Viral Viral Hemorrhagic Hemorrhagic

FeversFeversThe FilovirusesThe Filoviruses

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VivianVivian

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Ebola Virus Outbreak

Viral Hemorrhagic Viral Hemorrhagic FeversFevers Severe multi-system syndrome Severe multi-system syndrome

(multiple organs affected).(multiple organs affected). Vascular system is damaged and body Vascular system is damaged and body

loses the ability to regulate itself.loses the ability to regulate itself. Accompanied by hemorrhaging.Accompanied by hemorrhaging. Many VHF viruses cause life Many VHF viruses cause life

threatening diseasesthreatening diseases Most have no established treatment or Most have no established treatment or

cure.cure.

VHF Caused by VHF Caused by Viruses of 4 Viruses of 4 FamiliesFamilies ArenavirusesArenaviruses

Filoviruses (Ebola and Marburg)Filoviruses (Ebola and Marburg) Work with filovirus species Work with filovirus species

requires Biosafety Level 4 (BSL-requires Biosafety Level 4 (BSL-4) “space suit” containment 4) “space suit” containment (HIV requires BSL-2 “space (HIV requires BSL-2 “space suit” containment).suit” containment).

BunyavirusesBunyaviruses FlavivirusesFlaviviruses

Features of these VirusesFeatures of these VirusesRNA Viruses, covered in RNA Viruses, covered in lipid coatinglipid coating

Humans are not natural Humans are not natural reservoir, but can transmit reservoir, but can transmit virus virus

Viruses are restricted to Viruses are restricted to areas of their host speciesareas of their host species

MarburgMarburg

Caused by a zoonotic virus Caused by a zoonotic virus of the filovirus family.of the filovirus family.

Mortality Rate 23-25% Mortality Rate 23-25%

First recognized in 1967 when First recognized in 1967 when simultaneous outbreaks occurred in simultaneous outbreaks occurred in Marburg and Frankfurt, Germany, and Marburg and Frankfurt, Germany, and in Belgrade, Yugoslavia.in Belgrade, Yugoslavia.

37 people became ill. The ill were 37 people became ill. The ill were mostly laboratory workers and mostly laboratory workers and medical personnel. medical personnel.

Original people who became ill had Original people who became ill had been exposed to the tissues of been exposed to the tissues of African green monkeys, which were African green monkeys, which were imported from Uganda for research.imported from Uganda for research.

Location:Location:The area to which the virus is native is The area to which the virus is native is unknown, but it is believed to include parts unknown, but it is believed to include parts of Uganda, Western Kenya, and Zimbabwe.of Uganda, Western Kenya, and Zimbabwe.

Transmission Transmission The animal host to the Marburg Virus is The animal host to the Marburg Virus is unknown, and so is the way that the animal unknown, and so is the way that the animal transmits the disease to humans.transmits the disease to humans.

People who have been exposed to infected People who have been exposed to infected monkeys or their body fluids have become monkeys or their body fluids have become infected in the past.infected in the past.

Transmission (continued)Transmission (continued)The disease is easily The disease is easily transmitted between humans. transmitted between humans. Direct contact with an Direct contact with an infected person, or exposure infected person, or exposure to their body fluids, are both to their body fluids, are both ways by which the disease is ways by which the disease is thought to be transmitted.thought to be transmitted.

EbolaEbola Believed to be caused by a zoonotic Believed to be caused by a zoonotic

member of the filovirus family. member of the filovirus family. Believed to be carried by an animal Believed to be carried by an animal host that is native to Africa.host that is native to Africa.

Named after a river in the Democratic Named after a river in the Democratic Republic of Congo in Africa (formerly Republic of Congo in Africa (formerly Zaire) where first outbreak occurred in Zaire) where first outbreak occurred in 1976.1976.

First Ebola outbreak in Zaire (1976)- First Ebola outbreak in Zaire (1976)- 318 Human cases, 88% of those people 318 Human cases, 88% of those people died of the disease. died of the disease.

Great Plague of Great Plague of AthensAthens

529 B.C.529 B.C. Thucydides wrote Thucydides wrote about a disease with about a disease with symptoms that are symptoms that are very similar to Ebola, very similar to Ebola, including:including: High Fever, High Fever,

Vomiting, Chest Vomiting, Chest Pain, Diarrhea, Pain, Diarrhea, ffetid etid breath and a bumpy breath and a bumpy red rash.red rash.

