Ebola virus

Ravi Kanta Mishra

MPH, Third Batch

National Medical College, Birgunj

Ebola virus disease

Introduction

Ebola first appeared in 1976 in 2

simultaneous outbreaks, in Nzara,

Sudan, and in Yambuku, Democratic

Republic of Congo.

The latter was in a village situated near

the Ebola River, from which the disease

takes its name.

Genus Ebolavirus is 1 of 3 members of

the Filoviridae family (filovirus), along with genus

Marburgvirus and genus Cuevavirus. Genus

Ebolavirus comprises 5 distinct species:

Bundibugyo ebolavirus (BDBV)

Zaire ebolavirus (EBOV)

Reston ebolavirus (RESTV)

Sudan ebolavirus (SUDV)

Taï Forest ebolavirus (TAFV).

Natural host of Ebola virus

In Africa, fruit bats, particularly species of the

genera Hypsignathus monstrosus, Epomops

franqueti and Myonycteris torquata, are

considered possible natural hosts for Ebola

virus. As a result, the geographic distribution

of Ebolaviruses may overlap with the range of

the fruit bats.

BDBV, EBOV, and SUDV have been associated with

large EVD outbreaks in Africa,

whereas RESTV and TAFV have not. The RESTV

species, found in Philippines and the People’s

Republic of China, can infect humans, but no illness

or death in humans from this species has been

reported to date.

Transmission

Close contact with the blood, secretions, organs

or other bodily fluids of infected animals.

In Africa, infection has been documented through

the handling of infected chimpanzees, gorillas,

fruit bats, monkeys, forest antelope and

porcupines found ill or dead or in the rainforest.

Transmission…

Ebola then spreads in the community through

human-to-human transmission, with infection

resulting from direct contact (through broken

skin or mucous membranes) with the blood,

secretions, organs or other bodily fluids of

infected people, and indirect contact with

environments contaminated with such fluids.

Transmission…

Signs and Symptoms

EVD is a severe acute viral illness oftencharacterized by

Sudden onset of fever

Joint and muscle aches

Weakness

Stomach pain

Lack of appetite

intense weakness,

headache and sore throat.

This is followed by vomiting, diarrhoea, rash,impaired kidney and liver function, and in somecases, both internal and external bleeding.Laboratory findings include low white blood cell andplatelet counts and elevated liver enzymes.

Some patients may experience:

Red Eyes

Hiccups

Cough

Chest pain

Difficulty breathing

Difficulty swallowing

Bleeding inside and outside of the body

People are infectious as long as their blood and secretions contain the virus. Ebola virus was isolated from semen 61 days after onset of illness in a man who was infected in a laboratory.

The incubation period, that is, the time interval from infection with the virus to onset of symptoms, is 2 to 21 days, 8-10 days is most common.

Diagnosis

Other diseases that should be ruled out

before a diagnosis of EVD can be made

include:

malaria, typhoid fever, shigellosis, cholera,

leptospirosis, plague, rickettsiosis, relapsing

fever, meningitis, hepatitis and other viral

haemorrhagic fevers.

Diagnosis..

Ebola virus infections can be diagnosed definitively in a laboratory through several types of tests:

antibody-capture enzyme-linked immunosorbentassay (ELISA)

antigen detection tests

serum neutralization test

reverse transcriptase polymerase chain reaction (RT-PCR) assay

electron microscopy

virus isolation by cell culture.

Samples from patients are an extreme biohazard risk; testing should be conducted under maximum biological containment conditions.

Vaccine and treatment

No licensed vaccine for EVD is available.

Several vaccines are being tested, but none

are available for clinical use.

Severely ill patients require intensive

supportive care. Patients are frequently

dehydrated and require oral rehydration with

solutions containing electrolytes or

intravenous fluids.

No specific treatment is available. New drug

therapies are being evaluated.

Prevention and Control

How can Ebola infections be prevented ?

There is no vaccine or treatment for Ebola virus

disease.

