Viruses & Ebola
What is the treatment of Ebola?
(No proven treatment available) Supportive Therapy: - Rehydration with fluids and treatment of symptoms No effective antiviral drug (yet) - Zmapp: shows promise - Composition: 3 monoclonal antibodies - Targets: main surface protein of Ebola virus - Prevents death if given within 5 days after onset of infection
How long can Ebola survive on surfaces?
- On plastic: 8 days - On stainless steel: 4 days - On Tyvek (used in positive pressure suits): 11 days - In dried blood: 5 days - In liquid blood outside of the body: 14 days
What is the purpose of a capsid?
- accounts for most of the virion's mass - Composed of protein subunits (protomeres) that surrounds the nucleic acid genome - Gives form to the virus
What is the purpose of an envelope?
- composed of lipids, proteins, and carbohydrates - Surrounds the capsid - "Naked virus" = no envelope
What is the transmission of Ebola?
-Direct contact with contaminated blood, feces, secretions, organs, fluids...
Ebola Zaire
-Representative pathogenic human strain -1st Recorded Outbreak: 1976 -Location: Democratic Republic of the Congo (used to be known as "Zaire") - in a village near the Ebola River -Infects: Humans Source: Unknown -Carrier: Fruit bats -Incubation Period: 4-16 days -Fatality rate: ~50% à can vary between 25%-90% (dependent on strain)
How are they different from bacteria?
-Viruses are dependent on host cells to multiply bacteria doesn't -viruses are not susceptible to antibiotics bacteria is susceptible to antibiotics
What are viruses?
-smallest disease causing agent in living organisms -Take over a host cell and using the host cell's resources to make more viruses
What are the clinical symptoms of Ebola?
1-2 days later: § Fever turns into hemorrhagic fever § Severe multisystem syndrome where the overall vascular system is damaged and the body cannot regulate itself. § Vomiting § Diarrhea § Rash § Kidney and liver impairment Day 11(ish): § EXTREME internal and external bleeding § Coagulation abnormalities Day 12(ish) § Continued EXTREME internal bleeding § Neurological complications § Passing out § Seizures § Death Survivors have memory antibodies present for 10 years POST recovery!!
What is the life cycle of a virus?
1. Attachment - Virus binds to ____________________ via receptor molecule on the host cell surface 2. Entry ____________________________________________ 3. Replication - Viral genome is copied (using _____________ _________________) = expression of ___________ 4. Assembly - Viral proteins and genome copies assemble and form viral particles 5. Release - Completed viral particles exit the cell to
What are the biosafety levels of clinical labs?
1. Biosafety Level 1: Low risk microbes - Required: Lab coat, gloves, eye protection as needed - Example organisms researched: E. coli Biosafety Level 2. Agents associated with human disease (pathogenic or infectious organisms) - Required: Restricted area, lab coat, gloves, eye protection, possible face shield - Example organisms researched: HIV, Staphylococcus aureus 3. Biosafety Level 3: Indigenous or exotic microbes, can cause lethal disease through inhalation - Required: Restricted area, locked doors, lab coat, gloves, eye protection, respirators - Example organisms researched: Yellow fever, west nile virus, M. tuberculosis 4. Biosafety Level 4: Rare. Highly dangerous and exotic (fatal) microbes with no known treatment or vaccine. - Required: High security clearance, locked doors, full body positive pressure suits - Example organisms researched: Ebola and Marburg viruses
What different types of nucleic acid can a virus have?
1. Double-stranded DNA (like humans) 2. Single-stranded DNA 3. Double-stranded RNA 4. Single-stranded RNA (like humans)
What are the 3 types of viruses?
1. Icosahedral - Sphere-like - 20 triangular faces - Protomeres ) aggregate in groups of 5 or 6 to form a capsomeres 2. Helical (filamentous) - Rod-like - Protomeres bound in a ribbon-like structure - Folds into a helix 3. Complex (head-tail) - Icosahedral "head" and helical "tail" - Contains all the viruses that do not fit in first 2 groups - Poxvirus and rhabdoviridae
What 2 groups is the Filovirus family separated into?
1. Marburg 2. Ebola
Why should someone vaccine?
1. Prevent the spread of Ebola virus 2. Treat the disease (and not just the symptoms) 3. Provide widespread preventative vaccination of at-risk populations 4. Provide protection to children and those at higher risks of developing the disease 5. Discourage use of Ebola Virus
What is the diagnosis procedure for Ebola
1. Whole blood sample: Taken ≥ 8 days after onset of symptoms 2. Oral swabs: For children - although, not recommended due to lower sensitivity
Who did it infect and what were the symptoms?
100 monkeys
When and where was the first (and second) outbreak?
1st outbreak: 1989 2nd outbreak: 1990, same facility
How do they reproduce?
Can ONLY multiply if they have infected a host cell
What group can be separated further, and into what groups?
Ebola 1. Zaire (Ebola) * * Causes disease in humans (Africa) 2. Sudan * * Causes disease in humans (Africa) 3. Taï Forest * * Causes disease in humans (Africa) 4. Bundibugyo * * Causes disease in humans (Africa) 5. Reston ✚ ✚ Causes disease in monkeys and pigs (Philippines) 6. Bombali ¢ * ¢ Recently identified in bats - unknown if it can cause disease in humans (Africa)
Ebola Virus Family?
Filovirus
What is the flow of transmission?
Fruit bat to Monkeys to Humans
Shape
Helical
How long is a patient contagious with Ebola?
Incubation period: 2-21 days (average 8-10 days)
What are the 3 main components of the structure of a virus?
Nucleic acid + capsid + envelope
Envelope?
Yes
What are the preferred sites of attachment of Ebola?
macrophages and monocytes
What types of Ebola vaccine are being studied right now?
rVSV & ZEBOV
What is the most significant Ebola vaccine currently being studied?How would it be implemented if an outbreak were to occur?
rVSV-ZEBOV would be distributed under a ring vaccination strategy
Nucleic Acid?
single-stranded RNA
How long can Ebola survive outside of the human body AFTER recovery?
• Semen: 18 months -- 1 man tested positive 565 days after he had recovered from the illness • Breast milk: 16 months • Vaginal secretions: 33 days • Urine: 64 days • Dead body: 1 week • Saliva: 22 days • Tears: 28 days • Cerebrospinal fluid: 9 months
