ebola virus november 2014- a final update?

04/08/23 Dr. Vaibhav V. Rajhans 1

November 2014

This is a group of viral diseases, apparently zoonotic in nature, with typical hemorrhagic features caused by viruses belonging to two families- Arenavirus and Filovirus

Hemorrhagic manifestations can be seen in other viral diseases also.

Arenavirus and Filovirus have localised distribution in South America and Africa

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Lymphocytic Choriomeningitis [LCM] virus

Junin virus Machupo virus Lassa fever virus

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Filum- thread Size- 80 to 800-1000 nm Two important viruses- Marburg and Ebola These virus are among the most virulent

pathogens known to infect humans, categorized under Bio safety level- 4

Both these virus are included in Class A of Bioterrorism, along with Small pox, Plague etc and other virus causing hemorrhagic fever

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The research on these viruses is still in primitive condition, mostly due to-

Difficulty in field studies in remote areas Sudden and unexpected occurrence of

cases Very brief duration of outbreaks Requirement of High level containment-

BSL 404/08/23 Dr. Vaibhav V. Rajhans 5

First observed in 1967 In Marburg, Frankfurt {Germany} and Belgrade {Yugoslavia} in Laboratory workers.

Source- African green monkeys from Uganda

Person to person transmission Fatality rate in primary cases was 30%,

secondary cases were non-fatal

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Virus was then grown in tissue culture and guinea pigs from blood and tissues of patients

Virus appeared to persist in the body and isolated even after 80 days of onset of illness from semen and anterior chamber of eye

A case of sexual transmission has also been recorded

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This virus is transmitted by direct contact- with the blood, body fluids and tissues of

infected persons Transmission of the Marburg virus also

occurs by handling ill or dead infected wild animals (monkeys, fruit bats)

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In Africa, the Old World fruit bats of the family Pteropodidae, particularly species belonging to the genus Rousettus aegyptiacus are considered natural hosts for Marburg virus.

There is no apparent disease in the fruit bats

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(formerly known as Marburg haemorrhagic fever)

A severe and highly fatal disease Rare, but have a capacity to cause

dramatic outbreaks with high fatality.

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Illness begins abruptly, with severe headache and severe malaise

Many patients develop severe haemorrhagic manifestations between days 5 and 7

fatal cases usually have some form of bleeding, often from multiple sites

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After the first appearance, Marburg virus again appeared in 1975 in South africa [3 cases]

And In 1980 in Kenya [2 cases] And then in the Democratic Republic of

Congo from 1998-2000 and the outbreak in Angola in 2005, both having 80% fatality

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Marburg virus infections can be diagnosed definitively only in laboratories, by•enzyme-linked immunosorbent assay (ELISA);•antigen detection tests;•serum neutralization test;•reverse-transcriptase polymerase chain reaction (RT-PCR) assay•virus isolation by cell culture.

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No specific antiviral treatment or vaccine is available.

The predominant treatment is general supportive therapy

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Avoid pigs becoming infected through contact with fruit bats

Reducing the risk of bat-to-human transmission by wearing gloves and other appropriate protective clothing

avoid any exposure to blood and body fluids and to direct unprotected contact with possibly contaminated environment

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Samples taken from suspected human and animal Marburg cases for diagnosis should be handled by trained staff and processed in suitably equipped laboratories

People who have died from Marburg should be promptly and safely buried.

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Morphologically similar to Marburg virus but antigenically different

First cases noticed in 1976, in Sudan and Zaire [Democratic Republic Of Congo] beside Ebola river

Reservoir of virus or natural course of this virus are still unclear but Fruit bats of the Pteropodidae family are considered to be the natural host of the Ebola virus

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Species nameVirus name (Abbreviation)

Bundibugyo ebolavirus Bundibugyo virus (BDBV; previously BEBOV)

Reston ebolavirus Reston virus (RESTV; previously REBOV)

Sudan ebolavirus Sudan virus (SUDV; previously SEBOV)

Taï Forest ebolavirus Taï Forest virus (TAFV; previously CIEBOV)

Zaire ebolavirus Ebola virus (EBOV; previously ZEBOV)04/08/23 Dr. Vaibhav V. Rajhans 20

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Ebola virus disease (formerly known as Ebola haemorrhagic fever) is a severe, often fatal illness, with a case fatality rate of up to 90%

one of the world’s most virulent diseases Mode of transmission- by direct contact

with the blood, body fluids and tissues of infected animals or people

Severely ill patients require intensive supportive care

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High risk group- health workers, family members and others in close contact with sick people and deceased patients.

Ebola virus disease outbreaks can devastate families and communities, but the infection can be controlled through appropriate protective measures

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Fever (greater than 38.6°C or 101.5°F) Severe headache Muscle pain Weakness Diarrhea Vomiting Abdominal (stomach) pain Lack of appetite

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Symptoms may appear anywhere from 2 to 21 days after exposure to ebolavirus, although 8-10 days is most common.

Some who become sick with Ebola are able to recover. However, patients who die usually have not developed a significant immune response to the virus at the time of death.

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Endothelial cells, mononuclear phagocytes and hepatocytes are the main targets of infection

After infection, a secreted glycoprotein (sGP) known as the Ebola virus glycoprotein (GP) is synthesized

Ebola replication overwhelms protein synthesis of infected cells and host immune defenses.

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The virus then binds to the endothelial cells lining the interior surface of blood vessels

These white blood cells also serve as carriers to transport the virus throughout the entire body to places such as the lymph nodes, liver, lungs, and spleen.

