Ebola is a virus which causes rare but deadly disease Ebola virus disease (EVD) or Ebola
hemorrhagic fever (EHF) which is a disease of humans and other primates. Symptoms start two days to three weeks after contact with the virus. Symptoms area fever, sore throat, muscle pain, and headaches. Typically nausea, vomiting, and diarrhea follow, along with decreased functioning of the liver and kidneys. Around this time, affected people may begin to bleed both within the body and externally.
Ebola’s natural reservoir is unknown.Non human primates have been the source of human infections but are not thought to be the reservoirs.
Ebola Taxonomy or Scientific Classification
Genus: Ebola like viruses
Ebola-Zaire, Ebola-Sudan,Ebola-Ivory Coast-disease in humans
Ebola-Reston-disease in nonhuman primates
Filoviridae or “Filoviruses”
• Most mysterious virus group
• Pathogenesis poorly understood
– Natural history/reservoirs unknown
– Exist throughout the world
– Endemic to Africa
– Filamentous ssRNA– (antisense) viruses
Named after the Ebola River in the Democratic Republic of the Congo (formerly Zaire), near the first epidemics.
Two species were identified in 1976:
- Zaire ebolavirus (ZEBOV)
- Sudan ebolavirus (SEBOV)
Case fatality rates of 83% and 54% respectively.
A third species, Reston ebolavirus (REBOV), was discovered in November 1989 in a group of monkeys (Macaca fascicularis) imported from the Philippines.
Ivory Coast ebolavirus – Only one case. Unlucky scientist.
Outbreaks of EBOLA
Most Recent Incident
April 25 – June 16 2005 total of 12 cases including 9 deaths were reported in Etoumbi and Mbomo in the Cuvette Quest Region
• Enters Bloodstream
– Skin, membranes, Open wounds
• Cell Level
– Socks with cell membrane
• Viral RNA
– Released into cytoplasm
– Production new viral proteins/ genetic material
• New viral genomes
– Rapidly coated in protein
– Create cores
• 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
– Virus evolved to occupy special niches in the wild
Modes of Transmission
There are 3 modes of infection
- Unsterilized needles
- Suboptimal Hospital conditions
- Personal contact
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
– Onset of fever.
– Intense weakness.
– Vommitting, Diarrhoea.
– Impaired Kidnay and liver function
• Early Diagnosis
• Very difficult
• Signs & symptoms very similar to other infections
• Laboratory Test for the diagnosis of Ebola Virus
• PCR detection
• ELISA (enzyme-linked immuno-absorbant) assay
Is there a cure for Ebola?
• There are no known curative medications for Ebola.
• However, there have been very recent developments in preventative medications.
• No Standard Treatment available
• Patients receive supportive therapy
• Treating complicating infections
• Balancing patient’s fluids and electrolytes
• Maintaining oxygen status and blood pressure
• No vaccines!
• Patients are isolated
• Medical Staff Training
• Western sanitation practices
• Care during stay
• After patient dies
• Infection-control Measures
• complete equipment and area sterilization
• In June, Jones and his colleagues, Dr. Heinz Feldmann of Winnipeg and Dr. Thomas Geisbert at Fort Detrick, Maryland announced that they had successfully vaccinated monkeys against the deadly Ebola virus
• The Ebola vaccine is based on the 1976 strain of the Zaire species and protects from the 1995, but not the other 2 species that affect humans.
Risk of Bioterrorism?
Airborne transmission of Ebola Zaire has been demonstrated in monkeys in a controlled laboratory experiment
Virus contagious in fluids for days
• Burial use extreme caution
– Handling and transport
– Cultural practices/ religious belief
– Incinerate all waste!!!!
– 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
• Reservoirs in Nature
– Largely unknown
– Possibly infected animals (primates?)
– 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
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
Ebola Information Posters