4 Types of Ebola Virus4 Types of Ebola VirusEbola-ZaireEbola-ZaireEbola-SudanEbola-SudanEbola-Ivory CoastEbola-Ivory CoastEbola RestonEbola Reston

All of these strains have been known to cause All of these strains have been known to cause disease in humans, except for Ebola-Reston, which disease in humans, except for Ebola-Reston, which has only caused disease in Non-Human Primateshas only caused disease in Non-Human Primates. .

Electron Micrograph of Ebola Virus

Location:Location: The Ebola The Ebola

Virus has been Virus has been reported in the reported in the Democratic Democratic Republic of Republic of Congo, Gabon, Congo, Gabon, Sudan, the Sudan, the Ivory Coast, Ivory Coast, and Uganda. and Uganda.

Map of Ebola Outbreaks in Africa

Ebola-Reston outbreak at Ebola-Reston outbreak at primate research facility in primate research facility in Virginia. Virus was carried by Virginia. Virus was carried by monkeys that had been monkeys that had been imported from the Phillipines. imported from the Phillipines. 4 humans were infected and 4 humans were infected and

developed antibodies, but developed antibodies, but none of them became sicknone of them became sickMap of Ebola Reston

Infected Monkeys in

Philippines

TransmissionTransmission It is believed that the first human It is believed that the first human

becomes infected with Ebola through becomes infected with Ebola through contact with an infected animal.contact with an infected animal.An outbreak of Ebola-Zaire occurred in An outbreak of Ebola-Zaire occurred in Gabon in 1996 after people had eaten Gabon in 1996 after people had eaten an infected monkey.an infected monkey.

One Scientist who had conducted an One Scientist who had conducted an autopsy on a wild chimpanzee in the autopsy on a wild chimpanzee in the Tai Forest in Ivory Coast was diagnosed Tai Forest in Ivory Coast was diagnosed with Ebola-Ivory Coast in 1994.with Ebola-Ivory Coast in 1994.

People can become infected with Ebola People can become infected with Ebola if they come into contact with the blood if they come into contact with the blood or secretions of an infected person.or secretions of an infected person.

People can also become infected People can also become infected through contact with objects, such as through contact with objects, such as needles, that are contaminated with needles, that are contaminated with secretions or blood. secretions or blood. In 1976, in England, a person became In 1976, in England, a person became infected with Ebola-Sudan after being infected with Ebola-Sudan after being accidentally pricked with a accidentally pricked with a contaminated needle.contaminated needle.

Because the disease is easily Because the disease is easily transmitted, Nurses must wear transmitted, Nurses must wear protective clothing when protective clothing when interacting with a patient and interacting with a patient and must dispose of all needles and must dispose of all needles and other medical supplies other medical supplies properly.properly.

Nurses in full protective gear in Gabon, 2002

Patients who have died of the Patients who have died of the disease must be buried disease must be buried properly. Care must be taken properly. Care must be taken that there is no contact with that there is no contact with the deceased patient.the deceased patient.

Burying Ebola Victim in Gabon, 2002

The Ebola Virus takes a The Ebola Virus takes a psychological toll as well, psychological toll as well, causing devastated villagers to causing devastated villagers to search for scapegoats.search for scapegoats.

Posted, February 21, 2003 8:37 AM ESTPosted, February 21, 2003 8:37 AM EST

Brazzaville, Congo- Congolese villagers Brazzaville, Congo- Congolese villagers have stoned and beaten to death four have stoned and beaten to death four teachers accused of casting an evil spell to teachers accused of casting an evil spell to cause an outbreak of the deadly Ebola cause an outbreak of the deadly Ebola disease that killed nearly 70 people, a disease that killed nearly 70 people, a local official said Friday. (Reuters)local official said Friday. (Reuters)

Relief , joy and celebration Relief , joy and celebration after the Gabonese Health after the Gabonese Health Ministry declares that the Ministry declares that the Ebola outbreak has ended. Ebola outbreak has ended. (May 6, 2002)(May 6, 2002)

PleomorphicPleomorphic Definition: having the ability to Definition: having the ability to

assume different forms or shapesassume different forms or shapes Four main shapes: long filamentous, Four main shapes: long filamentous,

U shaped, 6 shaped, circularU shaped, 6 shaped, circular

• Filoviruses are non-segmented negative strand viruses• Composed of a helical ribonucleoprotein complex(nucleocapsid)• Covered with a host-cell derived membrane envelope• Matrix between the envelope and nucleocapsid is filled with a protein lattice

StructureStructure

Viral GenomeViral Genome

Viral GenomeViral Genome Consists of seven genesConsists of seven genes These genes encode seven proteins in the These genes encode seven proteins in the

Marburg virus and eight in the Ebola Marburg virus and eight in the Ebola virusvirus

