Marburgviruses and Ebolaviruses – History, Fiction, and the Facts

MIT Faculty Dinner Series on Biosecurity

September 29, 2005

Jens H. Kuhn

The Media and Public Perception

The Preston-“Outbreak” Scenario1. An ebolavirus emerges in Africa and is imported

into the U.S. by its monkey host or a sick patient

2. The virus is highly contagious, spreads quickly and infects thousands of people en route

3. The infections are characterized by “crashing” patients with liquefying organs; patients die from extensive blood loss

4. The military acquires the virus and builds the “perfect biological weapon”

Phylogeny, Endemicity, Human and Animal Case Numbers

Filovirus Hosts, Transmission, Clinical Presentation, and Treatment

Initiation of coagulation cascade

Activation of antioxidation

systems (decrease of

malonic dialdehyde amount

on day 3) and follow ing

exhaustion

Development of lethal coagulation disorders (decrease of prothrombin index, bleeding, sporadic hemorrhages in internal organs)

Consumption of blood platelets on day 7-9

Activation of f ibrinolytic system (appearance of

paracoagulation products in plasma on day 5-9)

Non-adequate presentation of Zaire

Ebola virus antigens to T lymphocytes

Breach of kidney functions (rise of

blood urea level and beta-lipoproteids amount on day

7-9 )

Strengthening of lipid peroxidation (raise of malonic dialdehyde amount on day 5-6)

Activation of B lymphocytes (single

mitoses in lymphoid cells in the blood on day 3)

Release of TNF-

alpha and other

cy tokines into

blood

Ac

tiva

tion

of b

on

e m

arro

w c

ells

Export of juvenile thrombocytes on

day 5-9

Export of juvenile

granulocytes on day 5-9

Zaire Ebola virus

on neutrophils

Decrease of lymphocyte

amount in blood and lymph nodes

on day 5-7

Breach of phagocytic

mechanisms of neutrophils

Necroses in liver and breach of its

functions (raise of sGOT and sGPT

activities on day 5-9)

Reproduction in macrophages

Release of toxic products into the

blood

Damage of tissues and cells

(endotheliocy tes)

Reproduction in liver

M

Export of juvenile

lymphocytes on day 3-9

Reproduction in endotheliocytes and fibroblasts

Imm

un

olo

gic

al d

iso

rders

Сo

ag

ula

tion

dis

ord

ers

Sig

ns o

f

hep

ato

ren

al

syn

dro

me

Export of eosinophils

on day 9

Suppressive factor settling on neutrophils (sGP?)

Imbalance of cytokine amount

in blood

Apoptosis of cells

Production of antibodies capable to

form immune complexes

Settling of immune complexes on different tissues and cells :

on lymphocyteson liver cells

on kidney cells on platelets

Production of autoantibodies with

great potential to destroy cells

B

T

Breach of neutrophil-macrophage interaction

on macrophages

Breach of macrophage

functions

Generalized destruction of macrophages

Pathogenesis

Filovirus Particle Characteristics

RNA

L

NP

VP35

VP40 VP30

Membrane

VP24

GP1,2

?

Molecular Biology

OR

GP VP30

IRIR

VP40

3‘-HO

NP VP35

IR

l

IR1

IR

t

19,104

P -5‘

LVP24

Biosafety and Biosecurity Classification

Preston and “Outbreak“ RevisitedTrue Filoviruses are endemic in

Africa and could be imported

False Primates are filovirus hosts Filoviruses are very

contagious Filoviruses are very stable

entities Hemorrhages and liquefying

organs are typical symptoms

Filoviruses are perfect biological weapons

The Media and Professional Perception

The Alibek Scenario

The Soviet KGB acquires marburgviruses covertly by recovering corpses of the 1967 marburgvirus disease outbreak in Germany

Military work begins immediately to create powerful bioweapons

A laboratory accident provides extremely virulent “strains U and V“

At the end of the 1980s, “chimeras“ of these strains and variola virus are created

12

Soviet Filovirus Research

Some Publications of Concern Volchkov V. E., et al. (2001) Recovery of Infectious Ebola Virus from

Complementary DNA: RNA Editing of the GP Gene and Viral Cytotoxicity. Science 291: 1965-1969

Towner J. S., et al. (2005) Generation of eGFP expressing recombinant Zaire ebolavirus for analysis of early pathogenesis events and high-throughput antiviral drug screening. Virology 332: 20-27

Vorontsova L. A. (1992) Electron microscopic studies of Marburg virus and pathological changes in animal organs caused by this virus. Dissertation to obtain the degree Candidate of Biological Science. SCRVB "Vector" Russia

Zelenkov V. N., et al. (1990) Cultivating Marburg virus on Vero cell monolayers treated with 1-chloromethylsilatran and 1-etoxysilatran. In: Biological activity of compounds containing silicon, germanium, and tin. Abstract collection of the 4th All-Union conference, June 12 - 14, U.S.S.R. Academy of Sciences, Irkutsk Institute of Organic Chemistry, U.S.S.R., pp 6

Frolov V. G. (1994) Study of the factors determining stability and dynamics of thermoinactivation of Marburg virus in freeze-dried media. Development of an "accelerated storage" test for prediction of Marburg virus activity during long-term storage. Dissertation to obtain the degree Candidate of Technological Science. SRCVB "Vector“, Russia

Alibek Revisited

True Soviet laboratory

infection provided opportunity to characterize new filovirus strain

False KGB acquired

filoviruses All filovirus research

was classified Strains U and V were

basis of developed Soviet bioweapons?

Filovirus chimeras were created at the end of the 1980s

Summary

Overall human filovirus infection case numbers and their properties should make these viruses a low research priority (HIV-1, TB!)

Filoviruses are interesting bioweapon candidates for state-sponsored programs because of new possibilities for manipulation developed in the West in recent years

However, manipulation of filoviruses demands highly skilled researchers. The development of an efficient filovirus bioweapon still requires overcoming major obstacles such as instability and ineffective transmission