Fever and inflammation ensues

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The cytopathic effect, from infection in the endothelial cells, results in a loss of vascular integrity

And damage to the liver leads to coagulopathy

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1976- Zaire/ DROC- 318- 88% 1979- Sudan- 34- 65% 1994- Gabon- 49- 59% 1995- Zaire/ DROC- 315- 81% 1996- Gabon- 91- 72% 2002- Gabon and Zaire/ DROC- 122- 79% 2005- Cuvett Quest Region- 12- 75%

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The 2014 Ebola outbreak is one of the largest Ebola outbreaks in history and the first in West Africa. It has principally affected four countries in West Africa:

Guinea, Liberia, Sierra Leone and Nigeria

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The World Health Organization, in partnership with the Ministries of Health in Guinea, Sierra Leone, Liberia, and Nigeria reported 13567 suspect cases of EVD, including 7728 laboratory-confirmed cases, and 4960 deaths.

CFR- 64.18 %

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Ref: http://www.cdc.govupdated on 31.10.2014

WHO declared the outbreak an international public health emergency on 8 August 2014

Ram Manohar Lohia Hospital in New Delhi has been designated as a treatment centre for Ebola Virus Disease (EVD) cases in India

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Researchers believe that the first human case of the Ebola virus disease leading to the 2014 outbreak was a 2-year-old boy who died 6 December 2013 in the village of Meliandou, Guéckédou Prefecture, Guinea. His mother, 3-year-old sister and grandmother then became ill with symptoms consistent with Ebola infection and died. People infected by those victims spread the disease to other villages.

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In Guinea- total 1667 cases 1409 cases- laboratory confirmed 1018 deaths In Liberia- Total 6535 clinical cases 2515 cases laboratory confirmed cases 2413 deaths

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Ref: http://www.cdc.govupdated on 31.10.2014

In Sierra Leone Total 5338 cases 3778 laboratory-confirmed cases 1510 deaths

In Nigeria- Total 20 cases 19 laboratory confirmed cases 8 deaths.

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Ref: http://www.cdc.govupdated on 31.10.2014

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http://www.who.int/csr/disease/ebola/maps/en/

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http://www.who.int/csr/disease/ebola/maps/en/

CountryTotal Cases

Laboratory-Confirmed Cases

Total Deaths

Mali 1 1 1

Senegal 1 1 0

Total 2 2 1

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Ref: http://www.cdc.govupdated on 31.10.2014

CountryTotal Cases

Laboratory confirmed Cases

Total Deaths

Nigeria 20 19 8

Spain 1 1 0

United States

4 4 1

Total 25 24 9

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Ref: http://www.cdc.govupdated on 31.10.2014

The outbreaks of Ebola Virus Disease (EVD) in Senegal and Nigeria were declared over on 17 October and 19 October 2014, respectively. A national EVD outbreak is considered to be over when 42 days (double the 21-day incubation period of the Ebola virus) has elapsed since the last patient in isolation became laboratory negative for EVD.

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The Guinean Ministry of Health, the Ministry of Health and Sanitation of Sierra Leone, the Ministry of Health and Social Welfare of Liberia, and the Nigerian Ministry of Health worked with national and international partners to investigate and respond to the outbreak.

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Ebola virus infections can be diagnosed definitively in a laboratory by•Antibody-capture enzyme-linked immunosorbent assay (ELISA) •Antigen detection tests•Serum neutralization test•Reverse transcriptase polymerase chain reaction (RT-PCR) assay•Electron microscopy•Virus isolation by cell culture.

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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.

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An experimental treatment is a combination or cocktail of three monoclonal antibodies that is designed to bind to the protein of the Ebola virus, neutralizing the virus so it can’t do any further damage.

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Reducing the risk of wildlife-to-human transmission from contact with infected fruit bats or monkeys/apes and the consumption of their raw meat

Animals should be handled with gloves and other appropriate protective clothing

Animal products (blood and meat) should be thoroughly cooked before consumption.

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Close physical contact with Ebola patients should be avoided, particularly with their bodily fluids

Gloves and appropriate personal protective equipment should be worn when taking care of ill patients at home

Regular hand washing is required after visiting patients in hospital, as well as after taking care of patients at home.

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Communities affected by Ebola should inform the population about the nature of the disease and about outbreak containment measures, including burial of the dead

People who have died from Ebola should be promptly and safely buried

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On 21 July, three Dwarka, Delhi residents were placed under surveillance after WHO confirmation that one of the passengers on the flight had tested positive for Ebola; however, none of the three had shown any symptoms of the disease

On 8 August, India placed all of its airports on high alert and stepped up surveillance of all travellers entering the country from Ebola-affected regions

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From 9 August, passengers coming from Ebola-affected countries were made to complete a form before landing; the form had a checklist for symptoms and asked travelers from West Africa for information about places visited, length of stay and other important information.

A 24-hour emergency phone helpline is functional. Its numbers are (011)-23061469, 3205

and 1302.

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The estimated 47,000 Indians in the affected countries were contacted by area diplomatic missions and supplied with educational material about the disease.

No confirmed case of EVD has been reported from India until now.

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This deadly outbreak stirred the whole world with the grave consequences of so many deaths.

All we can do is that take all the possible rational effective measures to contain this virulent pathogen and treat those who acquired it, with great care.

Lets hope that this outbreak will end soon as it did in Senegal and Nigeria.

Wish the best to us all.

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http://www.cdc.gov/vhf/ebola/outbreaks/guinea/ http://www.cdc.gov/vhf/ebola/outbreaks/2014-

west-africa/case-counts.html http://www.who.int/csr/don/archive/disease/

ebola/en/ http://www.who.int/csr/disease/ebola/en/ http://en.wikipedia.org/wiki/

2014_West_Africa_Ebola_virus_outbreak#India Ananthanarayan and Paniker’s Textbook of

Microbiology, University press, 9th ed.

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