Both viruses have a 3’ leader and 5’ Both viruses have a 3’ leader and 5’ trailer sequence that is highly conserved trailer sequence that is highly conserved and has a high degree of complementarityand has a high degree of complementarity

These extragenic seguences are These extragenic seguences are important in the initiation of important in the initiation of transcription and replicationtranscription and replication

Viral ProteinsViral Proteins

NP: Nucleoprotein – the primary NP: Nucleoprotein – the primary structural protein associated with structural protein associated with the filovirus nucleocapsidthe filovirus nucleocapsid

* Ebola virus only

Viral ProteinsViral Proteins

VP35: acts as a cofactor in VP35: acts as a cofactor in transcription and replication of transcription and replication of the viral proteinsthe viral proteins

* Ebola virus only

Viral ProteinsViral Proteins

VP40: a matrix protein, also the VP40: a matrix protein, also the most abundant viral protein; may most abundant viral protein; may facilitate in the budding processfacilitate in the budding process

* Ebola virus only

Viral ProteinsViral Proteins

GP: Glycoprotein – makes up the GP: Glycoprotein – makes up the virion spikes or peplomers and virion spikes or peplomers and mediates entry into host cells mediates entry into host cells through receptor bindingthrough receptor binding

* Ebola virus only

Viral ProteinsViral Proteins

sGP: secreted from the cell, present sGP: secreted from the cell, present in large amounts in the blood of in large amounts in the blood of Ebola victims; may help to inhibit Ebola victims; may help to inhibit the immune response the immune response

* Ebola virus only

Viral ProteinsViral Proteins

VP30 – a minor nucleoprotein VP30 – a minor nucleoprotein that may be involved in securing that may be involved in securing the RNA to the C terminus of NPthe RNA to the C terminus of NP

* Ebola virus only

* Ebola virus only

Viral ProteinsViral Proteins

VP24: unknown function, VP24: unknown function, possibly a matrix proteinpossibly a matrix protein

Viral ProteinsViral Proteins

L: Polymerase L – acts as the L: Polymerase L – acts as the polymerase and is the largest polymerase and is the largest and least abundant viral proteinand least abundant viral protein

* Ebola virus only

Interactions with Interactions with CellsCells

Entrance into CellsEntrance into Cells Mediated by the Glycoprotein on the Mediated by the Glycoprotein on the

envelope surfaceenvelope surface

Structure of GPStructure of GP Precursor form GPPrecursor form GP00 is cleaved yeilding GP is cleaved yeilding GP11

and GPand GP22, they are connected via one , they are connected via one disulfide bonddisulfide bond

Form a heterodimerForm a heterodimer Peplomers are then formed by the Peplomers are then formed by the

association of three of these heterodimers association of three of these heterodimers to form a homotrimerto form a homotrimer

GPGP22 is responsible for trimerization, fusion is responsible for trimerization, fusion of the envelope and cell, and has an of the envelope and cell, and has an immunosuppressive motifimmunosuppressive motif

GPGP11 is the receptor binding domainis the receptor binding domain

Receptor - Lipid Receptor - Lipid RaftsRafts

Receptor, while for most cells unknown, Receptor, while for most cells unknown, appears to be located in LIPID RAFTS : appears to be located in LIPID RAFTS : less fluid areas of the membrane high in less fluid areas of the membrane high in cholesterol and glycosphingolipid; the cholesterol and glycosphingolipid; the cholesterol-binding caveolin is also cholesterol-binding caveolin is also closely associated with the raftsclosely associated with the rafts

EndocytosisEndocytosis Caveolae are present in the plasma Caveolae are present in the plasma

membranes of most cell types and membranes of most cell types and are thought to form from lipid raftsare thought to form from lipid rafts

The major structural protein is The major structural protein is caveolin, a multipass protein caveolin, a multipass protein

Caveolae invaginate and collect Caveolae invaginate and collect their cargo proteins, but do not their cargo proteins, but do not require the assembly of a cytosolic require the assembly of a cytosolic protein coatprotein coat

EndocytosisEndocytosis

TranscriptionTranscription Takes place in cytoplasm of cellTakes place in cytoplasm of cell The seven genes are transcribed to The seven genes are transcribed to

produce seven monocistronic produce seven monocistronic polyadenylated mRNA’spolyadenylated mRNA’s

Each gene has a conserved Each gene has a conserved transcriptional stop and start transcriptional stop and start sequencessequences

