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Dr. Sonu kumari Agrawal PGIMER, CHANDIGARH

• Introduction

• History

• Epidemiology

• Current outbreak

• Mode of transmission

• Replication

• Pathogenesis

• Diagnosis

• Prevention

• Animal models

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Ebola virus is pathogen of viral haemorrhagic fever

causing severe disease and high case-fatality rates

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Nearly 40 years ago

Belgian scientist travelled to a remote part of the Congolese rainforest

Unknown and terrifying disease

September 1976

Institute of Tropical Medicine Antwerp

Electron Microscope

MARBURG VIRUS

YAMBUKU

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Group: Group ss RNA

Order : Mononegavirales

Family: Filoviridae

Genus: Ebola virus

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• Shape of a shepherd's crook or in the shape of a " U" or a " 6" and they may be coiled or branched

• Linear non-segmented, single-stranded RNA Virus

• 80 nm in width , but vary some what in length

Structure of Ebola genome and proteins -

• 7 structural and 1 nonstructural

• 7 structural proteins -

• Nucleoprotein (NP)

• 4 viral/virion proteins (VP35, VP40, VP30, VP24)

• Glycoprotein (GP)

• RNA-dependent RNA polymerase (L protein)

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Mortality rate

ZEBOV 60-90%

SEBOV 40-60%

BEBOV 20-30%

CIEBOV 0%

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First cases of filovirus haemorrhagic fever - 1967 Germany and the former Yugoslavia - Marburg virus

In northern Zaire, now Democratic Republic of the Congo (DRC) -1976

EBOLA VIRUS

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2005 Congo Zaire 12 10 83%

2007 DRC Zaire 264 187 71%

2007 Uganda Bundibugyo 149 37 25%

2008 DRC Zaire 32 14 44 %

2011 Uganda Sudan 1 1 100%

2012 Uganda Sudan 24 17 71%

Year Coutry Ebola Species

Cases Death CFR

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Initial outbreak in Guinea

His mother 3 year-old sister Grandmother

Two people -carried the disease to their village

Funeral

March - dozens of people were dead in eight Guinean villages

killed 23 35 cases

A 2-year-old boy died

6 December 2013- Guéckédou, Guinea

15 March 2014 WHO reported that the Ministry of Health of Guinea

86 suspected cases

59 deaths

23 May

23 April , confirmed cases -242

142 deaths

23-27 May ,2014 Boffa, Télimélé, Boke and Dubrék

Mid- Jun e

25 July

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8 August , 2014

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What in the world is Zaire ebolavirus doing in West Africa, far from its usual haunts in Central Africa?

why no Ebola virus has ever been seen before?

before?

Why now?

Exposures related to Hunting and consumption of fruit bats

Poor Economy

To stay alive - to find wood to make charcoal and deeper into mines to extract minerals -Risk of exposure to Ebola virus

• Neglected health-care facility where a supply of gloves, clean needles, and no disinfectants

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• Bats are considered the most likely natural reservoir of the EBOV

• Bats were known to reside in the cotton factory in which the first cases for the 1976 and 1979 outbreaks were employed

• The absence of clinical signs in these bats is characteristic of a reservoir species

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• A wide range of hosts were infected with ebola bats

• They got infected, replicated virus, and survived infection

• Detect anti-Ebola virus antibodies and Ebola virus RNA in fruit bat species

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Could Zaire ebola virus have been recently introduced into Guinea from Central Africa?

Introduction from a human traveler seems Unlikely

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• 45,000 Indians in the affected countries – At risk

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of the ebola virus

Health care worker

Contacts & family member

Mourners who have direct contact with bodies

Parenteral injection was the primary mode of administering nearly all medicines

disseminated into the surrounding villages serviced by YMH

the index case, a 44 year-old male teacher at the Mission School, sought medical intervention for a febrile illness he thought to be malaria

parenteral injection of chloroquine (an anti-malaria drug) from Yambuku Mission Hospital (YMH)

YMH did not use disposable needles or sterilize the needles

On September 1, 1976, four days after returning from a tour of northern Zaire

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Direct contact with blood or bodily fluids from an infected person

contact with contaminated medical equipment, particularly needles and syringes

No Airborne transmission

Bats drop partially eaten fruits and pulp

Then land mammals such as gorillas ,chimpanzees and duikers feed on these fallen fruits

Not entirely clear how Ebola is spread

Natural host of Ebola virus -

fruit bats - species of the genera Hypsignathus monstrosus,Epomopsfranqueti and Myonycteris torquata

10 % Health care worker affected

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• Incubation period: 2-21 days • Stage I (unspecific): Extreme asthenia (body weakness) Diarrhea, nausea and vomiting, anorexia Abdominal pain Headaches , arthralgia, myalgia ,Back pain Mucosal redness of the oral cavity, dysphagia , conjunctivitis Rash

