Ebola outbreak update

  • 292 views
Uploaded on

an update and forecast of the Ebola outbreak elicited jointly by StratAdviser Ltd and the Fench Society of Disaster Medicine

an update and forecast of the Ebola outbreak elicited jointly by StratAdviser Ltd and the Fench Society of Disaster Medicine

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
292
On Slideshare
0
From Embeds
0
Number of Embeds
4

Actions

Shares
Downloads
8
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Current Ebola outbreak is like none before Cases, 1,848 Deaths, 1,013 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000 Su,DRC DRC n/a Su n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a CdI,Ga DRC Ga n/a n/a n/a Ug Ga Co Co Su Co n/a DRC,Ug DRC n/a n/a Ug DRC Ug Gu,Li,SL,Ni 197619771978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005200620072008200920102011201220132014 AxisTitle Number of cases/deaths per year since first outbreak Wednesday, August 13, 2014 StratAdviser/SFMC Dr Jan-Cedric Hansen 2
  • 2. Epidemiologic specificity of current Ebola outbreak You can’t get Ebola through air (vs Influenza) – Neither through water nor food You get Ebola through body fluids and fomites – Mucosa contact at higher risk than skin Only families and friends are at risk – because they come in close contact with infectious secretions when caring for ill individuals Standard European Hospital Hygiene protects – Gloves, Gown (fluid resistant or impermeable), Eye protection (goggles or face shield), Facemask, hand washing, … Wednesday, August 13, 2014 StratAdviser/SFMC Dr Jan-Cedric Hansen 3
  • 3. So how come the cumulative figure is this one ! cumulated numbre of case, 4,235 cumulated number of death, 2,603 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 AxisTitle 4 774: threshold of x2 cases before 2014 3 180: threshold of x2 deaths before 2014 Wednesday, August 13, 2014 StratAdviser/SFMC Dr Jan-Cedric Hansen 4
  • 4. Because … Health Authorities use standard epidemic compartmental models to build on their response plan – SIR (Susceptible–Infectious–Removed) – SEIR (Susceptible-Exposed-Infectious-Removed) Those epidemic models are based on the assumption that : – Behaviour of all parameters is homogeneous throughout models – The number of secondary cases generated by an index case in the absence of control interventions is between 1.83 and 1.34 (R0) – Control measures (including education and contact tracing followed by quarantine) are implemented immediately – Efficacy of control measures is optimal thus reducing the final epidemic size by a factor of 2 Wednesday, August 13, 2014 StratAdviser/SFMC Dr Jan-Cedric Hansen 5
  • 5. Unfortunately … Heterogeneity exists: – Heterogeneous spatial distribution of host populations – Heterogeneous health status of populations (multi- hosts for many diseases such as HIV and pandemic influenza) – Heterogeneous susceptibility among age groups and other social categories – Heterogeneous social behaviour among groups regarding caring of their relatives or friends There also exists an epidemic equilibrium: – either a globally attracting disease-free equilibrium – or a globally attracting endemic equilibrium Wednesday, August 13, 2014 StratAdviser/SFMC Dr Jan-Cedric Hansen 6
  • 6. It impacts epidemic models The Department of Mathematics and Statistics, University of Victoria, BC, Canada demonstrated in 2012 that: – If R0 ≤ 1, then the disease-free equilibrium is globally asymptotically stable and the disease dies out from all groups or stages – If R0 > 1, then the disease persists in all groups or stages, and the endemic equilibrium is globally asymptotically stable As stated in a previous slide for Ebola 1.34 < R0 ≤ 1.83 – The Ebola outbreak is likely to become endemic in West Africa Wednesday, August 13, 2014 StratAdviser/SFMC Dr Jan-Cedric Hansen 7
  • 7. References of interest – Hae-Wol Cho, Chaeshin Ch. A Tale of Two Fields: Mathematical and Statistical Modeling of Infectious Diseases. Osong Public Health Res Perspect. 2011 September; 2(2): 73–74. – Shuai Z & van den Driessche P. (2012). Impact of heterogeneity on the dynamics of an SEIR epidemic model. Math. Biosci. Eng, 9(2), 393-411. Wednesday, August 13, 2014 StratAdviser/SFMC Dr Jan-Cedric Hansen 8
  • 8. Contacts for more advices StratAdviser Ltd – 2nd Floor, Berkeley Square House, London, W1J 6BD UK • Phone: +44 (0) 207 8874510 • Fax:+44 (0) 207 8876001 • www.stratadviser.com • contact@stratadviser.com – Dr Jan-Cedric Hansen • Mobile UK: +44 (0) 796 4330504 • Mobile F: +33(0) 631830868 • jc.hansen@stratadviser.com Société Française de Médecine de Catastrophe – 38 rue Dunois - 75647 PARIS Cedex 13 France • Tel : +33(0)6 43 26 81 51 • medecine.cata@gmail.com • http://www.sfmc.eu • med.cata@gmail.com Wednesday, August 13, 2014 StratAdviser/SFMC Dr Jan-Cedric Hansen 9