Ebola Virus Disease outbreak, 2014

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EBOLA 2014

description

An introduction to the 2014 West Africa Ebola outbreak for educational use, with additional sources for health professionals in need of up-to-date information. Updated on 7th December, 2014, with additional infographics and WHO data. Infographics may be requested for professional use on a creative commons/source attribution basis (micrognome.priobe.net). An interactive version will be available for educational use via the Nearpod share site.

Transcript of Ebola Virus Disease outbreak, 2014

Page 1: Ebola Virus Disease outbreak, 2014

EBOLA 2014

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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 7th December, 2014.

For updates on geographical, epidemiological and clinical developments, readers should check CDC, WHO and other regularly updated official information sources.

Caveat

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SITREP 2nd December

• Spain declared Ebola-free• Cases levelling off in parts of Liberia• Reduced case increase in Guinea• Cases still increasing in Sierra Leone• Preparedness stepped up in neighbouring countries• Target of 70% quarantine; 70% hygienic burials• Transmission in Mali localised

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The current situation

Despite the large numbers of cases resulting from continued transmission within the three West African countries of Liberia, Sierra Leone and Guinea, few cases and little continued local transmission has occurred elsewhere. Spain and Senegal have been declared Ebola-free. Mali and the USA have had limited local transmission. Nigeria and Senegal have been successful in mobilising a public health response before EVD took hold. Other nations in West Africa at risk of disease spread via their land borders have managed to prevent cross-border spread so far [at 2-DEC-14].

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The numbers to dateCountry Total Deaths

Liberia 7650 3155

Sierra Leone 7420 1609

Guinea 2186 1349

Nigeria 20 8

Mali 8 6

Senegal 1 0

Outside Africa 5 1

TOTAL 17290 6128

Source = AFRO, WHO, as of 2nd December, 2014. Total cases = confirmed, presumed & suspected. Data collation requires time, and confirmation demands specialist laboratory services which are in high demand. All figures are provisional and subject to revision as new data becomes available.

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Clinical timelineDays 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

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Laboratory confirmation

• WHO risk group 4 status requires all work on live Ebola virus to be performed under high level containment

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

• Specialist laboratory services are required to confirm EVD by detection of EBOV RNA (PCR), antigens or live virus in tissue culture

• 18 laboratories currently provide confirmation of EVD in the three countries with continuing high level transmission, all within 24hr of sample collection. 3 additional labs are pending, with an aim for same-day confirmation to support faster contact tracing and disease control.

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Clinical management• As no antiviral agent or vaccine had been licensed for EVD prior to the

current emergency, specific treatment options are still under investigation.

• Experimental drugs and blood product transfusion from recovered patients are under trial.

• The mainstay of clinical care for infected patients is supportive care, particularly intravenous 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 comprehensive contact precautions are followed.

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PPE• The Centers for Disease Control now recommend complete

body surface covering with personal protective equipment when caring for patients with EVD

• This includes all of: – protective face mask, plus goggle or visor– suit with hood, or high neck gown plus balaclava hood– Protective leggings– Double overshoes– Double gloves

• For front-line care of high risk patients, waterproof aprons, positive pressure hoods and heavy duty outer gloves are preferred

• All PPE use should be restricted to trained operators, working under direct supervision and with access to decontamination support / contaminated waste disposal during PPE removal

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International response to Ebola epidemicTreatment centres already open (green) are either close to the rural communities where the epidemic started, or in major cities. Those under construction (orange) are near the West African coast, while planned centres (grey) push along the coastal strip and further inland. [Information source: BBC. 10-OCT-14, based on national government, WHO & USAID data].

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Origins of the 2014 epidemic

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

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International spread

Shortly afterwards suspected cases were identified in Sierra Leone and Mali, but were not confirmed by the teams sent to assist. However, new cases were reported from two rural districts in northeastern Liberia, bordering on Guinea.

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Further local spread

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.

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Virus transmission

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

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

2. Contact with contaminated medical products such as syringe needles

3. Consumption of wild animal meat (“bushmeat”)

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The Ebolavirus

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.

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Cellular pathogenesis of Ebolavirus diseaseRedrawn from original to show how cellular response to Ebolavirus leads to clinical outcomes [Mohamadzadeh et al. Nature Reviews Immunology (2007) 7, 556-567]

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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 along your route. Any contact with known or suspected cases of Ebola Virus Disease should not travel away from home during the quarantine period of 21 days.

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

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Key points• Ebola haemorrhagic fever is now called Ebolavirus Disease (EVD)• Transmission is by direct contact with patients or their body fluids,

contaminated medical products, or bushmeat.• EVD is fatal in up to 90% cases; around 60% in the current epidemic. This

figure will alter when the epidemic stats to falter.• Experimental antiviral treatment (Zmapp & TKM-Ebola) and vaccine

candidates are under investigation.• Although cases of EVD have been managed outside Africa during this

epidemic in the USA and Spain, no further transmission has occurred outside hospital in these locations to date.

• The international response aims to meet the diagnosis, treatment and infection control demands of the West African Ebola epidemic but is still short of its objectives in high transmission locations.