Transcripts are thought to have 5’ Transcripts are thought to have 5’ capscaps

Gene overlaps - function unknownGene overlaps - function unknown

Unusual GP Unusual GP TranscriptionTranscription In the Ebola Virus the GP gene codes for GP and In the Ebola Virus the GP gene codes for GP and

sGPsGP sGP is the primary gene productsGP is the primary gene product Full length GP is expressed by transcriptional Full length GP is expressed by transcriptional

editing of a single adenosine at a run of seven editing of a single adenosine at a run of seven uridine residues in the genomic RNAuridine residues in the genomic RNA

TranslationTranslation sGP and GP are sGP and GP are

translated by translated by membrane bound membrane bound ribosomes and enter ribosomes and enter the ER and follow the ER and follow the exocytotic the exocytotic transport route to transport route to the cell surfacethe cell surface

All other viral All other viral proteins are proteins are translated by free translated by free ribosomes in the ribosomes in the cytosolcytosol

ReplicationReplication Build up of proteins Build up of proteins

signals switch to signals switch to replicationreplication

Switch results in Switch results in synthesis of + sense synthesis of + sense RNA as a templateRNA as a template

Depletion of Depletion of proteins causes proteins causes switch back to switch back to transcription, transcription, eventually eventually equilibriumequilibrium

Budding and Budding and ReleaseRelease

Invasion Invasion ProcessProcess

MonocytesMonocytes

Immune SystemImmune System

Immune System Immune System EvasionEvasion

Host dies with little evidence of an Host dies with little evidence of an immune responseimmune response

Mitosis of lymphoid cells seen to Mitosis of lymphoid cells seen to decrease 2-3 days postinfection decrease 2-3 days postinfection with eventual apoptosiswith eventual apoptosis

Swelling of MPS and stromal cells Swelling of MPS and stromal cells and eventual lysisand eventual lysis

Dendritic (antigen-presenting) Dendritic (antigen-presenting) cells also undergo apoptosiscells also undergo apoptosis

Immune System Immune System EvasionEvasion

sGP may bind to neutrophils and sGP may bind to neutrophils and inhibit their activationinhibit their activation

sGP as a decoy? – absorb neutralizing sGP as a decoy? – absorb neutralizing antibodiesantibodies

VP35 may act as an IFN antagonistVP35 may act as an IFN antagonist GPGP22 may have an immunosuppressive may have an immunosuppressive

rolerole Ebola shown to inhibit induction of Ebola shown to inhibit induction of

immunomodulatory and antiviral immunomodulatory and antiviral genes in endothelial cells (MHC I, IFN, genes in endothelial cells (MHC I, IFN, etc…)etc…)

Cytotoxicity,Cytotoxicity, Hemorrhage, and Hemorrhage, and

ShockShock GP expression causes downregulation GP expression causes downregulation of the cell-surface expression of of the cell-surface expression of integrins – cell rounding and integrins – cell rounding and detachment seendetachment seen

Disruption of cell functions in generalDisruption of cell functions in general Release of vasoactive agents Release of vasoactive agents

(cytokines, chemokines, histamines (cytokines, chemokines, histamines and peroxidases) from infected and peroxidases) from infected monocytes and endothelial cells could monocytes and endothelial cells could increase hemorrhaging and induce increase hemorrhaging and induce shockshock

Risk FactorsRisk Factors Travel to Asia or AfricaTravel to Asia or Africa Handling of animal carcassesHandling of animal carcasses Contact with sick animals or Contact with sick animals or

peoplepeople Arthropod bites within 21 days of Arthropod bites within 21 days of

onset of symptomsonset of symptoms Transmission is highest during Transmission is highest during

latter stages of illness.latter stages of illness.

Reservoir UnknownReservoir Unknown Bats?Bats? Birds?Birds? Insects?Insects? Plants?Plants?

Spread of EbolaSpread of Ebola Direct contact with the blood Direct contact with the blood

and/or secretions of an infected and/or secretions of an infected person. (Family setting)person. (Family setting)

Contact with objects, such as Contact with objects, such as needles that have been needles that have been contaminated with infected contaminated with infected secretions. (Health care setting)secretions. (Health care setting)

Ebola InvasionEbola Invasion Effects innate immune system Effects innate immune system

(non-specific responses)(non-specific responses) Enters through broken skin, Enters through broken skin,

mucous membrane or exchange mucous membrane or exchange of bodily fluidsof bodily fluids

Can also enter through ingestion, Can also enter through ingestion, inhalation, injection of infectious inhalation, injection of infectious materialmaterial

Ebola BasicsEbola Basics Incubation period of 2-Incubation period of 2-

21 days21 days Mortality rate of 50-Mortality rate of 50-

90%90% Some primary targets Some primary targets

are hepatocytes and are hepatocytes and endothelial cells, which endothelial cells, which produce the greatest produce the greatest amounts of furin in the amounts of furin in the human bodyhuman body

Stable at room Stable at room temperature but is temperature but is destroyed at 60 destroyed at 60 0 0 C.C.