If you are or have been in a region where an

Ebola outbreak has occurred, take these

precautions.

1. Avoid direct contact with blood, saliva, vomit, urine and other bodily fluids of people with Ebola virus disease or unknown illnesses.

Avoid direct contact with bodies of people who died of Ebola virus disease or unknown illnesses.

Avoid contact with any medical equipment, such as needles, contaminated with blood or bodily fluids.

If you are a health care worker, practise strict infection control measures. This includes isolating infected individuals and using personal protective equipment (gowns, masks, goggles and gloves).

If you are a health care worker, properly use and disinfect instruments and equipment used to treat or care for patients with Ebola—like needles and thermometers—before throwing them out.

2. Avoid close contact with wild animals and

avoid handling wild meat.

Avoid potential carriers, both live and dead,

since both can spread the virus. Potential

carriers of the virus include:

chimpanzees

gorillas

monkeys

forest antelope

pigs

porcupines, and

fruit bats

3. Know the symptoms of Ebola virus

disease and see a health care provider if

they develop.

Seek medical attention immediately if a fever

and any other symptoms arise during or after

travel.

Be sure to tell your health care provider that

you have travelled to a region where Ebola

virus disease was present.

Prevention

1. Controlling Reston ebola virus in domestic

animals

2. Reducing the risk of Ebola infection in people

3. Controlling infection in health-care settings

Case Definition for Ebola Virus Disease

(EVD)

Early recognition is critical for infection control.Healthcare providers should be alert for andevaluate any patients suspected of having EVD.

Person Under Investigation (PUI)

A person who has both consistent symptoms andrisk factors as follows:

1) Clinical criteria, which includes fever of greaterthan 38.6 degrees Celsius or 101.5 degreesFahrenheit, and additional symptoms such assevere headache, muscle pain, vomiting,diarrhea, abdominal pain, or unexplainedhemorrhage; AND

2) Epidemiologic risk factors within the past 21days before the onset of symptoms, such ascontact with blood or other body fluids or humanremains of a patient known to have or suspectedto have EVD; residence in—or travel to—an areawhere EVD transmission is active*; or directhandling of bats, rodents, or primates fromdisease-endemic areas.

Definition…

Probable Case

A PUI who is a contact of an EVD case with either

a high or low risk exposure .

Confirmed Case

A case with laboratory confirmed diagnostic

evidence of ebola virus infection.

Definition..Contacts of an EVD Case

Contacts of an EVD case have different levels of exposure

risk, as follows:

High risk exposures

A high risk exposure includes any of the following:

Percutaneous, e.g. the needle stick, or mucous membrane

exposure to body fluids of EVD patient

Direct care or exposure to body fluids of an EVD patient

without appropriate personal protective equipment (PPE)

Laboratory worker processing body fluids of confirmed

EVD patients without appropriate PPE or standard

biosafety precautions

Participation in funeral rites which include direct exposure

to human remains in the geographic area where outbreak

is occurring without appropriate PPE

Definition…

Low risk exposures

A low risk exposure includes any of the following

Household member or other casual contact1 with

an EVD patient

Providing patient care or casual contact without

high-risk exposure with EVD patients in health

care facilities in EVD outbreak affected countries*

No known exposure

Persons with no known exposure were present in

an EVD outbreak affected country* in the past 21

days with no low risk or high risk exposures.

