By Abhinay Sharma Bhugoo

EBOLA VIRUSEBOLA VIRUS

Family Filoviridae Genus Ebolavirus History

First emerged in 1976 Ebola River Valley, Africa

Sub-types (well-known)1. Zaire 2. Sudan3. Reston 4. Tai (Ivory Coast)

Classification Enveloped SS negative-sense RNA

Structure Long, filamentous, “thread-like”

structure of a filovirus “U” or “6” appearance

EBOLA VIRUSBRIEF BACKGROUND

• Structure-function analysis of the soluble glycoprotein, sGP, of Ebola virus– Transmembrane protein, GP(1,2)– GP gene encodes the soluble

glycoproteins sGP and Delta-peptide.• Genome has 7 genes:

– NP, VP35, VP40, GP, VP30, VP24, and L

• GP1 Viral Entry• GP2 Fusion and Entry

• Likely pH dependent

EBOLA VIRUS

CURRENTLY BELIEVED ANIMAL RESERVOIR OF EBOLA VIRUS?

• Despite extensive studies, the natural and animal reservoir is unknown– Seems to be the rain forests on the African continent and in the Western Pacific.

• Non-human primates as a source of infection for humans – Carcasses of gorillas, chimpanzees and duikers during outbreaks in 2001 and 2003 – High mortality from infection in these species disqualifies them from acting as reservoirs

• Other considered Reservoirs– Plants, arthropods, and birds

• IRD researchers have identified bats as a potential natural reservoir of Ebola virus – Of 24 plant species and 19 vertebrate species experimentally immunized with Ebola virus,

only bats became infected. • No clinical signs were observed in these bats• This is characteristic of a reservoir species

• Current proposal– Bats

• Good vectors– If bats are among the culprits

• Likely to pass virus to great apes humans

• May infect humans directly– Dry season

• More contact because of food competition

• Bats’ immune systems modified • Virus reproduces easier

• In 2001-03– Survey of 1,030 animals

(including 679 bats) from Ebola-affected areas

– Found three bat species – Viral genome fragments (RNA)

in the liver and spleen – Evidence of immune response

• antibodies against virus in the serum

CURRENTLY BELIEVED ANIMAL RESERVOIR OF EBOLA VIRUS?

• Direct contact

• Blood , secretions , organs

• Unsterilized needles

• Burial ceremonies

• Documented human infections

• Handling of infected chimpanzees, gorillas, forest antelopes

• Airborne transmission

• limited evidence of human-human

• Incubation period

• 2 to 21 days

• Contagiousness

• Not during early stages

• As the illness progresses, bodily fluids represent an extreme biohazard

TRANSMISSION OF EBOLA VIRUS

Initial Signs

• Fever (at least 102°F)

• Weakness & exhaustion

• Pain

• Severe headache

• Muscles & joints

• Abdominal pain

• Sore throat

• Nausea

• Dizziness

Progressed Symptoms • Vomiting• Diarrhea• Extensive bleeding

– Red eyes• hemorrhage of sclerotic arterioles

– From mouth, nose, eyes, rectum & mucouse membranes

• Maculopapular rash – Spreads over the body (often

hemorrhagic)• Other secondary symptoms

– Hypotension , Hypovolemia , Tachycardia

– Organ damage – Internal and external bleeding

SYMPTOMS OF EBOLA VIRUS

• Hemorrhagic fever syndrome• late symptoms:

– toxic shock, hemorrhaging• Direct tissue damage

• liver, combined with massive viremia

• Disseminated intravascular coagulopathy

• Endothelial susceptibility• Subverts innate and adaptive immune

responses • Terminal stages

– diffuse bleeding, and hypotensive

shock accounts for many Ebola virus fatalities

TISSUE DAMAGE LEADS TO HEMORRHAGING

• Specialized laboratory test on blood specimens for detection of

– Antigens– Genes of the virus– Antibodies against the

virus• New techniques

– Non-invasive methods: saliva and urine samples

• Diagnosing• ELISA Assay• IgM ELISA• PCR

DIAGNOSTIC

Courtesy of: http://www.ncbi.nlm.nih.gov

• Infection Prevention– Isolation– communication– Limit direct contact– Monitor those who had lose contact with

infected– Disinfect reusable equipment– Sterilize equipment

• Lab Safety Precautions– Education about organism– Sterile environments– Protective clothing– Proper disposal of waste products– Limit contact with contaminated medical

equipment – Communication

INFECTION PREVENTION AND LAB SAFETY PRECAUTIONS

• One study found that guinea pigs were protected from Ebola virus infection by immunization with plasmids containing the viral genes for either the secreted or transmembrane forms of the viral glycoprotein (GP). This protection was correlated with antibody titer and antigen-specific T-cell responses to secreted GP or membrane GP.

• Another study found that harmless-Ebola-like particles (eVLPs) could confer immunological protection from Ebola virus infection. These eVLPs were found to be immunogenic both in vitro and in vivo. Mice were vaccinated with these eVLPs, and developed high titers of Ebola virus specific antibodies, including neutralizing antibodies. Additionally, all the mice in the study were protected from Ebola virus inoculation.

CURRENT RESEARCH ON VACCINES

• Biological warfare (BW) aka biological weapons, is the use of any pathogen, bacteria or virus as a weapon of war.

• After initial release of virus, secondary infections may occur as a result of infected individuals traveling from areas of contamination to other locations.

• In 1972 the Biological Weapons Convention outlawed creation and storage, but not usage, of these weapons.

BIO-WARFARE

• Benefits of US Aid

- Russian Allies- Collaborative efforts in finding a

cure for Ebola- Decreased Fear- A cut of the profits

• Hazards of US Aid

- VECTOR removed from biowarfare threat list; however, 4 other weapons labs exist with no U.S. inspection

- Difficult to verify whether former Soviet Scientists are using the American supported research for peaceful purposes

- Lack of Accountability

BENEFITS AND HAZARDS OF U.S AID

THANK YOU!