Also destroyed by Also destroyed by gamma and UV gamma and UV radiation, lipid radiation, lipid solvents, and bleachsolvents, and bleach

Marburg BasicsMarburg Basics Incubation period of Incubation period of

2-14 days2-14 days Mortality rate of 23-Mortality rate of 23-

25%25% Stable at room Stable at room

temperature but is temperature but is destroyed at 60 destroyed at 60 0 0 C.C.

Also destroyed by Also destroyed by gamma and UV gamma and UV radiation, lipid radiation, lipid solvents, and bleachsolvents, and bleach

Unsuspecting VictimUnsuspecting VictimYour eyes are red and itchy. You're Your eyes are red and itchy. You're

feeling a little stuffed up. Your feeling a little stuffed up. Your body aches, and you feel warm.body aches, and you feel warm.

You think you have a case of the flu You think you have a case of the flu coming on. Nothing a few good coming on. Nothing a few good nights' rest won't cure, you think. nights' rest won't cure, you think. The next morning, your head The next morning, your head throbs. Your skin aches. You feel throbs. Your skin aches. You feel feverish, and your chest hurts. You feverish, and your chest hurts. You can't get out of bed.can't get out of bed.

In the new few days, your fever In the new few days, your fever skyrockets. You are disoriented skyrockets. You are disoriented and delirious. You throw up and and delirious. You throw up and notice the vomit is laced with notice the vomit is laced with blood. Next, you feel a liquid blood. Next, you feel a liquid trickle out of your ears. With trickle out of your ears. With horror, you realize that it's more horror, you realize that it's more blood. Soon blood is seeping from blood. Soon blood is seeping from your nose, gums, and eyes. The your nose, gums, and eyes. The pain is excruciating. Inside your pain is excruciating. Inside your body, an army of microorganisms body, an army of microorganisms eats away at your veins and eats away at your veins and arteries and turns your organs into arteries and turns your organs into a sort of bloody cottage cheese. In a sort of bloody cottage cheese. In 36 hours, you're gone. You die in a 36 hours, you're gone. You die in a pool of blood that has oozed out of pool of blood that has oozed out of every part of your body.every part of your body.

Early SymptomsEarly SymptomsThe first signs usually are:The first signs usually are: Prolonged fever that does Prolonged fever that does

not respond to not respond to antimalarial treatment or antimalarial treatment or antibioticsantibiotics

Joint pains and Joint pains and generalized body achesgeneralized body aches

HeadacheHeadache Generalized weaknessGeneralized weakness Nausea and vomitingNausea and vomiting Abdominal pain and Abdominal pain and

diarrheadiarrhea FatigueFatigue ArthritisArthritis Sore throatSore throat RashRash HiccupsHiccups

After 5-7 DaysAfter 5-7 DaysThe fever may get associated The fever may get associated

with spontaneous bleeding with spontaneous bleeding e.g.:e.g.:

Bleeding from the gums, nose, Bleeding from the gums, nose, eyes, earseyes, ears

Eyes may turn red Eyes may turn red (conjunctivitis)(conjunctivitis)

Anal bleeding or bloody Anal bleeding or bloody diarrhea, gastrointestinal diarrhea, gastrointestinal bleedingbleeding

Genital swelling (labia and Genital swelling (labia and scrotum)scrotum)

Bleeding from the skinBleeding from the skin Difficulty in swallowing and Difficulty in swallowing and

dryness of the throatdryness of the throat Increased sense of pain in skin Increased sense of pain in skin Blood does not clotBlood does not clot DepressionDepression Hypotensive shockHypotensive shock Liver damageLiver damage

Treatment for Ebola Treatment for Ebola and Marburgand Marburg

Isolation and quarantineIsolation and quarantine Quick containmentQuick containment No standard treatmentNo standard treatment Supportive therapy, which includes Supportive therapy, which includes

balancing the patient’s fluids and balancing the patient’s fluids and electrolytes, maintaining their oxygen electrolytes, maintaining their oxygen status and blood pressure, and treating status and blood pressure, and treating them for complicating infections.them for complicating infections.

Mechanical ventilation, renal dialysis, Mechanical ventilation, renal dialysis, and antiseizure therapy may be required.and antiseizure therapy may be required.

What is the key to What is the key to survival?survival?

