
•
•
•
http://jid.oxfordjournals.org/content/179/Supplement_1/S28.abstract?ijkey=abfe
90425a73c9ce1038aa73546a1c73d76b556b&keytype2=tf_ipsecsha
http://vir.sgmjournals.org/content/95/Pt_8/1619.full
http://jid.oxfordjournals.org/content/196/Supplement_2/S142.full
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1997188/pdf/ijexpath000040005.pdf
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3035551/
http://jid.oxfordjournals.org/content/179/Supplement_1/S87.long
http://www.ncbi.nlm.nih.gov/pubmed/10881895
http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20920
http://www.hpsc.ie/AZ/Vectorborne/ViralHaemorrhagicFever/Guidance/VHF2012/File,14071,en.pdf
http://www.phac-aspc.gc.ca/lab-bio/res/psds-ftss/ebola-eng.php
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1675587/pdf/brmedj014760011.pdf
Ebola epidemiology
Virus culture and reverse-transcription polymerase chain reaction (RT-PCR) results from 54
clinical samples collected from 26 patients with laboratory-confirmed Ebola hemorrhagic fever.
Bausch D G et al. J Infect Dis. 2007;196:S142-S147
© 2007 by the Infectious Diseases Society of America
Virus culture and reverse-transcription polymerase chain reaction (RT-PCR) results from 33
environmental samples.
Bausch D G et al. J Infect Dis. 2007;196:S142-S147
© 2007 by the Infectious Diseases Society of America