This presentation is intended for educational use

and should not be used as a sole source of

professional guidance.

The information used to prepare this presentation

was correct on 18th August 2014.

For updates on geographical, epidemiological and

clinical developments, readers should check the

information sources given at the end.

Caveat

A short history of the 2014 epidemic

Country First cases* Location Total Confirmed Deaths

Guinea 25-MAR-14 southeast 519 376 380

Liberia 31-MAR-14 northeast 786 190 413

Sierra Leone 27-MAY-14 East 810 733 348

Nigeria 27-JUL-14 Lagos 12 11 4

Source = AFRO, WHO’s African bureau, as of 13th August, 2014. This data was available to the WHO when they

decided to declare an international health emergency. Total cases = confirmed, presumed & suspected. Data

collation requires time, and confirmation demands specialist laboratory services which are in high demand at

present.

Geography of the 2014 epidemic

First reports of Ebola Virus Disease came from four rural districts in the southeast of Guinea in March 2014.

international spread

Suspected cases were identified in Sierra Leone and Mali shortly afterwards, but these

were not confirmed by the teams sent to assist. However, new cases were reported

from two rural districts in northeastern Liberia, bordering on Guinea.

further spread of infection

Additional cases began to appear in Guinea’s capital, Conakry, followed by Monrovia in Liberia. Westward spread extended to Sierra Leone, and eventually to the capital, Freetown.

distant dissemination

In spite of the large numbers of cases resulting from transmission within and between the three West African countries, there was very little distant spread, until shortly before the WHO declaration when a case was notified in Nigeria’s capital, Lagos. There have been additional suspected cases in Nigeria since. The surrounding nations are at potential risk of disease spread via their land borders. Only two cases of fatal EVD have occurred outside Africa during this epidemic so far; one in a contact who returned to Saudi Arabia, and one in a volunteer from Spain who died after medical repatriation. Two further confirmed EVD infections have occurred in expatriate aid workers who were repatriated to the USA for medical treatment.

Ebola Virus Disease (EVD), West Africa 2014

Data source: AFRO, 13th August, 2014. These numbers are subject to change as further cases are notified, alternative diagnoses are established and laboratory confirmations are fed through to the teams of epidemiologists working on the epidemic.

The proportion of confirmed infections resulting in death is significantly lower in Sierra Leone than in Guinea. This may not be a genuine trend. It is too early to say whether the strain of Ebola Virus (EBOV) responsible for this epidemic has lost any virulence.

The 2014 epidemic is remarkable for its size, geographic scale and longevity.

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the virus

Drawn from micrograph of the first Ebola virus isolated from a human patient in Vero cell cultures in 1976. Magnification, approx. x 40,000. Virions are fused end-to-end and resemble spaghetti. The appearance varies considerably. Source of electron micrograph: F.A. Murphy, School of Veterinary Medicine, University of California, Davis.

The current epidemic is due to an Ebola virus (EBOV) strain belonging to the Zaire clade. Ebolaviruses are filoviridae, so called because of their tubular or cylindrical virus particles of 80nm diameter and up to 1000nm long. EBOV is a negative sense, RNA virus with a matrix, nucleocapsid and envelope. The envelope comprises a lipid bilayer from which glycoprotein spikes project. The Zaire lineage is the most virulent of the Ebolaviruses. Ebola virus is a WHO Risk Group 4 pathogen.

virus transmission

The Centers for Disease Control and Prevention list three route of Ebola virus transmission:

– Direct contact with human body fluids from people with infection: blood, faeces, urine, vomit and other secretions

– Contact with contaminated medical products such as syringe needles

– Consumption of wild animal meat (“bushmeat”)

clinical timeline

Days from infection Stages Clinical features

7-9 Early symptoms Headache, lassitude, fever, myalgia

10 Escalation Sudden onset high fever, haematemesis, passivity

11 Deterioration Bruising, bleeding from mouth, nose and rectum, signs of brain damage

12 Conclusion Internal bleeding, fits, loss of consciousness, death

laboratory confirmation

Specialist laboratory services are required to confirm EVD by detection of EBOV RNA (PCR), antigens or live virus in tissue culture• WHO risk group 4 status requires all work on live Ebola virus

to be performed at PC4

• The field laboratory teams deployed to assist in outbreak response operate at PC3 or higher.

• Inactivation and extraction of EBOV RNA allows subsequent laboratory work to be performed safely at PC2.

clinical management

• As no antiviral agent or vaccine had been licensed for EVD prior to the current emergency, the only specific treatment options are investigational.

• Experimental drugs are being tried under special emergency dispensation

• The mainstay of clinical care for infected patients is supportive care, particularly fluid replacement and organ system support. Clinical staff are at potential risk of secondary infection (see virus transmission, above) and require personal protective equipment to ensure consistent contact precautions.

risk management

• Inward travel to West Africa: is your journey really necessary? If so, check your travel insurance covers medical evacuation under quarantine conditions, and be prepared for major travel disruption.

• Outward travel from West Africa: is your journey really necessary? Public health authorities have closed some international borders and will be applying rigorous checks at several stages along your route. Any contact with known or suspected cases of Ebola Virus Disease should not travel away from home during the quarantine period. The incubation period is up to 30 days.

• Health workers travelling to assist: detailed advice on personal protection is available from WHO, public health authorities in country, and NGOs such as MSF.

• Further details from http://micrognome.priobe.net

Key points

• Ebola haemorrhagic fever is now called Ebola Virus Disease (EVD)

• EVD is fatal in up to 90% cases; around 50% in the current emergency. This figure may alter in coming weeks

• Experimental antiviral treatment (Zmapp & TKM-Ebola) are unproven. A vaccine candidate is also under evaluation.

• Transmission is by direct contact with patients or their body fluids, contaminated medical products, or bushmeat

• Although cases of EVD have been managed outside Africa during this epidemic in Saudi Arabia, the USA and Spain, no further transmission has occurred in these locations to date.