Demise or improvement usually Demise or improvement usually occurs around day 7 to 11, when occurs around day 7 to 11, when humoral antibody response can humoral antibody response can be detected.be detected.

Known that patients who die Known that patients who die usually have NOT developed a usually have NOT developed a significant immune response to significant immune response to the virus at the time of death. the virus at the time of death.

Convalescence and Convalescence and RecoveryRecovery

Slow – takes 5 Slow – takes 5 weeks or moreweeks or more

Can still harbor Can still harbor infectious viral infectious viral particles up to particles up to 82 days after 82 days after presentationpresentation

Weight loss and Weight loss and amnesia in early amnesia in early stages of stages of recoveryrecovery

SurvivorsSurvivors Psychosocial Psychosocial

disturbancesdisturbances Loss of memory Loss of memory Central nervous system Central nervous system

disordersdisorders Loss of hair, hair Loss of hair, hair

elasticity and hair elasticity and hair dryingdrying

Permanent hearing lossPermanent hearing loss ArthralgiaArthralgia UveitisUveitis OrchitisOrchitis

Death and BurialDeath and Burial Villagers traditionally Villagers traditionally

help sick, transport help sick, transport and kiss the deadand kiss the dead

Wash and dress body Wash and dress body for the afterlifefor the afterlife

Burial practices last Burial practices last daysdays

Dead buried near homeDead buried near home Hiding of bodiesHiding of bodies

Clinical Diagnosis of Clinical Diagnosis of EbolaEbola

In early stages, it is difficult to In early stages, it is difficult to diagnose because early diagnose because early symptoms, such as red eyes and a symptoms, such as red eyes and a skin rash, are nonspecific and skin rash, are nonspecific and are similar to other diseases that are similar to other diseases that occur much more frequently.occur much more frequently.

Use RT-PCR and ELISA to Use RT-PCR and ELISA to diagnose Ebola and Marburg.diagnose Ebola and Marburg.

RT-PCRRT-PCR

Enzyme-linked Enzyme-linked immunosorbent assays immunosorbent assays

(ELISA)(ELISA)

Detects early immunoglobuling (Ig) M antibody Detects early immunoglobuling (Ig) M antibody responses to the VHF-causing agentsresponses to the VHF-causing agents

Challenges to Vaccine Challenges to Vaccine DevelopmentDevelopment

In past, rare occurrences of Ebola In past, rare occurrences of Ebola and remote locations of outbreak did and remote locations of outbreak did not favor vaccine development.not favor vaccine development.

Also required industrial support, Also required industrial support, which was not feasible since it was which was not feasible since it was predicted there would be no market predicted there would be no market for the vaccine.for the vaccine.

However, this changed with the However, this changed with the existing threat of bioterrorism. Now existing threat of bioterrorism. Now Ebola is categorized as a ‘List A Ebola is categorized as a ‘List A agent’.agent’.

Ebola Protection Ebola Protection Using Using

ImmunotherapyImmunotherapy Antibody titers against Ebola virus Antibody titers against Ebola virus GPs are detected in patients who GPs are detected in patients who recover. However, serum from recover. However, serum from recovered patients did not recovered patients did not consistently protect against consistently protect against infection or exhibit neutralization of infection or exhibit neutralization of virus replication in cell culture.virus replication in cell culture.

Passive transfer of antibodies in Passive transfer of antibodies in animal models only delays onset of animal models only delays onset of symptoms and does not alter overall symptoms and does not alter overall survival.survival.

Ebola Protection Ebola Protection Using Using

ImmunotherapyImmunotherapy Monoclonal antibodies isolated from bone Monoclonal antibodies isolated from bone marrow of recovered patients confer marrow of recovered patients confer immune protection in a murine model of immune protection in a murine model of Ebola virus infection and in guinea pigs.Ebola virus infection and in guinea pigs.

But it is relatively easy to protect against But it is relatively easy to protect against infection in the mouse model and infection in the mouse model and protection of guinea pigs required a high protection of guinea pigs required a high dose of antibody administered very close dose of antibody administered very close to the time of virus challenge.to the time of virus challenge.

Conclusion: antibodies alone do not Conclusion: antibodies alone do not provide protective immunity in a natural provide protective immunity in a natural context. May not be applicable to humans.context. May not be applicable to humans.

Antiviral TherapyAntiviral Therapy Use of S-adenosyl-L-homocysteine Use of S-adenosyl-L-homocysteine

hydrolase inhibitors.hydrolase inhibitors. The drugs are active The drugs are active in vitroin vitro and and

in mouse and nonhuman primate in mouse and nonhuman primate models.models.