Epidemiology

Cases of Ebola Hemorrhagic Fever in Africa, 1976 - 2014

Country Town Cases Deaths Species Year

Dem. Rep. of Congo Yambuku 318 280 Zaire ebolavirus 1976

South Sudan Nzara 284 151 Sudan ebolavirus 1976

Dem. Rep. of Congo Tandala 1 1 Zaire ebolavirus 1977

South Sudan Nzara 34 22 Sudan ebolavirus 1979

Gabon Mekouka 52 31 Zaire ebolavirus 1994

Ivory Coast Tai Forest 1 0 Taï Forest ebolavirus 1994

Dem. Rep. of Congo Kikwit 315 250 Zaire ebolavirus 1995

Gabon Mayibout 37 21 Zaire ebolavirus 1996

Gabon Booue 60 45 Zaire ebolavirus 1996

South Africa Johannesburg 2 1 Zaire ebolavirus 1996

Uganda Gulu 425 224 Zaire ebolavirus 2000

Gabon Libreville 65 53 Zaire ebolavirus 2001

Republic of Congo Not specified 57 43 Zaire ebolavirus 2001

Republic of Congo Mbomo 143 128 Zaire ebolavirus 2002

Republic of Congo Mbomo 35 29 Zaire ebolavirus 2003

South Sudan Yambio 17 7 Zaire ebolavirus 2004

Dem. Rep. of Congo Luebo 264 187 Zaire ebolavirus 2007

Uganda Bundibugyo 149 37 Bundibugyo ebolavirus 2007

Dem. Rep. of Congo Luebo 32 15 Zaire ebolavirus 2008

Uganda Luwero District 1 1 Sudan ebolavirus 2011

Uganda Kibaale District 11* 4* Sudan ebolavirus 2012

Dem. Rep. of CongoIsiro Health

Zone36* 13* Bundibugyo ebolavirus 2012

Uganda Luwero District 6* 3* Sudan ebolavirus 2012

Guinea, Sierra Leone,

Liberia, Nigeriamultiple 1176* 660* Zaire ebolavirus 2014*Numbers reflect laboratory confirmed cases only.

Year Country

Ebolavirus

species Cases Deaths Case fatality

2012 Democratic Republic of Congo Bundibugyo 57 29 51%

2012 Uganda Sudan 7 4 57%



2008 Democratic Republic of Congo Zaire 32 14 44%

2007 Uganda Bundibugyo 149 37 25%


2005 Congo Zaire 12 10 83%

2004 Sudan Sudan 17 7 41%

2003 (Nov-Dec) Congo Zaire 35 29 83%

2003 (Jan-Apr) Congo Zaire 143 128 90%

2001-2002 Congo Zaire 59 44 75%

2001-2002 Gabon Zaire 65 53 82%

2000 Uganda Sudan 425 224 53%

1996 South Africa (ex-Gabon) Zaire 1 1 100%

1996 (Jul-Dec) Gabon Zaire 60 45 75%

1996 (Jan-Apr) Gabon Zaire 31 21 68%


1994 Cote d'Ivoire Taï Forest 1 0 0%

1994 Gabon Zaire 52 31 60%

1979 Sudan Sudan 34 22 65%


1976 Sudan Sudan 284 151 53%


Key Facts

Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever, is a severe, often fatal illness in humans.

EVD outbreaks have a case fatality rate of up to 90%.

EVD outbreaks occur primarily in remote villages in Central and West Africa, near tropical rainforests.

The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission.

Fruit bats of the Pteropodidae family are considered to be the natural host of the Ebola virus.

Severely ill patients require intensive supportive care. No licensed specific treatment or vaccine is available for use in people or animals.

Scenerio of Nepal Regarding

EVD

No cases found yet

Establish Health Desk at Tribhuwan International

Airport (From Today)

Referral hospital Sahid Sukraraj Tropical Hospital,

Teku

Isolation ward established at Zonal, Regional

Hospitals

Formally Call Technical Export from WHO by

Health Minister Khag Raj Adhikari

Awareness through Radio ,Television and

Newspaper.

Refrences:

http://www.who.int/mediacentre/factsheets/fs103/en/

http://www.cdc.gov/vhf/ebola/symptoms/

http://www.phac-aspc.gc.ca/id-mi/vhf-fvh/ebola-

prevention-eng.php

http://www.who.int/mediacentre/factsheets/fs103/en/

http://www.cdc.gov/vhf/ebola/symptoms/

http://www.phac-aspc.gc.ca/id-mi/vhf-fvh/ebola-prevention-eng.php

THANK YOU

Ebola virus

Health & Medicine

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