• Stage II (Specific): Hemorrhage - Anuria , Tachypnea

• Late Complications: (>2 weeks after onset)

Shock, convulsions Migratory arthralgias Ocular disease (unilateral vision loss, uveitis) Orchitis, suppurative parotitis Pericarditis Illness-induced abortion among pregnant women

Petechiae, ecchymoses, uncontrolled oozing from venepuncture sites, mucosal haemorrhages -30 to 40%

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Differential diagnosis

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Clinical feature Laboratory Diagnosis

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• suspected - (alive or dead person with fever and at least

• three additional symptoms, or fever and a history of contact with a person with hemorrhagic fever or

• a dead or sick animal, or unexplained bleeding)

• Probable - meets the suspected case definition

• and has an epidemiologic link to a confirmed or probable case

• Confirmed -

• suspected or probable case that also has laboratory confirmation

.

Category A Diseases/Agents

Category B Diseases/Agents

Category C Diseases/Agents

High-priority agents include organisms that pose a risk to national security because they can be easily disseminated or transmitted from person to person result in high mortality rates and have the potential for major public health impact might cause public panic and social disruption require special action for public health preparedness.

Second highest priority agents include those that are moderately easy to disseminate; result in moderate morbidity rates and low mortality rates; and require specific enhancements of CDC's diagnostic capacity and enhanced disease surveillance

Third highest priority agents include emerging pathogens that could be engineered for mass dissemination in the future because of availability; ease of production and dissemination; and potential for high morbidity and mortality rates and major health impact.

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Category A Category B Category C

•Anthrax (Bacillus anthracis)

•Botulism (Clostridium

botulinum toxin)

•Plague (Yersinia pestis)

•Smallpox (variola major)

•Tularemia (Francisella

tularensis)

•Viral hemorrhagic fevers

Marburg]and arenaviruses

[e.g., Lassa, Machupo])

Brucellosis (Brucella species) Epsilon toxin of Clostridium perfringens Food safety threats (e.g., Salmonella species, Escherichia coli O157:H7, Shigella) Glanders (Burkholderia mallei) Melioidosis (Burkholderia pseudomallei) Psittacosis (Chlamydia psittaci) Q fever (Coxiella burnetii) Ricin toxin from Ricinus communis (castor beans) Staphylococcal enterotoxin B Typhus fever (Rickettsia prowazekii) Viral encephalitis (alphaviruses [e.g., Venezuelan equine encephalitis, eastern equine encephalitis, western equine encephalitis]) Water safety threats (e.g., Vibrio cholerae, Cryptosporidium parvum)

Emerging infectious diseases such as Nipah virus and hantavirus Category Definitions

EBOLA VIRUS

Risk Group 4 pathogens

Biosafety level -4 containment

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Triple packaging using absorbent material With cold chain

•Institute Pasteur, the European Mobile Laboratory • CDC in Guinea •the Kenema Government Hospital Viral Hemorrhagic Fever •Laboratory in Sierra Leone • Liberia Institute of Biomedical Research

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Sample

Timeline of Infection Diagnostic tests available

Within a few days after symptoms begin •Antigen-capture enzyme-linked

immunosorbent assay (ELISA) testing

•IgM ELISA

•Polymerase chain reaction (PCR)

•Virus isolation

Later in disease course or after recovery •IgM and IgG antibodies

Retrospectively in deceased patients Immunohistochemistry testing PCR Virus isolation

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Serology

IgM anti-bodies can appear as early as two days post onset of symptoms and disappear between 30 and 168 days after infection

IgG-specific antibodies develop between day 6 and 18 after onset and persist for many years

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v

Virus isolation

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Cell line – VeroE6 and MA104

Cells were observed for cytopathic effect for 2 weeks

Causes lytic infections in cell culture

All cell cultures were tested for viral antigen by immunofluorescent

Molecular method

RT-PCR specific for a 419-bp region of the L gene of the filoviruses

A confirmatory RT-PCR was performed on the filovirus-positive samples to amplify a 428-bp region of the EBOV NP

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Other test

• Thrombocytopenia <150,000 cells/µL

• ALT, AST

• Coagulation profile

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Present treatment strategies are mainly symptomatic

and supportive

Hydrating the patient, maintaining their oxygen status and blood pressure and treating them for any complicating infections

On isolation of patients

use of strict barrier nursing procedures

Is there any role of Ribavarin in Ebola?

No in-vitro or in-vivo effect on filoviruses

severe adverse effects associated with the drug

Ribavirin is not recommended for Ebola virus infections

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What drugs exist to combat the disease?