Drugs act through accumulation Drugs act through accumulation of S-adenosylhomocysteine and its of S-adenosylhomocysteine and its selective inhibition of virus selective inhibition of virus methylation reactions.methylation reactions.

Blood TransfusionsBlood Transfusions In 1995 Zaire outbreak, 8 In 1995 Zaire outbreak, 8

patients given blood transfusions patients given blood transfusions from individuals who recovered from individuals who recovered from Ebola.from Ebola.

7 out of 8 patients survived.7 out of 8 patients survived. However, study size was small However, study size was small

and patients were young so and patients were young so actual effectiveness remains actual effectiveness remains unknown.unknown.

Vaccine Vaccine DevelopmentDevelopment

Vaccine made with heat inactivated Vaccine made with heat inactivated virions but level of protection was virions but level of protection was inconsistent. Guinea pigs were inconsistent. Guinea pigs were partially protected in one study and 4 partially protected in one study and 4 out of 5 baboons survived challenge. out of 5 baboons survived challenge.

However, inactivated virions did not However, inactivated virions did not induce sufficient immunity in induce sufficient immunity in hamadryl baboons against a lethal hamadryl baboons against a lethal challenge.challenge.

May not be effective in humans.May not be effective in humans.

Vaccine with eVLPVaccine with eVLP Recently, vaccine developed that is Recently, vaccine developed that is

based on a single or combinations of based on a single or combinations of virus-encoded structural proteins to virus-encoded structural proteins to induce immunity.induce immunity.

After vaccination with eVLP (Ebola After vaccination with eVLP (Ebola virus-like particles), mice developed virus-like particles), mice developed high titers of Ebola virus-specific high titers of Ebola virus-specific antibodies, including neutralizing antibodies, including neutralizing antibodies. The mice were 100% antibodies. The mice were 100% protected from Ebola virus.protected from Ebola virus.

Protective MaterialsProtective Materials Rubber boots which can Rubber boots which can

be disinfected be disinfected Washable trousers over Washable trousers over

the boots the boots Washable jacket or Washable jacket or

blouses with long sleeves blouses with long sleeves which can hold at the which can hold at the wrists wrists

Rubber aprons which can Rubber aprons which can be disinfected or be disinfected or disposed disposed

Two pairs of latex gloves Two pairs of latex gloves for certain manipulations for certain manipulations or rubber gloves (heavy or rubber gloves (heavy duty gloves) duty gloves)

Masks Masks Protective eye wear Protective eye wear

(glasses/goggles) (glasses/goggles) Headgear Headgear

BSL4 Safety ProceduresBSL4 Safety Procedures

BSL ClipBSL Clip

WeaponizationWeaponization

Characterized as “class A” Characterized as “class A” weapons weapons

because of their:because of their:High virulenceHigh virulenceDemonstrated aerosol Demonstrated aerosol infectivity in the laboratoryinfectivity in the laboratory

Ability to cause a state of Ability to cause a state of intense fear and anxiety intense fear and anxiety

Most likely method of attack would Most likely method of attack would be aerosolization of virus into highly be aerosolization of virus into highly infectious particles in the 1-5 infectious particles in the 1-5 micrometer range. (particles remain micrometer range. (particles remain suspended in air)suspended in air)

Although protective measures are Although protective measures are in place to prevent contamination in place to prevent contamination of food and water supplies, it of food and water supplies, it would be impossible to ensure a would be impossible to ensure a constant supply of purified air.constant supply of purified air.

The tremendous surface area of The tremendous surface area of the lungs make them highly the lungs make them highly susceptible to microbial/viral susceptible to microbial/viral infection. infection.

A large scale attack would A large scale attack would seem unlikely, as such an seem unlikely, as such an attack would require correct attack would require correct conditions of wind, conditions of wind, temperature and humidity. temperature and humidity.

Terrorists are much more Terrorists are much more likely to carry out a smaller likely to carry out a smaller attack via a vulnerable attack via a vulnerable ventilation system.ventilation system.

Difficulty in Detection Difficulty in Detection If terrorists were to carry If terrorists were to carry out an attack, it would be out an attack, it would be a week before the first a week before the first cases of illness appeared. cases of illness appeared. (not known if disease is (not known if disease is contagious in incubation contagious in incubation phase)phase)

Even after the illness appeared, it Even after the illness appeared, it would be very difficult to would be very difficult to determine that the illness was determine that the illness was caused by a filovirus because of:caused by a filovirus because of:

The similarity of the early The similarity of the early symptoms of Ebola and Marburg, symptoms of Ebola and Marburg, to those of other diseasesto those of other diseases

The unlikelihood that a case of The unlikelihood that a case of these diseases would occur these diseases would occur outside of Central Africa.outside of Central Africa.

