2. Ebola Virus Introduction
• First appeared in Africa 1976
• “African Hemorrhagic Fever”
– acute,mostly fatal disease
– causes blood vessel “bursting”
– systemic (all organs/tissues)
– humans and nonhuman primates
• Excluding ‘2000 outbreak
– 1,500 cases
– over 1,000 deaths
3. Ebola Taxonomy
Scientific Classification
Order: Mononegavirales
Family: Filoviridae
Genus: Ebola like viruses
Species: Ebola
Subtypes
– Ebola-Zaire, Ebola-Sudan,Ebola-Ivory Coast
• disease in humans
– Ebola-Reston
• disease in nonhuman primates
Copyrighted
Dr. Fre:derick A. Murphy, D.V.M., Ph.D. 1976.
4. Filoviridae or “Filoviruses”
• Most mysterious virus group
• Pathogenesis poorly understood
• Ebola
– natural history/reservoirs unknown
– exist throughout the world
– endemic to Africa
– filamentous ssRNA- (antisense) viruses
Image courtesy of the Centers for Disease Control
5. Ebola Pathogenesis
• Enters Bloodstream
– skin, membranes,open wounds
• Cell Level
– docks with cell membrane
• Viral RNA
– released into cytoplasm
– production new viral proteins/ genetic
material
• New viral genomes
– rapidly coated in protein
– create cores
Copyright: Russell Kightley Media, Australia
6. Ebola Pathogenesis, cont
• Viral cores
– stack up in cell
– migrate to the cell surface
– produce trans-membrane proteins
– push through cell surface
– become enveloped by cell membrane
• ssRNA- Genome Mutations
– capable of rapid mutation
– very adaptable to evade host defenses and environmental change
• Theory
– virus evolved to occupy special niches in the wild
7. Symptoms and Diagnostic Tests
• Early symptoms
– muscle aches, fever, vomiting
– red eyes, skin rash, diarrhea, stomach pain
• Acute symptoms
– bleeding/hemorrhaging from skin, orifices, internal organs
• Early Diagnosis
• very difficult
• signs & symptoms very similar to other infections
• Laboratory Test
• PCR detection
• ELISA (enzyme-linked immuno-absorbant) assay
8. Treatment
• No Standard Treatment available
• Patients receive supportive therapy
• treating complicating infections
• balancing patient’s fluids and electrolytes
• maintaining oxygen status and blood pressure
9. Prevention
• No vaccines!
• Patients are isolated
• Medical Staff Training
– western sanitation practices
• intake
• care during stay
• after patient dies
• Infection-control Measures
– complete equipment and area sterilization
10. Prevention
After Death
Virus contagious in fluids for days
• Burial use extreme caution
– handling and transport
– cultural practices/ religious belief
– incinerate all waste !!!!
11. Ebola Epidemiology
• Reservoirs in Nature
– largely unknown
– possibly infected animals (primates?)
• Transmission
– direct contact blood/secretions of infected person
– possible airborne (Reston primate facility)
• Onset of illness abrupt
– incubation period: 2 to 21 days
– infections are acute and mostly deadly
12. Latest Morbidity and Mortality Reports
• Ebola-Reston Virus Infection Among Quarantined
Nonhuman Primates -- Texas, 1996
– report describes death and blood testing of cynomolgus
monkey imported from the Philippines held in a private
quarantine facility in Texas
• Outbreak of Ebola Hemorrhagic Fever ---Uganda,
August 2000--January 2001
– report describes surveillance and control activities
related to the EHF outbreak
– presents preliminary clinical and epidemiologic findings
13. Current Basic Research
• The assembly of Ebola virus nucleocapsid requires virion-associated
proteins 35 and 24 and posttranslational
modification of nucleoprotein
• Report describes distinct VP35 and VP24 proteins mechanism of
regulation for filovirus assembly
• suggests new approaches for viral therapies and vaccines for Ebola
and related viruses
• Detection of antibodies against the four subtypes of Ebola
virus in sera from any species using a novel antibody-phage
indicator assay
• assesses the presence of specific antibodies in serum
• describes development of a novel assay for the detection of
seroconversion irrespective of Ebola virus subtype or animal
species
14. References
• Reemergence of Ebola Virus in Africa; Anthony Sanchez et al,EID Volume 1 * Number 3 July-September 1995
http://www.cdc.gov/ncidod/EID/vol1no3/sanchez.htm
• Viral Hemorrhagic Fever, Healthlink, Medical College of Wisconsin, 2000
http://healthlink.mcw.edu/article/955159073.html
• Isolation and Phylogenetic Characterization of Ebola Viruses Causing Different Outbreaks in Gabon
Emerging Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention ,February 5, 1997
http://www.cdc.gov/ncidod/EID/vol3no1/courbot2.htm
• Hemorrhagic fevers; Julia Barrett, Gale Encyclopedia of Medicine, Gale Research, 1999
http://www.findarticles.com/cf_dls/g2601/0006/2601000652/p1/article.jhtm
l
Key Issues in the Prevention and Control of Viral Hemorrhagic Fevers Clarence J.Peters, MD, Special Pathogens Branch/Division of Viral and
Rickettsial Diseases, National Center for Infectious Diseases/Centers for Disease Control and Prevention, 1997
http://www.cdc.gov/od/ohs/sympsium/symp43.htm
• Scientific Stock Images Library; Russell Kightley Media,Australia
http://www.rkm.com.au/imagelibrary/index.html
• Outbreak of Ebola Hemorrhagic Fever ---Uganda, August 2000--January 2001,
Morbidity and Mortality Weekly Report, Vol 50, No 05;73, 02/09/2001 / 50(05);73-7
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5005a1.htm
• Ebola-Reston Virus Infection Among Quarantined Nonhuman Primates -- Texas, 1996
Morbidity and Mortality Weekly Report, Vol 45, No 15;314 ,April 19, 1996 / 45(15);314-316
http://www.cdc.gov/mmwr/preview/mmwrhtml/00040920.htm
The assembly of Ebola virus nucleocapsid requires virion-associated proteins 35 and 24 and posttranslational modification of nucleoprotein, Huang
Y et al, Mol Cell. 2002 Aug;10(2):307-16. PMID: 12191476 [PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12191476&dopt=Abstract
Detection of antibodies against the four subtypes of ebola virus in sera from any species using a novel antibody-phage indicator assay.; Meissner F
et al , PMID: 1235035
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12350354&dopt=Abstract
Editor's Notes
(monkeys, gorillas,chimpanzees)
biosafety level 4 agents because of the extreme pathogenicity of certain strains and the lack of a protective vaccine or effective antiviral drug
Examples of coiled virions are shown in the background.
The core of the Ebola protein thought to mediate membrane fusion
Nosocomial transmission(spread of a disease within a health-care setting,
Non disposabel needles or syringes:they, or may not have been sterilized, but only rinsed before reinsertion into multi-use vials of medicine.
lack of protective clothing
contact with contaminated objects
improper sterilization of medical equipment
Medical Resources scarce Africa
Handling and transport
protective clothing
body sealed in body bag and coffin
sanitation of all equipment before and after
risk for exposure special steps need to be taken to protect the family and community from illness.
family only
why open casket not possible
some practices cannot be done