Combines two different serums made by two different companies San Diego firm Mapp Biopharmaceutical & ZMAb ( Canadian company Defyrus Inc)

August 2013, Mapp Biopharmaceutical -working with the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID)

Biological weapon

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In June 2012, Defyrus tested ZMAb in Rhesus Macaques -100% of infected monkeys survived (24hr) & 50% survived when treated 48 hours after exposure

Before ZMapp could begin human trials and get approval from the U.S. FDA

Ebola outbreak began in Guinea

The next challenge was producing enough MB-003 for an effective dose.Antibodies could be grown inside genetically engineered Nicotiana Benthamiana (Australian tobacco plant)

Testing the MB-003 serum on monkeys

43% of the infected monkeys survived

Inject Ebola into mice, and extract three types of antibodies that fight different parts of the virus

spliced in human DNA to produce chimera antibodies acceptable to humans

MB-003

Two American missionary workers infected with Ebola (Kent Brantly and Nancy Writbol)

ZMapp were given Improved

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TKM-Ebola is an exprimental drug for Ebola disease

Developed by Tekmira Pharmaceuticals Corp

Small interfering RNAs targeting three of the seven proteins in Ebola virus: L polymerase membrane-associated protein (VP24), and (VP35) – phase 1 trial

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Standard precaution measures

Vaccine

• Active case identification and isolation of patients

• Identifying contacts of ill or deceased persons and tracking the contacts daily for the entire incubation period of 21 days

• Investigation of retrospective and current cases to document all historic and ongoing chains of virus transmission

• Identifying deaths in the community and using safe burial practices

• Daily reporting of cases

• Education of health-care workers -appropriate use of personal protective equipment

The aim - to avoid contact with the blood or secretions of an

infected patient

Direct contact with the body of the deceased patient should be avoided

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• Practice careful hygiene

• Avoid contact with blood and body fluids

• Do not handle items that may have come in contact with an infected person’s blood or body fluids

• Avoid funeral or burial rituals that require handling the body of someone who has died from Ebola

• Avoid contact with animals and raw meat

• Avoid hospitals where Ebola patients are being treated

• After you return, monitor your health for 21 days and seek medical care immediately if you develop symptoms of Ebola

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Hand Hygiene

• Perform hand hygiene immediately after removing PPE. – If hands become visibly contaminated during PPE removal, wash hands before continuing to

remove PPE

• Wash hands with soap and water or use an alcohol-based hand rub

PPE Use in Healthcare Settings

* Ensure that hand hygiene facilities are available at the point needed, e.g., sink or alcohol-based hand rub

PPE Used in Healthcare Settings

Gloves – protect hands

Gowns/aprons – protect skin and/or clothing

Masks and respirators– protect mouth/nose

Goggles – protect eyes

Face shields – protect face, mouth, nose, and eyes

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Key Points About PPE

Before contact with the patient - generally before entering the room

Use carefully – don’t spread contamination

Remove and discard carefully, either at the doorway or immediately outside patient room

Remove respirator outside room

Immediately perform hand hygiene

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Sequence for Donning PPE

Gown first

Mask or respirator

Goggles or face shield

Gloves

Sequence for Removing PPE

• Gloves

• Face shield or goggles

• Gown

• Mask or respirator

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Public Health Agency of Canada (PHAC) has donated up to 1000 doses of its experimental VSV-EBOV candidate

Consists of transgenic vesicular stomatitis virus that expresses the Ebola glycoprotein

The vaccine, which has only been tested in animals, protected 100% of macaques when administered 21 days before an otherwise fatal infection

when administered immediately after exposure to Ebola: when it was given to primates 30 minutes after inoculation with the virus - four out of eight survived

NIH and GlaxoSmithKline

A recombinant adenovirus that expresses the glycoproteins of two different strains of Ebola virus

100% protection when used prophylactically in primates

phase 1 trials

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Objectives of Epidemic Preparedness and Response

1. Anticipation/prediction • so that epidemics be prevented

2. Early detection • to know when there is a

problem

3. Rapid Response

• guidelines/trained staff/supplies

• in place before epidemic

4. Effective Response

• appropriate control methods

• adequate resources and logistics

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Outbreak Detection and Response

Without Preparedness

Delayed

Response

DAY

CASES Opportunity

for control

Late

Detection

First

Case

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Outbreak Detection and Response

With Preparedness

Rapid

Response

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CASES

Early

Detection

Potential

Cases Prevented

Components of Epidemic Preparedness

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No need to panic

"put in operation the most advanced surveillance and tracking systems" for the hemorrhagic virus

The government is setting up centres at airports and ports to deal with travellers showing any potential symptoms of Ebola, spread through close contact with bodily fluids of people who who are sick.

All air passengers arriving in India from Ebola-affected countries must now fill in a symptom-checklist form and provide addresses as the government builds a database to track people who might develop symptoms.

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Syrian golden hamster

Mice

Guinea pig

Cynomolgus monkey

African green monkeys

Baboons

Be

Prepared !