It is during this period (the opening phase of It is during this period (the opening phase of the outbreak) that the possibility of the outbreak) that the possibility of transmission of the disease is greatest. transmission of the disease is greatest.

Family members and health care workers who Family members and health care workers who are treating the diseased person, but do not are treating the diseased person, but do not yet know the nature of their illnesses have an yet know the nature of their illnesses have an extremely high risk of contracting the virus.extremely high risk of contracting the virus.

The Detection of a deliberately caused outbreak The Detection of a deliberately caused outbreak will be based on the detection of an usual will be based on the detection of an usual number of severe illnesses within a short period number of severe illnesses within a short period of time.of time.

Availability of filovirusesAvailability of filovirusesSamples of Marburg and Ebola were Samples of Marburg and Ebola were distributed to many research distributed to many research laboratories after their initial laboratories after their initial outbreaks in the 1960’s and 1970’s. It outbreaks in the 1960’s and 1970’s. It is feared that samples may have been is feared that samples may have been stolen and distributed to wealthy stolen and distributed to wealthy terrorist organizations.terrorist organizations.

Aum Shrinkyo (Japanese cult Aum Shrinkyo (Japanese cult responsible for Sarin gas attack on responsible for Sarin gas attack on Japanese subway) has reportedly Japanese subway) has reportedly attempted to obtain the Ebola virus by attempted to obtain the Ebola virus by sending some of its members down to sending some of its members down to Zaire in the early 1990’s.Zaire in the early 1990’s.

Independent terrorist organizations Independent terrorist organizations may have a sympathizer infiltrate a may have a sympathizer infiltrate a BSL-4 lab with the intent of stealing a BSL-4 lab with the intent of stealing a filovirus sample or they may attempt filovirus sample or they may attempt to purchase it from a scientist to purchase it from a scientist working in the lab.working in the lab.

Attempts are being made to Attempts are being made to improve security at these labs, but improve security at these labs, but detecting the loss of the tiny detecting the loss of the tiny volume of seed material needed to volume of seed material needed to start a new culture is extremely start a new culture is extremely difficult.difficult.

The Soviet Union reportedly took an The Soviet Union reportedly took an active interest in filoviruses and their active interest in filoviruses and their potential for use in bio-weapons.potential for use in bio-weapons.

Soviet laboratories acquired a sample Soviet laboratories acquired a sample of the Marburg Virus after the 1967 of the Marburg Virus after the 1967 outbreak.outbreak.

Research reports published by Research reports published by Russian investigators after the Russian investigators after the collapse of the Soviet Union show a collapse of the Soviet Union show a strong interest in the stability of strong interest in the stability of freeze dried Marburg virus, and its freeze dried Marburg virus, and its aerosol infectivity.aerosol infectivity.

Soviet Scientist Nikolai Ustinov Soviet Scientist Nikolai Ustinov accidentally pricked himself in the accidentally pricked himself in the finger with a syringe that contained finger with a syringe that contained Marburg Virus.Marburg Virus.

Ustinov began to vomit blood, pass Ustinov began to vomit blood, pass bloody black diarrhea, and sweat bloody black diarrhea, and sweat blood from his pores.blood from his pores.

Scientists kept this strain of Marburg, Scientists kept this strain of Marburg, named Strain U , after Ustinov and named Strain U , after Ustinov and processed it into inhalable dust.processed it into inhalable dust.

The strain was extremely potent. The strain was extremely potent. Upon testing, it was found that Upon testing, it was found that

only one to five particles of only one to five particles of Variant U, lodged into the lungs Variant U, lodged into the lungs of a monkey, was almost of a monkey, was almost guaranteed to make the monkey guaranteed to make the monkey crash and die ( It takes 8000 crash and die ( It takes 8000 spores of Anthrax in the lungs spores of Anthrax in the lungs to guarantee death)to guarantee death)

In addition to the sickness and death that it In addition to the sickness and death that it would cause, a filovirus attack would cause would cause, a filovirus attack would cause tremendous disruption of social and tremendous disruption of social and economic activity.economic activity.

Ebola has the benefit (to terrorists) of Ebola has the benefit (to terrorists) of having a reputation for causing horrifying having a reputation for causing horrifying illnesses. illnesses.

Increased anxiety would occur if people Increased anxiety would occur if people were to see the effects of the disease, as were to see the effects of the disease, as well as the full protective gear that law well as the full protective gear that law enforcements officials, doctors, and nurses enforcements officials, doctors, and nurses would be wearing. would be wearing.

Conclusion