The Ebola Virus Epidemic - Tennessee Public Health Association

Report
THE EBOLA VIRUS EPIDEMIC
Current Status and Future Prospects
William Schaffner, MD
Professor of Preventive Medicine and Infectious Diseases
Vanderbilt University Medical Center
Consultant, Communicable Disease Control
Tennessee Department of Health
OUTLINE
Ebolavirus ecology and epidemiology
Ebolavirus disease – clinical aspects
Public Health Response
Research: Treatment and Vaccines
Ebola in the USA
Filovirus family (filo, Latin for filament)
Hemorrhagic Fever Viruses
Five subtypes
West African epidemic: Zaire subtype
Ebolavirus Ecology
• Likely reservoir: Fruit bats
– Large, roost in large colonies, migrate
• Infected hosts: Great apes, forest antelopes
Humans likely infected via hunting/butchering animals
Perhaps contact with bat urine, droppings or saliva on
partially eaten fruit
EBOLA CLINICAL ASPECTS - 1
Incubation period 5-10 Days (range, 2-19)
ONSET: Abrupt – Fever, Headache, Myalgia
Soon Thereafter: Nausea, Vomiting, Abdominal
Pain, Diarrhea
Ongoing: Jaundice, Pancreatitis
CNS – Somnolence, Delirium, Coma
Bleeding (1/3) – Petechiae, Hemorrhages
EBOLA CLINICAL ASPECTS - 2
Electrolyte abnormalities – sodium and potassium loss
Liver failure → low serum protein → edema
Bleeding from low platelets
Fatality rate, current outbreak: ~50%
Human – to – Human Transmission
Patients become infectious to others when they
become sick
Ebolavirus is NOT spread by respiratory route
Spread from intimate contact with body fluids or
tissues of a sick person or a corpse
Two Primary Risk Groups
for Transmission
• Healthcare workers: all who touch patients,
soiled environment, funeral/burial workers
• Family members
– Caring for the sick
– Preparation of loved one’s body for burial
cultural bathing, touching of respect
Dec, 2013
2 y.o. boy
Gueckedou, Guinea
Intersection of 3 nations
1 week
Mother, sister, grandmother
Mourners to another village
Health worker
another village
doctor
Relatives
other towns
Relatives
other towns
Mar, 2014
Ebola recognized
Dozens Dead in 8 Guinean towns
Suspected cases in Liberia, Sierra Leone
Funeral of traditional healer
14 women infected
Koindu, Sierra Leone
MOLECULAR GENETIC STUDY OF THE
WEST AFRICAN EBOLA VIRUS
Investigators: Harvard, Broad Institute, Kenema
Hospital in Sierra Leone
Sequenced RNA, 99 virus samples
All the viruses are closely related-traced back to
single introduction by traditional healer
Outbreak NOT caused by repeated introductions
from nature: all human-to-human spread
Contributions to Rapid Spread - 1
• Previous outbreaks in small, remote villages
• Current: A border region, more dense population
Roads improved, people travel a lot
• West Africa had not experienced Ebola before
• Economy poor, low education, recent political
instability
• Rumors that Ebola was a myth or a political fiction
Contributions to Rapid Spread - 2
• Limited healthcare facilities, few healthcare
personnel poorly trained, no personal
protective supplies
• Abandonment of healthcare facilities
• Facilities refuse to treat anyone with
suggestive symptoms
• Families keep ill at home and keep quiet to
avoid stigma
HEALTHCARE LIMITATIONS
“Beds” may be pallets on the floor or ground
Facilities often do not provide support services
Families prepare food for patient
Hygienic care by family
Facilities may not have capacity to do CBCs,
electrolytes, other blood tests
Some do not have running water
RESPONSE
• Treatment of the sick
– Humanitarian and public health goals
• Rigorous surveillance
– How many ill, ages, where located
•
•
•
•
Contact tracing, quarantine and observation
Education/Community engagement
Disposal of the dead
NOT cordon sanitaire
RESPONSE LIMITATIONS
• Country governments poor, lack public health
infrastructure, slow sense of responsibility
• Doctors Without Boarders (MSF) cried an
alarm, but without a response
• WHO suffered budget cuts – its epidemic
response unit profoundly diminished
INTERNATIONAL RESOURCES
Personnel: Clinical, public health
Administrative, logistical
WHO, NGOs, CDC, Faith-based
Personal Protective Equipment
Masks, gloves, impervious gowns, etc., etc.
Equipment for clinical care
labs, beds, IV fluids, etc., etc.
TREATMENT RESEARCH
ZMAPP. Molecular biologic production of 3
antibodies against Ebola
SHOWN TO WORK IN EXPERIMENTAL INFECTIONS
In monkeys: all 18 who got 3 infusions
survived
3 untreated died
NOT yet shown to work in humans
VACCINE RESEARCH
• GSK/NIH
Chimpanzee adenovirus vector that expresses
Zaire and Sudan glycoprotein
Phase I trial started
• Public Health Agency of Canada/NIH/Walter Reed
Vesicular stomatitis recombinant vaccine
Phase I trial soon
Please Remember – this is Research
Experimental: No proven therapeutic or
preventive effect
Safety in humans: Unknown
If something works: Implementation research
Ethical, cross-cultural issues
No magic bullets
WILL EBOLA COME HERE?
Virus has been in labs here for years
High profile patients (Kent Brantly, Nancy
Writebol, Rick Sacra)
Ebola candidate patients – show up at Hospital X
Ebola will NOT establish itself in the US
HOSPITALS CAN CARE FOR EBOLA
PATIENTS SAFELY
Isolation room
Personal Protective Equipment with Sentinal
Environmental, Waste Disposal, Lab Safety
Mock patient drills, Education
SAFE HOSPITAL CARE
STAT contact with Tennessee Department
of Health
Communication and education
Media relations
Would be intense
EBOLA IN WEST AFRICA
NEAR-TERM FUTURE
Grim
Predictions up to 20,000+ cases
Many Months
Concern for spread to other West African countries
Food supplies
Transport
Economic/Political destabilization
USA
EBOLA
INFLUENZA
New
Mysterious
Unknown
Deadly
0 infected
3 hospitalized
0 deaths
No sense of personal control
Old – annual
Conventional
Known
Often deadly
5-20% infected annually
200,000 hospitalized
~32,000 deaths
Wash hands
Avoid coughers
Get vaccinated!

similar documents